ML20147B300
| ML20147B300 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 02/23/1988 |
| From: | Advisory Committee on Reactor Safeguards |
| To: | |
| References | |
| ACRS-T-1647, NUDOCS 8803020061 | |
| Download: ML20147B300 (502) | |
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, fC2ST-/4t/ 7 ORIGIjy j e UNITED STATES
!- NUCLEAR REGULATORY COMMISSION 1
. ADVISORY COMMITTEE ON REACTOR SAFEGUARDS I
In the Matter of:
DIABLO CANYON LONG TERM SEISMIC PROGRAM l
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Pages: 1 through 259 Place: Burlingame, California
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1 PUBLIC NOTICE BY THE 2 UNITED STATES NUCLEAR REGULATORY COMMISSION'S 3 ADVISORY COMMITTEE ON REACTOR SAFEGUARDS 4
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7 The contents of this stenographic transcript of the 8 proceedings of the United States Nuclear Regulatory 9 Commission's Advisory Committee on Reactor Safeguards (ACRS),
10 as reported herein, is an uncorrected record of the discussions 11 recorded at the meeting held on the above date.
12 No member of the ACRS. Staff and no participant at 13 this meeting accepts any responsibility for errors or 14 inaccuracies of statement or data contained in this transcript.
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L UNITED STATES NUCLEAR REGULATORY COMMISSION 2 ADVISORY COMMITTEE ON REACTOR SAFEGUARDS 3
4 In the Matter of: )
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5 DIABLO CANYON LONG TERM SEISMIC PROGRAM )
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6 7 Tuesday, February 23, 1988 8
The above-entitled matter came on for hearing, 9 pursuant to notice, at 8:30 a.m.
10 BEFORE: DR. CHESTER P.SIESS Chairman 11 Professor Emeritus of Civil Engineering University of Illinois 12 Urbana, Illinois 13 ACRS MEMBERS PRESENT:
14 DR. WILLIAM KERR Professor of Nuclear Engineering 15 Director, Office of Energy Research University of Michigan 16 Ann Arbor, Michigan 17 MR. JESSE C. EBERSOLE Retired Head Nuclear Engineer 18 Division of Engineering Design Tennessee Valley Authority 19 Knoxville, Tennessee 20 DR. DADE W. MOELLER Professor of Engineering in Environmental Health 21 Associate Dean for Continuing Education School of Public Health 22 Harvard finiversity Boston, Massachusetts 23 24 25 V
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2 1 ACRS COGNIZANT STAFF MEMBER:
2 Al Igne 3 NRC STAFF PRESENTERS:
4 Bob Rothman 5
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3 1 PROCEEDINGS 2 DR. SIESS: This is a meeting will come to order.
3 This is a meeting of.the ACRS Subcommittee on the Diablo Canyon 4 Power Plant. I am Chet Siess, Chairman of the subcommittee.
5 And we have a lot of ACRS members and consultants in attendance 6 today. Let's see if I can spot them.
7 At the far end. Consultants Seavuzzo, Davis, Page, 8 Member Moeller, Kerr, Ebersole. Consultants Maxwell, Trifunac.
9 Did I miss anybody? Okay. The cognizant NRC Staff member for 10 today's meeting is Mr. Igne, who is sitting here.
11 The purpose of this meeting is to review the status 12 of the Diablo Canyon long term seismic program. The rules for 13 participation in the meeting has been announced as part of the 14 notice published in the Federal Register on February 5. The 15 meeting is being conducted in accordance with provisions of the 16 Federal Advisory Committee Act and The Government and Sunshine 17 Act. And'it is requested that each speaker first identify 18 himself or herself and speak with sufficient clarity and volume 19 and/or use a microphone so that he or she can be readily heard 20 and their remarks be properly transcribed.
21 I think one of the conditions when the long term 22 seismic program was set up was that the ACRS would review it or 23 that they would report to the ACRS annually. On that basis, 24 this is our second annual meeting. We are running a little bit 25 behind. But since the last progress report was No. 9, I guess Heritage Reporting Corporation (202) 628-4888
4 1 we are only a quarter behind.
2 As I recall we reviewed the plans for the,long term 3 seismic program at a meeting in March '85. I looked over the 4 list of people who were present at that meeting, at least 5 members of the committee who were present, and I am the only 6 one although some of our consultants certainly were present at 7, that time. We met in Washington in July of '85 to review the 8 Staff's evaluation of the proposed program and I believe that 9 that was the point at which the program began in July of '85.
10 We met in flovember '86, which was our first annual 11 review and at that meeting, Mr. Ebersolo and Dr. Moeller were 12 present. So, they're in on it'for the second time. And I 13 mention this simply because those that are making presentations 14 should realize that several of the members that are present are 15 hearing much of this for the first time. That, of course, is 16 not true for our consultants, many of whom have been in on it 17 from the very beginning.
18 And some of the geological-seismological consultants 19 have been following this between meetings rather c'losely by 20 attending work shops and going on field trips.
21 You have a copy of an agenda in front of you. It 22 goes through noon tomorrow for the formal portion of the 23 nesting. Tomorrow afternoon, some members of the subcommittee 24 and some consultants are planning to make a trip to the Diablo 25 Canyon Power Plant. I would suggest that during our first O
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1 break this morning that those who plan to make the tour 2 tomorrow get together with Mr. Cluff at some convenient corner 3 of the room and give him some idea of what you want to see.
4 They need to make some plans at the site for a tour and if 5 different people want to see different things, I think it can 6 be arranged to break it up into two or three groups or 7 whatever, but not too many groups. So, I will remind you at 8 the time of the first break, either at the beginning of the 9 break or at the end of it, get together with Mr. Cluff.
10 Do any of the members of the subconatittec have any 1
11 comments at this time or any questions about the agenda?
12 MR. EBERSOLE: Chet, I've got a comment to make.
13 DR. SIESS: Sure.
14 MR. EBERSOLE: Not long ago, I attended a meeting on 15 the topic of thermal hydraulic neutronics in Los Alamos and as 16 you must always know, I am a generalist. I am going to be 17 listening to you in the hope of hearing from you -- not you 18 walking around in your own particular area of expertise in 19 churning up old data, regrinding what we already knew because 20 nothing much has happened I think in the last few years, but I 21 am going to be looking for what I could express, say, to some 22 Member of Congress as to where you were and what you are going 23 to do with what you have got and what you hope to get out of it
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24 in the context of practical changes, if any, to Diablo.
25 Now, I don't know whether 1 am going to hear that or C
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1 not, but I am going to be listening for it. In short, I would 2 like to have you walk out of your private world of expertise 3 and-make some statements to the ordinary practicing engineers 4 who must do something to the plant or not do it.
5 DR. SIESS: I'll second,that motion. I think most of 6 us on this side of the table, not the consultants, the members 7 certainly are generalists and we have some consultants who are 8 probably at least as specialized as those that are sitting over 9 there. And it is important that you try to either address your 10 remarks to the generalists or be prepared to answer questions 11 from the generalists.
12 I am not sure I agree with Jesse that it should be
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13 such that we could explain it to a Member of Congress --
14 MR. EBERSOLE: Maybe that was too much.
15 DR. SIESS: -- not too much of a standard, if I could 16 pick the right Member of Congress, I guess.
17 The principal speaker for the Pacific Gas and 18 Electric will be Lloyd Cluff, to my right. And the lead off 19 from the Staff will be Harry Rood who is project manager for 20 Diablo Canyon. I think we will let the Staff take over. I 21 could make some background remarks, but I am sure they would 22 end up repeated by either the Staff or PG&E. So, let Harry 23 start. And you might introduce the people you have with you.
24 MR. ROOD: Thank you, Dr. Sless. On my left is Bob 25 Rothman from the Staff. I am Harry Rood. On my immediate
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. I right is Mr. Bagchi at:d on the other side of him is 2
Mr. Chokshi.
3 DR. SIESS: Are they generalists?
4 MR. ROOD: They are the specialists.
5 DR. SIESS: What is their specialty?
6 MR. ROOD: Well, Mr. Rothman is a geology --
7 MR. ROTHMAN: I am Bob Rothman. I am a geophysicist 8 with the Staff and.I am coordinating the technical review. And 9 I am basically a seismologist by education and experience.
10 MR. BAGCHI: I am Bouton (ph) Sagchi. I am a Chief 11 of the Structural and Geosciences Branch, but I am a generalist 12 by any term.
13 MR. CHOKSHI: I am I11s (ph) Chokshi with 14 Probabilistic Risk Assessment Branch, Office of Research. By 15 education, I am a structural engineer. And I also consider 16 myself a generalist. ,
17 DR. SIESS: Thank you.
18 MR. ROOD: I would like to make a statement here on 19 the status of a licensing related issue. As you know, the 20 Diablo Canyon long term seismic program which we are here to 21 discuss resulted from a license condition in the Unit 1 22 license. In the fall of last year, PG&E, the licensee, 23 requested that we amend the license to extend the completion 24 date for one year from July 1988 to July 1989. And the basis 25 for that was the conflict of certain key personnel -- they were
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S 1 also needed to participate in a California Public Utility 2 Commission hearing. This request for an extension was 3 published in the Federal Register. Letters were received 4 objecting to the extension. And, at present, a decision as to 5 whether to hold.a.public hearing on this issue is pending.
6 With that,. I would like to introduce Bob Rothman who 7 will give a quick summary of the technical. aspects at this 8 point.
9 MR. ROTHMAN: Good morning. I'm Bob Rothmcn. I am a 10 geophysicist, as I said, with the Staff. I am going to give 11 you a summary of the Staff's program as it now stands. I will 12 give you a brief background on the history of the Diablo Canyon 13 Program.
14 (Slides shown.)
15 In the early 1970's the Hosgri fault was identified 16 about 5.8 kilometers from Disblo Canyon and considered to have 17 a potential for a magnitude of 7.5 earthquake. The Hosgri 18 reanalysis was performed and it required modification of some 19 of the structures and components. John Bloom performed the 20 reanalysis for the PG&E, the utility, and Nathan Numark 21 performed the reanalysis for the NRC Staff.
22 And a lot of Humark's conclusions were based on his 23 experience and judgment. And following this reat.alysis in 24 1978, the ACRS recommended that possibly a seismic reevaluation 25 be performed in about 10 years following that day.
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c 8 1 In the early 1980's new geologic information and-2 differing interpretations of coastal California tectonics 3 b'ecame available and in 1984, the NRC Staff proposed options 4 for the reevaluation of the seismic design bases for Diablo 5 Canyon. And the commissioners imposed a condition on the 6 Diablo Canyon Unit I license requiring this reevaluation 7 program.
8 This is a brief summary of the license condition, 9 There are basically four parts to the condition. There was:
. 10 evaluate relevant geologic and selsmic data available since 11 1979, which was the date of the cperating license hearings, and 12 reevaluate early information, if necessary. Reevaluate the 13 magnitude of the earthquake used a's seismic basis. Reeve.luate 14 the ground motion as a result of this earthquake and assess tea i
15 significance of the first three using PRA and deterministic 16 studies to assure adequacy of seismic margins.
17 A three-year program plan was submitted in January 18 1985 and approved by the NRC in July 1985.
19 Under the direction of the Commissioners and the 20 ACRS, the Staff was urged to have a strong review &nd an 21 independent parallel program. And the NRC review and parallel 22 program includes review of the tectonics and geology, also, 23 independent work by NRC consultants in this area; evaluation of 24 the earthquake magnitude, including independent work being done 25 by NRC consultan*o, review of the seismology and ground motion g3 O
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4-f 1 and independent work in both of these area; soil structure 2 interaction; deterministic assessment and probabilistic risk 3 assessment.
4 And in all these areas, there is an independent if 5 somewhat limited program being po formed by'the NRC 6 consultants.
7 In the geologic, tectonics and geophysics area, the 8 NRR Staff is responsible for review with RES Staff, Office of 9 Research Staff providing support. And we have technical 10 assista'nce from the U.S. Geological Survey and the University 11 of Nevada at Reno.
12 In the seismology and ground motion, the NRR Staff ir.
13 responsible for the review and we have technical assistance f
14 from the USGS, including an independent ground motion 15 assessment. And we have a panel of experts which was put
,16 together by Lawrence Livermore National Laboratory for us who 17 are reviewing the theoretical numerical modelling of the ground 18 motion at the site.
19 Soil structure interaction, NRR is responsible for 20 this with RES Staff support. And we have technical assistance 21 from a panel of experts which was put together,by the 22 Brookhaven National Lab.
23 In the probabilistic risk assessment, the Office of 24 Research has the lead responsibility with NRR Staff support and 25 we have technical assistance from a Brookhaven National Lab 7-L)
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1 review team.
2 DR. MOELLER: While you are changing, could I ask a 3 question?
4 MR. ROTHMAN: '!e s .
5 DR. MOELLER: For your NRC technical assistance, you 6 called upon National Laboratories in three cases and in the 7 first one, of course, USGS I understand. How was the selection 8 of the University of Nevada at Reno made? Do they have unusual 9- expertise?
10 MR. ROTHMAN: They have a neotectonics laboratory 11 there which is headed by Bert Slemmons who is a world 12 recognized expert in neotectonics. And he is leading a group
') 13' there with several other faculty members and a number of
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14 graduate students. And he has worked on some issues like this 15 in other areas for the Staff.
16 DR. MOELLER: Thank you.
17 MR. ROTHMAN: I might say that this whole review 18 program is unique as far as the NRC Staff is concerned.
19 Normally, when a utility is performing a study for a site, they 20 do their study, they submit a report to the Staff which then 21 reviews the report and asks questions. And we go througn a 22 process of meetings of questioning and reviewing. In this 23 program, we had a very close interactive program with a large 24 number of meetings in which the PG&E consultants and staff have 25 made presentations to the NRC Staff. We have reviewed their 7
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. 12 1 reports and given them feedback. So, it has been an 2 interactive, very close interactive program.
3 Here we have listed the number of workshops, meetings 4 and field trips on each of the studies that we have had so far.
5 And you can see this is quite a considerable number if you 6 figure this has been over the past two years.- We have had 7
quite a number of meetings taking place.
8 MR. EBERSOLE: I wonder if you could clarify a point 9 for me? In the final analysis, all we are trying to find out 10 is in an earthquake can this plant TRIP and thus cease .
11 defission and then can we get the heat out. That is the TAP 45 12 picture, too. At what point does this program interface with,
- 13 in essence, the final objective? Is it just with the v
14 structural aspects of the plant, not including the detailed 15 equipment at the plant or not.
16 MR. ROTHMAN: Let me say that PG&E is going to 17 present their part of the program, but they are going through a 18 very detailed level 1 PRA study to try and look for weak points 19 in the plant, for systems that are going -- that may cause 20 problems and the consegtonces from that.
21 ;4R . EBERSOLE: I mention this partly in the context 22 of remembering our old member, Glenn Reed who says these plants 23 need a way to feed and bleed as the final way to get the heat 24 out once you can get them TRIPPED. And I am curious as to how 25 far PG&E is going to let the plant degrade and, yet, still make
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1 it safe.
2 MR. ROTHMAN: I think you will have to talk to --
3 that is a little bit out of my area, i
4 MR. EBERSOLE: In the end, that's the route we are 5 all going down, though, is how to do that.
6 MR. ROTHMAN: The idea of the program was to review 7 the input to the plant and see if there was going to be a 8 problem and then to evaluate,this through deterministic and 9 probabilistic studies.
10 Now, the probabilistic program started at the very 11 beginning, although -- if it is rhown that the design basis or 12 the reanalysis basis of the plant, it was adequate, you 13 wouldn't have to go into the plant. But because of the time f
14 lag, the program has started at the front end, also. And they 15 are well along on this program.
16 DR. SIESS: Excuse me. You said something I am not 17 sure is right. Isn't it conceivable that the geological 18 seismological studies could show that the original seismic 19 hazard was adequate and, yet, th'e PRA could show that the plant 20 had some outlier or some local weakness?
21 MR. ROTHMAN: Yes, I think that's possible. That's 22 right. But under the license condition as the license 23 condition was written originally by the Commission, it was to 24 perform deterministic and probabilistic studies as necessary.
- 25. So, in reality, the program is going on, but it was not a c'
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9 1 direct requirement of the license condition that they started g
2 initially at the biginning of the program.
3 DR. SIESS: Now, looking at this with the PRA, is 4 that significantly different than what would be done under the 5 severe accident policy program of the IPEs?
6 MR. BAGCHIt No. This is independent from the IPEs.
7 Some discussions are going on within the staff with respect to 8 external ends for consideration within IPE. This is not the 9 case for Diablo Canyon. We are addressing the long term 10' seismic program license condition.
11 DR. SIESS: But wouldn't the PRA, wouldn't the 12 seismic PRA they are doing here satisfy one condition of the f 13 IPE of looking for outliers?
14 MR. BAGCHIt More than likely it is going to reveal 15 plant weaknesses because we are not going to stop at a 16 particular earthquake level PRA. We are certainly going to 17 look at all the hazards, the entire spectrum of the hazard.
18 MR. EBERSOLE: Would that appear in the form of what 19 I will call the pinch points in the plants. I recall one 20 mid-West plant found out its Achilles' heel was in the long 21 stemmed dependent pumps that weren't properly braced and so
, 22 they lost suction on critical cooling water. Is that going to 23 come out of this particular program or out of some subsidiary 24 program related to this?
25 MR. BAGCHI The PRA is certainly going to look at
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I component fragility and the Staff is going to do some plant 2 walkdown along with the detailed review by the consultants. I 3 feel something of that nature would certainly come out of the 4 PRA.
5 DR. SIESS: But if a PRA were not being done, this 6 would become a very compartmentalized, very specialized study 7 unique to Diablo Canyon simply reviewing the seismic design 8 basis without really reviewing the plant response to that.
9 MR. BAGCHI: I would have to agree with that, but 10 there are some interesting questions on the specification of 11 the ground motion in this particular area. And I am sure that 12 a lot of you are quite familiar with that and we are all hoping
) 13 that it would extend the state of the art, really.
14 DR. SIESS: There is no question we are going to 15 extend the state of the art. I just wonder sometimes whether 16 we are setting a new basis for siting nuclear power plants 17 seismically.
18 Go on, please.
19 MR. ROTHPAN: I might point out now that the original 20 intent of the license condition was just to reanalyze the 21 seismic margins. The utility, itself, voluntarily decided to 22 do a full scope level 1 PRA. That was not a requirement. Just 23 a seismic PRA was a requirement of the Staff.
24 DH. SIESS': I think the original intent was to review 25 the seismic design bases.
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2 DR. SIESS: Which was more than just the margin of 3 the hazard. -
4 MR. ROTHMAN: To date, at the present time, the St,aff 5 has not seen anything in this program that would cause us 6 concern about the plant. We have had this constant interactive 7 review. We have made comments to the utilities both in writing 8 and in meetings. Comments on the way they were doing the 9 program, on some of the results that they were getting, they 10 have incorporated some suggestions that the Staff has made.
11 And the program is ongoing.
12 There was one thing, there was a broad notification 13 last spring at a workshop and field trip in the San Louis Bay f-14 area, the PG&E notified us that they discovered a capable fault 15 in the sea cliff approximately 10 kilometers from the plant and 16 a possible extension closer to the site. And also that the 17 active strand of the Hosgri fault was found to be about four 18 kilometers from the site rather than the previously assumed 5.8 19 kilometers.
20 I would like to show you a little diagram just to 21 show you: This is the plant in the center. These circles are 22 one. kilometer between circles. This is the 10 kilometers, end 23 of sea cliff. In San Louis Bay there was this displacement in 24 the sea cliff. There is a possible extension at Pecho Creek or 25 Deer Creek. There was.a possibility of downwarping in the t )
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1 beach terraces which might have been an extension of the fault.
2 And PG&E had indicated that they had looked at some of the 3 offshore work and there was a possibility of some disturbances 4 in the sea floor. ,
5 If this was to extent it would have put that 6 approximately two kilometers from the plant. And this is the 7 active strand that is depicted by PG&E about four kilometers 8 from the plant. .
9 The Staff didn't feel that this offered a great 10 safety significance to the -- safety concern to the plant. But 11 we have an office letter that requires us to issue'a board 12 notification if there ir, any new information on a plant which f 13 might be of public interest, congressional interest or media 14 interest. So, a board notification was issued to the 15 Commissioners informing them of this. And that's about the 16 stopping point as far as the Staff is concerned.
17 MR. EBERSOLE: Let me add one more thing. In our 18 zeal to protect the plant from earthquakes, it is always true 19 every time you do a good thing, you do a bad thing. And, , t 20 would guess that Diablo Canyon probably is the richest source 21 of the reverse effects of adding constraints and hydraulic and 22 friction snubbers and so forth. And one might take a reverse 23 looks to what extent have we increased the hazard of pipe 24 faults and disruptions in mechanical constraints necessary to 25 expansion due to pressure and temperature and so forth. Have Heritage Reporting Corporation (202) 628-4888 -
18 I we found it necessary to go back and clean up at Diablo than 2 any other plant some of the constraints found not to be 3 necessary with further analysis of the mechanics of structure.
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DR. SIESS: It,seems to me about four years ago a 5 study on that was made, four or five years ago, of the effect 6 -- the probability of snubber failure -- we asked: What 7 happens if one snubber fails? And two assumptions were made 8 It failed locked up or it failed loose. It turned out you were 9 a lot better off if it wasn't there.
10 Does anybody remember that?
11 MR. BAGCHI: Let me try just a part of that. N411 12 allows higher damping value than was considered in the design
) 13 basis for Diablo Canyon. Diablo Canyon came in with two 14 programs. One is trying to optimize the snubber population.
15 And another one is to get approval of the staff to use 16 N411 damping values which is higher damping values and 17 supposedly would allow them to reduce these types of hard 18 restraints, snubbers, what have you.
19 DR. SIESS: The snubber reduction program?
20 MR. BAGCHI: It has been approved, N411 and the 21 snubber reduction program. It is ongoing. I am not aware fully 22 of the status of that program.
23 MR. ROTHMAN: Aside from that, as far as I know, as a 24 result of this program that we are undergoing now, the three-25 year program, there have not been any changes made at the Heritage Reporting Corporation (202) 628-4888
19 1 plant. It has not resulted in any conclusions today.
2 DR. SIESS: This program?
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3 MR. ROTHMAN This program, the seismic reevaluation 4 program.
5 DR. SIESS: Before you mit down, let me ask you a 6 question that isn't really related to Diablo Canyon. Where we 7 are right now, how far is that from an active fault?
8 MR. ROTHMAN: Well, the San Andreas fault is right 9 over here. It runs along the west side of the peninsula.
10 DR. SIESS: How far?
11 MR. ROTHMAN: I would have to look at a map.
12 DR. SIESS: Less than four kilometers?
) 13 MR. ROTHMAN: No. Not less than four.
14 MR. EBERSOLE: The San Andreas fault from here? From 15 this location here?
16 DR. SIESS: Yes.
17 MR. EBERSOLE: It's about 12 kilometers.
18 MR. ROTHMAN: It's closer than that.
19 MR. EBERSOLE: Closer than that? Four or five, I 20 guess.
21 DR. SIESS: Anybody look for seismic margins with 22 this building before?
23 (Laughter.)
24 MR. ROTHKAN: And in the past where the San Andreas 25 fault has been characterized for nuclear power plants, we have Heritage Reporting Corporation (202) 628-4888 A
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20 1 usually considered earthquakes of a magnitude 8-plus on the San 2 Andreas fault.
3 DR. SIESS: 8-plus a few kilometers is pretty close.
4 .Isn't it?
5 Any other questions for Mr. Rothman?
6 (No response.)
7 DR. SIESS: Thank you, Bob.
8 MR. ROTHMAN: Thank you.
9 DR. SIESS: That concludes the Staff's presentation 10 at this stage?
11 MR. ROOD: Tht's correct.
12 DR. SIESS: Harry, I think I told you, as we go 13 through :nis and take up the various items that are listed here 14 on the agenda, I would like a staff status report at the 15 conclusion of each one. That is geology, seismology, 16 geophysics. Then you can tell.us where the Staff stands on 17 that. Ground motions, et cetera, right down the line.
18 We will try to dispose of these in order so that when 19 we get through there is nothing hanging.
20 MR. ROTHMAN: I would like to point out, though, the 21 Staff hasn't reached any conclusions.
22 DR. SIESS: That is an acceptable -- well, that is a 23 status report, whether it is acceptable or not. But we just 24 want to know where you stand on it.
25 Mr. Cluft?
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G 1 MR. BRAND: Thank you, Dr. Siess. My name is Don 2 Brand. I am the Senior Vice President of Engineering
-3 Construction for PG&E. I have spoken to you before. We are 4 pleased to be back with you again today. We have had an 5 ambitious and very expansive broad prograa underway for a good 6 number of years. We believe we have made e.",vil?nt progress 7 with that program and we.will be presenting that to you here in 8 a moment.
9 Following the thrust of some of your earlier 10 questions, I certainly am a generalist in terms of my 11 contribution here today. At the same time, let me put this in 12 some perspective with regard to the units at Diablo. Unit 1
'N 13 was placed in commercial operation in May of 1985. Unit 2 14 placed in commercial operation in May of 198'6. Since that 15 time, both units have operated in our estimation and concurred 16 with by several others have operated excellently. And let me 17 cite a couple of capacity factor numbers just to put this in 18 some context.
19 For the first cycle, first two cycles of Unit 1, 20 capacity factors have been 85.5 percent and 86.6 percent 21 respectively. With Unit 2, the first cycle was 83.9 percent.
22 We are in the second cycle and its capacity factor thus far has 23 been 90.2 percent.
24 he are very, very pleased with this operating record
,_s 25 that we have achieved and it just denotes I think the design
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e e-22 1 and the operation and the significant contributions of all of 2 our people in managing a very ambiticus but still a very 3 important power generator for the western United States.
4 Let me then introduce our first specialist. This is 5 Lloyd Cluff, our manager of geosciences and the program manager 6 for the long term seismic program that will lead off with PG&E 7 presentation for today.
8 Lloyd?
9 MR. CLUFF: Thank you, Don and Dr. Siess. My name is 10 Lloyd Cluff and, as Don just mentioned, I am the program 11 manager for the long term selsmic program and manager of the 12 geosciences department for PG&E. With regard to the question
) 13 about generalists and specialists, I qualify as both in some of 14 these areas. By academic training, I am a geologist having 15 also been involved in seismological activities in my formal 16 education. But by experience, however, for the last 25 years, 17 I have worked on a number of critical facilities in the United 18 States and around the world having to do with siting and review 19 ,
of existing facilities. And, so, in that sense, I am a 20 generalist in knowing what the focus ought to be in terms of 21 specialized results and how they impact on the general aspects 22 of a facility like Diablo Canyon.
23 Let me start off with the first view graph which is 24 the agenda. And just kind of give you a little road map on my 7- 25 presentations and the continuing PG&E presentations.
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23 III -
1 (Slides shown.)
2 I am going to be talking about quite a bit of 3 background material as noted on the agenda as you already see.
4 Others have already touched on some of these items. While 5 there wil' be a little duplication, I think I will be 6 complementary and kind of expand and emphasize certain points.
7 And I will probably move through this fairly quickly, but don't 8 hesitate if there are any points that if I am going to fast 9 giving this background material to slow it down a little bit 10 and we can look at aspects if needed.
11 My guess is that we will probably get through this 12 quite a bit quicker than the time that we have allowed for
) 13 this. And then I will introduce the various participants. I
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14 will begin the status of the various elements of the long term 15 seismic program and then as we move into that, I will introduce 16 the various PG&E and our consultant participants who will be 17 making the presentations.
18 By way of the background and this has already been 19 mentioned, but this letter of 1978 where the ACRS suggested 20 that the seismic design for Diablo Canyon be reevaluated in 21 about 10 years. And then in 1984, the ACRS subcommittee, this 22 subcommit tee in Los Angeles reviewed a proposed license 23 condition on the operating license, and then tne full ACRS l '24 meeting in Washington later that year also looked at that 1 .
25 license condition.
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1 The ACRS letter of 1984, we have abstracted materials 2 out of that letter of 1984. It talks about the elements of the 3 proposed license condition by the Staff stating that it will 4 provide a suitable basis for meismic reevaluation. And it 5 talked about the conduct of this program which later became 6 known as the long term seismic program. PG&E would take the 7 lead with the strong suggestion that NRC Staff independent 8 evaluation be conducted as the work is being done and that the 9 involvement of the USGS and others.
10 Also, there was some mention at that time of the 11 performance of a PRA and the note is there about, useful to 12 give insight in terms of -- also in terms of PG&E's people x
I 13 having an active role in this. And, as you will see later, a 14 PG&E person will be presenting the PRA status that we have 15 later on. So, we have had very active participation by a 16 member of the PG&E professionals. And then the request to make 17 sure that there was adequate review as the program was being 18 conducted. And I will talk in more detail about that later.
19 And then in '84, the operating license with the license 20 condition which is --
21 MR. EBERSOLE: liet me ask a question.
22 MR. BRAND: Yes.
23 MR. EDERSOLE: It is interesting that the PRA is 24 brougnt up in the context or background of the seismic problem.
s 25 And one could almost infer that it was put up there to examine
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- 1. the seismic hazard. Do you happen to know whether it is a PRA 2 that is in a general configuration that looks a probably the 3 infinitely higher probability that the plant will get in 4 trouble from some source of trouble other ,than earthquakes?
5 MR. CLUFF: We have, it's a full level 1 PRA that 6 looks at all hazards --
7 MR. EBERSOLE: Would it be the kind of thing you 8 would put in a ISEP7 9 MR. CLUFF: Let me show you the full license 10 condition that Bob Rothman abstracted that. The four elements 11 of the license condition. The first one being evaluating the 12 seismic and geologic data in terms of existing data, new (g) 13 hypotheses that had been presented and also, if needed, to 14 gather new data. And I will show you how we are following that 15 license condition.
16 The second element is to take the information from 17 this reevaluation of existing plus new information and to 18 reevaluate the magnitude to be used in our evaluation of the 19 seismic margins at Diablo Canyon and then in item 3, to take 20 the data from 1 and 2 and to reevaluate the ground motion at 21 tho site and considering other information that exists as well i
22 as information becoming available from additional recordings of 23 earthquake or additional theory on earthquake ground motions.
l 24 So, the fourth element is to assess the significance i 25 of the results of the previous three parts of this program l
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) 26 1 through reevaluation in a probabilistic sense and deterministic 2 . studies as necessary. And the focus on this program is to 3 assess the adequacy of the seismic margin of the plant. So, we 4 ara looking at this as a seismic margin evaluation. And the 5 program schedule was 1.1-ted to complete this program within 6 three years following ' oval and then program progress in 7 terms of our quarter 1 ; ports and meetings with the Staff and 8 their consultants and then, of course, these annual meetings 9 with the ACRS.
10 Let me go back to the program pisc as it was 11 submitted on January 30, 1985. It was divided at that time 12 into a number of elements of the plan in terms of geologic and
( 13 earthquake magnitude, ground motions, both by empirical and 14 numerical analysis, soil / structure interaction, seismic hazard, 15 fragility and probabilistic risk assessment.
16 And, at that time, in the submittal, it was highly .
17 emphasized of the dynamic character of this program, that it 18 must be flexible to achieve a successful completion and the 19 elements of the program must not be viewed as absolute. We 20 might find reasons to make some modifications in what was 21 presented at that time. And we must structure the program to 22 accommodate change if, in fact, we found things that required 23 us to restructure things. And then, as the program evolves and 24 progresses, within the framework of the approved plan. And we 25 follow that very carefully and where w9 have made any changes
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[ J l 1 in the program, we.have fully informed the NRC and we haven't 2 made any' major changes, but we have, restructured things to be
- 3 more focused.
4 -Continuing with the meetings in~ October of '84 with 5 PG&E and NRC to review the proposed investigation. Then a 6 series of meetings. I won't dwell on these. I just wanted you 7 to see that there was a lot of interaction prior to PG&E's 8 submittal of the program plan and then after the program plan 9 was submitted and while the NRC Staff was reviewing '.c, there 10 were a series of meetings leading to tb sueetings thet we had 11 with the ACRS in July of '85 and tbsn, of course, on July 30th, 12 based on thosse discussions and understandings, the NRC approved
( 13 our program plan.
14 Throughout all of these activities, PG&E felt it 15 important to establ'ish a consulting board for the long term 16 seismic program. Members of the consulting board and their 17 specialty, but many of you know most of these individuals.
18 And, as you know, while.they are all specialists, they have 19 general knowledge of things and would all be considered 20 generalists with respect to the overall objective of reviewing 21 Diablo Canyon.
22 Now, this consulting board has been an integral part-23 of our. ongoing activities. Their function is summarized here 24 in terms of'providing guidance and advice and review as we step 25 through the various pnases of the program. Phase I being the Heritage Reporting Corporation (202) 628-4888 ,
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1 development'of the program, several meetings with our 2 consulting board to give us guidance and advice in that.
3 In'the Phase II activities which we desaloped details 4 of the scope of work to be done and then pairi.ig out which is..
5 Phase III, what we are reporting on the status now and the 6 conduct of the work and then they will be.very much involved in 7 a review capacity in completing the final report.
8 Let me just show you: There was som,e question'from 9- the NRC Staff that we had convened this prestigious group of 10 people that were very prominent individuals and were very busy.
11 They weren't so sure we would be able to capture very much of 12 their time. Well, we had a meeting where those members met
(, 13 with us and the NRC Staff and reassured everyone that they were 14 fully committed to work with us as needed.
15 Here is'a list of the meetings we've had, formal 16 meetings with our consulting board to review and advise and 17 give us guidance and we have had regular meetings, the last 18 ones being last October. And we have one that will be coming 19 up shortly.
20 With respect to others, I will expand a bit on what 21 Bob Rothman mentioned with regard to the advisors and 22 consultants to the NRC. As mentioned, Dr. Slemmons of the 23 University of Nevada is working not only as an individual, but 24 several of his faculty and a number of his graduate students
. 25 are not only participating in what we are doing in the field in Heritage Reporting Corporation (202) 628-4888 .
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gathering geologic data and reviewing the existing data, they 2 are also carrying out independent studies-on their own. They 3 are doing some parallel work in terms.of. field work and so 4 forth. And we get together every so often with the NRC and the 5 U.S. Geological Survey to review that progress.
6 I notice that I meant to put on here as well the 7 U.S. Geological Survey and for some reason that.got left off.
8 They are involved in a review capacity. Ik)b Brown, with the -
9 Survey is their key. contact person, but from time to time, as 10 many as'five or six USGS seismologists, geologists and
- 11 geophysicists have participated in our workshops that we have 12 had.
1 ) 13 There is a panel that was convened for ground motions
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- 14 that is shown here with these individuals. Also a panel on 1
15 soil / structure interaction, and a fragility panel and then a 16 panel on the probabilistic risk assessment group organized by 17 the Brookhaven National Lab.
18 DR. SIESS: Excuse me, Lloyd.
19 MR. CLUFF: Yes.
- 20 DR. SIESS
- I wouldn't even make a try at correcting l
21 the spelling of Rensselaer, but I would like to point out that 22 Dr. Veletsos is not Andrew. It is Anestos, unless he has 1
23 changed his.name.
24 MR. CLUFF: Sorry for the typographical errors.
25 , DR. SIESS: A former associate student of mine.
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30 1 MR. ROTHMAN: I think this slide is a little bit 2 dated. I might, point out that the. ground. motion panel, except-3 for' Jean Savy who is a Lawrence Livermore employee, they are 4 all. university professors and they (11 hold doctorates, also.
5 Steve Day is now with' San Diego State University. He has left 6 S-Cubed. And from the USGS, we have Dr. Kenneth Campbell is 7 performing independent empirical ground motion studies and is 8 also reviewing the empirical ground motion work being done by' 9 PG&E.
10 MR. CLUFF: Yes. I had that on a former part of this 11' slide. Apparently, in the final preparation, a few errors crept 12 in as well as some names were left off.
) 13 MR. SEAVUZZO: Can you give a little more background 14 on the fragility panel?
15 MR. CLUFF: 'The fragility group, no, I'm not the one 16 to comment on that. Maybe the NRC -- .
17 MR. CHOKSHI: Dr. Fitzpatrick -- It might be Michael 18 Bohen. He is with Sandia. He was at one time program manager 19 for SSMIP. And has also extensive work done for A45 PRAs --
20 seismic external PRAs.
21 Jim Johnson was also involved in SSMIP work. He is a 22 structural engineer and has done a lot of probabilistic 23 structural analysis work. And Dr. Ravindra with Bob Kennedy is i
l 24 one of the earlier prac+.itioner of the fragilitic type of l
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- N, (j . - ' 31 1 MR..SEAVUZZO: Are you doing some work with some of 2 the new seismic analyses or tests that are' being conducted -by 3 EPRI and so forth?
'4 DR. SIESS: The seismic pipe.
5 MR. CHOKSHI: Yes. The: experience data, yes.
6 101. CLUFF: After the program approval and the comments that we had received from the Staff and their
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7 8 consultants, we felt that it was appropriate for us to go 9 through in the initial phase of this, which we called Phase II, 10 what we termed the scoping study. You all have received copies 11 of the results of that.
12 Let me just review what the purpose of that was and
[ 13 it was to be more focused. While the plan that PG&E submitted 14 included absolutely everything, it seemed like it included so 15 much that it needed to be more accurately focused.
16 So, one of the commitments that we made to the Staff 17 is that in the early part of our program we would do this study 18 to focus on the scope of work to identify priorities and so 19 forth and, so, we went through that analysis to look at a 20 balanced program. It is well integrated. It is properly 21 focused on the important topics and a clear sense of the 22 priorities in a realistic schedule from a generalist point of 23 view.
' 24 MR. EBERSOLE: On the focus on important topics, does 25 that mean -- I think we are really interested in severe d,_s Heritage Reporting Corporation (202) 628-4888 ,
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3 MR. CLUFF Well, that is certainly one example: To 4 make sure that we are not worrying about interesting 5 earthquakes but in the end don't make any difference.
6 MR. EBERSOLE: Well, it'has always bothered me to 7 hear some of the so-called experts tell me the worst 8 earthquakes are those we are going to have where we have never-9 had any. But the focus seems to be to try to figure out what 10 earthquakes We are going to have from an existing place where 11 we did have them. And that has always bothered me. -
12 MR. CLUFF: This next view graph just shows'the
() 13 process that we used to conduct this study. This is'our first 14 restructuring. We organized the program into fewer elements.
15 We called the first one, geology, seismology and geophysics.
16 As I refer to this as we go along: GSG is the short form of 17 that. And then ground motions and hazard analysis are really 18 part of the same activity. Soil / structure' interaction and 19 fragility analysis and probabilistic risk assessment. So, we 20 kind of grouped activities within these elements. And this is 21 how we are carrying out the program.
22 So, for several months we took a look at various 23 issues'that had come up based on comments made by reviewers or 24 outside critics, our own judgments about certain activities.
25 And we focused information throughout the program in an Heritage Reporting Corporation (202) 628-4888
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'3 everyone was. concerned with.
4 The scope of that, the result of that work resulted 5 in a report which outlined the objectives of the whole program' 6 with the seismology, geology and geophysics-giving the work 7 tasks. Since this has been in a report, this is just a table 8 of contents, but I just want to focus on the priorities. These 9 are not necessarily listed in priority, but characterizing the 10 Hosgri fault 'in terms of Existing data, the onshore and 11 ' offshore geologic and geophysical data and interpreted data.
12 Quaternary studies in terms of the region and close to the site
() 13 14 and as we moved -- I won't spend a lot of time on this.
wanted to no'te that we had structured this to be source I just 15 specific. The Hosgri, of course, was viewed by everyone as 16 being the dominant contributor. But we had a task that 17 addressed other nearby faults. And I will show you later the 18 significance San-Maguelito, Edna and some other structural
- n 19 features that, some of which' lie closer to the plant than does 20 the Hosgri. And, so, it was important to look at those in 21 terms of whether or not they were capable of generating 22 earthquakes that were important to consider.
23 DR. SIESS: Lloyd, in the original submittal for 24 Diablo Canyon, what was the governing fault?
25 MR. CLUFF: In the 1976-80 time frame?
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L-i DR. SIESS: PSAR.
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2 MR. CLUFF: Yes. That was the Hosgri. Oh, in the 3 first PSAR. I thought you said FSAR.
4 DR. SIESS: PSAR.
5 MR.'CLUFF: The governing earthquake was an assumed l 6 earthquake directly under the plant of magnitude of 6.75. That 7 controlled the analysis and --
8 DR. SIESS: And San Andreas was far enough away that 9 ~ it didn't control, so, you had to-assume something at the 10 plant. -
- 11 MR. CLUFF: Yes. There was an advice that was given i
12 by Dr. Benieoff in terms of a large earthquake on the San
() 13 Andreas which is about more than 50 kilometers to the east.
was assumed that that large magnitude earthquake on the San It 14 15 Andreas could be associated with aftershocks. And that it was 16 assumed that even though there was no known structures, that it 17 would be a conservative assumption that there could be a 6.75 18 -. magnitude aftershock very close to the plant.
19 MR. EBERSOLE: At that time, was it true that you had 20 to find something. So, you did. You put an earthquake under 21 the plant. Was it true at that time wherever a plant existed 22 at the edge of the water that the seismic investigation stopped 23 at the water's edge and didn't go outward into the water? I'm 24 talking about anywhere.
25 MR. CLUFF: The answer to that is: It depends.
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j) ' . 35 XI 1 Maybe I could address that --
2 MR. EBERSOLE: I'm talking about even the East Coast.-
3 MR. CLUFF: In this case, there was consideration 4 given to offshore information. Due to.the irregular nature of 5 this coastline and often other coastlines, having personally 6- being involved'in looking at a lot of siting facilities on 7 coastlines often from a geologic and seism'ic point of view, you 8 learn so much more from information on' land when you have an 9 irregular coastline that you cannot --
10 MR. EBERSOLE: I know. But tht is like looking for 11 your watch you lost under the street light. I am trying to get 12 a general picture. Were we at that time not p.roperly
() 13 - considering plants, other plants on coastlines when we should 14 have unless the oil companies are out there digging around.
15 MR. CLUFF: I was not involved this project until 16 just three years ago. Let me ask someone who was involved that 17 might more accurately respond to that.
18 Bill White, is your voice available to --
19 MR. WHITE: Let me point out that at the time of the 20 Hosgri reanalysis in '76, the actual work for this plant had 21 been done in the late Sixties and ear'ly Seventies. See, you 22 are talking about plants of tht era rather than plants that 23 were being investigated --
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l 24 MR. EBERSOLE: That was my question.
25 DR. SIESS: At the PSAR stage.
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1 MR. WHITE: Which was the late Sixties.
2 DR. SIESS: Which was the late Sixties. What was the 3 safe shutdown earthquake and what.was it based on?.
4 MR. WHITE: During the PSAR stage, there were 5 actually two earthquakes that controlled. Four were considered.-
6 In the PSAR they were called A, B, C, D. The one that was 7 directly under the plant controlled over some frequency range.
8 That was Earthquake D, as I recall. Earthquake B, which was 9 another-earthquake, that was from a real fault controlled over 10 . the lower frequency range. So, we overlapped those two spectra 11 and that is what really controlled the overall seismic 12 criteria. ,
13 DR. SIESS ' And San Andreas at 50 kilometers 8 point
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14 something didn't control anything?
15 MR. WHITE: It did not control. It got worn out 16 before it ever got to the site.
17 DR. SIESS: And how much offsite information did you 18 have at that time? Offshore, excuse me.
19 MR. WHITE: I think there was a limited amount. And 20 the reason they hypothesized the Earthquake D, the one that was 21 directly under the site, was to compensate for tht information.
22 DR. SIESS: Now, the Hosgri -- what was the origin'al
. 23 -SSE zero period acceleration? DDE?
24 MR. WHITE: DDE, they called it in those days, it was 25 point 4.
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1 DR.' SIESS: Okay. You hadia point 2 design 2 earthquake and then the double earthquake was point:4.
3 MR. WHITE: ,
That's correct.
4 DR. SIESS: The'Hongri reevaluation then involved the 5 Hosgri fault at about what? 5 kilometers?
6 MR. WHITE: 5.8.
7 DR. SIESS: What magnitude? .
8 MR. WHITE: 7.5.
9 DR. SIESS: 7.5. And that ups it to 10 MR. WHITER .75.
11 DR. SIESSt .75.
12 MR. EBERSOLE: Well, you know, what I am looking for 13 is we are indebted to the petroleum industry to have found the
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14 Hosgri fault and extended our inquiry out beyond the waters' 15 edge. It would be embarrassing, indeed, if I found a bunch of 16 East Coast plants that didnt have any interest in oil and, 17 yet, there were faults out there.
18 MR. ROTHMAN: Yes. There have been studies done for 19 some East Coast plants. I personally know that for St. Lucy, 20 we had the utility go out and do some specific work.
21 MR. EBERSOLE: We are not about to have another 22 Diablo Canyon finding made, then,,on the East Coast?
23 MR. ROTHMAN: One of the problems we have had on the
-24 East Coast is that even the faults that we have identified have 25 not been capable faults to date. But we have done offshore O
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work on~the East Coast where onshore-or other-in' formation has 1
-2 indicated there might be faults.
3' 'MR.-EBERSOLE: Triggered by the Hosgri finding, I 4 .
guer'. ,
5 MR. ROTHMAN: I have only been with the~NRC for the 6 last eight years.
7 DR. SIESS: The USGS studies on Charleston have 8 involved offshore.
9 MR. ROTHMAN: Involved offshore, but not for any 10 specific plant site. A lot of offshore work was done under the 11 NRC Charleston program. .
12 MR. CLUFF: Let me just focus on a general question.
13 In terms of utilizing scientific data bases to assess the 14 seismic potential of a region,~one certainly wants to look at-15 the geologic and particularly the . geologic aspects that relate 16 to seismic activity, look for any evidence of paleoseismicity.
- 17. as well as geophysical data tht might! be useful and the 18 historical earthquake record that.is recorded either in 19 historic reports or instrumentally.
20 And, so, when you l'ook at those data bases, one has l 21 to be very careful in just taking one of them like geophysics, 22 offshore geophysics and just because you see a fault or a fold 23 or a structure, making the judgment that: Aha, that is a fault 24 that is capab'le of releasing a large earthquake. One needs to 25 combine all the data to make that final assessment. And why my I Heritage Reporting Corporation (202) 628-4888
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12 of speculation based on using a limited data base that doesn't 3 integrate all the data to allow you to say what is the answer -
4 you get out of combining everything. And tht is what this 5 program is doing It is integrating all the data.
6 MR. CLUFF: Let me move on to the ground motion.
7 This is strictly, again, a continuation of -- it is a listing 8 of the activities, work tasks and so forth in terms of 9 attenuation, developing a response spectra, the time histories 10 and looking if we have any side effects. And then taking a 11 look using numerical modeling techniques to see what we could 12 learn out of that and particularly in terms of calibrated
('~) 13 numerical modeling. ,
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14 In the seismic hazard analysis activity, it is a 15 matter of locking at probabilistic ground motion estimates and 16 peak acceleration plus duration and then I want to make sure to 17 alert you and further speakers later today, perhaps even ,
18 tomorrow, we have adopted a spectral acceleration. We find 19 much more useful in this projects. I will let others talk 20 about that later on.
21 DR. SIESS: What you are calling seismic hazards is 22 simply probabilistic basis for describing the ground motion?
23 MR. CLUFF: Yes. This is the input, the hazard's 24 curves that would go into the PRA.
25 MR. EBERSOLE: Well, this is all in the context of Heritage Reporting Corporation (202) 628-4888
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-1 translating an earthquake at some distance to the point.of 2' interest. .Isn't it?-
3 100 CLUFF Well, it is looking at all of-the aspects 4 in terms of the size of the earthquake, what we think-the ,
5 realistic probabilistic earthquake magnitude would be. And 6 then the frequency of occurrence or the return period of that.
7 MR. EBERSOLE: But I mean it is all based on the idea 8 that you are going to translate the effects.
9 MR.- CLUFF: That's right.
10 MR. EBERSOLE: From some other point of origin other
, 11 than the plant proper.
12 MR. CLUFF: That's right. We look at the travel path 13 from the origin to the sito and then take into account the sitt
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14 condition.
15 DR. KERR: You referred to numerical models. What 16 other kind is there?
17 MR. CLUFF: Well --
18 DR. KERR That seemed to be in contrast to something 19 else.
20 MR. CLUFF Well, it is just the term that's been 21 used in terms of using mathematical models based on computer 22 driven aspects to be able to look at hypothetical cases.
23 DR. KERR: Okay. I understand.
24 MR. CLUFF: That's used in a lot of other activities.
25 It is the numerical modeling of ground motions.
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- ' 1 DR. KERR: That is'versus empirical?
2 MR.;CLUFF: Yes, that's right.
3 MR. EBERSOLE: You speak of the-San Andreas fault 4- being' worn out before it gets to this pisnt site. To me, that 5 . brings-up the interesting question'of how -- what is the, 6 dist ce through an unbroken plate you have to go before you 7 said, "This is where we are going to have a new break."
8 MR. CLUFF: That is a question that has been raised 9 on many projects that I have~been involved in.. And we.can,.I 10 think, demonstrate that when you are in an environment like the 11 coast of California that is influenced by the San Andreas and 12 its related fault, that what it takes to break new crust of
' 13 material is so much more difficult to accomplish when you have 14 got already developed planes or zones of weaknes's that that is 15 not a consideration that we worry about.
16 If you are in a stable continental block where you 17 have some small earthquakes going off, you are not so sure in 18 those environments.
4 19 MR. EBERSOLE: That is because this is the limited 20 range or expansive unbroken -- in California, that is rather 21 limited, whereas, in the East, it is not. Is that right?
22 MR. CLUFF: Well, we have in the area of the coast
- 23 ranges of California, we have well developed. faults like the l- 24 San Andreas and a number of others that I'll be showing you.
25 MR. EBERSOLE: I think what you are telling me: You O
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have had your big breaks.'Now, you are just worried about-1 2 further movement on them.
3 .1 MR. CLUFF: Well, it is not'necessarily you get a big 4 bang when it initially breaks. It is a matter of evolution as 5 it develops. And it takes, often, several million years for a 6 big fault like the S3n Andreas to develop. And then it 7 continues to localize earthquakes and it is interesting in that 8 context to share with you that we used to think of th'e San 9 Andreas as a fault that would produce magnitude 8 earthquakes
. 10 or greater all along its entire length. .
11 Now, we are finding in new studies that have been.
12 completed in the last few years, that there are segments of the
('x- ) 13 San Andreas' fault that are slipping at the same rate as other 14 segments that produce magnitude 8 plus earthquakes and the 15 consensus of the scientific community that those other segments 16 may only result in what we call characteristic earthquakes of-17 magnitude 6, just more often.
18 And we are now finding that in only a couple of 19 places on the San Andreas fault is capable of 8 plus 20 earthquakes, most of the Andreas fault is around magnitude 7.
21 And that is a new realization that has just come about and 22 really focusing on how to segment how faults behave and how 23 they behave on different segments. And we are taking a'dvantage 24 of looking at tht new information to apply it to other faults 25 in the region. It is a very important concept.
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1 MR. EBERSOLE: .Thank you.
2 MR..ROTHMAN: : Were you ~asking this for pertaining tx)
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3- East. Coast. earthquakes, also? ,
4 MR. EBERSOLE: Yes. I am really trying to get 5 something of a feel about how big an unbroken plate has to be.
6 MR. ROTHMAN: Well, the East Coast of the United 7 States is not a plate boundary. That-plate boundary is out at 8 the mid-Atlantic ridge-9 MR. EBERSOLE: But in California, these are.
10 MR. ROTHMAN: Yes. .
11 MR. EBERSOLE: And at what point do you begin to get 12 nervous that apart from the-distant earthquake, you can 13 generate new faults?
}
14 MR. ROTHMAN: I was just worried that you may have 15 thought that the East Coast was a plate boundary.
16 MR. EBERSOLE: I know the East Coast -- at least I 17 think I do.
18 (Continued on next page.)
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1 MR. ROOD: What I think you are hearing _is something 2 to the effect that everything that can happen has already 3 happened.
4 MR. CLUFF: That's true. And we know enough about
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5 the past history from a theoretical look in terms of seismic 6 source characteristics as well as'what we call paleose'ismicity,-
7 evidence from the geologic record of past earthquakes, and the 8 instrumental seismicity that we can characterize where and how
-9 big and how often.
10 DR. SIESS: Within the past 100 years, have there 11 been any surprises?
12 MR. CLUFF I guess it depends on how you define a 13 surprise. Surprise., let's say differences. The point that I
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14 just mentioned on the San Andreas, that is not necessarily a 15 surprise, but it is a change in thinking about this big plate 16 boundary fault that in many places it may not produce any 17 bigger than magnitude 6 earthquakes. Five_ years ago I don't 18 think you,would find many people that would subscribe to that 19 conclusion.
20 DR. SIESS: That last earthquake at the end of the 21 Whittier, was that a surprise to anybody? It was obviously a 22 surprise to some of the people that built there.
23 MR. CLUFF It was a surprise to the people on that 24 early morning, as many of you watched them on television, 25 ducking under tables in the'aftershocks.
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45 1 Yes, and no. That earthquake occurred along a-
- 2. northwesterly extension of a known zone of faulting -- the
,3 Elsignor-Whittier fault -- but it did occur in an area where 4 the actual fault that slipped had not been represented on a 5 geologic map. But that trend corresponded to a zone of.very 6 young geologic deformation. From that perspective, it was not 7 a surprise in the magnitude 6, about, earthquake. We know from 8' that event a.Coalinga event, when you have intense, when you 9 have a geologic deformation that you can quantify, that you
, 10 should be worried about moderate or earthquakes of say around 11 magnitude 5 to 6.
12 DR. SIESS: If I looked at a hazard map, would that 13 have indicated that?
'}
14 MR. CLUFFt A hazard map in California I think would 15 have included that as a zone because all of that part of the 16 Los Angeles Basin is Zone 4. And the basis for mapping source:
17 for hazards I think included that general trend.
18 MR. MAXWELL: .Lloyd, was it the San Fernando 19 earthquake, the very destructive one, somewhat of a surprise?
20 MR. CLUFF: Yes. In some ways it was a surprise.
21 That's a good example, John, to look at that. That was a 22 magnitude 6.5 earthquake that occurred in an area where no 23 published active faults had been identified.
24 I personally, and many members of the Geological 25 Survey, and other universities, said well, let's take a look at O
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Had we done studies like we do for large dam projects, 1 that.
2 nuclear power' plants, would we have recognized that fault that 3 slipped? And the answer is yes. There was abundant geologic, 4 geomorphic, paleoseismic evidence of repeated slips on that San 5 Fernando fault. No one had really looked. There was no need 6 to. There was no emphasis to look in that area.
7 So in a sense it was a surprise. But when we looked 8 at it terms of nuclear power plant siting, it was not a 9 surprise.
'10 Just going on very quickly, this outlines the various 11 tasks in the other elements of the program. The following 12 speakers will be talking about our progress and some of the 13 tentative results that ue have achieved in terms of looking at
)
14 the site conditions. And some of this we have already
' 15 presented to you at the last meeting a year ago November.
16 The free field input motions; then, looking at the 17 two methods of modeling the soil structure interaction to the 18 CLASSI and SASSI programs, and the 3-D structural dynamic 19 models, and then correlation with that reported data and then 20 some parametric studies, and the following activities in that 21 element.
22 In the fragilities area, the work tasks for simply 23' stated at that time a.s shown here'. In terms of looking at the 24 dominant contributors to seismic risk, this may respond to some 25 of the questions earlier. And to incorporate the soil Heritage Reporting Corporation (202) 628-4888 ,
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47 f"i
('~ structure interaction results and to look at impro'ving our 1
2 ability to focus on important contributors,-and then the median in-structure response -spectra and looking at the lower tails 3
4 of the fragility. curves, and looking at the balance of the 5 plant piping and other aspects of the fragility. assessment.
6 And then of course look at items that were not considered in 7 the Phase II fragility analysis.
8 From the standpoint of the program and its schedule 9' as it is now constituted, we have the beginning of the program 10 that started back in 1985, July of 1985, af ter a program 11 approval, and here is where we,had major kinds of whatever 12 information'we had, in a tentative fashion, we would have input
(' )
'V 13' into the various elements of this long term seismic program.
14 Because of the need to finish this pro' gram in a reasonable 15 amount of time, while ideally you would like to do these 16 sequentially the programs are all going on at the same time so 17 ve have a continual flow of updating of information and using 18 tentative results and then modifying them as we get more 19 accurate results as the time goes on.
~
20 So what we see here is the flow where we are right 21 now in early 1988. We are about to get another update from the 22 GSG end of the ground motions. And then that will flow into 23 the probabilistic risk assessment and the soil structure 24 interaction aspects. Actually, these two areas down here 25 connect up to this flow down here and this is just an update of Heritage Reporting Corporation
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' (' ' ' ' 'l these.two aspects here to look at what we-had_ tentatively 2 concluded over here.
3 The final input we show here is in late 1988 or early 4 1989 in terms of our final conclusions that we believe we will 5 have reached in the GSG part of the program, will flow into the 6 ground motions and then once we know from this what we've 7 concluded about the seismic sources that need to be considered, 8 the size of the earthquakes that we have concluded that we will 9 use', and then taking that into the ground motions into the SSI 10 and then the fragility and 'the PRA, to allow the final rungs on
. 11 the PRA to be done in the last few months of the program.
12 That means that these programs all this time are f'7p 13 continually doing work and looking at various aspects, J
14 sensitivity studies and so forth. But we won't have reached 15 conclusions that we will be presenting to the staff and so -
16 forth in workshops prior to these input times. We have 17 workshops scheduled here late in 1988 and we will have 18 subsequent workshops in ground motions and so forth to review 19 with the staff what conclusions we have reached, what will 20 appear in our final report that will be produced when we 21 complete the program.
22 Now, you notice here that I'm showing the completion 23 of a program assuming that the requested license amendment will 24 be granted.
25 MR. DAVIS: ' Question on that?
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./^}- -49 1 MR. CLUFF: Yes.
2 MR. DAVIS: Is the PRA that is referred to on the 3 bottom line here the Level.1 PRA,that you talked about earlier?
4 MR. CLUFF: Yes, that is correct.
5 MR. DAVIS: I'm not sure what your definition of 6 Level 1 is but the conventional definition excludes 7 consideration of the containment response and its safety 8 systems.
9 In other words, a Level I PRA looks only at the 10 probability of core melt. So I am a little concerned that you 11 are using the same definition. Will this exclude any 12 consideration of containment response and containment safety 13 systems?
14' MR. CLUFF: I'm not the one to answer that question, 15 and Bruce Smith, the PG&E engineer that's in charge of the PRA 16 aspect, Bruce, could you comment? You need to speak up so that 17 they can hear you.
18 MR. SMITH: Sure. The PRA is an official Level 1 19 PRA. However, in coming up with our plant damage dates, we do 20 take some consideration of the state of the containment, 21 whether or not the containment is intact or not, as part of our 22 plant damage statement.
23 So yes, we do, in some form.
24 MR. DAVIS: Okay. Maybe you are going to talk about 25 this in a little more detail. But in the past, there have been 0 -
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occasicis where there are interactions between the containment
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1 2 safety <;ystems and for example the emergency core cooling 3 systems -
4 And when you exclude any consideration.of the 5 containment safety systems, you may be missing some important 6 sequences that could be generated by a seismic input' event.
7 -Also, there have been vulnerabilities found in 8 containnsnt structures in other plants. And I'm just concerned 9 that you may be cutting things off a little bit early on the 10- PRA.
11 Do you intend ever to extend the Level 1 into a Level 12 2 and 3 PRA? .
MR. SMITH: We have not made that decision yet. The
) 13 14 PRA is set up to go to those higher levels if we deem that 15 necessary.
16 ' MR . DAVIS: You may have to do it for the IPE, but 17 that is another subject.
18 MR. CLUFF: Let me just say that it is not our ,
19 intention to go beyond the PRA that we have envisioned here 20~ based on what we have right now.
21 As mentioned before, there's been a lot of 22 involvement of reviewers and so forth. Let me just show you 23 very quickly not only we're going to make sure that we're not ,
24 working in a vacuum with the PG&E and their consultants and the 25 flRC and their consultants, but it was expressed early on that O
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l' we want to make sure that we have a chance to review this in a 2 peer reviewed aspect in professional society meetings and 3 journals and so forth.
4 So let me just.briefly show you --
5 MR. EBERSOLE: Before you get to that, lot me ask 6 you, in quick passing, you mentioned you were going to look at 7 the balance of the plant. And I wonder if you are looking at 8 the possibility of absolute, or rather of sudden and gross 9 intrusion of salt water into the secondary system as a result 10 of condenser tube failure or some such thing as that?
11 MR. CLUFN: Again, I'm not the one to answer that 12 question, r 13 DR. SIESS: Why don't we save that?
)
14 MR. CLUFF: Yes. I think we'll have an opportunity, 15 and.please ask that later on.
16 We have had a number of symposia held that have been 17 conducted through the Seismological Society of America, the 18 Geological Society of America and the American Geophysical 19 Union, at least two meetings of all of'these societies where we 20 haven't had symposia that focus on the Diablo Canyon but 21 symposia that includes the geographic area of Diablo Canyon.
22 Let me just show you as just examples -- here is one 23 of the titles of papers for the Cordilleran Section of the 24 Geological Society df America held last year. It was in May of ;
25 1987. We had three sessions. Session I was on seismotectonics t
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52 1 of the Central California Coast Ranges. ~And the presiding-2 individuals here, Ina Alterman at that time was with the staff 3 of.the NRC. -Bob Brown was the representative for the U.S.
4 Geological Survey, and myself, and then Dick McMullen is on-5 staff at the NRC and Burt.31emmons with the University of 6 Nevada. So the presiders of this conference we're all 7 individuals. But we sent out a notification that we were 8 having these special symposta and we invited others to 9 participate. And so we had, as you notice here, these two 10 authors were not members of tha review of working group on this 11 project, and all of thess papers were'made with respect or 12 presented with respect to this area in Central California Coast 13 Ranges.
14 So we have had an opportunity thrcugh that. Let me 15 just quickly show you other parts of that same meeting. This 16 was 2, the Session 2 of that again showing the various aspects 17 in terms of geology, seismology and geophysics and so forth.
18 These were all organized with respect to various aspects of 19 addressing the tectonics of the coast ranges.
20 And then Session 3 of that symposium was to address
~
21 the issue of the relationship between folds in faults and slip 22 rate on various seismic sources and again, a list of 23 participants there, many of which are part of this program but 24 also a number of them being outside people who have done work 25 in the area and were eager to present some of their results.
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. 1 This was a.very useful mechanism to understand work' 33 2 that was in the process of.being conducted at the time.
3 And then the last part of that Phase 3 was two more 4 papers _and then I gave a general. summary.of that entire ,
5 session.
6' This, by the way, these series of papers, all the
~
7 authors of those papers'have been invited to contribute either 8 an expanded abstract or a full paper to a peer review journal.
9 This will probably be a Geological Society of America journal 10 where all of this information will be out in the literature and 11 it should come out during this year.
12 ,
Just quickly to show you some other examples. I don't want to spend too much timo on this.
) 13 14 But this was the American Geophysical Union meeting 15 called the edge. This is a consortium of universities doing 16 work on the edge of the continents trying to understand 17 offshore / onshore relationships in Central California. And 18 again you will notice, Dr. Pen Page was a participant and 19 presented some of the work in that. And again, a lot of the 20 people working on this project, both from the PG&E perspective 21 as well as reviewers, and other interested researchers at 22 universities and the U.S. Geological Survey, were involved.
23 At the Seismological Society meeting again, special 24 sessions on strong ground motion. Most of these were on other 25 aspects. But we had a number of people, this paper down here O
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1 by Sommerville and Helmberger, and I think there may be -- I 2 guess that was the only one in that session. But we've had an 3 active participation in looking. I won't spend any more time
~4 on this. Just to show that we've got a lot of -- these are all 5 in the handouts that you've received. And a number of symposia 6 and meetings where we've had an opportunity to talk about, 7 without it being focused on Diablo Canyon, to look at the 8 aspects of understanding the regional geology and seismicity 9 and so forth and geophysics as it might pertain to this 10 geographic area. .
11 This' fall the most recent meeting in December of 1987 12 was a special session that had to do with -- and a number of
(')
v 13 the reviewers and so forth and participants in our program, 14 these two papers down here as well as Professor Bolt who was on 15 our consulting board, participated in that meeting. And we are 16 watching when important earthquakes occur, and of course the 17 Whittier Narrows, there was a special session there. And some 18 of our workers were involved in looking at that, particularly 19 Professor Bolt, on our consulting board. And then some of our 20 work on one of our consultants in simulation of accelograms and 21 so forth, in looking at the importance of that earthquake and 22 incorporating that data into our analysis.
23 Let me go on to just a recap then of the involvement 24 from the beginning or from the beginning, which was May 1984, 25 in the draft discussions of the license condition through the l (
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i3 55 1 point'where the program plan was approved, and then a listing 2 of the various workshops that we have had in giving some 3 tentative results or status reports o'n our Phase 3 efforts.
4 Here is a workshop in soil / structure interaction and 5 ground motions. We had a coordination meeting, and then some 6 more ground motion workshops. He've had a lot of activities 7 where the NRC staff and PG&E orofessionals with their 8 consultants meet for sometimes a full day, sometimes three 9 days, to conduct not only workshop sessions but field trips.
10 You see a number of places where we've had several field trips.
11 And we've had the opportunity of some of your consultants 12 participating in these workshops and field trips.
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13 I know that Dr. Page and Dr. George Thompson have I 14 think been present at almost all of our workshops on geology,
, 15 seismology and geophysics, and field trips that we have had.
16 And so they have been able to participate and keep track of 17 where we're going. This brings us up to date to the ones that 18 we most recently had in 1987, in looking at all aspects of our 19 program. And the most recent meeting we had was in January of 20 this year to discuss where we are in the PRA program.
21 DR. SIESS: Excuse me. As I recall, the last time 22 we met, the staff was complaining that they weren't getting 23 enough paper to review. Could the staff tell us whether that 24 situation has improved? By improve, I mean you are getting 25 more paper.
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1: 101. ROTHMAN: Yes. I.would say yes. I was -- there 2 was a' hiatus of my involvement in the program due to NRC
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3 reorganization, at the time of the last meeting, so I wasn't
'4 , involved with that._ But I think we.are happy with the number 5 of reports and the quality of reports we are receiving now.
6 DR.'SIESS: Thank you.
7 MR. CLUFF: Thank you. I would like to emphasize 8 that not only the amount of paper but wc have tried to focus on 9 the significance and importance. And I'm glad to hear Bob say 10 he is pleased with the quality.
11 This is the last viewgraph I have that kind of leads 12 us into the next part of the program where we'll get into the 13 results of various elements of the program. This kind of
)
14 summarizes where we are in terms of the various elements in 15 being complete.
16 In the parts of the program where we're collecting a 17 lot of data in terms of existing data or data that we didn't 18 know about that existed but jsst discovered it or data that we 19 are generating by conducting our own field work or analysis.
, e0 And in the geology, seismology, geophysics, at the present time 21 that is about 75 percent complete. And then we're in our 22 analysis and interpretation phase, which is about 65 percent 23 complete. .
24 The ground motion again has both data acquisition 25 analysis. And until we get more Parthquakes, I think we have O
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57 1 -about got all we'need in that. But as you know, earthquakes 2 .are always occurring and we are always conscious of 3- incorporating the data. As many of~you mayfbe aware,_the 4 Whittier Narrows earthquake by-itself generated probably many; 5 more times the ground motion records that totally existed from 6 a lot of other' earthquakes in the past.
7 So we are carefully looking at the results of what is 8 coming outfof various interpretations and doing some analysis 9 and interpretation of our own, of not only that earthquake but' 10 the Mexic&n and the Chilean earthquake and others that have
- 11 happened since this time. And we're incorporating that 12 information into our data base and interpretations.
') 13 14 And soil / structure interaction, again, we're about 75
_ percent complete. Fragility analysis about 80. And the PRA is 15 about 85.
16 You have to understand that all these programs are 17 going forward and they are driven by the results that will
. 18 finally come out of here. And that will be essentially 19 complete later thia year. We expect that that part, of course, 20 in terms of all the data acquisition and analysis and 21 interpretation, will be complete by late this fall, early 22 winter. And then from then on in that part of the program we 23 will be finalizing our final report and we will be treating the 24 final information down in here, and these other people will 25 then'be adjusting the analysis and interpretations they have O
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' l' 1- made based on that final input.
2 So this is kind'of the last and the lead-in to the 3 next section. It might be appropriate even though we're kind 4 of ahead to take a break now. I'm the next speaker-for a while 5 in the next part. And if it's'all right, I'd like to take a 6 quick break.
7 DR. SIESS: Does this conclude your discussion under 8 the heading "Background" 9 MR. CLUFF: That's correct.
10 DR. SIESS: We are really a little ahead. But in any 11 case, it's time for a. break. We'll take a 15-minute break. Be 12 back at 10:20. And I'd like to remind, about what I said 13 earlier, those that are planning to take the plant tour
)
14 tomorrow, I would suggest that if you are going to get coffee 15 get it, and come back in here and meet with Mr. Cluff or 16 whoever he designates to talk about what you want to see at the 17 plant.
18 MR. CLUFF Could we just meet right up here in front -
19 by this viewgraph machine?
20 (Whereupon, a brief recess was taken.)
21 22 23 24 25 O '
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- 11 i DR..SIESS
- I was just looking.at'the agenda and for.
2 some reasonlit'says 4:00 p;m. today. ~Is there a good reason
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- for setting'4:00 p.m? Thatfis flexible unless somebody 4 notifies me that they have got to.go somewhere at 4:00.- Five-
- 5 - would tm a -little more' reasonable, I.think..
6 Okay proceed. .
7 MR. CLUFF Thank you, Dr. Siess.
8 As a matter of fact, with regard to the schedule, 9' based on the discussions that we had up here of the people
- 10. going on the field = trip, we found an interest in a number of
,11 things that we can certainly accommodate and'do. But to do
- 12. that in the short period of time that we have, as the schedule 13 shows, leaving here afternoon, and there are people who are on
)
14 that trip that need to be back to San Francisco'at 6:00.
15 I would propose that we do the best we can to 16 achieve, like we are ahead of schedule right now, to continue 17 that so that we could leave earlier if that is agreeable in the 18 morning rather than at noontime.
19 DR. SIESS: We will certainly aim for that. I don't, 20 however, intend to repeat the performance at the last meeting 21 where we finished up the night before after dinner. Wasn't 22 that the Diablo meeting? Yes. And disappointed a reporter who 23 showed up the next morning and so forth.
24 But if it looks like working a little later tonight, 25 and we will certainly try to finish up tomorrow. What would be Heritage Reporting Corporation (202) 628-4888
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U 1 a good time to aim for tomorrow?
? MR. CLUFF: Okay, I have checked with our plane that 3 we will be us,ing, and we can leave as early as 10:00 from here, 4 and if we could do that, I would like to try to do that.
5 DR. SIESS: Okay, we will watch the agenda. And if 6 10:00 looks reasonable, about 5:00 we will review the situation 7 and decide whether we want to go to six. I don't think we want 8 to go much later than 6:00 though, although ACRS members are 9 used 6:00, 6:30. Hadn't been much later than 6:30 since Bill 10 ,Kerr has been' chairman, but he's not chairing this session,.
11 Okay. t 12 MR. CLUFF: Fine, d' ) 13 (Slide.)
r ~/
14 MR. CLUFF: We are going to move now into the status 15 of the various elements of the program. And the first one r 16 being Geology / Seismology / Geophysics.
17 This first slide strictly emphasizes that this 18 program is focused on important issues based on studies that we 19 did early on, develop the scope of work, and we are data- ,
20 driven. We haven't come to preconceived conclusions about 21 models, tectonic or geologic models, but we are looking at [
22 data. And once we get totally incorporated and integrated and 23 interpreted those data bases, then we will be giving the 24 results in terms of the outcome of this work. So that is where [
25 we are right now is in gathering, or analyzing and interpreted Heritage Reporting Corporation j
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2 And we are going through four steps in this activity.
3 Is the acquisition of data existing, or new, or what others are 4 doing, analysis of all of those data bases and then
. 5 interpretation and integration of all the data bases focused on 6 characterizing seismic sources. .
7 And so that last step is only done after we have 8 integrated all the important information. And one has to be 9 careful about coming to conclusions or judgments based on a 10 limited data base, or without integrating the appropriate data.
11 (Slide.)
12 In terms of data acquisition, we of course have an g' extensive data base in the literature that was developed on the o} 13 14 D'iablo Canyon project prior to this program going ahead, but we 15 augment that and have been in contact with researchers and 16 people that have been working in this geographic part of 17 California, and looking at particularly some new information in 18 terms of marine and fluvial terraces, and the dating of those 19 terraces, and I will talk about the significance of those in a 20 moment.
21 And then we have conducted in specific locations 22 where we targeted areas, we get some new information and 23 actually going out in the field and exposing some of those 24 materials through trenching techniques that have been very 25 helpful.
O '
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}v 1 Then in'the offshore, combining the offshore and .
2 onshore geophysics, Dr. Savage with PG&E will be talking about 3 this in detail.a little bit later on'in what we call the COMAPS r 4 high resolution, a nearshore study that PG&E conducted a little >
5 more_than a year ago and then a deep crustal survey that PG&E 6 conducted using Dig 1 con. These are the contractors that we had 7 conduct that work.for us under our directiorn ,
8 And also in that onshore / offshore geophysical 9 program, there_was an integrated interest in this HARC group.
10 Stanford University and Rice University and the U.S. Geological 11 Survey and others had a great interest in this. And when the 12 discovered that we are going to be doing some more work, they l rT 13 concentrated their efforts in coordination with ours.
V 14 So everyone benefits in getting access and getting I
15 more data than what one individual group might have gotten.
16 And Dr. Savage will talk about that in more detail a little bit ;
17 later.
18 Then some geophysical surveys that have been done by 19 the petroleum industry that Western and Nekton, and these are 20 just acronyms on the type of data that it is, and Woody will 21 talk about that later.
22 In acquiring data that 'vas developed for the 23 petroleum industry, again the petroleum industry generally is 24 not interested in seismic sources. They are interested in 25 looking at faults or folds or structures that trap petrole,um. ,
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63 1 ~And so they tend to be fault happy in terms of the~more faults, 2- the more trapped petroleum you can-find, the more' people will
- 3. pay attention and go out and drill holes.
And so you tend to 4 encourage _a lot of-fault interpretations that may_or may not be 5 realistic.
6 -
So we wanted to get the basic data that they 7 developed. Then process it from the_ perspective that we-were 8 in'terested in looking at the stratigraphic and geologic 9- relationships that would lend itself to-integrating that with 10 our other data bases to interpret the importance of soismic 11 sources, so that the objectives in that. So that's what this 12 reprocessing.is all about. ,
') 13 14 And then the State of California has been conducting nearshore, shallow, high resolution work that is aimed at 15 seismic hazards assessment, so offshore exploration and 16 petroleum production. And we have been working together with 17 the people that have been involved in that to share and help 18 collect data of common interest. And this is in the 3-mile 19 limit area.
20 And then the Central Coast Seismic Network, this is a 21 network that PG&E has installed. It is operating, fully 22 operational now specifically for the Diablo Canyon project.
23 And Woody Savage will be giving you progress report on how that 24 system i's operating and what value the information that we are 25 receiving is in our analysis.
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1 (Slide.)
-2 Let me show you now a map that kind of shows in map 3 form where we were when we started this program. This is a 4 representation of the State of California, Division of Mines .
5 and Geology map of this area. Plant. Here, the blue line, 6 represents the coast line. And one sees a lot of lines on this 7 map, and the question is, well, which ones are important in 8 terms of Diablo Canyon.
9 Of course, we have always known that this zone that 10 is represented out here, named here the Hosgri fault, is one 11 that is important to us.
12 But nevertheless, there are some smaller lines, ,
13 smaller faults, at least in terms of this pictorial
{)
14 representation here, the San Miguelito fault here that if in 15 fact that's an important fault and if it is accurately mapped, <
16 or maybe it extends, we ought to know more about that, and so 17 t' hat's an obvious choice.
18 The Edna fault and there has been some other faults.
19 I am going-to end up at the end of my presentation here in a 20 few moment with a map that shows the faults that we have --
21 where we are in the program now that are important, and I will 22 put two on the two viewgraphs so you can sea the difference in 23 where we have come, and the progress that we are making and 24 fo'cusing on, the structures, faults and folds that we think are 25 most important to us.
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, :1: As you kr'ow, : there have been a number of dif ferent
'2 _ hypotheses presented in terms of the tectonic style.of~the
, '3 deformation. 'Irr cther words, there has ~ been great debate on j 4' - the' geometry of a lot of.these faults, and namely, tho'Hosgri.
D- 5 Is it a near vertical fault? Or does it incline at some' angle 6 wit!h the horizontal? - If so, at what angle, and how does that ,
7 relate to the other faults that are shown on this?
8 And as we are gathering the data and going through~
.9 this analysis, we are now unfolding, I think,'a very realistic 10 . picture of really how these faults, and the ones that are ..
11 important to us are interrelated. And, of course, that's the 12 aim of this project when it is completed.
~
13 Now thero are a number of studies that came out of 14- our scoping of Phase III that specifically focused on the 15 important structures, and for the next little while I am going 16 to focus strictly the onshore information. And so there were 17 some specific studies aimed at some of these faults here, San 18 Miguelito and Edna. And then because of the suspected 19 relationship or connection between the Hosgri and the San 20 Simcon faults, the San Simeon fault, this fault right up here.
21 And on some maps they are shown as the same fault. Other 22 interpretations, they may be separate and so forth.
23 And so since that fault comes on land up at San 24 Simeon, it was a good opportunity to look at those 25 relationships. So I am going to show you a series of slides O
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- (v) i now that --
2 MR. EBERSOLE: Before'you throw that down. j 3 MR. CLUFF Yes.
4- MR. EBERSOLE: There are t,wo large areas up there, 5 one out in the water and one in the upper center in which'there 6 is a sparsity of faults, f 7 MR.-CLUFF: Yes.
l 8 MR. EBERSOLE: How would yo,u characterize the j 9 subsurface that lwads to that degree of absence of faults? t 10 MR. CLUFF: Yes, let me defer that until you show --
11 this represents the state of' understanding at the time that 12 this map was published back in mid '70s. And we will be
') 13~
14 showing some viewgraphs later on that Dr. Savage will be showing that will show -- we have looked at data bases that go 15 offshore to a great extent, and we now know whether or not this 16 large blank area is truly free from faults, or whether or .
. 17 not --
l 18 MR. EBERSOLE: Well, it merely was because you hadn't ;
] 19 looked there.
20 MR. CLUFF: Well, sometimes that's the case, and Dr. {
21 Savage will address that as he shows that offshore. He will be 22 addressing the offshore and the seismicalogical studies a 23 little bit later. .
24 (Slide.) :
25 So let me now use the same base map as the basis for j Heritage Reporting Corporation f (202) 628-48B8 ,
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1 illustrating the studies that we hove been conducting. This 2 one in the stickel pattern outlined in yellow represents the 3' extent of Quaternary Terrace deposits.
4 ,
Now let me explain to you why these are important, 5 and I will have some slides.I will show you in a moment that 6 illustrates that.
7 We find that these Quaternary Terrace deposits exist 8 all along the coast of California, but particularly for 9 application to understanding the tectonic environment 10 surrounding Diablo Canyon, the area that I have noted here from 11 the edge of the Santa Maria Basin, northward along the coast, !
i 12 to the San Simeon region. This is a unique opportunity to look
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13 these deposits and it's a mechanism from which we can gain an 14 understanding of the rate of deformation and' faulting, of any 15 faults that intersect or folds that are nearby that might l 16 influence thes's features, and I will tell you why as I show 17 some things from slides tha't follow. (
18 Let me move this over to this, and then through some ;
19 chotochrome slide. Now maybe we could -- yes, let's turn this 20 one off.
i 21 (Slide.)
22 This is a view, an oblique view looking along the (
23 coastline. The plane was about here where San Luis Bay comes 24 out. And the Diablo Canyon Power Plant, you can barely see 25 part of the structures right up here in the background. This
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a 68 V[l I white area up here is the offshore' sea stacks, those rock 2 outcroppings are out in the ocean just offshore from the power 3 plant.
. 4 But the point I want to stress here is that you have 5 this topographic, almost flat there, an inclined near flat 6 plane that you can see here well represented, that follows 7- around the coast, and I am going to quickly take you along the 8 coastline, this being the most southerly part, although these 9 extend even farther to the south.
10 And what these features are is that this represents ,
11 both a time line and.a physical line in terms of a reference 12 plane that is a platform that was cut by a former stand of the 13 sea. In other words, these areas were at a lower elevation at
{) one time, and due to regional uplift where the most of the 14 ,
15 coast of California is, generally speaking, uplifting at 16 various rates. ,
17 And so as the surf planes off these surfaces, it 18 creates what we call a wave cup platform, and then on top of ,
19 that platform are deposited materials of the terrace deposit, I 20 which were termed Quaternary Terrace deposits. This was all 21 accomplished in the last couple of million years.
22 And so what we have are a whole sequence of wave cup ,
23 platforms, terrace materials on top of those. The ages of-24 which we know, or in a study we have determined.
25 And so we know when those were formed, and since they f Heritage Reporting Corporation l
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69 1 are plane surfaces, the ocean being the reference base, then we 2 can look at the amount of deformation or faulting and come to a 3 lot of very important conclusions ebout which faults to worry 4 about, which faults not to worry about, and which folds might 5 be causing fold deformation that might reflect f aults at depth-6 that don't expose themselves at the surface.
7 So it is a very valuable strain gauge, as I like to 8 look at it,, and the youngest terrace, the modern one that's 9 being planed just offshore right now. The next one is about 10 83,000 years old. And we'actually have 12 terraces. You can 11 only -- the trained eye can see two terraces in here. I won't 12 take the time to go into that now, but we have identified as se gh 13 go along the coast 12 terraces going back to more than 1 14 million years.
15 The older ones aren't as well preserved, so that the 16 strain gauge data are only limited for some of those that may 17 be 700 to a million years old. But, nevertheless, their 18 relative position with the younger ones that are essentially 19 continuance, the 83,000 year and 240,000-year terrace are 20 almost continuously preserved and are an excellent opportunity 21 to allow us to look at the faulting, the rate of faulting and 22 the rate of deformation in this entire region.
23 (Slide.)
24 The next slide is continuing along, and now you can 25 see how well developed these are. And in these e.reas not only
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70 1 did we do detailed mapping and surveying of a zillion points 2 along these surfaces and drilled down to look at the character 3 and the depth, and geometry of what we call the shoreline angle 4 to be able to assess the continuity and any deformation that 5 are related to these features in the plant.
6 (Slide.)
7 The next slide just moves on to show the plant. The 8 plant is located on those Quaternary d'eposits' and wave-cut 9 terraces, the younger ones. And as you can see, they continue.
10 (Slide.)
11 The next slide continues on northward around the 12 point here. These white rocks that we can see from down south, gl 13 Continuing on to the north then.
14 (Slide.)
15 And the next slide shows very plain our 16 representation of these two younger terraces that are here.
17 (Slide.)
18 And the next slide shows as we are up at San Simeon.
19 Now this is the -- these terraces continue on up the coast of 20 California. And in a general sense have been very helpful in 21 understanding the deformation and f ault behavior in other 22 places. But for the benefit of this project, this is as far as 23 we need to go in terms of understanding.
24 And the San Simeon fault comes right through here.
25 At this angle it traverses off and goes offshore again here.
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1 And so this is a rare opportunity to look at'the interplay of 2 the San Simeon fault and the number of terraces that we have 3 identified here, and to be able to date the rate of faulting ,
4 and so forth on the San Simeon fault and the style of faulting 5 and the character in terms of the fault beh&vior. And even we 6 have identified evidence for some past earthquake activity in 7 terms of looking at the amount of slip and relate it to the 8 size of past earthquake.
9 (Slide.)
10 . So the next slide then looks back -- or, no, it is 11 continued on. This is over the top of this area where the San 12 Simeon fault comes on land here or offshore. And you notice 13
- here that at this point we get quite a high topographic relief,
)
14 and I will just make mention of this right now, and Woody 15 Savage will talk more about this when he shows the results of 16 some of our instrumental seisimity interpretation where we have 17 essentially division between strike slip fault that is coming 18 through here and some vertical dip slip, or reverse slip 19 faulting that goes inland along'another fault trend at this 20 location, and this bifurcation. Not only is it represented 21 topographically and geomorphically, but in the seismic history 22 that othen slides will illustrate, ,
I 23 (Slide.) !
24 The next slide I think is the last slide that looks !
25 back then. We just turned around, looked back. The power ;
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j yy 1 plant is out on the -- this area here of the Irish Hills, and 2 this is looking down, the erosional trench cut by this steam 3 canyon. The stream is following that because of a. crushed zone 4 along the fault. And then one can see the features out there 5 that represent a series of these wave cup platforms and terrace 6 deposits.
7 And we have done a lot of detailed studies up here to 8 characterize that relationship and assess the behavior and 9 characteristics of the San Simeon fault.
10 So that is the last slide. Let me turn this 11 viewgraph back on over here.
12 (Slide.)
- m
) 13 What I just showed you was a sequence of aerial shott.
14 from about right here, all along across the plant, and then all 15 the way up to this place in San Simeon. So this is a unique 16 data set that is very important to us in assessing the amount 17 of deformation that has occurred in the past approximately 18 million years.
19 Let me go back since this is a little more convenient 20 on this side with my right-handedness.
21 (Slide.)
22 Show you where we have gathered some additional data 23 to supplement that in f o rmation . This is bore hole water well 24 data that have been very important to us with respect to the 25 plant site. We.did a lot of boring here, not having anything v
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1 to do with water well, but to help us identify and characterize i 2 the ages and the geometry of those wave cup platforms and 3 terrace deposits. So that was an area of intense concentration 4 to examine that area.
5 Then in the area where the San Miguelito fault is, we 6 had some additional detailed subsurface information that we 7 felt would be helpful. And then in this area some, water well 8 data and other information were gained from some bore holes.
9 That existed in some that we in addition drilled ourselves. ,
10 And also up in this area near San Simeon, the same 11 kind of information was acquired there, and also an area here 12 near Morrow say where I will talk about a little bit _later, (a) 13 Woody Savage and I, about the importance of the disap'pearance 14 of'these strain gauges as they come up here. They just end.
15 And what we found out is there is another fault that is not 16 shown on this map that actually terminates those terraces.
17 They are not there, and this area is actually subsiding, and we 18 have been able to quantify the rate of that subsidence due t.o 19 water well data and the stratigraphy that we have gotten out of 20 those existing well data sets.
21 Now some other information that we have been 22 gathering and evaluating is from trenching. Here is places 23 where we have come in, and this has focused our understanding 24 whether or not this San Miguelito fault has evidence of 25 . disrupting these strain gauges, these wave cut . terrace platform Heritage Reporting Corporation
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1 and as well as up'on the hillside'here, any information 'from
.2 the younger deposits to see 'if there had been any deformation 3 in the last few hundred thousand years. So that's what these l
l 4 locations were, aimed at.
5 These were aimed at the Edna fault, and then these ,
t 6 out here where there is not a fault shown there because of the 7 state of knowledge of this map, this other fault that we have 8 discovered through completing this stage of this program, is 9 the Los osos fault, and that's what these trenches, to try to ,
10 understand behavior of that fault.
11 And then the detailed studies that we conducted up ,
12 here at San Simeon to understand the behavior of the San Simeon l
() 13 14 fault on shore.
(Slide.)
l t
15 The next is -- let's' see, you are going to do the ;
l 16 geophysics after this?
17 MR. SAVAGE: Yes. ;
18 MR. CLUFF: Yes, and then I am going to summarize the 19 importance of integrating both the wave cut marine terrace data 20 with the geophysical data that Woody will present. So Woody 21 will show mostly the offshore geophysics and seismity, and ther. :
22 I will come back and pull this material together to show you 23 the results of some of the tentative conclusions that wo 24 reached so far.
i 25 DR. SAVAGE: My name is Woody Savage. I am a [
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1 seismologist with Pacific Gas and Electric. And I am a 2 specialist seismologist. I have spent the last 15 years or so 3 working both with the U.S. Geological Survey as well as in'an 4 industrial capacity studying earthquake activity. But I am 5 also a generalist. I think it's important to be a generalist 6 in proceedings like this, because one of our objectives is to 7 integrate multiple data sets. And again,.that's been part of 8 my professional activity for the last decade and a half.
9 Well, Lloyd's development of the program as we have 10 been carrying it out left off with part of the discussion of 11 our. data acquisition efforts. And what I will do is briefly 12 give you the location, primarily the location information of f'S I (v j 13
- the data sets that we have been acquiring most recently.
14 Now, in November of 1986, we met with you and
- 15 presented quito a bit of information about the locations and 16 some of. the results from processing and interpreting offshore 17 geophysical data, and certainly offshore geophysical data has 18 been very important in understanding the Hosgri fault zone and 19 its relationship to onshore geologic and tectonic structures.
20 Well, following the interval of -- following the time 21 of *: hat meeting last year, we have collected some additional 22 data sets, and just for the sake of completeness I would like 23 to make sure that the geography and significance of those data 24 s eats is fairly clear.
25 (Slide.)
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1 I don't'have a figure that shows where we had data up 2 until this time, but it was basically along the entire stretch 3 of the Hosgri, with a' lot of emphasis in the southern portion 4 of the Hosgri, because this is the area'where, as Lloyd 5 mentioned earlier, there has been longstanding oil exploration 6- interest, and much of the data that have been collected 7 offshore have.been specifically for oil exploration purposes.
8 The first data set I will describe is called.the 9 COMAPS data set. It was collected by PG&E by the contractor 10 COMAPS, and is what's called a high-resolution study. The high 11 resolution.means'that the emphasis is on studying the shallow 12 set of entry structure from the sea floor surface down to as G
13 deep as a few kilometers. ,
14 The energy sources that are used are high frequency 15 and they range from side-scan sonar which collects a fairly 16 realistic image of what the ocean floor looks like in a side-17 looking sense. Those soundings were collected, and then two 18 very high frequency geophysical sources were used. 3.5 19 kilohertz device and what's called a boomer which image tho' 20 sallow set of entry structure down to a depth of about between 21 10 meters and perhaps as deep as 50 meters. So, again, it is 22 very shallow penetration data acquisition.
23 ' The remaining geophysical technique used is called 24 CDP, common depth point reflection surveying, and this 25 reflection profiling was done with a relatively high-frequency O
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1 source, not the same sort of seismic source as is used by the 2 deeper penetration oi1> company explorations.
3 So within this region extending from the middle of 4 San Luis Obispo, Bay, acro,ss the Hosgri, extending _into the 5 interior of the Estero Bay and on up past.where the San Simeon 6 fault comes on shore, we collected a number of lines of data.
7 Most of the lines have the orientation, as how shown 8 schematically in this figurechere, cross both the. trend of the 9 Hosgri as well as the trend of some of the other geophysical 10 structures that we have seen offshore.
11 But there were also northwest going lines which serve 12 to tie these data together.
- /'~) 13 We will see the application of this COMAPS data set
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14 later on this morning in a hig'h resolution geophysics look at 15 the Hosgri fault zone.
l 16 (Slide.)
17 The next geophysical topic as seen on your right here 18 is the Dig 1 con survey. I am going to put the microphone down 19 here to align this slide.
20 As Lloyd mentioned, we had an opportunity -- well, 21 first of all, we had a need to develop a better understanding l
22 of the deeper crustal structure within the region. The plant 23 site being right here southwest at San Luis Obispo.
24 The oil company data and in general other geophysical 25 techniques that have been used have penetrated with good
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.78 1 returns only a few kilometers, 2, 3, 4, 5 kilometers at best.
2 And there are questions about what's happening in a deeper
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3 crustal sense and in a regional sense that we felt-merited a 4 true depenetration geophysical survey, and that' survey was 5 discussed very briefly with you at the last meeting in 6 November,.because we had just come back form the field having 7 collected those data a that point. ,
8 So these were the lines that we shot using a very ,
9 large airgun source, and we shot one cross line here. We also 10 recorded'airgun shooting onshore, so we ended up having the 11 ability to image the crustal structure across the coastline.
12 It's certainly been commented that lots of time geology seems 13 to end at the coastline.
14 Well, obviously it doesn't, and this is one of the 15 techniques to develop a clearer understanding of the 16 . onshore / offshore relationships.
17 And these lines crossed not only the offshore St.
18 Lucia Bank, an elevated basement platform in the offshore, but 19 went across what's called the Santa Lucia escarpment, which is 20 a relic of the subducting process, plate tectonic subduction 21 that was occurring some 25 to 30 million years ago that 22 terminated at that time period.
23 MR. MAXWELL: Could I ask you a question?
24 Do you really get subsurface data across that 25 coastline?
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1 MR.. SAVAGE: Yes, and we will have a chance to look
. 2 at the product of that..
3 It's like all geophysical techniques applied in the 4 arena of studying faults. What one gets are geophysical data [
5 which are then processed using very sophisticated computer
, 6 processing techniques, which are then interpreted by 7 geophysical specialists.
8 . And what comes out of that are lines on a cross-9 section or contoured surfaces. The relationship between those 10 products and questions that are of significance to this kind of 11 a proceeding takes another step of interpretation. Simply 12 seeing an image on a geophysical section doesn't mean that
[v) 13 that's an active fault. It doesn't mean that it is a fault 14 that is capable of a particular size earthquake. l L
15 That relates to the integrate,d effort that Lloyd ;
i 16 referred to earlier. .
17 But to directly address your question of what we get 18 across this boundary, yes, we will see some examples shortly. i 19 Tor those of you who are interested in the specifics l 20 of this kind of a survey, the refraction survey used a 10,000 i 21 cubic inch tuned airgun array. It was tuned to long periods, !
t 22 because these airgun sources look'like small earthquakes 23 occurring offshore. In fact, our seismet network last for the ,
r 24 last several weeks been going crazy detecting an airgun survey !
i 25 offshore, i Heritage Reporting Corporation (202) 628-4888 p L
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80 1 We shot once a minute, and extended about 120 2 kilometers offshore, and we were able to see this airgun source 3 off on the far side of the San Lucia escarpment.
4 The r9flection survey, these are the parameters 5 associated with recording the 6,000 cubic inch gun. This gave 6 us penetration down to depths of several tens of kilometers.
- / And you will see a bit later what at least one of the images 8 looks like coming from the depenetration study.
9 (Slide.)
10 Another data set that we have acquired and 11 incorporated recently consists of some selected mora recently 12 shot lines from oil company files, Western and Nekton, and r
(Ks,/ 13 those are again kind of schematically represented here. We 14 felt that we would like to have a better, deeper control on 15 geophysical imagery, particularly in San Luis Obispo Bay and 16 the Estero Bay area, looking at some of the structures that 17 come from the onshore and extend offshore. The Los Osos fault 18 being one in particular that we have looked at in detail.
19 These data are traditional oil company two to five 20 second data. They are not high resolution data. So they do 21 not give a clear representation of young deformation as that 22 deformation may be expressed within the upper sediments in the 23 ocean.
24 MR. EBERSOLE: Tell me your generalized theory as to 25 why these lines run northwest-southeast rather than some other v
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'-(a) 1 1 direction 2' MR. SAVAGE: Why the --
3 MR.'EBERSOLE: Yes, all of them,_the whole. family of 4 them.
-5 'MR. SAVAGE: That's right. Well,'that's actually a 6~ quite fundamental observation, and has to do with the long-term
' 7 . history of not only the San Andreas fault but the evolution of 8 this ontire plate margin.
9 It has been a margin of lateral transport 10 tectonically for tens of millions of years. And this 11 structural grain, the' northwest-oriented structural grain has 12 been established for a long time. It relates to the comment
() 13 14 Lloyd made earlier about these -- these northwest-oriented structures being the preferred vehicles for allowing motion to 15 be accomanodated.
16 MR. EBERSOLE: YOu used the word "grain". To me that.
17 augcested_ slumping into the south.
18 MR. SAVAGE: No, I'm sorry. Grain was in a very 19 large-scale sense.
20 MR. EBERSOLE: I know.
21 MR. SAVAGE: It's a preferred trend orientation.
22 The reprocessing -- Lloyd mentioned this briefly 23 earlier -- was done on records such as these Western and Nekton 24 records, as well as many of the older, the previously acquired L 25 data sets that PGEE has been using and interpreting, to see if O .
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1 by.using modern processing techniques on data that were 2 acquired 10 and 15 years ago, whether we might improve the ,
3 resolution. ,
4 And that resolutio.n has to do with reducing noise on 5 the record, reducing proce's sing artifacts, defractions that may ;
6 obscure our ability to see structure within those geophysical
- 7 profiles, and also to enhance penetration with depth.
8 We would really like to be able to see images that I
9 may be related to geologic structure, particularly faults 10 within the basement rocks. In a nutshell, our reprocessing was 11 vary offective in reducing noise within the upper kilometer or 12 kilometer and a half of these records. And those data have f 13 been -- those enhanced images have been incorporated in our 14 interpretative offort.
15 However, the ability to image in the basement was not 16 enhanced by the reprocessing. That was an objective that we i 17 very seriously tried to achieve, and it in general was not very 18 successful. ,
i 19 (Slide.) l t
20 The last data set I would like to mention is one that
[
21 we have very recently acquired through cooperation with the 1 22 California State Lands Commission. I 23 The state is acquiring data to be used for geohazards >
I 24 assessunts in the event that. i. hero is a leasing of oil leases ;
i 25 in the nearshore region, within the 3-mile limit. And so this i
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2'. And,'again, it.is a high resolution data setJwhich we 3' will using to look in. detail et.the way these' faults extend
.4 . offshore, onshore and offshore area it's called the~Casmalia 5 fault. You will see-that term later on today also, the Lions 6 Head fault. But also the Hosgri fault zone comes within the 7 State Lands limit near its southern termination. And so these 8 data will be very useful in further understanding the southern 9 end of the Hosgri zone itself. '
L .
10 Let me make sure I don't get out of. place here.
11 (Slide.)
12 I would like to move on to a discussion of another i
13 relative -- for PG&E's operation framework anyway, a new data 14 acquisition, an that's the Central Coast Seismic Network.
- 15 To put the seismicity data into a more regional 16 context., here is a map of the California - Nevada area showing 17- earthquake activity located and presented by the U.S.
18 Geological Survey for the years 1980 through 1984. An.d we can
- 19. see represented in both the lines plotted on the map, which are 20 some of the major faults within California, as well as 21 seismicity. That in some cases the seismicity, the micro 22 earthquakes, these are earthquakes greater than magnitude one 23 and a half, and generally most of the events here are in the 24 magnitude of one and a half to about two and a half with l~
l 25 relatively few larger ones.
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1 Well, these little earthquakes certainly show us 2 where the San Andreas 2nd the Kalaveras Hayward fault systems 3 are in central California, and the San Yosento fault, the San 4 Andreas'would be up here, the southern portion of the Whittier 5 Elson fault system. Those are expressed by the location 6 patterns of smaller earthquakes.
7 But there are areas that are not so clearly defined 8 by the -- at least the mapping of little earthquakes.
9 Also, there are certainly large differences in the 10 level of earthquake activity. We see here in the -- along the 11 San Andreas portion of southern California a very dense pattern 12 of earthquakes representing a very high level of earthquake 13 activity.
14 Within the coastal region we are looking at-here, we 15 see a high level of activity along the San Andre'as, a few hot 16 spots of activity here that we will be looking at in more 17 detail, and then a low level of activity in other portions 18 onshore. And'when we get offshore, there is an apparent hiatus 19 in earthquake activity.
20 MR. PAGE. Woody, would you point out the site 21 MR. SAVAGE': Yes, I'm sorry. It is hard to see here.
22 That is the Diablo Canyon site is right at that location.
23 MR. PAGE: I wondered if it was where that little 24 cluster is to the north.
25 MR. SAVAGE: No, that's up at. San Simeon and we will Meritage Reporting Corporation (202) 628-4888 6
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2 (Slide.)
3 Okay, the site again sits right here, and these are 4 earthquakes that we have plotted up for the same time period 5 taken from both Cal Tech and U.S. Geological Survey. And so, 6 roughly speaking, it's the same data set shown in mor'e detail.
7 And one of the important observations here has to .do 8 with the apparent lack of earthquake activity extending in the 9 far offshore area, and a lack of earthquake activity seen in 10 the nearshore area.
11 A very pertinent question was raised earlier about 12 whether these white areas on the fault maps represent places jh 13 where there just hasn't been work done to identify faults, or 14 whether there is a real absence of faulting.
15 In this area here in the offshore Santa Maria Basin, 16 the situation is there, there is an absence of recent geologic #
17 activity. We see that in terms of an absence of micro 18 earthquake activity.
19 DR. SIESS: Excuse me. When a geologist says recent, 20 I have to ask for a transaction.
21 MR. SAVAGE: Okay, that is in the context of seismic 22 sources that are. concerned to us from say a strictly 23 speaking --
24 DR. SIESS: Is recently 1986?
25 MR. SAVAGE: Pardon me?
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1 DR. SIEsS: Does recent mean 1980 to 1986 2- MR. SAVAGE: Well, for a seismologist, that's very
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3 recent, but I was' referring to'the relationship between 4, seismicity in a historic or very recent human lifetime sense as 5 well as geologically recent meaning late Quaternary-6 deformation.
7 DR. S.IESS: Years?
8 MR. SAVAGE: And that would be in the 500,000 to 9 10,000 year time frame.
10 DR. SIESS: I need to get calibrated --
11 MR. SAVAGE: Okay, I appreciate that.
12 MR. EBERSOLE: To what do you, attribute all the blank gh 13 space out there to the left?
p 14 MR. SAVAGE: We vil) see a geophysical cross-sectica 15 here using the Digicon lines. We wil.1 look at a cross-section 16 going through this area here. And we will see that in the 17 offshore Santa Maria Basin, there As an undeformed, and this 18 again in the recent geologic sense the last million years or 19 two million years, an undeformed basin. That basin is bounded 20 on one side by the San Lucia Bank and on the other side by the 21 Hosgri fault zone, and uplifted basement to the east.
22 So this is a real quiet area both seismically 23 speaking in terms of the last -- here seen the last six years l
l 24 and as far back as we have seismic instrumentation to the early I
25 1900s, as well as geologically. This is a very quiet area.
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1- (Slide.)
2 Just to address the other quiet areas seen on'the 3 fault. map, that was in this region here. This is both 4 geologically in a million year time frame as well as in terms.
5 ~o f seismicity, a quiet area. There is very little deformation 6 going on internal to this region. This is a block of granite 7 that has been moved along the San Andreas fault. And while
~
8 there is-a-lot of deformation occurring on its eastern margin 9 and a bit of deformation occurring on its western margin, the 10 interior of the block is very quiet.
11 Yes, sir.
12 MR. DAVIS: It looked like you had a five southeast l 13 of the site, right on the coast _
14 MR. SAVAGE: Yes. Yes, that's a magnitude 5.1-15 earthquake, and we^will see in a few minutes a very detailed
)
16 look at.this area.
17 HR. DAVIS: What as the ground acceleration 18 asrociated with that event? Do you have any feel.for that? ,
19 MR. SAVAGE: Let's see, that event was -- it occurred 20 in 1980,-and it was recorded at the Diablo Canyon Plant site 21 with a few thousandths G. The peak acceleration was a few 22 thousandths G.
23 MR. DAVIS: So you don't know what it was right at 24 the 5 --
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1- measuring: instruments there. This is just slightly offshore.
2 DR. SIESS: - Ek) you remember where the site was'for 3 the Sun Desert plant ~ .
4 MR. SAVAGE: No. .
5 DR. SIESS: It was over in there.
6 MR. SAVAGE: Yes, out in here.
7 .
Okay. Well, we were talking about this figure, not 8 only to set,the background of seismicity data that are used in 9 the project, but also with respect to PG&E Central Coast 10 Seismic ' Network. And that seismic network covers the coastal 11 region from up here near and north of San Simeon, where there D
12 ' is a dense concentration of~ activity. This is the area where, l 13 as Lloyd mentionea, there is the strike slip San Simeon fault 14 appears, and yet there is obvious evidence 4f. uplift on closely ,
i 15 related fault systems. -
16 This is a complicated atructure geologically, and 17 what we see is a lot of compleA ty i in terms of st.iall earthquake 18 activity as well.
19 The seismic network covers down the coastline, past .
20 the plant site to the area of Point Sal, and the 21 instrumentation extends a bit inland as well, and we can see 22 that in this figure here.
, 23 _ (Slide.)
24 When we planned the installation and long-term 25 operation of the Central Coast Network, Jt was with the Heritage Reporting Corporation (202) 628-4888
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.iv ) 89 1 realization that this seismic network was oper'ating within an 2 area that the U.S. Geological Survey already had a seismic 3 network, although a rather sparsely distributed network.
4 ,
And so these two, the Central Coast Network 5 highlighted in green, as well as the USGS stations, seismic 6 graphic stations operating,is shown by the uncolored symools, s ..
7 So you can see that along the coastline here from the 8 Sa,n Simeon area down to Point Sal we have provided fairly dense 9 coverage, station spacing of 10 to 15 kilometers.
10 Just as a point of interest, the area up here along 11 the San Andreas fault is Parkfiel'd where the U.S. Geological 12 Survey has a major research project going to augment their lh 13 capabilities to p.redict earthquakes. There is an active 14 earthquake prediction for a magnitude 6 earthqueke there now.
15 And it's entirely possible, in ' fact, that the amount of 16 instrumentation installed in Parkfield has permanently turned .
17 off the possibility of that magnitude 6 earthquake occurring.
18 (Laughter.)
4
- 19. People at the survey don't talk about it that way 20 though.
~
21 In outline, the seismic network is a very modern and 22 fairly automated design. The data in the field are collected ,
23 using continuously operating systems which both high-gain and ,
24 low-gain, which the data are transmitted continuously via low-25 power radio telemetry to a couple of locations at PG&E's x/
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90 1 microwave. system. And there the data are multiplexed 2 together, entered on the microwave system and transmitted up to
.3 our offices in San Francisco.
4 . There the data are digitized and processed by an on-5 line computer system to identify the occurrence of earthquakes, 6 and distinguish the occurrence of earthquakes from noise
- 7. events. We are not able to distinguish earthquakes for airgun 8 shots, it turns out.
9 And then those data are analyzed using a seismic work 10 station. So we can call up the data on the screen, do our 11 location and magnitude determination analyses in --
12 MR. EBERSOLE: Tell me something. We are picking up l 13 dynamic ovents. Isn't there some correlation of these events 14- with some static measurements of displacements, extremely 15 accurate oneo that are being made now? And do you interrelate 16 the two 17 MR. SAVAGE: Yes, that is another good point.
18 In recent years, well, say in the last several 19 decades, the U.S. Geological Survey in particular has performed 20 a lot of triangulation studies, geodetic measurements which are 21 the static deformation -- of the static deformation sort.
22 Within the last few years, the accuracy of satellite 23 location ~ systems has become so great that it's now possible to "24 in essentially a real time sense measure plate motions using
. 25 what's called very long base line interfermotery.
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'l- 'And in fact these data sets have been influential in 2~ how -- in both the very regional tectonic understanding of 3 crustal deformation within California, but also in particular 4 with respect to understanding the nature of movement along the 5 Hosgri fault sound.
6 In fact, part of the literature review that Lloyd 7 referred to earlier has to do with our keeping track of what 8 people are finding with these VLBI data sets, and geodetic ,
9 analyses. And those -- many of those VLBI analyses are keyed 10 to Vandenberg down here, and using the satellite geodesy it's 11 possible to essentia11y' watch this piece of earth on with-12 vandenberg located, move to the northwest with respect to the gh 13 continental period.
14 MR. EBERSOLE: Do you anticipate that being related 15 when something is going to be released?
16 MR. SAVAGE: In terms-of a possible earthquake.
h i 17 Well, that's definitely a speculative research area 18 that the USGS is addressing now. To my knowledge, there is no 19 definitive ability to make those sorts of measurements in a 20 predictive fashion. It's really a case of doing the research 21 to understand the phenomena.
22 DR. SIESS: What's the rate of movement between the 23 plates?
( 24 MR. SAVAGE: The current estimate for the rate of 25 movement along the San Andreas fault here -- sorry. For the Heritage Reporting Corporation (202) 628-4888 1
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.ss 1- rate of-movement across the San Andreas fault from the interior 2 of the continent to somewhere way offshore here is about 5 3 centimeter per year.
4 .So that's the Pacific plate moving northwest past the
'S continental plate. -
'6 Lloyd, in his presentation, will talk in more detail 7 about rates of deformation, slip rates on faults that have been 8- developed to more accurately' define the distribution of that 9 deformation, certainly to the west of the San Andreas. And-
~
10 that's where our kseping track of those VLBI and other geodetic 11 results are certainly important to understand-tectonic 12 relationships.
) 13 DR. KERR: Five centimeters is a. relative motion.
14 MR. SAVAGES- Yes, it's relative hatween the interior 15 of the conti'nent and way offshore.
16 Along the San Andreas fault, the rate is about 37 17 raillineters a year, 3.77 centimeters per year. So there is 19 some other motion taken up both to the east of the San Andreas 19 and to the west.
20 (Slide.)
21 Well, the Central Coast Seismic Network has operated 22 for more than a year now, and here is a figure showing in a
~
23 comparative sense what we see using this network compared to 24 what we have been seeing using data coming from the Geological 25 Survey O
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1 I think one very important feature here is that this 2 is a general pattern of seismicity that we see, and this is 3 activity recorded from September 1987 to I guess the last event 4 shown on this map is -- it's a week old.
5 The pattern of seismit:ity here is very similar. We 6 see no activity occurring in the near offshore area until we 7 get down to the latitude of Point Sal, and then the activity.is 8 distributed of f to the southwest. just as we see in this figure 9 here. .
10 We see a scattered pattern of very small earthquakes 11 occurring in the onshore area. The most concentrated area of 12 activity is up in the region north of San Simoon. So many of l 13 the same features that we see here, using what, seven years of 14 data, we see in a nine-month period using a much more 15 sensitive, more hiob resolution seismic network.
16 DR. SIESS: How did you pick that time element?
17 MR. SAVAGE: Well, the network actually began 18 operation, we first began reporting data in July of '76. And 19 one can take the view that these things are somehow controlled.
20 But from about that time until September of '87, the level of 21 micro earthquake activity within, particularly within this 22 region here essentially was absent.
23 So we had -- in fact, I was beginning to think that 24 we had another Parkfield problem where --
,_ 25 MR. ROOD: Excuse me. Did you mean July of 186?
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. 94 J-1 MR. SAVAGE: Yes.
2 MR. ROOD: As opposed to '867 3 MR. SAVAGE: Yes, '86.
4 Another Parkfield situation where we had -- as soon 5 as we put the instrumentation in, the earthquake activity 6 stopped. It turns out, unfortunately, I guess that didn't 7 actually happen.
8 MR. DAVIS: Where is the plant on this?
9 MR. SAVAGE: I'm sorry. It's right here, just about 10 at the center of the netserk.
11 hell, just as a quick example of what an earthquake 12 looks like on this network, here is an earthquake that gfh 13 ' occurred, in fact, thia is the most recent event shown on the 14 figure. This is an earthquako that occurred near Piedras 15 Blancas in the San Simeon area right up in here. And it is an 1G earthquake of magnitude 0.7.
1~ This is not as small an event as we can routinely 18 detect with a network. We are still learning how small the 19 earthquake activity can be that we will be able to see with the 20 network. But it's about a half magnitude unit or more below 21 the threshold of detectability that the U.S. Geological Survey 22 has in the same region.
23 MR. SEAVUZZO What are the axes on that?
24 MR. SAVAGE: So what we are seeing here, and we are 25 seeing in the other figure is a time trace of that earthquake.
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1 The. figure I showed before -- I'm sorry, I-was getting a little 2 fast here. We will just put that on as well.
3 ~ (Slide.)
4 This!is~an image taken off of the computer system of 5 what the. earthquake-looked like on multiple stations. And we 6~ are seeing out here, that's the closest station at the top and 7 we are moving out in distance away from the hypocenter of the 8 earthquake. And this fourth station here, the event is 9 entering the noise. We are starting to lose the detection of
~10 the event, and this is about 20 kilometers away from the 11 epicenter'of the earth.
~
12 DR. SIESS: What's plotted there?
f
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13 MR. SAVAGE: What's plotted is time going 14 horizontally, and just an arbitrary time of initiation here.
15 And this is moving. In time, this is the arrival time of the 16 signal.
17 DR. SIESS: What's the vertical coordinate?
18 MR. SAVAGE: The vertical scale is in digital counts.
19 It is not converted to ground motion. These are velocity 20 sensors.
21 DR. SIESS: Oh, these are velocities.
22 MR. SAVAGE: Yes, these are velocities.
-23' VOICE: What is the magnitude that we are looking at?
24 Inches per second or something.
25 f!R . SAVAGE: Oh, I don't know. It's very small.
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2 MR. ROTHMAN: It's probably on the order of 3 mi11 microns or something like that.
4 MR. SAVAGE: Yes. ,
5 MR. ROTHMAN: It's ground motion.
6 MR. SAVAGE: It's extremely small.
7 MR. DAVIS: How can you be sure this was ,a seismic 8 event versus some man-caused motior' ,
9 MR. SAVAGE: Well, there are two quick bases for
~
10 identify that. ~
11 One is that when we locate this earthquake, we have a 12 pretty good velocity model now and can triangulate the
() 13 14 location. When the location comes out to being -- in this case, it was a depth of about 5 kilometers. So that's probably 15 the single most usoful diagnostic feature.
16 Also, as seen in this reporting down here, we have a 17 vertical component. It's this station right here. We have a 19 vertical-couponent record which shows the key wave very 19 clearly. We also have horizontal componen'ts which show a very 20 strong S wave, which is another diagnostic feature of 21 earthquakes as opposed to explosions.
22 MR. DAVIS: Thank you.
23 MR. SAVAGE: That's a summary of the seismic network 24 operations.
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,. 1 the data' analysis elements of_the long-term seismic, program.
2 (Slide.)
3 As Lloyd indicated earlier, we are doing many things 4 simultaneously.. The organization of our presentat' ion here was 5 to give you an overview of the data acquisition _ activities that 6 are occurring, and then to describe the ways in which we are 7 analyzing those data.
8 That will be followed by a discussion of'some of the r
9 interpretations that we are drawing from these analyzed data.
10 As I mentioned kind of briefly before, when we 11 collect offshore geophysical data in terms of say these high 12 resolution geophysical surveys, or the more deeper penetration
(?-)
f
/ 13 -reflection profiling studies, what we get is somethin'g that 14 only a computer can deal with in terms of data analysis. I'm 15 sorry, in terms of data processing.
If That processing is done using parameters and using 17 decisions in parameter selection that are guided by what we 18 would like to L' able to image. And, thus, the image that 19 comes out, the festures that are seeing on these recordo that 20 we then interpret using all of the geophysical and geological L 1
21 skill and informa; ion we have, those images are in a sense 1
22 controlled by whrt we tell the computer to produce.
23 So we have to be very careful to not only make good 24 decisions about how the processing is done, but keep in mind :
t 25 that what we are looking at when we see say a record section i
(
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98 1 profile isn't necessarily an exact representation of the truth.
2 What we have to do is interpret that record using
. 3- multiple data sets, using correlations with geological -
4 information derived say from wells, using regional geological 5 structure information to arrive at a best interpretation of 6 those particular data.
7 Well, when we start off with an analysis of a
, 8 geophysical data set, what we have been doing in the project is ,
9 developing a series of representations of interpretation of f
10 those data. Those includd trend maps which'is a surface map 11 representation of the orientation of faults. That is a 12 particular interpretive feature we are after.
(,)
13 What we have seen with the~Hosgri is just in this 14 older map that ~21oyd showed.
15 ( 31'ide . ) ,
16 This '.c a picking and a correlating of issages seen on 17 multiple lines that seem to fit together in a pattern as 18 represented here.
19 Well, to help understand and interpret the reality of 20 that pattern, we also construct contour and isopack maps.
21 These are derived by taking a lithologic or a stratigraphic 22 interpretation from these vertical reflection profiles, use 23 well data to help us identify which particular lithologic unit 24 or stratigraphic unit we are looking at, and then correlate 25 those from line to line to form both contour maps of the
( .
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4 j) 99 L 1 surface of that particular-stratigraphic' unit, or a' map that 2 'shows.the thickness of that unit. .
3 And the analysis of these maps then will. help tell us 4 about the history of tectonic activity as represented by=she 5 geophysical data, as well as then looking specifically at fault 6 behavior to evaluate the history of movement along particular.
7 faults.
8 Structural sections are these vertical profiles-that 9 come from the geophysical data acquisition with the 10 stratigraphic structure inserted, and then depth corrected.
11 So in order to develop these structural sections, we 12 have to have a very cl. ear idea about the function of --
-f ) 13 'sorry -- the relationship of seismic velocity within. rocks 14 versus depth.
15 Then we can.also interpret these m:11tiple data sets, 16 ejeophysical data sets to identify fault surfaces to try and map 17 in thrso dimensions the orientation and lateral extent of fault ,
18 surfaces. This is an activi~cy that we are just in the process 19 of doing now, and certainly with respect to understanding the 20 behavior of the Hosgri fault is a very important activity.
21 And, finally, we can use the'very high resolution 22 shallow data, both ocean depth soundings corroborated by the 23 very shallow high frequently geophysical data to develop maps 24 of ocean floor topography.
25 MR. EBERSOLE: May I ask a question. l Heritage Reporting ' Corporation (202).628-4888 ,
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2- MR. EBERSOLE: It may be. buried in your terminology 3 and I can't hear it.
- 4. But you seem to be talking about' influence
~
5 propagatipn at 90 degrees to the fault itse1f. 'Is that the 6 predominant worry, or what about prolongation of the fault in 7 the linear direction? ,
o I see lots of faults, so to speak, aimed at Diablo 9 but they never -- you never talk about the ever getting there.
10 I guess I am crack conscious.
11 MR. SAVAGE: Well, I think we all are.
12 (Laughter.)
- 13 We will see some -- a high resolution _ image of these
~('^)g 14 particular features. It turns out, just to respond to your 15 comment here, that while there are geophysically identified 16 -features in the~ subsurface offshore that have tnis trend, the 4
17 trend that's parallel to the imaging of the Los Osos fault.
18 Our onshore geologic work that Lloyd described has precluded 6 19 the recent geologic activity of those features.
20 So it really brings up I think an important point 21 here. With the geophysical data, we look back in time hundreds 22 of thousands to tens of millions of years. And yet what we are 23 interested in is not what happened 10 or 20 million years ago.
. 24 We are interested in what may be capable of happening during 25 the lifetime of a critical facility like Diablo Canyon.
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101 1 So to just see an image of a fault, offshore:and 2 corroborate that, yes, that is a true fault image doesn't meant 3 that it is of seismogenic significance.
4 And with respect to these particular features here, 5 they do not extend onshore, or they don't disrupt the marine 6 terrace surface that Lloyd described, and in fact haven't
. 7 disrupted that surface for approximately the last 750,000 8 years.
9 MR. EBERSOLE: There has been some sort of crack 10 breaker occurrence.
- 11_ MR. SAVAGE: At some point during the history of this 12 coastal region, that's true. And an important thing for us_is
() 13 14 that isn't occurring now in terms of -- in terms of these' structures being --
15 MR. EBERSOLE: Is tha't a different kind of rock that 16 the cracking counters i 17 MR. SAVAGE: You mean in terms of --
18 MR. EBERSOLE: Stops along that curious line.
19 MR. SAVAGE: I don't know. That's a question that we 20 are certainly trying to better understand right now.
21 MR. ROTHMAN: Excuse me.
22 MR. SAVAGE: Yes.
23 MR. ROTHMAN: What you are imaging there is not the 24 sea floor surface, but some depth like'the top of the maya seam 25 or something like that.
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'l MR. SAVAGE: In 'this figure 2 MR. ROTMMAN: In that figure, yes.
3 MR. 9 AVAGE: That is correct. ,
4 MR. ROTMMAN: So those are not faults that are at the-5 sea floor surface.
6 MR. SAVAGE: Yes.
7 MR. ROTHMAN: I think that's important.
8 MR. SAVAGE: Yes. We will see in-just a little bit 9 this region imaged at very shallow' depths using the high ,
10 resolution data. So we are looking'down maybe a half kilometer .
11 o.r so.
12 MR. EBERSOLE: What sort of depth am I looking at
T 13 there, in general? ,
J l 14 MR. SAVAGE: Well, it ranges from near ground 15 surface -- sorry -- near ocean floor surface, in this area here 16 say, within a few hundred meters to depths of maybe a half 17 kilometen or so down in the southern region here where we sre 18 looking through a rather thick sedimentary cover.
19 MR. EBERSOLE:' Okay.
20 MR. SAVAGE: Let me just briefly show a couple of 21 example of the analyses that have been done on several of our 22 geophysical. data sets.
23 (Slide.)
24 The first example, it's a bit hard to see this just 25 seen in a brief viewgraph presentation so I brought the O
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I's / ) 103 1 physical record section here for anyone to look at who is 2 interested, and I'll perhaps just tape it up on this board 3 during lunch. .
4 (Continued on next page.)
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1 DR. SAVAGE: What we have done to adopt as a mode of
- 2. preparation and presentation.of these profiles is to provide on 3 a single sheet of paper all of the acquisition and processing
.4 information. And this will be for a line that extends.with its 5 eastern end just cronsing the Hosgri in San Luis Obisbo Bay and 6 then extending well off to the Southwest.
7 We also present on that same figure an uninterpreted 8 section. This is just one end of that-line. The line starts.
9 here and goes off to the Southwest. And this is an 10 uninterpreted section. And two-way travel time is shown in the 11 vertical scale here going down to five seconds. So we would in
<. 12 theory be able to see structures down around eight to ten es . '
( 13 kilometers deep.
14 Well, in parallel with that figure, we present an 15 interpreted section. This is the eastern end ut the line.
4 16 Here are relatively shallow picks going down to the two and a 17 half seconds which corresponds to about three kilometers depth 18 for the Hosgri fault itself. We see the Hosgri in many, many 19 areas as an expression of the old basin boundary.
20 Here is elevated bedrock on the east. And this is 21 the offshore Santa Maria Basin extending well to the west. And 22 the basis for assessing the lack of deformation within that 23 basin is the thick stack of undisturbed quaternary and later 24 tertiary sediments with that basin. So this has been a passive 25 basin for literally millions of years.
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,/ ; . 105 s.J 1 .Well, the final representation of this interpreted 2 section is shown here. This is a depth corrected section. So 3 we have converted from two-way travel time to kilometers in
!r j 4 depth. And again it is important to realize that there is a 5 lot of interpretation associated with that. This is not 6 something, this conversion to an apparent geologic 7 cross-section is not done casually or quickly.
3 We have used well data such as the wells shown here 9 and a well shown here to enable us to identify which geologic 10 unit s th'ese are. And we know their ages, and we know their 11 extent. So we can correlate the seismic stratigraphy, the .
12 geophysit ally identified stratigraphy, with the real ithologic
()
.v 13 stratigre.phy in the offshore area, and come up with t'his kind 14 of geologic structural representation. So again, this is a
'15 typ1 cal product of the data analysis that would be one of the l ,
16 structural sections here.
17 I would like to go back at this point to the offshore 18 Digicon survey and show where we are at this point with respect 19 to the analysis of those data. Again this data analysis I
20 process is certain an active one within some of the elements of 21 the long-term seismic program.
(
22 With respect to this deep crustal data set, it is 23 also a very active program in the academic community. It is 24 too bad that George Thompson is not here today, because he has 25 been certainly one of the active participants along.with O
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I students at Stanford University, Rice University,-and the 2 Houston Area Research Council, UC Santa Cruz, and people at the 3 U.S. Geological Survey in analyzing data that all of those JL organizations acquired at the same time that PG&E was S conducting the-deep data acquisition effort.
6 A littl'e bit ago, we saw the base map here, the 7 Diablo Canyon plant site. This area, Point Arguello and the 8 ' San Simeon region up here. We saw in this figure the location
~
9 of the PG&E lines which we collected specifically for 10 utilization in this project. .
11 Well, the convenience of having the Digicon 12 mobilization all done allowed HARC and Rice Universities to
13 - collect some additional lines. And.those lines are shown bv
(')
-. ~
14 the dotted green symbols here.
15 Tie survey also collected a line of refraction data 16 onshore using the explosions that we set off. And both the 17 USGS and PG&E had seismic stations, earthquake recording 18 stations, operating during this time period. And so the data 19 acquisition effort combining what PG&E did with all of these 20 other groups is reall'y quite monumental. And it was the reason 21 for the Edge symposium as it was called, the program for 22 reviewing current results from the analysis of these data sets 23 by all of the various participants at the American Geophysical 24 Union last December.
25 There is a figure here in your packet that simply
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1 enumerates the.various activities, the data acquisition 2 activities, carried out by the various participants. And I 3 think that at this point that we will go to slides to show some 4 of the results. .
5 (Slides shown.)
6 DR. SAVAGE: This slides shows a migrated section 7 that ran along what we are' calling PG&E 3 or FLEC-3. You will 8 see that terminology used on these figures.
9 DR. SIESS: What does migrated mean?
10 DR. SAVAGE: Migrated is a data processing' term. And 11 it has to do with an attempt by the computer to take events 12 seen within the data. An~ event would be a packet of energy.
,s
( ,)
- 13 And to geometrically move that packet of energy to where the 14 computer thinks that it came from in a reflection sense. So it 15 is a step in processing these sorts of data to extract an image 16 of a meaningful geo'ogical i structure at depth.
17 This representation here is not something that is 18 easily interpreted, particularly seen in this scale and from 19 across the road. But it does represent some of the major 20 features of this data set.
21 We crossed the Hosgri fault zone which is seen in 22 here. And we crossed this flat lying, certainly in the last 23 few million years, undeformed offshore Santa Maria Basin. We 24 crossed an old fold called the Queenie structure which is an 25 unusual feature this far north within the Santa Maria Basin.
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108 1 Further south, there are more such folds that-are active at the 2 present time.
3 We see within this section old basement structures.
4 Here is an east dipping structural block. It is down dipped to 5 the east. Out here we see the east margin of the Santa Lucia 6 Bank, which is not an exposed basement but en uplifted basement 7 block. And then further to the west, we enter the region that 8 is presumed to be an ancient accretionary wedge associated with 9 subduction within the trench, the ancient trench seen offshore.
10 On this-figure, you just see a little corner of the sediment 11 filled trench that has been sitting out at the slope, at the 12 bottom of this slope for thirty million years or so. ,
I 13 MR. EBZRSOLE: How deep is that vertically?
"hN 14 DR. SAVAGE: This is --
15 MR. EBERSOLE: No, the whole picture.
16 DR. SAVAGE: Oh, the whole picture?
17 KR. EBERSOLE: Yes. [
18 DR. SAVAGE: We are seeing down 16 seconds. Which if 19 you can do the velocity conversion is about 30 kilometers. l t
20 MR. EBERSOLE: IF there were oil there, would you 21 have seen it?
22 DR. SAVAGE: Well, I would not have. I am not a 23 petroleum explorer. But the oil exploration interests is up in 24 there set of entry deposits here. So this sort of data is not 25 :ollected for petroleum purposes.
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, l 1 MR. EBERSOLE: But it might produce it nevertheless.
2 DR. SAVAGE: Well, I am sure that there will be some 3 interest in these very far offshore structures from the 4 petroleum industry.
3 MR. CLUFF: Well, you might want to reference.where 6 earthquakes are occurring in depth.
7 DR. SAVAGE: Let me jus,t go on to the next one.
8- These are a few further steps in both the processing and 9 interpretation of that particular image that we saw previously.
10 These figures are still represented in terms of not and not 11 distance. We will get to a distance section in a few minutes.
12 Buc there are some important features to look at i
/' m 13 here. This is called a stick diagram. And what is done is
.\ /)
14 depict images that may have some geological significance. We 15 see a lot of topography expressed in the upper seccion going ,
16 down two to throa kilometers. We see some images that appear 17 to be alpping to the east. We see some flat lying images. And 18 we see some images that appear to be dipping to the west. What 19 these features are, we at least have not gone far enough in our 20 analysis to really understand in detail.
21 Further to the west, we see another packet of 22 slightly east dipping sub-horizontal images. We see a much 23 more complicated shallow structural environment. And then in i
24 the far~ offshore off the Santa Lucia escarpment, we see another 25 sedimentary basin.
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1 And this is an interpretation of this figure actually 2 using the migrated version of this section combined with the 3 -identification of some deeper structure to. focus in particular
- 4. on the distribution and character of the. sedimentary structures 5 overlying the basement structures.
6 And Lloyd, the next slide, please. This shows now a l' , -7 depth'section going from sea level at the top down to a depth
! 8 of 24 kilometers. So this has been converting using in fact 9 some assumed velocity functions. We do not have good velocity l l 10 data at this point going down as deep as 24 kilometers.
11 And what we see here is that now the Santa Lucia l l
12 escarpreent assumes its real shape. It'is not a 45 degree snW c 4
t l 13 cliff.in the offshore. It is actually a rather substantial 14 slope for an oceanic envircnment, but it-is certainly more 15 gentle than'one sees in the unconverted time section. And we i
16 see this complicated sort of st'.cucture in bere and complicated
- l. 17 structure out here.
18 The question, Lloyd, that you mentioned about 19 earthquake depths. Within both the offshore and the onshore 20 area, we see earthquake activity basically no deeper than 21 12 to 14 kilometers. And most of that activity is concentrated 22 say in the 4 to 10 kilometer range. So we are looking below 23 the seismogenic portion of the crust.
24 The figure at the top here shows a presentation of -
25 gravity and magnetic field data as far offshore as those data o
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v 111 1 have been acquired. The basic features are that we see in the 2 gravity curve, which is the bottom one here, we see these 3 basement highs represented in the gravit'y. The regional 4 _ gravity trend is consistent with a thickening continental crust 5 in the east. So this would tell us that we would probably have 6 some dipping, some structure dipping, to the east on which the 7 crust is thickening. .
8 And the magnetic field data is not really clea,r. We 9 do not know at this point what geological structure that the 10 magnetic field data may be' associated with. It is pretty long 11 wave-length and fairly deep, certainly down in the basement.
12 ,
The advantage that we have with the kind of survey
. [g) 13 that we did with Digicon is that we not only have the offshore 14 reflection profiles, but we shot with air guns offshore and 15 reported those data onshore. So this gives us a. vehicle for 16 crossing the coast line in a fairly detailed fashion..
17 What is shown he.re, and you cannot quite see the 18 bottom legend hare, but these are individual air gun shots 19 lined up in a reflecting profiling sense extending from 20 150 kilometers offset which is out at the Santa Lucia 21 escarpment, the edge of the continental plate, and into near 22 ' the coastline. T;ie station itself is further inland, about 23 35 kilometers inland.
24 So this is the sort of data that we collected with 25 our refraction program. And on the viewgraphs now, I will show Heritage Reporting Corporation (202) 628-4888 -
112 1 the interpretation of those.
2 So here is that.same long distance profile. We 3 looked at the' recordings from the air guns seen at this 4 station. It happened to be called No. 1166. And this is.a 5 rate tracing model that was used to interpret those refraction 6 data.
7 The procedure here is an iterative one. You make a 8 preliminary interpretation, test your rate tracing mode,1, 9 revise velocities, revise geometries, and work to get both a 10 geologically consistent model as well as a model that fits the 11 travel time data for this particular. data set recorded at that 12 station. .
N 13 We certainly took advantage of the far offshore 14 reflection images. We not only looked at our records, but we
- 15 also looked at the records that Rice University and RARC had 16 collected.
17 And I should say that this particular rate tracing 18 model fit very well provided that we accurately took out the l 19 near surface geologic structure, again another use of the 20 combined interpretation of reflection and refraction 21 geophysical data.
22 And that let to what our current working model is 23 here, which again is consistent with what other scientists at 24 the Edge symposium presented.
25 We have an oceanic plate underlying the coastline l
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1 that dips gently to the east in this region. And those 2 reflections-that we looked at appeared to tut. associated with 3' the top of that oceanic plate.
4 ,
To the east, the plate appears to flatten or dip much. _
5 less steeply than it does up here. The actual data that we 6' have go back about to this region'here. So we are not sure 7 that the oceanic plate extends this far east.
8 ,
DR. SIESS: Where is the subduction zone now, or is.
9 there one?
10 DR. SAVAGE: There was'a subduction zone. There.was 11 an active subduction zone.
12 DR. SIESS: But none now?
() 13 14 DR. SAVAGE: But it has ceased.
intents and purposes essentially a static situation.
And this for all-15 DR. SIESS: So subduction on this part of the coast?
16 DR. SAVAGE: Not for thirty million years.
17 MR. EBERSOLE: What is below the plate?
18 DR. SAVAGE: This would be upper mantle material. I 19 am not'sure just where one enters the transition from what 20 would be called continental estenosphere to oceanic 21 estenosphere. But it is certainly upper mantle material below 22 this.
23 So we see here the thickening of the continental 24 crust to the east. The seismogenic zone goes down to about in 25 here. The granitic basement rocks velocities as shown lie to O
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w-114 1 the east of the Nacimiento fault in this area. And we have 2 pretty, solid evidence for the presence of a Franciscan 3 basement, certainly by its geologic exposure on_ land, but also 4 to a substantial distance offshore based on both limited 5 drilling data in this area as well as the excellent fit of the 6 rate tracing model to this particular velocity structure.
7 MR. EBERSOLE: What is'the units of the large 8 numbers?
9 DR. SAVAGE: These are in kilometers per second.
10 MR. EBERSOLE: Velocities.
11 DR. SAVAGE: They are velocities, yes. Velocities of 12 wave propagation within these various geological materials.
() 13 14 material?
MR. EBERSOLE: Is that wh'at characterized the 15 DR. SAVAGE: That is essentially the large scale 16 . seismological characterization, right. So this is the l
17 geological characterization put on top of that.
18 MR. SEAVUZZO: And these are the P wave velocities?
19 DR. SAVAGE: These are P wave velocities, that is 20 correct.
21 So we see in fact below the oceanic plate velocities !
22 typical of upper mantle material in other parts of the world. [
23 So I think that one of the important results of this sort of 24 analysis right now is that we sr.e that we are not dealing with
- l l 25 a very complicated multiple element basement structure. This l
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1 Franciscan basement-is the material that exists beneath much of 21 coastal California.
3 There do not appear to be, at least in this region 4- -here, any anomalous basement blocks or any major changes in
'5 velocity structure that would'be of influence in our 6 interpretations of earthquake causes in this region here.
7 From the standpoint of some of the other groups that 8 collected data during this November 1986 project, there is a 9 . lot of interest in understanding the tectonic relationships out
. 10 here, in unraveling the history'of tectonism and the plate 11- tectonics aspects of this region.
12 MR. EBERSOLE: Do you have a'ny feel for the variation 13 vertically in that picture?
}
14 DR. SAVAGE: Well, there are some general kind of 15 rules of thumb for the temperature variation. In the onshore 16 area, there have been temperature gradient measurements. And 17 the onshore area appears to be sort of normal continental 18 temperatures, not elevated temperatures. And I just do not 19 know about the offshore area. One would expect not to have any 20 unusual temperature regimen there.
21 DR. SIESS: There are two different basement 22 materials on either side of the Nacimiento fault?
23 DR. SAVAGE: That is cor' rect. This is a very simple 24 block model.
25 DR. SIESS: How did that come about?
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1- DR. SAVAGE: It came about by the long-term behavior 2 of the San Andreas f.ault system.
3 DR. SIESS The strike slip? ,
24 DR. SAVAGE: Yes.
5 DR. SIESS: Just moved up from the south?
6 DR. SAVAGE: That is correct. These are basement 7 pieces that have been slid along the San Andreas off this 8 figure. Actually, San Andreas would be'right in here, just 9 east of point six.
10 MR. ROTHMAN: About a year or so ago, some people at 11 the USGS were postulating a low velocity wedge on the coastal 12 side.
() 13 14-What has happened to that?
DR. SAVAGE: Let me-point out where that is. Just a 15 second.
16 (Pause.)
17 DR. SAVAGE: That was an analysis and interpretation
- ' 18 done by Ann Trahue and her colleagues at the USGS. And that 19 was based on their interpretation of some earlier work along 20 this line here. And I guess that what we are looking at in 21 this figure is an interpretation along this line here. If we 22 were to, for the purposes of comparison, just move to the 23 north, what we see, and again according to Trahue's model, is 24 that this granitic basement in part is underlain by a low 9
- 25. velocity zone.
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- Ts ,f 1 Her data did not go out very much further than~this.
2 So we were left at that time with an apparent wedge. I am 3 sorry, I am drawing that too high up. It was down in'here. A :
4 low velocity wedge in this region that had no known westward 5 extent. That was cortainly one of the. issues that we were 6 interested in looking et with these lines.
7 And what we found is that Trahue's low velocity 8 interpretation may well be correct, but that low velocity zone 9 on this line is very localized. It does' not extend to the i
10 coast, and-in fact may not be properly interpreted as a package 11 of low velocity sediments. ,
12 That same feature that could be interpreted as a low l 13 velocity zone does not exist on the southern line. So what we (v') 14 discussed in fact at the Edge meeting was that this appears to 15 be, that her interpretation appears to be some local phenomenon 16 that does not have regional extend.
17 DR. SIESS: Would you help me. If that section is on 18 that lower line, would you identify the Nacimiento on that?
19 DR. SAVAGE: Yes, sir. It is this fault. 5 20 DR. SIESS: That piece there. It is only labeled up 21 north.
22 DR. SAVAGE: The faults do get very complex in here.
23 So this is the granitic basement and the Fransican extends out ,
24 here. Okay. Just kind of noting what time it is here. l I
25 DR. SIESS: We are planning on breaking for lunch 7 Reporting Corporation I Heritage '
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1 about 12:30 wherever you are.
2 DR. SAVAGE: Okay. A third geophysical data analysis 3 that I would like to present to you has to do with the use.of 4 the bathymetry data, the ocean floor topography data. And what 5 we have prepared is seen in part in this figure here. And this 6 is a topographic map of the ocean floor. Here is Point Buchon.
7 The Diablo Canyon plant site is right in here.
8 The area that Lloyd described in terms of marine 9 terrace studies is this onshore region here in part extending.
10 The onshore work extended well to the south and well to the 11 north. So this is a rather large scale map where one kilometer 12 is a pretty sizable portion of the figure.
('N 13 And what we are looking at is, our purpose was to 14 acquire and process'the available bathymetric data which is 15 provided in great pa'rt by NOAAH, but we augmented that data set 16 with ship track bathymetry data, depth soundings.
17 And so our current ocean floor topographic map as 18 shown here is a contour interval of two meters. So that gives 19 a sense of the resolution of this particular map.
I 20 Well, just as one can use a topographic map onshore
~
21 to assess the geologic history of the region and look at the 22 possible fairly recent behavior of faults based on the presence 23 of scarps or oth'er geomorphic features associated with ,
r 24 faulting, we can do the same thing using this map looking at 25 the sea floor.
(
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1 .I should point out that on.this map that there are a-2 number of areas of rather sharp topography that are of just a 3 couple of meters height,to as much as several tens of meters.
4 .And those are emphasized by a bit of shading here. So you can-5 see that there is a scattered pattern of' what we are calling 6 sea. floor scarps. .
l 7 The origin of those scarps and their potential
~
8 significance or relationship to faulting are what we are 9 interested in evaluating.
.10 .Well again, just'as was the case with the onshore .
-l 11 marine terrace studies, it is very important to know where the 12 shoreline was and what its lateral extent has been. ;
) 13 Lloyd talked about ancient shorelines onshore. What i 14 we see here are old s'horelines extending offshore, the oldest [
15 of which was a longstanding sea floor feature that existed l 4
16 about 20,000 years ago, and developed a very wel'.eestablished :
17 seashore.
18 There are younger coastlines shown in the highlight ,
19 as indicated here. And it is important to recall that some of 20 these-scarps them that we see may well be associated with theso 21 shorelines. In fact, there is a coincidence between some of [
22 the scarp-like features and shorelines. You can just see the 23 spatial relationships here. t t
24 Well, the next comparison to make is with the l 25 location of faults as mapped geophysically. And again this is j Heritage Reporting Corporation f
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4 1 ,using the-high resolution geophysical' data. . We are' riot looking _
2 very deep. We want to see the correspondence between fault 3 strands and the presence of these-scarp-like featu'res, these 4 topographic' features on the sea floor.
5 And_what we see again-is some. apparent 6 correspondences. Let me make sure that'it is clear which lines-7_. are faults are here -lSo they are these orangy lines'here that *
-8 are high resolution trend map fault traces. And we do see a
-9 few correspondences. This curved feature here, up here. This 10 locality here and down in here. There are some correspondences 11' between the sea floor scarps and the locations of faults.
12 MR. EBERSOLE: Are you saying in essence that sudden 13 events caused a_ shoreline change?
, 14 DR. SAVAGE: No. I am saying that'we see expressed 15 today as a sea floor scarp could either have been produced by 16 an earlier coastline, as an earlier coastline, or it could have 17 been created by a.recent fault. ,
18 MR. - E8ERSOLE : That is what I meant.
19 DR. SAVAGE: Or it could have been created by erosion 20 along an older preexisting fault.
21 -
MR. EBERSOLE: Well, for the slow moving shoreline, 22 how much is that due to earth movement versus the moveme6t of 23 the sea itself, do you attempt to differentiate?
24 DR. SAVAGE: I am sorry, I am not sure that I' 25 understand your question.
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1 MR. EBERSOLE: Well, the shoreline can change by the 2- water coming up or down, or the earth coming up or down, or 3 both.
4 DR. SAVAGE: Correct.
5 MR. EBERSOLE: Do you differentiate?
6 DR. SAVAGE: Not in terms of this figure.- The sea 7 stands indicated here, the still stands, are derived from sea ,
8 level taken from other areas and brought into this area to 9 identify at what bathymetric leve1~that we should be-seeing 10 that still stand. So that is where the coast would have been .
~
11 eroding.
12 This is again another, data analysis product that can 13 be used to help understand in this case a variety of different
'}
14 erosional processes as well as the possibility of there being 15 active faulting occurring in the offshore area here. Just as 16 we look onshore'for the presence of scarps as one of a number 17 of diagnostic techniques to identify the location of faulting 18 and help evaluate its activity, so we use the correspondences 19 between the sea floor scarps and the presence of shallow 20 faulting as one of the tools to help us assess the presence and 21 level of activity of faulting.
22 We will come back to this figure later on in the 23 discussion, and talk about some of the implications of these 24 sea floor scarps. Well, let me see here, in our data analysis 25 discussion. I think that I am about to be covered with .
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E 1 viewgraphs here..
2 The next section of the data analysis discussion,.
3 let's see, will probably take fifteen minutes or so.
4 DR. SIESS: I think that this is a good time to stop
- 5. then.
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6- DR. SAVAGE: Okay.
.7 DR. SIESS: And come back in an hour. We will recess 8 for. lunch. ,
9 (Whereupon, at 12:30 p.m., the subcommittee recessed, 10 to reconvene at 1:30 p.m., this same day.
11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 O
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,'3 HDR . SIESS: We are ready to continue. I'do not knov
-4 if.anybody looked at your artwork up there during.the break.
5 DR. SAVAGE: Well, it is there for~anyone who is 6 interested.
7 Well, just to get back into the flow here. We have 8 been covering a variety of data analysis topics, and so far 9 have been concentrating on some examples from the geophysical 10 data analysis. .I will not describe in any detail these items 11 of analyzing the. data collected during the geologic studies.
12 Lloyd will be covering a lot of these analyses as applied to
% 13 the area of the San Luis-Gbisbo.
14 So he will be talking about how we have used the '
15 stratigraphic information. And the correlation of certainly 16 marine terraces constitutes one of those correlations. Studies 1
17 of geological materials to establish timing and rate of fault 18 and fold development, and in looking at recency of faulting.
19 And along with timing, the deformation rate of both the 20 behavior of faults as well as fold structures.
21 So I would like to do a brief review of a couple'of 22 seismicity data analyses that we have performed, and then move 23 on into the first of two of our data integration topics. And 24 that will finish my presentation, and then we will go back to 25 Lloyd.
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1 We talked at our last get-together in November of 7 2 1986 about some work that we had completed on the 1927 Lompoc 3 earthquake. This event was an offshore event that occurred in 4 ~ November of 1927, and is certainly' influential in a lot of the 5 decisions and judgments made during the course of the Diablo 6 Canyon project.
7 ,
What we did at that time as of November was to look 8 at long period seismograms at a particularly high quality ;
9 long-term station that is operated in the Netherlands. Since 10 then we have also looked at the regional seismogram data .:
11 recorded in California and Arizona.
12 We compared recordings of not only the 1927 Lompoc ,
i.
13 earthquake, but other more recent and more well understood
{} '
14 earthquakes using a seismograph modeling basis for the 15 comparison. And the figure that you saw last time that 16 represents this technique of developing a dynamic model for the. i 17 rupture associated with the earthquake for the fault plane 18 movement generating synthetic seismograms as those seismograms 19 would be recorded at either a nearby or distant point, and then I 20 comparing the synthetic seismograms with the observed data to l 21 either modify the model, the source model that is being 22 considered, or to finalize that model.
. 23 And based on both the long period data which you saw 24 before, long period analysis, as well as a confirmation using ;
L 25 regional data, this is the source picture that we come up with l Heritage Reporting Corporation (202) 628-4888
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1 for the 1927 earthquake.
2 It had a focal depth of about 10 kilometers. So it 3 was not an unusually deep nor unusually shallow earthquake. It 4 was a. reasonable, a reasonable crustal earthquake. The focal 5 mechanism is' essentially pure dip slip. There may be an 6 unresolvable small strike slip component in the mechanism. But 7 it is basically pure dip slip. One plane dips fairly steeply 8 to the northeast, and the other plane dips at a shallow angle 9 to the southwest.
10 . The seistnic moment is 1 times 10 to the 26th, nine 11 centimeters, which can be converted to a moment magnitude of
. ~ 12 6.6. We went back to examine Gutenberg's notepad data at Cal Tech to take another look at what had been reported.
} 13 14 Subsequently to the development of a magnitude scale in the 15 1930s, what had been noted by Gutenberg and his coworkers as 16 they, reviewed historical earthquakes.
17 And what we found there was that he had noted the 18 surface wave magr.itude of the 1927 earthquake at 7.0. We 19 compared the long period recordings, some'of which you saw in 20 the previous figure, with the Coalinga earthquake in particular 21 to assess the accuracy of this number using a modern recorded 22 earthquake and came up with the same value of 7.0 as the 23 appropriate surface wave magnitude.
24 MR. EBERSOLE: Can I bring up a translational 25 problem. Those last four parameters are a case in point where O
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126 1 you are talking as far as I am concerned to-a closed society.
2 I would like you to put those into other geometric terms.
3 DR. SAVAGE: Okay. The seismic moment is a 4 relatively modern parameter that is used to characterize the 5 large scale dimensions of an earthquake. Just es moment is a 6 moment arm times the surface, that is the same kind of static 7 quantity that is represented by this measurement here. It is 8 the amount of fault displacement times the fault area with some 9 elastic constants in there.
10 DR. SIESS: If I were a nuc' lear power plant, what 11 would it mean to me?
12 DR. SAVAGE: That is where these numbers come in.
13 The magnitude values are values that are used in the ground
{)
14 motion analysis.
15 DR. SIESS: Well, you told me that you were looking 16 for something like foot pounds or whatever. The seismic 17 moment, I think. .
18 DR. SAVAGE: I think that the important parameter 19 here to pay attention to I guess at this point is the surface 20 wave magnitude. This is one of the key magnitude values that 21 is used in developing comparisons with recent recordings of 22 strong motion data, and it is the measure that we use to 23 establish ground motion estimates.
24 MR. EBERSOLE: Is it non-dimensional?
25 DR. SAVAGE: The magnitude?
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1- MR. EBERSOLE: Yes. .
.2 DR. SAVAGE: Yes, it is non-dimensional.
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.It is 3 simply a number.- It is a ratio ac.tually.
4 MR. SEAVUZZO: How high would that number go for a 5; large earthquake?
6 DR. SIESS: It is open-ended.
-7 MR. SEAVUZZO: I realize open-ended, but what would 8 be typically?
9 DR. SAVAGE: Well, the surface wave magnitude scale 10 is generally considered to saturate. In other words, no matter 11 how great the rupture extent for an earthquake might be, the 12 surface wave magnitude appears to become limited at about a
( ) 13 magnitude of 8.5. But that surface wave magnitude is a 14 measurement made at 20 seconds period.
15 Now the moment magnitude is not so limited in its 16 dynamic measurement in the sense that this is intended to be a 17 very, very long period measurement. In this particular case, 18 we are using data that are of periods in the ten to twenty 19 second range. So it is a fairly long period value.
20 For instance, the basic definition of moment being 21 the static displacement on a fault rupture times that area of 22 the fault, this is an unbounded magnitude measure, moment 23 magnitude.
24 MR. EBERSOLE: Does seismic moment have something 25 like an energy release concept?
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(/ DR. SAVAGE: Only generally. One has to make some 1-2 assumptions to convert the energy density along the fault into 3 an energy radiated measurement. But it really is not normally 4 or typically used in that regard.
5 DR. SIESS: I recall hearing Clarence Allen say once-6 that a Richter magnitude had to level off somewhere around 7 11 or 12, because that would correspond to a fault 24,000 miles 8 long which would divide the earth into two parts.
9 DR. SAVAGE: Yes, I think that is prett.y reasonable, 10 a safe maximum magnitude.'
11 And the other magnitude value that was indicated on 12 the Gutenberg notepad was what is referred to as a long period rT 13 body wave magnitude, which was given a value of 7.3.
GJ 14 Now one of the other very interesting issues 15 associated wlth the 1927 earthquake is where it occurred. And 16 as I think all of us are aware, this has been a question that 17 has received a lot of attention using a variety of data sets 18 for the last fifteen or twenty years. And what I have 19 represented here as superposed on our last seven years of 20 seismicity data is a box here of magnitude 7 size that sits on 21 or is in the vicinity of what is called the Lompoc structure, 22 the Lompoc fold.
23 This is the area within which.there is evidence for 24 geologically recent sea floor deformation. There is a large 25 fold, and some faulting that is very young apparent on the sea O
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1- floor'and-just beneath the sea floor.
-. 2 As we have talked!before, this area is very different:
3' than the area 1 west of the Hosgri fault in-the offshore ;
.i' 4 Santa Maria Basin.~ South here, we begin'to pick-'up the 5 presence of~ young anticlines. And'in some ' cases, the presence of faulting at shallow depths in the young sediments.:
7 .
This region here is also the area in which several r
8 scientists have located after shocks'for this earthquake'using.
9 some relative measures of data taken at seismographic stations
, i 10 in the area, in=the Southern California area following the 1927 11 main shock. l 12 -Another important factor is that'this earthquake did.
13 generate a sonom'y, a local sonomy,_which was reported'with wave ,
heights of four to six feet a.ong this area-here, and in' fact 14 ,
15 was being recorded in Helo, Hawaii on the water level meter,
{
t 16 the title meter in Helo. j a.
i
- . 17 So the situation with this earthquake is that l
18 although at this point that we do not have, and I do not know 19 of anyone who has any more definitive location of where the [
20 earthquake occurred, that this is the most likely candidate i i
21 area. There is the presence of deformation of the sea floor. I f
22 That deformation combined with this sort of focal mechanism, a l
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23 vertical fault movement mechanism, would be capable of 24 generating the sonomy that was observed. ;
a' 25 So at least as a working hypothesis, this is the area f O l Heritage Reporting Corporation i (202) 628-4888,, ,
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1 that we are considering te be a likely epicentral area for the 2 1927 earthquake. And this is the mechanism of that earthquake 3 represented in what we call the beach ball representation.
4 Again the mechanism strikes. In this direction, a 5 strike that is parallel to the strike of the Lompoc structure.
6 It is also worth noting that that is a strike parallel to the 7 Hosgri fault zone in this region. One of the differences being at n, rt d rma n, r h o the case 10 along the Hosgri.
11 . DR. SIESS: Why do you not know the location of the 12 Lompoc?
13 DR. SAVAGE: This earthquake occurred just before the 14 operation of seismograph stations in California with good 15 timing to be able to use modern location techniques to locate 16 that main shock. We have used a number of inferential means to 17 locate the event that basically all fit together. But there is 18 not what one would call at this point an absolutely known 19 location. j 20 DR. SIESS: It was enough to get a magnitude, but not- 7 21 enough to get a location?
22 DR. SAVAGE: That is in fact correct.
23 Another aspect of looking at the seismicity data in 24 the area is to assess how well located these modern events are.
25 And apart from the 1927 earthquake in this area, one of the :
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! U l' 1 largest events offshore and along the coast here occurred in 7
2 1980 in the magnitude of 5.1 earthquake.
+ 3 And so we used the data, the' seismicity data in this 4 area, in a procedure to evaluate the accuracy of earthquake 5 locations. And that procedure is called a master event {
l 6 technique, where we take a very recently occurring and very 7 well recorded earthquake and calculate residuals in terms of 8 that particular recent location at seismograph stations on the
~
9 on-shore area within fifty to a hundred kilometers, and then go i 10 back with the station corrections and relocate the earthquake l
11 activity in that vicinity.
12 We have done that process here for the earthquake 13 activity seen in t.his little region here near the Casmalia 14 fault along the Hosgri fault on the offshore. And what we find 15 is that the center of the locations of these earthquakes 16 occurring just west of Point Sal move by'about two kilometers 17 compared to the routine USGS earthquake locations which are 18 shown in thic figure. In fact, at essentially the scale of
~
19 this figure, you cannot see that the locations have changed.
20 In particular, we have relocated the main shock which 21 moved it from sitting out here to being right in the middle of 22 this pocket of earthquake activity. The focal mechanism we
. 23 rechecked with the mechanism that had been determined by the 24 USGS, and it seemed to be just fine, and ' suggested an 25 occurrence of faulting along the slip planes oriented parallel O
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( ) 132 1 to the Casmalia fault, not oriented along the Hosgri fault.
2 We particularly tested how stable the orientation of 3 those planes were to .see if in fact this event really 4 represented movement along the Hosgri, and the orientation of 5 the mechanism seems to indicate that it does not.
6 When we look at these data in cross-section, looking 7 in this case along a direction or view parallel to ,the Hosgri 8 fault zone, so the Hosgri sits on the plane perpendicular to 9 the plane of view here, we see the distribution of activity.
10 Most of the earthquakes occur in the depth rahge of about 4 to 11 9 kilometers. The largest event in the 1980 earthquake is at a 12 depth of about 8 kilometers.
() 13 14 One of the hypotheses that we are looking at in termt.
of' regional tectonic activity in the coastal area and 15 particularly with respect to the Hosgri is to see if there is 16 evidence for the presence of and the seismogenic capability of 17 possiblisti: faulting. And that would be seen in this figure 18 as it has been suggested, that maybe there is a fault that is 19 expressed near the surface here, but that flattens with depth.
20 If that model were appropriate for this particular 21 situation, the flattening would occur at about this depth. And 22 what we see is that 'nese earthquakes appear to be occurring 23 below the level cc that possibilistic faulting. This is one 24 locality along a Hosgri fault zone where we have the ability 25 t.o combine both focal mechanism studies and relocationa to gain Heritage Reporting Corporation (202) 628-4888
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1 another piece of evidence useful to' evaluate alternative 2 tectonic hypotheses as well as fault orientation and fault 3 behavior hypotheses. ,
4 I would like to move on now to a brief discussion of 5 some of the data interpretation activities, and I will do a 6 brief high resolution tour along the Hosgri fault zone moving 7 from the northern termination through the area. I will start 8 with the northern end up here to look at the hear here opposite 9 the San'Luis Obisobo incline here, and look at the portion of 10 the Hosgri down in this reach south of the Pecho fault here, 1
11 and extending down the.Casmalia fault which is this offshore 1 1
12 extension here.
(')
~s 13 And then we have not completed out high resolution 1
14 look down here, but I will make a few comments on the southern 15 extension. -
16 At the previous ACRS meeting in November of 1986, we 17 discussed in quite a bit of detail th'e work that had been done 18 in the onshore area along the San Simeon fault. Lloyd referred 19 to this briefly this morning. And some of the key products of 20 that work was to identify the San Simeon fault as a 21 predominantly strike slip fault as it exista here in the 22 onshore area near the south end of its onshore expression with 23 a rate of slip of a few millimeters per year, and evidence for 24 activity in the holocene.
25 So this is a geologically active fault, predominantly Heritage Reporting Corporation (202) 628 *.888
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1 strike slip moving _it up at not a very high rate, but~certainly 2 a rate that is adequate to provide geologic evidence for 3 ongoing deformation. -
4 Well, earlier today, we saw several difforent kinds 5 of geophysical data that were collected in this_ portion of the 6 offshore area. It is one of the products of our analysis of 7 those data that is represented by the majo,r trends seen in this 8 figure here, and in somewhat less detail the trends along the 9 northern and central portions of the Hosgri fault zone seen in 10 this figure.
11 So what I will mention first, here we see just the 12 very soqthern tip almost out of reach of San Simeon. The 13 Hosgri fault zone, as we are considering it, characterized by
'14 high resolution geophysical data ends at its northern end right 15 here. This is the northern most element of that fault. And .
16 let me see, I am sorry. This is the northern most element of 17 the Hosgri.
18 North of this point not shown on this figure but seen 19 again in the high resolution data passing to the north, the 20 faulting turns to the west and becomes very, very broken up, 21 very disconnected. And we lose the association, the clear 22 association, between thrs Hosgri fault zone as seen in this 23 reach with the edge of the basin, the offshore Santa Maria 24 Basin.
25 To move back to this figure, and what we are seeing O .
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1 is the northern end of the relatively youthful Hosgri fault.
2 When we try to trace the San Simeon fault to the sou,th, we see 3 clear geophysical evidence. We have lines that cross the 4 Hosgri right in the interior San Simeon Bay. And lose the 5 ability to see the fault along the coast here, because the 6 fault is too clos'e to the coast. But we do see a long linear 7 element of coastline up on the east, which is consistent with
- 8. the character of the San Simeon fault to the northwest.
9 We have a lot of detailed high resolution geophysical 10 data within the interior of the Estero Bay, and we do not see 11 the San Simeon fault extending beyond this region into Estero 12 Bay. ,
(,,) 13 What we do see in the high resolution data are two v
14 very key features in the offshore which I think tell us just 15 what is going on with this fault. Here we have a strike slip 16 f ault entering the of f shore and ending somewhere in this regior.
17 here. What occurs in this region are a series of late 18 quaternary basins that are filled with up to a few tens of 19 meters of sediment. The locat!rns of the basins are indicated 20 by these hatched symbo'.s.
21 We also ree within the basin or this basinal area few 22 tens of meters deep a series of small normal faults along which I 23 these basins appear to have formed. The mapping as represented -
24 in this figure is not very detailed. It does not show all of 25 the normal faults that have been identified as margins for Heritage Report ing Corporation (202) 628-4888 .
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-1 these_ internal basins.
2 What appears to be going ont and this is based not on
-just-looking at these particular data.here, but in comparison 4* with'the identification of these-kin'ds of features in many_
5 faults in other areas of the world, what is going on is that 6 there is strike slip movement that is being transferred from 7' the San Simeon fault to apparently the Hosgri fault offshore.,
8 That is the reason for the presence of.this set of quaternary-9 basins and the normal faults'in between.
10 so we have some very important.information about
-11 deformation that is entering into this fault system at its 12 northern termination.
' 13 Looking further down the Hosgri zone then, 14 superimposed on this trend map, this is the high resolution 15 data trend map, we see some of the topographic scarps that have 16 been identified in the bathymetry analysis. And as wo 17 discussed before, some of these do lie along traces of the 18 Hosgri fault, and those faults are shown represented here.
19 As we look along the Hosgri fault zone from north to 20 south, we see that the Hosgri becomes more complex. From 21 essentially a single trace, we see two and in a few three 22 traces weaving along. Some of these fault elements and fault 23 traces appear to end, and new fault traces begin. One case of 24 that is here.
25 Where there is an impingement of faults coming from O
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l onshore to the offshore, we also see in some cases some 2 identifiable features. In one case, the Los Osos fault extends 3 through this area here coming from onshore into the offshore.
4 And we see a small elevated block that is represented by these 5 fault scarp symbols here called 59 meter ridge. 59 meters is 6 the term used. And when we talk about mountain ranges, we
. 7 often talk about mountain 2733, which is the elevation at the 8 top. Well, 59 meters below sea level is the elevation at the 9 top of that block. So that is the origin of this 59 meter 10 ridge term.
11 And this appears to be a little block that is being 12 squeezed in between the Los Osos fault and the Hosgri. And it (v ) 13 may well represent some good evidence for current recent 14 geologic tectonism along the fault in this area here.
15 The high resolution data as used to identify these 16 individual traces does show evidence of late quaternary and 17 holocene deformation. Not at every crossing of every line, but 18 in enough of a pattern to allow us to consider that this is a 19 zone that has been moving in a fashion to reveal itself 20 geophysically.
21 As we go past the site here, we see a little scarp 22 associated geographically with the trend of the Pacho fault.
23 The Pacho fault, as it extends to the east, appears to dive 24 beneath undeformed late quaternary sediments, although there is 25 faulting that comes up within those sediments to a relatively Lj Heritage Reporting Corporation (202) 628-4888
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2, South of about this point hert<, the Hosgri fault zone 3 is seen in high resolution, and dives beneath undeforned late 4 quaternary sedimen,ts. So what we see is a pattern of
{= ,
5 5 youthfulness and possible sea floor expression in this area
" The traces are still 6 that ends es we move to the south.
7 evident and seen further down in the section, but the evidence
! 8 for youthfulness and for recency of movement hss diminished.
9 DR. SIESS: Excuse me. That slide or your left, what J
- t 10 are the green lines?
E 11 DR. SAVAGE: I am sorry. The green lines represent a
[ 12 couple of the normal faults, the small normal faults that exist
() 13 14 between the inferred extension of the San Simeon fault as it it postulated to como down here and end and the Hosgri,
[
k 15 DR. SIESS: I guess that you are trying to convince 16 me that the Hosgri does not connect up with the San Simeon?
= 17 DR. SAVAGE: Yes, that is certainly our 18 interpretation.
19 DR. SIESS: A'nd I guess that I did not hoar what is L
20 supposed to convince me or conversaly, the fact that they jog,
_ 21 that there would have to be a jog to make them connect up?
r 22 DR. SAVAGE: Well, this is a five kilometer wide 23 step-over.
24 DR. SIESS: But why could I not draw the red line 25 where you have got the green line?
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'l DR. SAVAGE: Because the sense of movement-seen along.
2 this fault here is not the same as seen here. The geophysical 3 expression of.these two faults is simply not the same.
4 DR. SIESS: Could you translate sense of movement to
.5 something that I.could understand a little better?
6 MR. CLUFF: Maybe I could address that very quickly.
7 DR. SIESS: Sure.
8 MR. CLUFF: This is a classic textbook of a right 9 'ateral step-over that we see in the faults in New Zealand, and 10 in other parts of California, and in other strike slip 11 environments, where you get a slip coming in this direction 12 here, and a slip coming in this direction here. And when you
,r.,
( ,/ 13 get two segments of a fault system or a zone of weak' ness that 14 is deforming in a strike slip sense, you get what we call a 15 pull-apart or a graven develop. And that pull-apart results.
16 from this shift, and it just forms this down drop block that is 17 being represented here by normal faults and depressions in 18 between. .
19 And that is a classic textbook pull-apart j 20 characterizing the ending of one fault and the motion i 21 transferring from one to the other. So we are using this to l
22 say that it looks like there is a significant component of i 23 strike slip which we feel that we have concluded up here with a l 24 great deal of confidence that is being transferred along this 25 part of the Hosgri fault here.
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$ 1 DR. SIESS: And the green fault is moving out? !
.1 2 MR. CLUFF: This green fault would be faults dipping !
l 3 at an angle. In other words, th'e hanging block is down with 4 respect to the other side.
5 DR. SIESS: A vertical movement? ,
6 MR. CLUFF: Yes, a pure dip slip.
7 DR. SIESS: Okay.
8 MR. CLUFF: In a normal sense.
9 DR. SIESS: And that is due to the graven effect'?
10 MR. ,CLUFF: Yes. It is a localized graven effect 11 that we found in other similar environments develop at the. ends 12 of these kinds of segmented faults.
() 13 14 DR. SIESS: And when the _
offset like that, that means that the energy is not likely to be combined in some way?
1
~
15 MR. CLUFF: Well, we have not finished our analysis 16 and interpretation of this, but this is a good reason.for being 17 able to characterize the end of a slip on a segment of this 18 fault. The Hosgri, as you have seen on this, is segmented into 19 even more finer segments. And this would say that this is l 20 unlikely to slip in a major earthquake any farther than this. ,
21 It is very rare that you get them to jump over that at a great 22 distance.
23 (Continued on next page.)
24 25 O
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~2_ ' mot i on it hi t, e ?!. . I; looked at this -- something's got {to be -
- 3
.3 - straining'.in between. - What's happening f inj between? .
- 4 MR;-CLUFF Yes,.this blocklis'. moving in this c :m .
l 5: . d irect ion. and _ th.is.. block... is :m.ovingl:in th is d irect ion. -
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6- ' Something strange that's' in between ~isiwhat's happening: here.
g 7. MR.-SEAVUZZO:' So you' re talking about~- .there's' a 8' strain- in th'ere,.is'that;what you' re ,saying?
4 9; .MR.LCLUFF: Well,- it's . being relieved by; this pull -
~
10~ : apart baserin terms of the. geometry here. It's a classic 11- . example'of'that. '
'12 MR. SEAVUZZO I' m looking on to the last ' scission.
s
- 13 -I don' tJ know whether those damn -- what's happened 'in- the-i- '; 14 -middle? .Som6thi ng -- is either straining, and building up
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' 15 strain, or Jit's relat ive mot ion.
=
16 M R. ROTHMAN: Well, you-get vertical displacement,
- 1'7 which accommodates some of the horizontal displacement, i
18 - beginning that quadrant is in.the third dimension.
'19L MR. .SEAVUZZO: Well, wouldn' t there be a crack some
' 20 place?
- 21. MR. ROTHMAN: He's showing those two green lines of 4 22 , vertical falls.
23- MR. SEAVUZZO: What's the spot between? It doesn' t 24 at-the end of the San Simeon and the end of the Hosgri are 25 - connected.
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,O 11: MR.. SAVAGE: That's right. You don' t. -- this figure
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x 2- doesn' t :show all of the details of.how this deformation is
^
'3 "accommodated.. These north-south' faults dofturn a' bit-to the 4 north'and serve to accommodate that, basically, thst-strain- -
5' that you' re ment ioning'.
6 .Just as a,last comment here -- with respect to-the 7 . south end of the Hosgri, we' l l be looking.at the state land 8 state we' re expecting in the near future h'ere,-which would help 9 9 identify the behavior of'the southern end of the Hosgri down in 10 this region. There are several hypothes's for Just .whereithe 11 Hosgri goes. Some would carry the fault down towards Point-i
. 12 Arguellot some would carry it in to connect with onshore 13 . faults. - and that's the reason we want to look at the high 14 . resolution data, to better estab.lish or to evaluate how this j )
15 deformation is being accommodated at its southern-end.
16 It's worth not in'g that, _ in a . relat ive sense, it 1 '7 . appears lthat the youthfulness of deformation seen up here does 18 not persist into the more southerly portion of the Hosgri. 'So 19 there's some evidence for a decrease in the rate of deformation 20- along the Hosgri heading towards the southern end of the fault.
21 Well, Lloyd I think I' ll pass the time-back to you.
22 MR. CLUFF: I' m going to very 'briefly now summarize 23 the. integration of a lot of the data, the interpretations that 24 ' Woody has just presented, and leave you with a comparison of 25 that first map, that we showed early on. And then the result.
L
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-143' "y :1- Here is one that I showed earlier this morning that A_f .
.2 ~shows the areas where.we did detailed' trenching studies,7and.if:
..n -
- j -3 : you recall',L I mentioned that we were aiming at evaluating the
-4 iniportance of the San Miguelito fault, saying that'.if..we could-5 find where that intersected variousigeological centers,_it 6: 'would-allow us to characterize that fault'and-as well as the 7- Edna fault, and as well, the Los Osos fault here that's not-8 shown on this map, but I'will show it e little bit later.
~
9 On the other screen I' ll show what we-have found.now, 10 and I want'to be careful in that the last major workshop'that 11 we had with the NRC staff and their consultants and reviewers 12 was last May, and that the story that I will tell here is 13 consistent with the results of that :workshopl and we've done 14 quite a lot more datal hasn' t changed our tentative conclusions 15 yet. It. strengthened some of theml and caused us to look in 16 . greater' detail in some of the others.
17 But I don' t want to go beyond what they have 18= reviewed.
19 But-this map here shows the extent and the importance 20 of these strain gauges that I talked about before, and these 21 numbers that are represented here from Montana De Oro to the 22 north down around the plante, and then into San Luis Bay, and 23_ then into San Luis Bay and then down past Pismo Beach.
24 We have found very useful horizons and things that we 25 can use to characterize the deformation throughout the time 4 Heritage Reporting Corporation '
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144 1 interval that-may have existed.. And the ones represented here 2 Do back as far as-in excess'of 700,000 years.
- 3. Well, to make a long story short, what we have found
~
'4 is that.the projection of the San Miguelito fault into the area 5 on this map here shows that that fault has not disrupted or 6 deformed those wave cut terraces for that period of time, and
- 7. based on that, and other trenching studies and so forth, we 8 have come to the conclusion that the San Miguelito fault is not 9 a potential source or a source -- it's not capable of 10 generating earthquakes.
11 We have come to the same conclusion for slightly 12 different reasons, but on the same basis, along the Edna. fault, 13 and in that detailed look, we found another fault that you-14 haven' t heard much about, other than Woody and I giving kind of
(~j')
g 15 general reference to it, and that's the Los Osos fault, and in 16 studying the region and in looking at some not only marine but 17 non-marine terrace deposits inland, we found the existence of 18 this feature here, that is, the Los Osos fault, and that does 19 show evidence of some multiple displacements in the late 20 quaternary time in the last few tens through hundreds of 21 thousands of years.
22 So we've classified two faults that were previously 23 thought that they might be seismic generators as noti and then 24 we found another one that we didn' t even know was there that is 25 a source of seismic activity based on its geologic evidence.
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145 f 1 And we' re in the process of characterizing that.
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2 As you can see from this map, it's a zone, a highly 3 distributed zone of surface displacements, and it seems to be 4 highly segmented, at least one or more segments in herei 5 another one in herel and another one in here. And this is 6 getting beyond where we have reviewed this with the NRC staff 7 and their consultants. But we have characterized that as a-8 reverse slip fault dipping to the southwest, and what we found
~
9 in lookin at these marine terraces, is these numbers: . 2, . 2, 10 and !we' ve got a lot more observations. There's a consistent 11 trend down to right here, where there is a disruption in the 12 wave cut terrace at that locationi and there had been no 13 deformation in the period of time that is represented by those fl 14 terrace, wave cut terrace and terrace depositsi V
15 This led us to looking at the two disruptions here, 16 the discovery of a fault. we've named the San Luis Bay fault.
17 And this asterisk here shows where that was first recognized.
18 A very minor feature and very difficult to see, and 19 has without going into a lot of detail, has a very low slip 20 rate. I' ll show you the results of our slip-rate analysis, and 21 it is Just barely deformed compared to other faults, like Los 22 Osos and others.
23 And so we see some minor faults here. One at this 24 projection of this, connects we think to a disruption in the 25 wave cut platform there. There's another disruption at this
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3 146' 1 locationi and then some off-shore profiling that we' ve done and
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2 . interpretation of some of the geophysical data, it seems like 3 if that fault does continue -- it could just stop. These are 4 minor faults that come and go, but it might continue out here 5- and in some form either be terminated or be related in some way 6 to the more through-going Hosgri.
7 So, based on the compilation of these data, both the 8 geophysical data,.the seismic geology data, the-geomorphic
'9 analysis and detailed geological mapping, we have concluded 10 that the strain gauges allow us to show that the northwesterly 11 trending Gan Luis Pismo syneline, has not been deforming in the 12 period of time that are represented by those quaternary terrace 13 deposits, up to as much as 700,000 years.
14 So the young folding that is represented in other
(~-}
s_
I 15 parts of the area seems to have ceased some million or so years 16 ago, and this area is being deformed as a kind of a rigid
- 17. block. You reca!I Woody talked about some rigid blocks over in
, 18 herei another one out in therei we seem to have found another 19 one here that's bounded on this side by well-defined, and we' re 20 characterizing that fault now and there is even some sub-21 boundaries that seem to be bounding that are represented by 22 these drainage patterns that would be very minor faults that 23 tend to bound this block behavior, and then the southwestern 24 side of that block, we' re st ill trying to understand, but it 25 seems to be clearly represented by the Hosgri on this one side.
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r o, _g47 ny 3 .o -1 -And then between the Hosgri and then as'we approach
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- ~ 2l the coastline here,-there seems to-be some zones.offweakness 3 .that are; experiencing some very minor rates of deformation 2.
'4. compared to~the other more active l faults in the region.
15 -Let me go to characterizing the1se'ismicLsources..
'6 This is, I think Woody probably showed that earlier. We' re 7 -looking at using source parameters --- develop source parameters 8 using the integrat ion of all of . the data sets that we' re
-9 talking about, characterizing ~the geometry and.then the
.10 magnitude of future events.that we think might occur. based on
-11 what we see and the. pattern that we can see based on the'past, 12 and estimating the size of the earthquake and the frequency of 13 occurrence with those earthquakesi and then while we' re doing _
(~'5 14 this being able to quantify the uncertainty about these
'u) 15 assessments and look at alternative tectonic models.
.16 Now, the comparison that I want to leave you with in 17 terms of the: result, is two maps here. The map on the right is.
18 .the one that-we started the program with, showing faults that
- 19. we weren' t certain -of which ones that were most important for 20 .the project, and the representation here in a relative sense, 21 shows the faults that right now based on the data that we' ve 22 gathered, have some -- show evidence of young displacement in 23 geologic timel and the comparative rate of slip, with the 24 ' largest being the San Andreas being the dislocation about 33 25 millimeters per year, so it's the biggest contributor to Heritage Reporting Corporation (202) 628-4888
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-1 regional seismicity and future events.
)
2 The next would be the range and order of. magnitude 3 less one to ten millimeters per year as Woody Savage mentioned, 4 we' ve been able to quantify the rate of slip at least at this 5 location. We believe it's appropriate to extrapolate that onto 6 the'Hosgri and that's somewhere between one and let's day four 7 millimeters per year.
8 Then, we have the next rate, which would be the Los 9 Osos fault here, and then the hundredths of millimeters per 10 hear which would be these small features here, the San Luis Bay 11 fault and one called the Wilmar fault and the Pecho fault and 12 some others.
13 This represents the current tentative interpretations i
(} 14 that we haven' t fully reviewed with the NRC staff, but I don' t think that's much different from what we presented to them last 15 16 May, although we' ve developed a lot more geophysical and on-17 shore data to help us focus on the important points.
18 Let me conclude by leaving, showing you the 19 conclusions we reached at the last November meeting in November 20 1986. The upper three bullets there show the conclusion that I 21 took off the viewgraphs of that time, and if you just go 22 through those, the on-shore near-shore geologic studies in San-23 Simeon are of value to us in characterizing the type of slip on 24 the Hosgri, sense of slip, near-surface geometry, the rate of 25 slip,and being able to characterize earthquake recurrence and
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1 displacement. ' And we' re going to use that in our final s_,
2 analysis.
3 And'then,the on-shore view physics is helping us 4 . clarify the lateral continuity and segmentation of the.various 5- faults and structural elements, their slip historyl we believe 6 that tney' ll help us understand the down-dip expression and 7 test the other crustal hypotheses or crustal models that have 8 been presented, and at that time, we said that, based on our 9 scope of work, that we have not found any surprises in --
10 identified what we had not included in our early seismic' source 11 characterization.
12 Here is where we are today based on the work we' ve 13 done since that time. And we' re emphasizing data 14 interpretation, leaving to the source characterization, and we
(")'t L- .
15 want to emphasize integration of multi-databases, and analyses 16 that allow us to look at various hypotheses to address 17 . alternative characterization of the area.
18 We haven' t concluded which mocel seems to fit, or 19 whether one model will be the final answer. And we have 20 reached the conclusion that both the San Miguelito and Edna 21 fcc ita a r's not capable, according to the NRC criterion, and 22 that the pismo synchinorium, or syneline trend, has not been 23 subjected to active faults for at least and probably longer 24 than, 100,000 years.
25 And that that block behaving as a block type motion,
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- -1 and.that that block is bounded by the Los Osos on one side and x J-2- a zone of faulting, the largest of which is the Hosgri over on 3 the southwest' in Wilmar, Oceana,-and San Luis Bay faults are 4 minor rates and points of deformation
- along a distributed 5 boundary.
6 And then the Lompoc earthquake we've come to what we 7 believe to be a competent conclusion about its magnitude, and 8 its mechanism, and with a little more work we will be coming up 9 before too long about where we believe the earthquake occurred.
10 So that in a thumbnail kind of brings you up to date 11 on where we are on the GSG part of this whole program, and the 12 next part of this is then to go into the ground motion aspects.
13 DR. SEISS: I thought there was still a question last
(')
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14 time as to whether the Hosgri was vertical or curved?
15 MR. CLUFF: We' re still analyzing and looking at 16 that. Let me say that, as we analyze and interpret the data, 17 we see a lot of reflectors that are both vertically inclined 18 and Just off vertical,and some that are very shallow.
19 The important thing that we' re trying to learn is 20 which one of those reflectors represent faults, and which ones 21 of them are tied to the deeper seismicity in the region. The 22 Listric model seems to be in the ones that have hypothesized 23 these, are so shallow that those Listric faults are not down to 24 the seismogenic depths that we' re seeing in the seismicity.
25 DR. SEISS: Does your ground motion studies take into n
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J 151 1 account'that uncertainty?
2 MR. CLUFF: Yes. As-Wen Tsai will.show, the ground 3 motion-studies have been operated with an assumption that we 4 haven' t told-them-which model to use, and so they' ve been 5 looking at'both sides of that, and his data will show, he's 6 incorporated both reverse slip faults and strike slip faults.
7 DR. SEISS: Okay. Are there any questions for Mr.
8 Cluff and Mr. Savage?
9 Do the consultants have any questions, especially the 10 _ geologists? Go ahead, Mike.
11 MR. TRIFUNAC: I Just wanted to ask, how did you get 12 the slip rates?
13 MR. CLUFF: Oh, okay, the slip rates are based on
~N 14 being able to date these quaternary terraces, particularly, or (d
i 15 other deposits and finding both multiple and indicuvual long 16 term slip rates and shorter term slip rates on a different 17 ages, and then Just calculating on what the rates of 18 deformation have been in those younger geologic deposits.
19 DR. TRIFUNAC: But how did you get the slip rates for 20 the areas that don' t have the terraces?
21 MR. CLUFF Okay, the slip rate that we' ve determined 22 on the San Simeon, we' re assuming is representative on slip on 23 the Hosgri. That's an assumpt ion right now that we' re st ill 24 working on the mechanics of how you do that, and we have young 25 terraces and deposits on along this fault, and here and along q
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1' the Wilmar fault, and the Rinconada, Bert Clemons has just m./
- 2 finished some studies up there where he has been able to 3 characterize the slip on Rinconada.
4 So all of these are based'on hard field data, with 5 the exception of not having exactly the information offshore 6 because of the resolution of both the deposits and the amount 7 of slip offshore?
8 D R. TRIFilNAC: These should be consistent with 9 Seismicity, shouldn' t they?
10 MR. CLUFF pardon me?
11 DR. TRIFUNAC: These slip rates should be consistent 12 with seismicity, shouldn' t they?
13 MR CLUFF: Yes.
('R; ') 14 DR. TRIFUNAC: What did you find, are they 15 consistent?
16 MR. CLUFF: Woody, that's a question to yeu.
17 M R. SAVAGE: There are different kinds of consistency 18 to look for here. Many of the faults shown in this figure are is not very fast-moving faults, and we wouldn' t necessarily expect 20 that a short, historical record would accurately represent the 21 rate of earthquake productive of each of those faults.
22 That's part icularly true -- well, it's essentially 23 true of all the faults that move at rates less than a 24 centimeter or so per year.
25 I think our experience in California where there are
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3 association between the good-size. historical' earthquakes,Eand s 4 those faults. -
5 But there are many' faults in. California that move at 6 Jeates in these ranges, over several orders of magnitude, some 7- of which have evidence of historical activity, and others of
?8- which do not.
m 9 So broadly speaking, the pattern we see of slip rates 10 representing deformation in;the region is consistent with both 11 the historical seismicity' pattern _and even the microearthquake 12 pattern, where we have faults or with reasonable amounts of 13 deformation we tend to get more of a small earthquake --
() 14 15 greater density of earthquake activity, but it's going to take
'a longer period of time than we have now to really clearly 16 establish that seismicity slip rate correlation.
17 -- D R. TRIFUNAC: I don' t understand why. -- I don' t 18 understand why you need more time. You have shown today a; 19 whole bunch of micro-earthquake events that you have --
20 MR. SAVAGE: Those are micro-earthquakes and they 21 accommodate on the scale of things very, very little 22 deformation. They serve to indicate where strain is being 23 released -- where stress is being released due to finer 24 fracturing. They help us understand the pattern of stresses 25 within say this larger region, but the recurrence of a
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(..f 2? represent.the behavior of an earthquaka - behavior of a. fault 3 in a large' earthquake, that-may have an; earthquake as_large as
-4' magnitude six or seven.
'S There;are many faults that are quiescent for a long 6 ; period'of time before they exhibit seismic activity.
7 In fact, the San Andreas, just in the southern corner
[ '
8 of this figure, in terms of seismicity, has been very quiet L
9 since 1857. We couldn' t locate the San Andreas fault using
[
f 10- micro-earthquake activity.
l 11 OR. TRIFUNAC: . I' m not suggest ing that --- I- think you
'12 didn' t quite understand me. I' m asking for consistency --
13 something can be inconsistent and still not disprove a 14 ^ hypothesis.
4( }.
15 MR. SAVAGE: So you are saying for how consistent are 11 6 the rates of --
17 DR. TRIFUNAC: You have seismicity data-in your hand 18 -- it's a short one, but that's all you' ve got. Then you have 19 'here slip rates. Now those are either consistent or not with 20 respect to whether this is a unique and complete estimation.
21 That's what I' m gett ing at.
22 MR. SAVAGE: Well, I guess I would view that 23 generally speaking, this kind of scale, yes, the seismicity is 24- consistent with where we see lots of slip being released.
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G4; :MR.lSAVAGE: ; Wells what we see, for' instance,.here is t5. a st'rong lineation;of seismicity, but the lination=is; ,
- 6 consistent with'a' big fault, but
- the amount of stress'being-7 released by this seismicity. is nowhere accounts for or doesn' t?
, :8 account;for, the kind of slip rateEwe see here.
9- But we also know that there is an historical record 10 of earthquakes including, magnitude sixes in the Parkfield area i t' and magnitude eight earthquakes to the. north and south -- that:
12 do tell us~that, yes, that' fault.is behaving in a fashion ~
13 consistent.with. historical record.
/~Y 14 For the faults in this region here, I-believe we
-Q.
15 don' t have enough, data to argue the consistency ~ that I think l6 ~ you' re _1coki ng for,-to be_able to say, well, these faults, when 17' th'ay have larger earthquakes, will accommodate the slip-that we 18 see on these features.here. If one adds up the rate of slip in 19 the little earthquakes shown on this figure, it isn' t enough to 20 represent the slip rate seen on that figure.
21 DR. TRIFUNAC: Excuse me, your problem is 22 understanding it I' m trying to understand the seismicity 23 curve, log normal, for this magnitude, for a given source 24 region, and I' m not suggest ing that we read off the small 25 events and match up this -- not at all.
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2 of log-log scale, it is either consistent or not, do you follow 3- what ' I' m saying?-.
4- MR. SAVAGE: Okay, now I understand.- In terms of 5 earthquake recurrence within a large region.
6 DR. TRIFUNAC: Is it consisteat or not?
7 MR. SAVAGE: Yes, it is consistent. But it is only
- 8. consistent when one takes a very large area. To take a 9 particular fault and look at the ~1og-N versus M data, no, it 10' does not work.- It does not work.
11 DR. TRIFUNAC It does not work for individual 12 faults?
13 MR. SAVAGE: It doesn' t work well for individual
(~ ') 14 faults. And that, there are some good examples of that, for t/
15 instance, in Southern California, the San Jacinto fault works 16 very.well --
- . 17 DR. TRIFUNAC: Keep the picture -- don' t go off away 18 -- stay here. I' m looking at this picture.
19 M R. SAVAGE: Okay, no. Take that fault by fault, the 20 seismicity data do not tell you.what the frequency magnitude 21 relationship would be that one might derive from slip rates.
22 Which is why, generally speaking, we would prefer to use slip 23 rates as a basis for estimating the occurrence of large 24 earthquakes, rather than taking the occurrence of magnitude two 25 and three earthquakes and extrapolating that up to magnitude Heritage Reporting Corporation l (202) 628-4888
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7c 2- DR. z TRIFUNAC: So how are y'ouLgoing to-use'this?-
3 DR.sSEISS: .Next presentation.
~ l41- IDR.,TRIFUNAC Oh, ' okay.-
5' DR.'.SEISS: 'I think.you read the ground motion.-.
p
, ., 6 DR. TRIFUNAC: You see,.this is the basic-input into ll , 7 this calculation, and it~is not consistent. I mean, how can 8 you --
'9 MR. SAOAGE: We're planning to look at two different 10 recurrence models, what's been called ' the "characterist ic" 11 earthquake model, which is a larger quake, with, again the 12 linear frequency magnitude relationship doesn' t apply very well 13 where there are repeats of larger earthquakes and a paucity of i #~ 14 smaller earthquakes, f f k.)T :
11 5 Or we will try where we feel that we have anL 16 appropriate amount of data to compare this sort of pattern of 17- earthquakes along a fault with the longer-term historical
-18 pattern to look for the' general consistency.
"19 By and large that approach doesn' t work very well.
20 It doesn' t provide a very good predictor. Slip rates appear to -
21 be a much better predictor for the occurrence of large 22 earthquakes, because large earthquakes carry most of the slip 23 along the given fault.
24 MR. MAXWELL: My question could sort of lead in to 25 'what you' re coming into now. Everything we' ve heard and seen
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'and, talked aboutfconcerns'the-geometry of faulting and'the' time ~
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f 70 Ynu isave three very distinct kinds-of rocks in-this
~5~ area, ;the big, . Franciscan mrilangel ~ the selenium block --
s 6 . crystalline rock 1 and locally, the very thick-bedded mainly-
.7~ tertiary rocks.
8 'And it seems to r.de that each of these sequences must 9 .have very different elastic properties that, somehow or others 10 they're directly on the energy and perhaps even on the slip
, 11. mode of earthquakes.
- 12 I just wondered if you'd taken this -- or will you s 13 -take'this-into accounti then you' ve taken it into account and 7"N 14 maybe you can' t take it into account, but'as a geologist, I Q) 15 would like to know.
16 MR.: SAVAGE: Well, certainly, in bulk terms, the 17 Franciscan melange is very different than an unfractured '
1 18 granite. But when we look at fault zones through either of 19: those two materials, to my knowledge, there may not be very.-- ,
20- they' re both -- the fault zones themselves, are gouge zones 21 filled with altered minerals with complicated fractured 22 materials, such that the mechanical properties of the gouge may-23 not be very different from Franciscan to granite.
24 MR. MAXWELL: Well, we' re talking about earthquakes, F
25 though, and there would be other factors on attenuation here Heritage Reporting Corporation :
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,_ 1 too that are very important.
2 .Had you attempted specifically to analyze earthquake 3 problems with respect to these very large bodies of different 4 kinds of rock?
5 MR. SAVAGE: Not in any detail Not in the detailed
- 6. sense that you' re suggesting, to look at, say, the propagation 7 properties of granite right here compared to the Franciscan 8 formation here.
9 Our sources -- the seismic sources that we will be 10 considering in the analyses, are pretty local, and they' re all 11 within the Franciscan baseman. So the impact of granitic-12 terrain _1 na ground motion sense is probably not so great.
13 MR. MAXWELL: When you feed this information into 14 what I assume you must, in this soil / structure interaction,
{a')
15 fragilities, and so on, is it cricket to use the data from all 16 kinds of faults in that as compared to -- and then say that's 17 what is going to happen in this mainly Franciscan sequence, I 18 guess that's --
19 MR SAVAGE: Yes, that's a point that does need to be 20 argued. The case needs to be made for Justifying that.
21 DR. CEISS: Yes, Ben.
22 MR. pAGE: I' d like to mention something that Woody 23 alluded to earlier, and that is the revised estimate of 24 relative plate motions which is relevant, I think, to the H25 activity of fault along the coastal strip. About a year ago
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q 160 i the relative _ plate motion was revised or at least1 postulated to 2 be revised by Mitz, Gordon, and one other person, and as Woody 3 said, I think he said that the relevant motion now seems to be 4~ on the order of'4.8 centimeters a year.
5 Whereas, say three or four years ago, the common 6 wisdom was, the Ocean was about 5. 7. So it stopped by'nearly a 7 centimeter a year. That is to say, in all the faults to the 8 east of the San Andreas, and all the faults to the west of the 9 San Andreas, collectively only have to account for one 10 centimeter a year, if the recent calculations are valid.
11 So that, I think, lends plausibility to the rates 12 shown'here on this map. For instance, the green being one to 13 ten millimeters a year. According to these recent figures, it fT
%)
14 coul dn' t be greater than that, because the relative plate 15 mot iori doesn' t permit that.
16 Of course-this is assuming that all the latest 17 research is accurate.
18 MR. CLUFF: Thank you, Ben.
19 DR. SEISS: I have some recollection that you said 20 that several years ago, Ben?
21 MR. PAGE: I said something qualitatively like that, 22 but at that time the plate motions were much higher. I think 23 at that time they were six centimeters a year. Luckily, 24 they' ve been diminishing instead of increasing.
25 DR. SEISS: Other questions? Okay, Lloyd, go on to o
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161 1 the next part.
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2 MR. CLUFF: The next part of our program is the'next-3 element, the ground motions. I' m up here with Ben Tsai of 4 PG8E. We' l l make that presentation. Ben?
'5 MR. TSAI: My name is Ben Tsai. I'm a seismologist 6 on the pG&E staff working on the mountain seismic program 7 ground motion element. As I reported -- well, my job today is 8 to report to you the progress we have made since last meeting 9 on the ground motion area.
10 As I reported to you in the last meeting, the ground 11 motion studies within the mountain seismic program has two main 12 objectives. The first is to update the ground motion ,
13 assessment of the sitel and the second is to provide specific
/^')
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14 ground motion data for engineering analysist and to achieve 15 this objective, we need to make use of three sources of data.
16 One is an updated slow motion data base corrected 17 worldwide. The second is to use the information and data 18 derived from the geology, seismology, and geophysics element of 19 the program as you have heard earlier to date.
20 The third source of data to be used is the existing 21 ground motion recordings acquired at the site through the 22 years, and for this program.
23 To make use of this data we use both empirical and 24 numerical modeling methods.
25 Now, my main presentation is to give you a report on s/ Heritage Reporting Corporation (202) 628-4888
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'l the current status of the ground' motion studies, which include L._)
2 empirical studies, numerical modeling studies, and the 3 assessmert of special incoherence at the site, and the last one 4 1? the --
5 DR. i' ERR: Excuse me. This morning I asked about the 6 distancer. -hat go in or' numerical modeling method and something 7 else, ar d mention was mede of "numerical" and "empirical."
8 Now, I gather that the difference is that an 9 empirical study is empirical and a numerical study is semi-10 empirical? Is that -- an appropriate characterization?
11 MR. TSAI: Well, in this program, "empirical" can be 12 translated as real records, actual records. And "numerical" 13 meant to say that the ground motion estimate is based on
()
v 14 modeling -- numerical modeling, which has some empirical bases, 15 but also uses currently acceptable theoretical understanding.
16 DR. KERR: That makes it more clear.
17 MR. TSAI: Thank you. The fourth area I would like 18 to you is a summary of the ground motion data provided up to 19 date for engineering -- that is, this second objective of the 20 ground motion studies, and I will come back to this later on, 21 on each of these. I will start with the empirical studies.
22 For this presentation, I will show our compilation of 23 an updated slow motior, data base, and I will also show you some 24- examples of the environment in terms of peak ground oscillation 25 and spectra oscillation attenuation relationships, and also we r~
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, , 1 have done some progress to make site-specific ground motion 2 characterization to achieve the first objective.
3 This chatt will summarize what we have compiled in 4 that data base. It is that corrected records from 47 shallow-5 focused earthquake sites worldwide ranged from 4.6 to 7.4, and 6 the closest distance to the pohl-Roger surveys range from very 7 close to the board or 300 kilometers for peak values, and up to i' 8 about 50 kilometers for the spectrum values.
9 Those ratios are mainly recorded on rock or rock-like 10 site. And the total record available at this moment is 154 11 bore peak values, and 65 for special oscillation.
12 This is a list of the earthquakes, corrected, and it 13 is in the high mount of -- by the way, all the materials I am
~
() 14 reporting are contained in the written progress reports mailed
\_;
15 to you before the meeting, and the three separate progress 16 reports.
17 This is what we call a scatter diagram to show what 18 data are available for peak values. The horizontal axis is the 19 C 3 and the vertical axis is the C 3. So both of those 20 data reside in this area, between say 10 Km to about 100 Km and 21 mostly with C 3 of 6.5, whereas our main interest is in this 22 area and relatively few data or recordings are available, and 23 therefore, this is one of the main modifications that we need 24 to use empirical modeling on to make up this lack of 25 recordings. ,
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164-i MR. MAXWELL: You plotted that as a graph. Is there
'~
, 1 2 any relationship that theory would say these two factors should
!- 3 exhibit? I mean, should this be a straight line or a curve, or 4 is it Just a map?
5 MR. TSAI Yes. There are some relationships. For 6 example, for a magnitude lower than five, it is simply too weak 7 of a ground motion to be recorded.
8 Now, for say, a distance between what would be 100 9 Km, smaller earthquake would not be recorded. Now, for lack of 10 recording in this area, where there are not so many large 11 earthquakes, and also there are often not instrumented, in the 12 case of those.
13 MR. MAXWELL: Excuse me. I think you missed the t' 'i 14 questions the question was, was this simply a map, or should
-b/
, 15 we try to draw a line through these?
16 MR. TSAI: Yes, this is simply a map. A diagram 17 showing the availability of the records.
18 MR. MAXWELL: Thank you. Tlie range?
19 MR. TSAI: The range, yes. Thank you. And to a 20 related amount or quantity is this spectral data available in 21 our data base.
22 We then use this data base to look into the peak 23- value and spectrooscillation regression, or activation 24 relationship. And we use standard regression function of 4, 25 and take two states to determine the co-axes. First we do e,
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3 .when this question is determined, theniwe go to'the second 4 istate, use the whole set;of data, and_.let the parameters be 5 ~ determined byfthe exact ~ situation. !
.EF _. ~DR..KERR: You mean, 'after plotting the graph, which i
7 shows that ~ there really isn' t any fixed relationship between
~
8 magnitude and distance,1'you now set'up -- you ask-the'compv.ter 19 to find one? '
l 10 DR. S ISS: No, no. -This is PGA. Magnitude'and' ~!
11 distance are on.the right. j 12 DR. KERR Okay.
- 13 M R. TSAI: -Yes, This is the distance, R, and this is j i
(} 14 15 the magnitude, and on the left is the PGA.
DR. HERR Okay, there should be. [
16 MR. TSAI: And:this is one example over how that [
17- configurat' ion compare with the data points. On the horizontal. ]
18' axis.is the distance measure from this recording side to the 19- closest point of the ruptured fault studiesi here the vertical, 20 axis is the peak oscillation in C 3.
21' In this particular example it C 3 to 615. In the ,
22 data, points went from 6.3 to 6.6, and for the relationship is i
23 meant to represent the reverse or stress poles. You can see j e
. 24 the southern curve is median whereas the hatched lines are I 25 plus-minus one standard deviation and two standard deviation. f i
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2 you give them a' solid line? .Or is this --
3 MR. TSAI: Yes,that would be the mean, yes.
4 Operative.
5 MR. SEISS: Okay.
6 MR. TSAI: And so the estimate in prcving the best ,
7 estimate and dispersion about the best estimate,. We use quite 8 similar function of form for the SA -- spectral-acceleration 9 attenuation relationship regression.
10 Whereas here, we used three state procedure. First 11 as mentioned earlier, we first find out the pGA attenuation 12 relationship, and then for spectro-acceleration, we use the 13 normalized parameter SA over pGA for our dependent regression 14 parameter. And then we combined these two to get the absolute
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15 spectro-acceleration.
16 Again, the regression result also shows this 17 discretion.
18 This is one example for magnitude 6.5, and for a 19 period .18 second, that's about 8 hertz, for 5 percent bend 20 gain, and again, you can see the data points compare with the l 21 regression withrut a median plus-minus standard deviation 22 whereas the data point is out to 50 kilometers.
23 This is for another period of frequency of 4 hertz, 24 around 4 hertz, a similar amount, and this is then for 6 25 frequencies.
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-41 .Beside specific criteria,'we have'been referred to-as.
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. 7. -Among these four criteria, threeLof.them will be 8- determined by.the GSGS studies. . The Geology.and: Geophysical-
, <t p 9 . seismologist study in terms o*' magnitude distance, this is 10 related to the location and extent of the seismogenic' source, 111' and alsoLthe style of reporting. -i
.12 The fourth element is related to the site 13 conditioning, and in our case, we classify it~as'a rock site.
14 These are geology, site geology, and shear wave, but I will' ,
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15 save that for the final. 2
~16 Now, then we divide out a procedure, or actually use l
- 1 '7 two approaches, to make the estimate and for one of the 18 procedures we use a working :rnodel with regard to.this full 19 criteria to complete the development of the procedure.
l 20 MR. TRIFUNAC: Going back to the, specs on two or 21 three. I' m not sure I understand -- does the direction come in 22 only for pGA7 Or is the configuration basically different in 23 different period ranges in SA? ,
25 MR. TRIFUNAC: Do you understand wha +. I mean? I
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- 4
- MR. .TSAI:' 'Well,-thiscis?then for'different. periods.
' 5 LMR..TRIFUNAC . ~ Yes, . yes. ThatLis only a factor
~6' saying-how much bigger or smaller.SA is relative to PGA. So 7 the whole spectrum has'the same attenuation equation.-
.8 MR. TSAI: Now,this allows.for_different 9 amplification for different' periods.
J+'
V;- 10: MR. TRIFUNAC: Is CN upstairs different_for different ,
p 11 periods or not? You see up on the-top?
12 MR. TSAI : No, this is fixed.
13 MR. TRIFUNAC: But-there is only one attenuation l']
\.-
14 : equation. <
15 MR. TSAI- We allow for this one, let's see, this one. I 16 and this one, to be determined. And that is based on we have j
. 17 devalued the most rock-site and soil-site data-to see that 1 18 within about 50 kilometers, the spectra shape is'relatively
.15F constant. It's not sensitive to the distance and magnitude.
I l
20 In particular for magnitude higher than six.
21 DR. TRIFUNAC: There is only one C for every --
22 everythine, right?
23 MR. TSAI: Right. And for this particular work, we i 24 nearly have two approaches. Traditionally, you derive site-25 specific response spectrum or ground motion of peak values from ,
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2 relatively crossed to an extended source and where a relatively 3 small amount of data is available.
4 .Now, if we soley rely on this, we essentially will
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5_ rely on observations made at a distance smaller magnitude to 6 project for our-side in terms of closer distance, higher 7 magnitude. And so then, I think that there may be an 8 alternative approach, and that is, we go direct-through the 9 recordings. Whole recordings of the magnitude and the distance 10 range which are of most interest to us, and in this case, we 11 limit our magnitude to about 6.31 distance within 20 Km and 12 with slag or rock site and used a smaller member of soil site 13 outer adjustment for this particular purpose, and at the
(} 14 moment, we make the assumption that the style report wil1Jbe 15 equally likely between strike state and reverse.
16 Now, I will talk about this part, and this is direct 17 result from the graduated relationship I just had shown you a 18 few examples earlier.
19 Okay so, since we need to determine the median and 20 dispersion, we need to have relatively large example of 21 records. And here is a diagram showing what our variable 22 recordings at rock site within a hundred Km and at about 6.3.
23 And after looking at this diagram, we found 13 records. And 24 that means we have 26 compliments.
25 And from that we heard that it's not quite large
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10' quota of 18 records msinly ranges from 6.3 to 7.41' distance 11 from 3 to 20 Km and total of 18 records under the_ survey. Of r i
12 s'x i components, five of them are from: soil records.
13
.You recall that for site-specific spectra estimate, l,( { .14 one uses a single magnitude, single distance and designated 15 style brought'in, whereas_the records range from different :
16 distance.and deferent magnitudes, and in some cases as soil- J 17 site condition, therefore, we need to adjust them to I i
18 approximately a uniform or single criteria, a single, single t
-19 set of criteria and so we have accomplished-this, and we need-20 to make a magnitude adjustmenti distance adjustmenti and site l 21 condition style brought i n, j 22 And those adjustments are documented in the written j j
23 report. I would just show you one example of the magnitude and 24 distance adjustment. This is normalized for a distance of 4.5. t 25 That's the distance for the present exercise. We pix a :
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r's 1 distance as 4.5 kilometers and for magnitude 7, this would be
- k) In other words,1f-2 the adjustment factor in individual records.
3- .the record was obtained at_10 kilometers, we would adjust an 4 upward to get an equivalent motion of 4.5 Km for magnitude, if 5 the record'was from a 7.5 in actual case 7.4 earthquake, we 6 were reduced that to this point for the 7.0 magnitude, and so 7 forth.
8 So there is three adjustment. One is magnitudel 9 distancel style of reportirijl and then for a smaller number of 10 five records, we adjust for site conditions.
11 MR. MAXWELL: But that means that the shape of.the 12 spectrum is not deemed to be definable?
13 MR. TSAIt Yes. For adjusting from soil to rock
(} 14 site, both the peak value and spectral shape, are adjusted.
use that frequency dependent upon spectrum adjustment.
We 15 16 MR. TRIFUNAC: I thought you just showed that 17 diagramming to be the previous viewgraph which has a 18 coefficient which you opted by or diminished the record, by a i
19 constant number?
20 MR. TSAI: Yes.
21 MR. TRIFUNAC: So that would mean that you are making 22 a correction which is assuming then that the spectra do not 23 depend on magnitude -- the shape of the spectra?
24' MR. TSAI Yes, on rock site or magnitude.
I i 25 MR. TRIFUNAC: Rock site to soil site donsn' t matter.
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- 2. M R. TSAI Yes. For a magnitude of about 6 or 6.5.
3 For smaller magnitude or low frequency part is dependent --
4 apparently dependent on the magnitude.
5 MR TRIFUNAC - So you develop like an average factor?
6 MR. TSAI: Is this -- for the site adjustment I have 7 a table here. Yes, this is the adjustment vur made for between 8 rock site and soil site.. The ratio of rock site and soil site, 9 you can see umbrification at a high frequency range, and the i 10 umbrification and low-frequency range.
11 MR. TRIFUNAC I' m thinking just about five inches no 12 facilities sites.
13 MR. TSAI Okay, the main view --
14 MR. TRIFUNAC: Just one adjustment?
}
15 MR. TSAI Yes, peak. With peak, adjustment for peak 16 value, and then constant shape for magnitude.
17 MR. ROTHMAN: Ben, you've been showing studies that 18 you' ve ' been doing for horizontal components of ground motion.
19 Are you doing equivalents for the vertical component to ground-20 motion?
21 MR. TSAI: Yes. I will not be showing you as much in 22 terms of ground -- vertical component as horizontal component.
23 MR. ROTHMAN: You' re doing equivalents?
24 MR. TSAI I' m doing a concurrent study, yes.
25 And then, for the current exercise we make two rh k_) Heritage Reporting Corporation (202) 628-4888
m 173 1 estimates on this, the spectrum one is the peak valuel the
)
2 other one is for a band, a frequency band, which has the 3 highest umbrification, and in our case, for the present case, 4 we pick an average between 3 and 8.5 hertz, and that compared 5 to other practices it's relatively close to what has been done.
6 MR. SEISS: Excuse me, I looked at that, and I did 7_ look at it before I came here, and I wanted to say, thank pG&E-8 for sending me all that good reading material. But I could 9 easily see how you picked 8.5, since it fell between 8 and 9,.
10 but I couldn' t figure out why you picked 3, except that it was 11 a nice round number, and everybody else had picked numbers like 12 2, 2. 3 and 2.5.
13 MR. TSAI: This, at the beginning was more or less
[') 14 prescribed by our engineering part of the program. Maybe Bob v
15 would want to respond to that?
16 DR. SEISS: It didn' t have any relation to what 17 people did before? Mr. Kennedy told you to take three and you 18 took three?
19 MR. KENNEDY: Basically, what records that were 20 associated with close-in recordingst higher magnitudes, on 21 rock-like sites, looked at the spectrum case from those 22 recordings and found that some of these high amplitude 23 recordings tended to start knocking off, to start deceleration 24 at around 3 hertz.
25 So this was an average shave based on a few
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174 1 recordings,.early in1the project.- ~I think the' shape has
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2: changed"dubsequently.
L 3 DR. SEISS: Bob, will you come up a little farther 4' ' h ere?. They can' t' hear you down- there.
5~ MR. KENNEDY: This was an average shape based on a 6 ~few recordings that'were< selected earlyLin the program by 7 Professor. Seed and myself, primarily. The recordings that'we-B. -. looked at were primarily-for Clamberdown, Toboz, and a couple.
9 others. This shape here is -- subsequently we have developed a-10- phenomenal shell more site-specific, spectra shapes for these-11 high-ground motions, both these shapes do start to drop off 12' pretty much like-this one does, at about 3~ hertz and tend to 13 have their highest amplitude in the 3 to something in the 8 to
(' 14 9 hertz range, and frankly, the 8.5 is Just half-way between 8 N
15 and 9 hertz?
16 DR. SEISS: Don' t say it drops off like that, because 17 that one doesn' t drop of f unt il 2. 5.
18 MR. KENNEDY: Well, it's supposed to drop of f about 19 three hertz, is where we have that drop off.
20 DR. SEISS: Thank you.
21 MR. TSAI: So this is schematic shaving ratio and how 22 it is then in the visual spectrum where you pick the pGA value, 23 and then average over this frequency band for each spectrum and 24 then come in the medium and 84 percent high, 16 percentile, and 25 so forth.
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a-i kl 175 37 3; 1: -And this is the result of that exercise showing-for
-QJ qp 2 ;slightly earthquake medium' spectrum,-thatJfrequency band is 3 1.07G, . 55G for ' pGA and 1B44 percen'E and 60 percent ' nigher,.with _ j T4 -respective-shown in the picture,' andlfor equal i probability of' I
. -5 strike slip and reverse fault-ins, we adjust 10 percent'of :
6 upward and_that will give us 1.85 G for the 84th_ percentile and 7 1.18 G. for'the median at .75 G for the-16th percentile. ,
8 And compare those numbers with direct. regression of 9 _the_same conditional that is, the same criteria of 97, 4.5 KmL i 10 rock and'a mixture of side slip and reverse, one can see.for 11 median 1.18'and one averages over this distance-frequency band, ,
12 one will get 1.33 G, and so forth.
f 13- So after this exercise, we felt that the approach l j (}' 14 that we were taking is reasonable, and we-believe that it is 15' more direct. t I
16 MR. TRIFUNAC: Excuse me, at the expense of confusing [
17 myself many, many times, you are relying on these numbers that [
r t
18 you' re talking about log-Normal distribution functions?
19 MR.TSAI Yes.
20 MR. TRIFUNAC: Have you tested whether the data you
~
21 have admits using log-Normal distribution?
22 MR. TSAI: It's not that -- we do not have enough ;
l 23 data to test that particular dispersion.
24 However, recently, Everett Humpsett of Municipal (
i 25 Creek, and now in the industry, used a small one irradiator, {
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1 where you have repeated recordings at one single station with
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2 -repeated earthquakes, and he and others that show that log-3- Normal distribution is a reasonable approach.
4 MR. TRIFUNACI- _For what, for spectra, or for --
5 MR. TSAI: In his case, it's for pGA.
6 MR.- TRIFUNAC: Yes, but' that's a oifferent thing.
7 MR. TSAI: And of course spectrum --
8 MR. TRIFUNAC: You are not looking at spectra here.
9 MR. TSAI: For spectra, at'the moment, I am not aware 10 of any independent study for that particular aspect, but from 11 the data we have in terms of this spectra shape, we feel that 12 log-Normal for the moment is a reasonable approach. Of course 13 the dispersion are different between pGA and Spectra value.
^
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U 14 Different frequencies.
15 MR. TRIFUNAC Would you use some other than log-16 Normal distribution if you were convinced that the log-Normal 17 does not fit the data? I mean, the log-Normal does not feed 18 the data when you take a large data sample. Wouldn' t it be 19 reasonable to suppose that it might not be the best thing to 20 have a small data sample?
21 MR. TSAI: If the data size shows that trend, then of 22 course, we need to consider that possibility.
23 DR. SEISS: If you didn' t use normal, what would you 24 use? What choices do yon have? Do you have anough data to get 25 the actual distribution?
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177 1 MR.'TSAI: No. And we haven' t tried that because 2 we're using state of the art approach, and up to this point, 3 most work is done based on a normal approach.
4 DR. SEISS: Excuse me, before you take that down, I 5 thought the last thing you said before we started asking 6 questions was, if you chose the statistics, the lower value, 7 .there were two choices there.
8 MR. TSAI: Yes.
9 MR. SEISS: What was the basis for choosing the lower i 10 of the two values?
l
( 11 MR. TSAI: This one?
L 12 MR. SEISS: I thought yon said that, on the basis of
[
I l 13 what you' d done, you had decided to go ahead using the I
(} 14 statistical basis rather than the regression curves?
That was our purpose, yes. At this point 15 MR. TSAI:
16 of the time. Of course, the final choice they will be based on l
l 17 the result from GSG in terms of magnitude, distance, and style 18 of reporting.
19 MR. SEISS: I' m sorry, you have two methods and they
! 20 give different answers by about ten percent. Why did you f
l 21 choose one?
22 MR. TSAI: Our preference -- I must say, our 23 preference is not based on the number we got, but on the 24 approach itself. We believe that the direct analysis of near-25 figure slow motion recordings give better representation than
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178 3,'^s1 1 say you use regression results, which are weighted more for v
2 more distance,; smaller earthquakes. And it's this great 3 spectral points, they' re based on that ground, not on the 4 numbers. It Just so happened that the numbers came out-lower.
5 Now,. I would then move to the numerical modeling 6 studies, first where it explains the development of a method we 7 call "semi-empirical simulation" method. And then I will show 8 you how this method was calibrated, and then I will show you 9 some of the preliminary accumulations.
10 Now, the purpose of the numerical simulations'for l-11 this program.are two-fold. First is to generate realistic 12 oscillation time histories, for engineering analysis, basically 13 to supplement the empirical records.
I~)
'wd 14 The second purpose is to perform sensitivity studies 15 on ground motion characteristics at the side with respect to e
16 those characteristics, propagation and site properties, which 17 may hcve some range of uncertainty and we need to perform the 18 sensitivity, the various sensitivity studies.
19 Now, the result developed for this particular so far 20 are actually three methods. We have first used an empirical 21 g reen' s function summation method, and the result of that was 22 reported to you during the last meeting in terms of developing 23 a sweep of time histories for earlier fragility analysis.
24 Since then, we have developed a semi-empirical 25 simulation based on single source function and we found that
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. ("N, i there are some deficiencies.in this methodt therefore, we then L) 2 moved'to the current method, which uses multiple empirical i
3 source functions. And I will explain to you the' reasons.for 4 this and some of the calibration without.
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_[ 1 respect to different assumptions.
i 2 The last part is the Green's function, which sets l s
3 forth the propagation effects between source and recording 4 side. We used the so-called generalized ray method, which some 5 of_the samples were shown earlier by Dr. Savage.
6 Then, in this calculation, we need to have a crustal 7 model, which is constrained by the site recordings, and after 8 this we also compare the result with some more complete method, 9 called frequency wave member integration method.
10 DR. KERR: What does it mean to say the crustal model 11 is constrained by a site recording? Does it means depends 12 upon?
,- 13 MR. TSAI: Basically, checked with the site
)
14 recordings. That's what I mean.
15 DR. KERR: Thank you.
16 MR. TSAIt Now, the need for using empirical source 17 function is several fold. One is, as I mentioned earlier, the 18 frequency dependent radiation pattern. And also there are 19 scattering near the source which we cannot account for in a 20 reasonably deterministic manner. And there are propagation 21 complexities due to multi-pattern or reverberations.
22 In the case of our simulation, we used a simplified 23 layer model. And there are irregularities within those layers l l
24 which cannot deterministically be accounted for. And so we l 25 thought that one way of accounting for that would be just to 7,
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' (. ; 1 use the rear records. And there are accumulations in'between 2 and near site scattering.
3 1k) those are the needs we consider justified to-use 4 our . empirical source functions.
5 As for the segment size, I mentioned it to you 6 earlier that it has to be small enough to meet the Fraunhoffer-7 approximation.
8 On the other hand, they have to be large enough so 9 that the rear record has enough signal to noise ratio. It is 10 significantly above the noise level. And they allow for 11 reliable estimate of the seismic moment, then use this moment 12' to steer upward to our target moment. That translates into the
, 13 number of segments we need to sum up.
14 And then that is the next one. And so we then check 15 that estimate with some observational data and that is shown in 16 the next one.
17 Typically, say, we are looking at this group and the 18 size is a few kilometers. So that is the sub-element size we 19 use in our simulation.
20 And the recordings we used which produced those 21 recordings, that earthquake needs to be accurately located, and 22 there are multiple recordings. And also they need to be 23 distributed around the area so that they can be used to 24 represent radiation at different areas.
25 And after this consideration, going to the available O Heritage Reporting Corporation (202) 628-4088
186 f f. I records, two sets of records were selected.
2 The first set consisted of-16-' recordings from the
=3- 1979 Imperial valley aftershock. The second set is 12 4 recordings of the-1983 Coalinga.aftershock.
5 It so' happened that this is a-strike' slip earthquake 6 and this is a reverse of thrust earthquake.
7 DR. KERR Is a barrier interval an interval over l 8 'which the fault is expected'to behave in the same way?
9 MR. TSAI: Yes. That referred to'a specific model.
l 10 This is called a barrier model, for the fault, and it 11 hypothesizes that the fault, when it ruptures, it ruptures *with 12 'certain' spots, not uniformly across the fault.or fault surveys.
.13 This is one of the models.
,-p ki- 14 DR. KERRt For this model a barrier interval 15 represents a sub-element?
16 MR. TSAI: We will get to that. It is reasonably 17 equivalent to our sub-element size.
18 So after this selection we then compare with the, I 19 think it is in the earlier slide, but I will just show the L
20 comparison.
21 This is the full amplitude spectrum, an average of 12 22 Coalinga aftershock records, 16 in solid lines, average of 16 23 Imperial Valley aftershock records in dotted lines. And down 24 here are an average of three local earthquakes. Three 25 earthquakes around the Diablo Canyon site. And what we are
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vL 1 comparing is the slope of this spectrum which we are mainly 2 concerned about the frequency range starting from roughly here 3 to about here. In some cases it extends to 25 hertz. And one 4 can see that the relative frequency content is quite comparable 5 between what we selected and what actually observed although-6 the ground motion level is one order.of magnitude lower at the 7 site than what we selected for our simulation. .
8 DR. KERR Excuse me. What you concluded was that 9 the shape of this curve ought to be independent of acceleration
~10 based on these two sets of data?
11 MR. TSAI: The slope. Basically, the slope. The 12 basis of frequency --
13 DR. KERR I understand. From these data you 14 concluded that the shape ought to be independent of 15 acceleration or independent of acceleration over some range or 16 what?
i 17 MR. TSAI: This two sets of records were used to ,
18 represent our projection of ground motion at the site. But 19 they are recorded somewhere else. And our concern is that if 20 for some reason the frequency content here is deficient in high 21 frequency --
22 DR. SIESS: Just a minute, please. It might help I 23 think if you explain what your vertical scale is. That's not !
24 acceleration, is it?
25 DR. KERR: This is a spectra acceleration. At full
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1 amplitude.
2 DR. SIESS: Transform, not acceleration. It'sJa 3 spectral content of acceleration?
4_ MR.'TSAI: Yes, that's right. Fu,ll' year amplitude of 5; the acceleration record.
6 DR. KERR So that the attenuation is independent of 7 frequency? ,
-8 MR. TSAI: No.
9 DR. KERR: If you get a recording that is done away-10 from the site, and therefore there has been a transmission over ,
11 -some distance, -- i
- 12 MR. TSAI These are all very close recordings.
13 DR. KERR: Okay. I misunderstood you.-
i )
\> 14 MR. TSAI And what this means to show is that we t 15 are, we do want to have our simulation to produce a record 16 whose frequency content can reproduce what is observed at the 17 site, 18 DR. KERR: Isn't there in this the assumption that 19 the frequency content is independent of the magnitude of the 20 earthquake?
21 MR. TSAI Yes. It is over here.
22 MR. TRIFUNAC: The problem I am referring to is that i 23 if you use the Imperial valley aftershocks. I would suggest f i
24 that they have a lot of surface wave image.
25 So even though the spectra shapes are consistent, the lieritage Reporting Corporation -
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- i_,) ' 1 . arrival times and the nature of the motion are simply quite 2 inconsistent.
a 3 DR. TSAI: These-aftershock records we checked,.they u
4 contain.relatively low surface waves, not like main shock.
5 Second, surface waves normally are in the-lower frequency part
.6~ instead of-at high frequencies. :
7 MR. TRIFUNAC: I disagree totally with that.
8 MR. TSAIt' This is an empirical way.to show that 9 observation method. This has been not modified in any fashion ,
,10 but just.to show the whole records. If you do the full year I 11 transform, you have the amplitude versus the same manner to the 12 site recordings.
13 MR. TRIFUNAC: That's fine. It's just unique.
f
\' 14 - DR. TSAI That's true. I agree with that statement, 15 yes.
16 DR. KERR Aside from being unique, is it 17 representative of what one expects it to eventually be used to
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18 represent? I mean, that's the important thing, it seems to me, 19 not whether it's unique or not.
20 MR. TSAI: This is to show that we, the set of I 21 record.ings we selected, the consistency with the site [
L 22 recordings in terms of relative frequency content.
23 MR. TRIFUNAC: But that's all. [
24 DR. TSAI: Yes, that's all. And that is the nature 25 of the empirical representation. [
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190 l' DR'._SIESS: Is this the only measure of how good it :
i 2 ,is? _
3 MR. TSAI We then compare with the end result.
F 4- MR. TRIFUNAC: You won't be using this simulation? '
5 'MR.=TSAI: I will show you without using those sets-6 of' simulations.
They just are the aspects whichLare
-7 MR. TRIFUNAC: -l l
8 sensitive to other aspects that you have not matched. 1 9 -Particularly, I think, you will be invoking coherence, and you 10 -will be using-the consequences of this simulation as.an input 11 into structure-interaction.
12- StR . TSAI Yes. Yes that is addressed over here. j 13 M.R. TRIFUNAC: And those are very sensitive to the !
V 14 other aspects that are not constrained by the' full a'mplitude.
15 MR. TSAI: Yes. The comparison of full amplitude is !
16 just one way of showing their consistency. There are, of 17 _ course, many other ways to show their consistencies.
18 DR. SIESS: Are you going to tell us what they are?
19 MR. TSAI For example, I show you the comparison 20 between the simulated wave form and the theoretical prediction.
-21 Those are in terms of the amplitude.
22 MR. TRIFUNAC: But that is in the period range which 23 .is outside our interest here. Those are displacements in the 24 long period range. And I think you agreed just a few moments j 25 ago we are talking about high frequencies.
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191 1 MR. TSAI: No. The comparison is acceleration.
2 DR. SIESS: Why don't we go ahead and we'll see when 3 we get to the end if you've covered it. If net, we'll come 4 back to it.
5 MR. TSAI: I will show you what has been done. Of 6 course, this has been discussed with the ground motion panel, 7 NRC ground motion panel, and there are comments of different 8 aspects of the approach.
9 MR. ROTHMAN: Could I add something to this? I think 10 the reason that comparison was made was that after the last 11 ground motion meeting which was early in the fall, some of our 12 consultants questioned the fact that they were using 13 aftershocks of the Imperial Valley earthquake, which is a i
14 thick, sedimentary site, to simulate motion at a rock site.
15 And the question was whether the high frequencies would be 16 attenuated due to the soft sediments in the Imperial Valley. I 17 think what they are trying to demonstrate here is that the high 18 frequency content is similar for those Imperial Valley 19 earthquakes as it is for those recorded on the site. I believe 20 that is all they are trying to show here, that they are not 21 abnormally attenuating the high frequencies in the Imperial 22 Valley.
23 DR. SIESS: Let's go on and get the whole story.
24 MR. TSAI: The treatment of fault heterogeneity we 25 have used a hybrid treatment. That is, upon slip distribution,
)
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192 n.
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I we used a non-uniform distribution, or time. function. We -
2 determined to^uso a round function with'a-locally stochastic 3 element' defined by motion distribution and so-forth. The
.4 rupture velocity also has that combination.
5- And.this is shown as'an example, for example, the 6 Imperial Valley earthquake there are many, quite a few studies-7 to determine the distribution of slip, amount of slip over the
-8 fault plane, and this is the distribution of strike slip 9 ' component based on teleseismic recording and on slow motion 10 recording ~and this is a combination of the two sets of 11 observations. It shows that there is a pattern where--the 12 distribution of slip is non-uniform and over a relatively large 13 scale.
'14 So we used this pattern, then simplified it into 15 discrete fault elements with different wave lengths. So this 16 is how the strip distribution is described.
17 And for the slip time function, at a given location, 18 the fault starts to slip. After a certain time it reaches its 19 static displacement. In between, we allow for certain 20 irregularities. And that is described as a Gaussian function.
21 DR. SIESS: The deviation from a straight line, or 22 Gaussian? Is that what you mean?
23 MR. TSAI Yes. And the rupture propagation st.arting 24 from the new creation point propagates outward with a uriform 25 velocity around locally for some variation and that vr.riation O Heritage Reporting Corporation (202) 628-4888
193 g
-i_) 1 ' runs ~between the beginning of the rupture to the.end of the 2 rupture 'across that sub-element ,cn: that sub-segment, fault 3 segment. 'And that distribution is Gaussian distribution.
4 . With regard to the Green's function, we used these 5- _ velocity profiles in terms of P-wave, S-wave: velocity profile 6 for the region surrounding theisite-and then through the 7 simulation calculate the theoretical Green's function and 8 compare with the' recordings at the site.
9 And these velocity profiles were derived basically on 10 the seismic network data using P-wave arrivers. However, for 11 grorind motion simulation, S-wave is of importance. And so we l
12 need to check the S-wave velocities in terms of the velocity l l
13 itself, in terms of the distribution, and so we simulate based d
(^i.
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i 14 on that model, here would be the P-wave velocity, S-wave motion 15 and this is in terms of time, normalized time with a given 16 velocity of 6.3 and here are distances, starting from zero up 17 to 50 kilometers. !
l 18 I'm sorry. This is vertical component. I 19 MR. SEAVUZZO: Which is the S-wave and the P-wave 20 there?
21 MR. TSAI The first arrival is the P-wave and the 22 second arrival is the S-wave. And this is a radio component.
23 Again, P and S-wave.
24 Next one. This is the potential component on the S-25 wave. And I would like to show you for example, there are two Heritage Reporting Corporation (202) 628-4888
p- .
I 194 i'b l T_){ '1: distinct arrivers. One is the direct arriver, the second one l l
2 is the reflection from the Franciscan interface. And these 3 double holes were observed at the site recordings. One example j 4 is.the site is over here. I will show you records from;this l E
l 5 carthquake recorded at the site. ;
6 This component is comparable to the potential j 7 component and one can see these double arrivers. The time !
a 8- interval is comparable to the predicted value. Also, we
$ '9 ' compared the' theoretical uodel S minus P arrival times as N
R 10 function of distance versus the observed one. And here the l
$ i
/- 11 solid symbols represent observed values whereas the open 12 symbols are theoretical predictions for two fault depths. One
. _ 13 is.five and one is nine. And you can see they follow each 14 other very closely, j J
15 This shows that the cluster velocity profiles we used I l
16 for our simulation is consistent with the available 17 observations at the. site.
18 DR. SIESS: How would you like a break, Mr. Tsai7 19 MR. TSAI: Yes. I need a break. Thank you, i i
20 DR. SIESS: We will come back at 4:15.
21 (Whereupon, a brief recess was taken.)
22 DR. SIESS: You may proceed, Mr. Tsai.
23 MR. TSAI This development of the method we then 24 carried the method with actual recordings from the 1979 25 Imperial Valley earthquake in terms of the fault records, time O Heritage Reporting Corporation l
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195 1 histories, the PGA values and response spectrum.
2 And the record we will be comparing will be around 3 the central array.
4 In this calibration we used the crustal velocity 5 profiles of the area and used the aftershock recordings as-6 empirical source functions. And here is the result.
7 On the left side is the simulation. On the right 8 side is the observed records. In terms of this horirontal 9 axis, is time and the scale is over here. This is the distance 10 from the fault trace, on one side of the fault and on the other 11 side of the fault. There are multiple recordings at different 12 distances and for 140 degree component. That is parallel to
\
13 the fault.
\ .7 ;
'-' 14 I can see here two arrivers. One is the arriver from 15 the high slip location. The other line would be the predicted 16 arriver from the closest point of the fault. And you can see 17 the simulations to reproduce the observed pause as it 18 predicted.
19 Now, we also compare the PIG values as function of 20 distance. On this figure this is the distance of 10 kilometers 21 and this is PGA in terms of GE. The symbol down here, observed 22 and simulated. And you can see there are a mixture between 23 simulations and observed and we believe that as a whcie the 24 simulations do reproduce what is observed. It is not biased on j 25 the lower side or on the higher side systematically, m
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196 p) 1 And we also compare the response spectrum. Over 2 here is the particular station components observed and 3' simulated and here is the acceleration response spectrum, for 4 frequency. .Above about two hertz the simulations follow 5 . closely the observed.
6 Another station on the other side is in the 7 viewgraph, but I will not show it here.
8 Next I will show you some of the simulations we made 9 for the site.
10 MR. TRIFUNAC: Can I ask a question? In this 11 comparison you are using aftershocks of Imperial valley 12 earthquake to simulate the main evene of.the Imperial Valley 13 earthquake.
14 MR. TSAI: Yes.
15 MR. TRIFUNAC: Now, because Diablo is in such a 16 different geologic environment, wouldn't it be more fair -- I 17 don't know what's a better word than fair -- to compare for 18 example your ability to simulate let us say by accelerogram 19 during San Fernando earthquake using Imperial Valley data? Or 20 wouldn't it be more honest to take the aftershocks of for 21 example San Fernando and simulate Imperial Valley? Because you 22 have ideal situation, and you don't have that in reality. Do 23 you understand the question?
24 MR. TSAI: Yes. We undertake these comparisons 25 because there are multiple recordings.1 O Heritage Reporting Corporation (202) 628-4888
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tf ~1 Now, after-the July workshop with NRC panel,.they-l 2 asked us to do so-called blind tests.
That'is, with' field .
1 3' ' recordings and less-known fault natures, to do the comparisons.
4 And we are in the process of doing that.
5 DR. SIESS: Bill?
i 6 DR._KERRt I guess you have answered part of my
- 7. question. It seems to me -- well, let me ask a question.
B .What you_have done has' demonstrated to your satisfaction that 9 you can take data from a number of earthquakes and can put j 10 together a model that will simulate that data? Now, are you 11 going t'o go beyond that and say I can also predict what an 12 earthquake that has.not yet occurred will produce?-
13 MR. TSAI This is our motivation of doing.this, 14 using this method to apply to the Diablo Canyon, which we won't-15 have record at least for some time of that ground motion.
16 DR. KERRt But that says then that you know enough 17 about earthquakes that will occur to assume that they are going 18 to be like earthquakes that have occurred, the data for which 1
19 are still, I gather, rather sparse.
20 MR. TSAIt Yes. Or no, to some extent. That is the, 21 the working assumption here really is that what occurred at 22 other places will occur at our site, to some extent, but there 23 will be distinct characteristics in the ground motion which 24 belong to the site.
25 And that is the basis for our undertaking numerical Heritage Reporting Corporation r (202) 628-4888 l
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l 198 (s' I simulations. Because if we use only empirical ground motions 2 which are recorded at other locations _for other earthquakes and 3 based on the first working assumption, we would say okay, !
4 those, whatever were observed as a group, we will be expecting i 1
5 that at our site.
6 But then we need to take account, into account the 7 site specific information. And that is where we are using the 8 recordings at the site to compare with wheit has been used as an 9 input for the simulation so that we introduco site specific !
10 information in that process.
11 But before that, we test the procedure at other 12 locations where similar information or input, and produce the )
i
, 13 simulations to compare with actual recordings at those places
(,)
14 to show the adequacy of the simulation procedure.
15 DR. KERRt I may be missing some of what you have i
16 done, I'm sure. But it appears to me that you have built a 17 model that has a great many what I would call fitting I 10 parameters involved in it, and that those fitting parameters 19 you have arrived at by using existing data.
I 20 And as a result of that you have been able to l 21 generate a model which will regenerate the data that you hava 22 used to build it. And that takes a good bit of doing, and is l l
23 an accomplishment, and will permit you to simulate earthquakes 24 that have already occurred.
1
( 25 That does not give me a great deal of confidence that I
(
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- \~ I l1- you1 can simulate . future earthquakes ,' 'unless you -are f convin' ed c
2i that there'will?be nothing' unusual'about future earthquakes
,f , 3: .that.hasonot ! already l been 1 observed.
4' .DR.' TSAI: 4 Yes.
That.is a~ general' criticism,of the 5- simulation method. -There are'just so many parameters involved 6: which one-can' adjust. But in our. approach, we are doing this
~ ~
7 mainly-out of: necessity and with the parameters which can'be 8 constrained we use what is'known to constrain them and then to ,
.9 compare:the'results to understand or investigate the deficiency
~
10 or some bias of that. And accordingly,1when we make 11 -applications of the-simulation-result, we are aware of those ;
-12 lin.imations . and we don' t step over those limitations.- And as .
13 an example,~you'can see the comparison earlier. Where is the' "
h' . 14 Imperial Valley? '
15 (Pause)-
16 MR. TSAIt For example, this~, the spectra 17 acceleration would be our: product for engineering applications.
18 Now, if you compare the observed and' simulated,~we see that for 19 frequency above around two hertz, they are relatively close to 20 each other whereas at low frequency the simulation 4
21 systematically is lower than the observed. And we know that 22 there are deficiencies in our low frequency, in the low
.23 frequency range from our simulations. And so if applications l- ~ 2 4. require those low frequency components, then the simulations 25
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j' l' DR. KERR: Thank you.
2 MR. TSAIt' For our prel'iminary simulation', we.
f3 simulate 120 cases for strike slip and so forth and out of this 41 120 cases we then selected 14 for the fragility analysis. We 5 also come back-to the sensitivity study on the 14 and the 6 comparison with empirical result.
7 This is a summary of the-120 cases. Three typesaof 8 fault, <'ch has 40 cases and then with different combinations
- 9. of location, rupture modes and source functions. Some of them 10 use Imperial Valley, some of them use Coalinga and the 11 simulations include three components of accelerations. -
12 This is the geometry of the faults with respect to 13 site. This is the site. We assume vortical strike 81.o fault, h- .14 60 degrees inclined oblique fault and 35 degrees inclined 15 reverse fault.
16 This is the train projection. The site is over here.
17 If you' project on the ground surface, the strike slip would be 18 a line whereas oblique would extend to this and reverse ~would 19 extend to the East of the site. In Other words, the site will 20 be right above the projection in the projection 'f the fault on 21 the ground surface.
i 22 MR. EBERSOLE: I wonder if you could clarify 23 something for me, as completely ignorant on some of the 24 technical aspects of this.
l 25 MR. TSAI: Yes.
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201 s,p . s-1 11 -- MR. EBERSOLE: 'The' spectral' distribution:at the-s-
12- source, at-the~ origin, is ore thing.
2 ;3 -MR. TSAI - Yes.
~
~4 MR. EBERSOLE -AreLthere substantial differences'in
- 5: the spectral.-distr 3 % tion at the receiver, and~do your 6- calculation ter.hniques allow- for that to be calculated? '
7 MR. TSAI: For the moment, we only distinguish
'8 .between soil and rock material. Now', the irregularities under
- 9 the. site'of even ock-you have-quite complicated. structures.
10 .We-have not done'thht yet. 'We have instruments I will show you-11 -later located at different locations around the~p]snt and that -
12 hopefully,' empirically, we can show --
13 MR. EBERSOLE: In general, you lose a higher amount-
.n
' b/ ' -14 -ofLthe higher frequencies, don't you, as you translate it
'15- through the strata?
.16 MR. TSAI: Yes. Genardlly.
-:17.- -MR. TRIFUNAC: In running these three-models,: strike 18 slip, oblique and reverse, are you using the~same aftershock-19 data as-Greene's functions or different ones or what?
20 MR. TSAI: No, two. Two.
' 21 ' MR. TRIFUNAC: Which are those two?
- 22 MR. TSAI
- It's randomnese, like there were y _23 combinations, 40 of them, and so --
24 'MR. TRIFUNAC: Well, just, are they still Imperial 25 Valley aft'ershock data?
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' ' (,) 1 MR. - TSAI:: No,-no. Coalinga and-Imperial Valley. I 2 .believe they are about equal.in. number.
3 MR. TRIFUNAC: Are you are' flip-flopping the two for 4- .these three geometrical cases?
5- MR.-TSAI: Yes.- All of them are mixed. Yes. And 6 this is'the' dimension of the fault. For strike slip it'is' 48 7 kilometers by 9 kilometers; for oblique it is more to the 8 square and for reverse it is 18 to 20, and.the segment size is 9 3 by 4 kilometers.
10 -One example of the simulation shows here. It is an 11 oblique fault in the rupture, northward and using Coalinga-12- source functions. And you can see the two horizontal and the
-13 vertical.
(,
^ ') 14 How, because of the time I would just show you the 15 result of 120 cases. The median response spectrum, 84th 16 percentile and 16th percentile for the east-west component at 17 the site.
18 Now, this table summarized those 40 cases, strike 19 slip, oblique and reverse. On top of here is the PGA value and 20 over here is the spectral value averaged over these frequency 21 bands. And what one sees is that the average of strike slip is 22 .91 versus 1.13, normalized to one.
23 And over here, the peak value is about the same 24 differences. The same ratios.
25 We also show the vertical versus horizontal component O Heritage Reporting Corporation (202) 628-4888
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-k._[ l' : ratio..
2' So.the average of the 120 cases we compare with
~
3' regression result and they are_quite comparable.
4 MR.:TRIFUNAC: Excuse me. 'Am I correct in 5 interpreting'the time functions as indicating'that your 6- aftershocks that you use as empirical means functions are 7 perhaps deficient in long period energy?
8 MR. TSAI: Yes. Yes.
9 MR. TRIFUNAC: Have you gotten to that situation 10 because you had too drastic a low pass filter, because the data 11 was of more-amplitude and so it was getting in the noise or do 12 you think there was just no energy generated at these periods?
13 MR. TSAI: I think it is simply no energy in the sa kl -14 original records.
15 MR. TRIFUNAC: You could have just added some long 16- period noise to get around that because the visual comparison 17 -would-have been much better.
18 MR. TSAI: Well, that is not our intention.
- 19. MR. TRIFUNAC: But the full-year transform is non-20 unique anyway.
21 MR. TSAI: Yes. The simulations really are geared to 22 our needs and our needs are for frequency about three, two or 23 three hertz. And we are really not doing the simulations, for 24 example, weaker by weaker, to try to reproduce what was 25 observed.
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,m kl ~1 And'.that_has been done by other researchers in 2 comparing the velocity wave forms, displaced wave forms.
3 What we have done'new here is to simulate in terms of e
4- acceleration. And that is in the high frequency range..
S MR.-TRIFUNAC: Yes, but you'are doing all of this I 6 suppose because-somebody down the line after you are done wants 7 to use this in terms of time input.
8 MR. TSAI: Yes.
9 MR. TRIFUNAC: If we were concerned only with full
' 10 year transform or spectral acceleration we wouldn't be looking 11 at these details.
12 So it seems to me that one's strongest motivation for-
~
_ 13 doing all of this that you are doing is to get a time function 14 that is physically meaningful.
15 MR. TSAI: That's right. Yes. _That is physically
- 16 justified. And I show you the justifications for our ,
17 simulation procedure and then at the end we take the result in 18 . terms of primary engineering characteristics which are PIG
- 19 values, time histories, spectral acceleration, acceleration 20 spectra. And those are three characteristics in the ground 21 . motion which are considered by engineering applications or 22 engineering community in general.
23 MR. TRIFUNAC: That's agreed. But my point is merely 24 this. That I see enormous effort here which I interpret to be 25 motivated by the need to have a time function which is 6 Ileritage Reporting Corporation (202) 628-4888 ,
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(_) 1 -ph'ysically meaningful for the site.
n 2 MR..TSAI: Yes.
- 3. MR. .TRIFUNAC: And yet you say that the constraints 4 on. coming up with that time function are really those that you 5, just enumerated but using those constraints I can produce-6' equally. good time functions without a hundredth of the effort 7 that has gone into this by just taking some random combinations 8 on these progra$s I have. You see what my point is. I mean, 9 if you postulate only those constraints that you have, there is 10- such tremendous-non-uniqueness that it is a question whether 11 the whole effort is worthwhile.
12 MR. TSAI: Yes, s 13 MR.-TRIFUNAC: You could get at it and get time 14 fanscions without doing all of this and they would still take 15 all the constraints that you have.
.t G MR. TSAI: Then nobody will Selieve it, you see.
17- This has this physical constraint and physical justification.
18 that is,-if we believe what seismologists say is correct, then 19 I believe that is more believable than say you just go in and 20 change all those parameters and produce, simulate good records.
21 DR. KERR: But it seems to me that you have shown 4 22 that your model is plausible.
23 MR. TSAI Yes.
24 DR. KERR: But I don't see that you have shown that i
l l 25 it is unique.
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' (,) ' 1 MR. TSAI: It is not unique. It is definitely not 2 .- unique. Yes.
3 Now, I-will go to this part, assessment of spatial
- 4. incoherence. .And the consideration behind that-is that we have 5 a site which is very close to an extended source.and the waves 6 coming from different parts of that source will have different 7 arrival times at the site even at two very closely spaced 8 . points, as illustrated here, and that will cause the 9 incoherence In ground motion at two points of the foundation of 10 a structure.
11 Besides that. there are effects coming from paths in 12 the site. And so to make an estimate of contributions from the 13 two parts, we separate them in terms of source and wave passage 14 as a factor and site and paths as another factor and combine 15 the two to get the overall spatial incoherence.
16 And those two factors may be estimated for the site 17 and path from a point source or a smaller event, whereas for 18 the extended source impact we estimate that from the simulation 19 before that we compare this result of this process with real
- 20 records. And that comparison is then with a set of recordings 21 from Imperial Valley main shock and aftershock recordings at 22 different arrays.
23 And I will skip this.
24 This is a map showing Imperial earthquake main shock 25 is located here and this is the map, rupture of the Imperial Heritage Reporting Corporation (202) 628-4888
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(_/' 1 -bowl.The array is located over here. There areisix
'2 instruments with different spacings and I will just show 3- examples between this one and this one.
n 4 lMR. EBERSOLE: Tell me, up to now, are you looking at 5 Diablo Canyon as a point receiver, and then are you going to 6 later talk about it as a distributed receiver?
7 MR.-TSAI: Yes. First we make the single point 8' estimation and then allow for effect of the spatial incoherence 9 as an adjustment.
10 MR. EBERSOLE: Okay.
I' 11 MR. TSAI: So this-is the combined coherence of 12 horizontal S-wave from simulation of the rupture and from l
, ,_ 13 observation of aftershock recordings. So those are two parts, k~_) 14 One is an extended source effect and then the path and site l
15 effect. And this is the combined coherence function as a 16 function of separations, 300 meters here, for different 17 frequencies. 3.5, 7.5 and 15 hertz. And one sees here that 13 ths coharency decreased with distance and with increasing 19 frequency.
20 And this is what is actually observed from the main 21 shock recordings, and so if one overlays the previous graph 22 with this one, they almost overlap on each other. And the
[- 23 previous figure shows the simulations for the main shock 24 combined with what is observed from the aftershock recording.
25 And this is the real one. So that comparison does give us some O Heritage Reporting Corporation (202) 628-4888
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, 11; confidence ofLthe procedure:weTare using.
12' .Now, at the site,Lwhenlwe, apply.that, we won't4have
'3 .the extended' source recordings. . We have to: simulate that.
41 However,'weido have some; point source recordings.
Tand I will-show you one example ofLthic." This is the site
~~
5-6- 'duringthe cluster profiling earlier! described by Dr. Savage.-
D -71 Wezhave a land face shot here and a: series of air gun shots
- 8 2over here.
9, We-have deployed.quite a number of instruments around 10 the site and:here-is an example of a pair between two points 11- which are about 300 meters apart. And these are the recordings 12 .at different frequency bands and the coherent functions.
13 And dot.n e shows the result of those three bands.
4.Q 14 MR. EC , ,J,d t Are you talking about shots that are 15 fired coincidentally?
16 MR. TSAIt. No'. Planned.
~
17 MR. EBERSOLE: Well, do you ever fire shots 18: coincidentally and pick up the summation of them at a distant 19 point?
~
20- MR. TSAI No, we haven't done that, because the land 21 shot is to be cleared. And just as part of the large program.
22 And the air gun shot is fired by the ship which is 23 constantly moving.
24 So for simultaneous shots we would need two ships or fn 25 more ships.
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209 7s,/. ' 1 MR. EBERSOLE: Oh, sure.
2 MR. TSAI: Yes.
~3 This.is the-result by combining simulations for:an o4 extended rupture.along the Hosgri with the observed coherence 5 function from the land' shots and~ air gun shots combined,-and 6- you-can'see the coherence function'again decreased with 7 separation and with increase in frequencies.
8 This is the model which has parameters determined as 9 .a function for these coherence functions. And so this part of 10 this result has been provided to SSI group for preliminary 11 studies of the effect of incoherence. ,
12 MR. TRIFUNAC: Excuse me.- Can I ask a question?
13 MR. TSAI: Sure.
14 MR. TRIFUNAC: I think that this coherence depends on 15 ,a lot of things which we didn't mention here, but would you 16 agree that looking at the shot data, you are looking 17 essentially at what horizontal energy arrival at various 18 locations throughout the plant site? Is that a fair statement?
19 The source is basically on the surface. That is what I am ;
20 getting at.
21 MR. TSAI: The first part is -- yes, that's the shot, 22 basically, is close to the surface whereas the earthquake -- ;
23 MR. TRIFUNAC: I didn't get to the earthquake yet.
24 But we agree on that?
25 MR.TSAI: Yes.
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210 l_/. -1 .MR. TRIFUNAC: ~ We go to Imperial Valley for_which you 2 also did show some data. And Imperial Valley of-course is a 3 sedimentary _ basin.and so it has'all the features that are 14 ' required for a horizontal wave guide as well. So that there we
~
5 also have a'similar situation, that energy travels mainly 6 horizontally.
7 MR. TSAI: Well, in terms of Imperial, Valley, 8 basically the wave approached the site almost vertically. Now, 9 the land shot, although the source is shallow, but because of 10 the distance, the wave is not necessarily coming directly. The 11 direct wave is not the first arriver but rather the refracted 12 wave. And that is, we have done some particle orbital studies 7-13 to show that they are basically approaching the receiver in a V 14 rather stiff incidence angle.
15 MR. TRIFUNAC: Yes. Nevertheless, you are not 16 calculating coherence on the basis of ane pulse of a rifle. You 17 are calculating coherence on the basis of the whole function.
18 MR. TSAI: Yes.
19 MR. TRIFUNAC: And so in the case of your explosions, 20 the source is almost on the surface, and the bulk of energy 21 goes to the horizontal wave guide even though it is a rock 22 site. Agreed?
23 MR. TSAI: Yes.
24 MR. TRIFUNAC: And in the Imperial Valley, the l
l 25 similar situation applies. The arrivals may be nearly
() '
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/ ~'s . . . -
' '( / 4 - 1: . vertical, but once'they get into the. soft surface layers,.they 2- keep; going _that way.-
- 3 So you have, I suppose, essentially a horizontally _
4 propagating wave.-
- 5 Now, I don't understand how you can apply that 6 conclusion or observation to a case which you think:is a 7 reversed fault which it as some depth where the energy comes 8 vertically directly.from the source:up to your site, where the 9- face _ velocity of your planes of arrivals is infinite. Do you
~10 understand my question?
11 MR. TSAI: Well, yes, but I don't agree with you that 12 waves are basically coming from the top layers. They are 13 coming, going down and then up. They may be trapped in the
(_- 14 surface layer close to the site but not in between the site and 15 ' source. And that is, I think it is very essential to this 16 approach.
17 MR. TRIFUNAC: The question really boils down to what 18 is the ground motion consisting of. Where is the energy in 19 strong ground motion? Now, if you can prove that the energy in
- 20 strong ground motion is all body waves, then you have the 21 point. But if somebody else can prove that the energy in 22 strong ground shaking, in the case of Imperial Valley, is 23 essentially 80, 90 percent, whatever, surface waves, or that 24' similarly may be ray waves in case of an explosion, you don't 25 have the point. So I think that is the issue you have to h Heritage Reporting Corporation (202) 628-4888
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2 MR. TSAI: Yes. I am aware of that particular 3 question, and the comparison between Imperial Valley main 4 shocks, I show you, for example array 5 and 8, between 5 observations and simulations. Those basically consisted of 6 -body waves, because in our simulation, the. generalized wave 7 . theory only accounts for body waves. And the comparison for 8 example, the two lines, the broken lines and solid lines, i ,
9 particular the dashed line shows the predicted arrivers and the 10 observed arrivers, were they are strong, they are both strong.
11 Not only the Imperial waves but the time arrival timewise. And 12 those are two very strong seismology constraints.
13 MR. TRIFUNAC: They are pulses, though. In between i
3 14 them there is a tremendous amount of wave formation. So if you 15 look from the point of view of energy, those pulses, though 16 they are visible to your educated eye, they are just parts of 17 the whole picture. Really, they are just 10 percent of the 18 energy that you see.
i 19 MR. TRIFUNAC: For a seismologist, it is not 20 satisfactory. But for engineers -- and I am converting myself 21 from a seismologist to an engineer requirement -- we are
! 22 looking at the peak values and looking at the behavior of the l 23 ground motion around that peak value. I conclude that the i
24 reproduced or simulated wave forms do provide or contain the 25 essential characteristics. Now, as a seismologist, one would l O-l Heritage Reporting Corporation l (202) 628-4888
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.. (-\ lif.e to see when~he reproduced the wave, where the observed has
(/ -1 2 La. peak, you reproduce a peak, there is a trough, you reproduce
~
3 La; trough. But in this case,Lthat is not, I don't think it is
'4- an. essential requirement for this particular application. I am 5 not saying --
6 MR. TRIFUNAC: You have to be careful. Because an 7 engineer is going to say that a seismologist colleague-of his-8 has proved that incoherence allows him to do some things such 9 as. TAU effects or things that go-along with-that, and he is 10 just going to quote you or another seismologist.that they have 11 demonstrated that this is the case. So you have to keep that .i n 12 mind.
13 MR. TSAI: Yes. Yes. This, for example, the
~
14 observation of Imperial Valley main shock, which has nothing to
~
15 do with simu1ations, you see the incoherence effect.
16 In terms of increasing distance, increasing 17 frequencies, those are irregardless of simulations. I think 18 that anybody looking at that observation will conclude that 19 there are spatial incoherences in there.
20 MR. TRIFUNAC: But Imperial Valley is a soft site, 21 and I wish you plotted incoherence with this wave length rather 22 than just the frequency. Diablo is a stiff site and so the 23 ratio of the wave lengths in question is quite significant.
24 MR. TSAI Yes. That is exactly why we need to have 25 recordings at the site. And that is, part of that we have
-~
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L'd 'l corrected from a shallow source, a small' source. ;
2 -Now,' we have in store a number of additional free
'3 field accelerographs at the site. This is a larger map showing 4 previously installed at three free. field sites. Now, we have
-5
~
installed one on top of.the overlook. So tomorrow when you go 6: to the site if you look toward the'back of the plant, on top of .
'7- here, a green hut, that will be the house ~for the instrument..
8 9 -
10 11 ,
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13 ,
10 ;
14 15 16 17 ,
c 18 19 20 21 22 ,
23 l 24 L
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215 1 MR. TSAI: Now closer to the plant we have in this-2 -particular location, in the open space, we have five of them 3 _ distributed in a cross shape with~a dimension of the basemat.
4 We also have instruments located around the site --
z 5 around the plant larger separations. And with this-6 additionally the croi Eph3 instruments which are solid state 7 memory based.
8 We hope that if there is an earthquake occur even 9 smaller in the nearby area you will be able to correct records 10 which-are of value to this program.
11 And we also -- for the last few months in the 12 existing supplementary system which as three free field 13 instrumenti and 52 channels inside the plant.
'D 14 We install a diarp unit in it which allow us to
-( )
15 interrogate the system from a remote location using modems.
16 And we' re doing that at my office and at the plant.
17 DR. SIESS: Just how big an earthquake would you like 18 to have?
19 (Laughter) 20 DR. TSAI: Well, in the past a magnitude 2.4 six 21 kilometer from the plant triggered the instrument. Now at 30 22 kilometer a magnitude around five triggered the system, which 23 produced up to 4 G percent per motion.
24 Okay. I now will quickly summarize what's provided for the 25 engineering analysis, one is for fragility consistent of first
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. starts of' empirical time: histories, whichlI reported.to~you in Q.c ~ '
2- lastimeeting except that I - .we have-aided'one records fromi
,-3 .the Canadian earthquake of 1985.
4 Now in addition to that we have provided 14, sets of
~
' simulated time histories based on.the 120 cases simulationi and:
5 Si -those consist'of different -- four types of different rupture-7 mode.
8- .This is -- in the high melt is copies showing the.12 l 9 empirical records. - This is the new addition. And this table Five of them are strike
~
10 shows the simulated time histories.
11~ . slip foldt seven of them are oblique foldt and two of them are
'12 reverse fold.
13 With source function from Coalinga and from Imperial 14- ' Valley as a mixture. And they' re all three company records.
['
J15 Now the - .this is spectrum of that time and period --
16 empirical recordst and this is an average of the 14 records -- ,
17 median 84th. percentile and 16th percentile of the two --
18 average of the two horizontal components.
~
19 They are comparable -- if you over -- one over the 2'O other. Now for exercise analysis, we' ve provided site specific 21 acceleration response spectrum for a median. They were in 22 shape of three bentin values, also vertical component was 23 provided.
24 Then we selected three pendulate time histories to 1 25 match -- for SSI people to match the spectrum. And this is the Heritage Reporting Corporation (202) 628-4888 5
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1 median astorite in response spectrum of three bentins'provided,.
2 shown in a~ graph' form.
3: I think that"concludes my presentation. Thank you 4' very much.
5 DR. SIESS: ~Any further questions?
i.
6 ~ (Pause) 7 DR. SIESS: Thank you, sir.
8 DR. TSAI: Thank you.
9 DR. SIESS: I'd now like to ask the NRC staff for any
- 10. comments they may have on what we've heard so far. I forgot to 11 ask them at the end of the GSG presentation. So this will 12 cover both the geology sized model -- t:3e geotechnical and the 13' ground motion work.
O': 14 And I'd like to have staff comments and the status of 15 their review.
16 MR. ROTHMAN: The staff has routinely, after each 17 workshop or meeting, or report that's been submitted, given 18 comments from the staff review; is under-consultants about the 19 PG&E.
20 Very often the comments were very similar to the ones 21 that the ACRS has made today, that Dr. Trifunac has made about 22 the -- as far as the ground motion simulation to suitability of
.23 using imperial valley aftershocks; and then matching it to the 24 ~1mperial valley earthquake rather than using some other 25 earthquake to try and match.
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- ( 't E ); 1- In general, comments have been in -- have been
'2 implemented into the program. . We haven't seen the results.of 3 this work yet. It has been implemented into the program. - Our 4 last meetings on.some of these things were last summer-and early fall.
5 6 We haven't had any meetings'on geology or geophysics 7 since then. In general so far -- except for these types of 8- comments we've been-fairly happy with the way the program has !
9 been progressing.
10 No, we haven't seen anything major that we disagree 11 with. We have comments on the amount of oblique or reverse
- 12 faulting that's being simulated.
_s 13 Possibly we think that more should be used'in the 14 ground motion.
15 DR. SIESS: More should be what?
16 MR. ROTHMAN: More reverse component in the ground 17' motion studies rather than --
18 DR. SIESS: And that gives a higher --
19 MR. ROTHMAN: Possibly higher. We've had to see what 20 happens if you increase it.
21 DR. SIESS: Didn't I read something recently that 22 indicated the reverse stress fault was just 20 percent more 23 than the strike slip?
24 MR. ROTHMAN: Well, there's some researchers that are 25 claiming maybe as high as 50 percent more. I mean it depends O-lieritage Reporting Corporation <
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- ,(_)( 'I on whose work you're looking at.
2 1k) we-would'like.:to-see'some sensitivity studies 3- don' tion this.- We've also' asked for-on -- because in the 4 fmodeling. study,' if there are so many parameters that can;be 5 varied we_ vest-for sensitivity studies on some of th'se e 6 parameters to see how they do effect the-results to see what 7 the assumptions that are made.
8 As far as the geology -- geophysics part of the 9 program, we've had some independent work being done by 10 University of Nevada and the U.S. Geological Survey.
11 University of Nevada has been doing field mapping;
.12 they've been looking at area photos. In general they agree
'13 that his most syn-form -- or snyclinorium, or has -- is. rising;,
14 but it'has been rising without defama -- internal defamation.
15 The capability of the Los Osos fault and the Wilmar 16 f ault have been aqreed with. The fact that the Edna fault is 17 not capable; has been basically accepted by the staff and its 18 consultants.
19 There is some question about the ability of an 20 earthquake to rupture through from the San Simeon fault on to 21 the Hosgri.
22 The fact that there is a step there on the surface is 23 acknowledged. But what the connection is at depth we don't 24 know yet, so that's a question whether we could rupture 25 through.
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). 1 JThe nature of---the connections of Los Osos, the 2 Casmalia, of Pecho and other faults to the Hosgri has not been
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3 determined yet. Those are the kinds of questions we have been 4 asking a lot of.
5 Whether faulting on the Hosgri could cause motion on 6 some of these subsidiary faults, just what the nature of the 7 connections are, whether they are splays off the fault, whether 8 they are faults that are interrupted by the Hosgri, or whether 9 they segment the Hosgri. Those questions have to be 10 considered.
11 DR. SEISS: How much difference does it make in the 12 site specific spectrum if the Hosgri connects up to the San 13 Simeon?
(~l\
x- 14 MR. ROTHMAN: Well, what that does, is it gives you 15 possibly a larger magnitude earthquake, which you would have to 16 evaluate, because the magnitude the earthquake made would 17 depend on the rupture length, the function of the rupture 18 length.
19 If you could rupture through say, 100 kilometers 20 rather than 50 you might increase the magnitude by quite a bit.
21 That's something that has to be addressed.
22 MR. TRIFUNAC: But what difference does it make?
23 MR. ROTHMAN: I don't know the exact numbers. If you 24 can could cause a higher magnitude, what the absolute number--
25 DR. SEISS: If you have a break on the San Simeon, Heritage Reporting Corporation (202) 628-4888
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(,) ' 1 which is a pretty good distance from the site, can you just add 2 the two?
3 MR. ROTHMAN: Well'there are, actually we have 4 programs going on right now trying to relate magnitudes t'o the 5 length of rupture, and the amount.the displacement. The PG&E
'6 has been doing some studies on that, and also our consultants 7 have been looking at a world wide data base to see what the
~
8 relationships are between amount of slip, rupture 1ength and 9 magnitude.
10 DR. SEISS: That's empirical.
11 MR. ROTHMAN: Base-d on, yes. Based on knowing the 12 faults.
. 13 DR. SEISS: This kind of study that Dr. Tsai has 14 shown us, can that be used to show that the effect is through 15 the San Simeon? What assumptions do you have to make about the 16 timing of the rupture, whether it starts up there and moves ,
17- down, or starts down on the Hosgri and moves up.
18 MR. ROTHMAN: You could possibly model that. ,
19 MR. TRIFUNAC: But don't you know this ahead of time?
20 I mean, you know you can just ask these people to go on and on 21 and on.
22 MR. ROTHMAN: Well, we're not, no. We're not--
23 MR. TRIFUNAC: We don't have to solve this - , which 24 is finished. You don't have to solve the problem in general, 25 just have a picture here, which has a site, which has a Hosgri
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(_) I here in San Simeon. I'mean, isn't the' answer almost obvious, 2- what it should be?
3 MR. ROTHMAN: Not obvious'to me, no. It is not 4 obvious to me.~
5 DR. SEISS: It won't go on and on. Like that, you 6 know, like that condition. There is a cut off point. Yes 7 John?
8 MR. MAXWELL: I just wonder why you worry about these 9 'small faults. I don't think anybody thinks there is any
'10 movement on them that would exceed the, would cause any 11 significant damage at the plant, would it?
12 MR. ROTHMAN: At the present time, no, we don't.
l13 MR. MAXWELL: It would seem rather non essential.
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'~/ 14 MR. ROTHMAN: And if it is considered non essential, 15 I'm sure PG&E will make that argument to us. And then we will 16 take that into consideration.
17 MR. MAXWELL: Well, but turn the thing around, and 18 just as an observer, do you see any way they could be 19 essential?
i l 20_ MR. ROTHMAN: Well, what we know about it now, no.
21 Not right now. That's why I've said from the beginning, right l
l 22 now we don't see anything that would supersede the Hosgri as 23 being the dominant contributor to the plant.
24 MR. MAXWELL: You don't, but you don't feel they have 25 necessarily eliminated the fault, the possibility of faults Heritage Reporting Corporation (202) 628-4888
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-MR. ROTHMAN: No.-
- 3 ..MR.; MAXWELL _ To the plant-site?
'4 MR. ROTHMAN: I: think we have identified _thef- , the-5 Los Osos,-the St. Luis' Bay. fault,'-the Wilmar, those are 6 'probably'the closest capable faults. ~What we know now. .And
- 7 they are minor players right now.
9 8 The question we come to is the junction between these e
'9 faults.and the Hosgri, are they segments in the Hosgri? - The ,
10 Hosgri'would.be segmented, thus limiting the magnitude.- That's - '
11- .something that PG&E is looking at.
12- Limiting the length of rupture. These are the kinds 13 of things I think that they are looking at, and it is going to k-)- ,
14 .become an' issue on establishing the magnitude of the re- '
15~ analysis, or what you would call it.
1 1 16 DR' SEISS:
Now at this point, PG&E has developed !
'17 'some spectra and some time histories that they are turning over ,
18 to the: fragilities people, are going to be incorporated, the 19 PRAs. Do you see anything that could change those 20: significantly or knowingly? !
21 MR. ROTHMAN: We've had some-- I 22 DR. SEISS: We may not know what significantly is i 23 until we have seen the results of the fragility studies and the 24 PRA. ,
25 MR. ROTHMAN: We've had some concerns on how these !
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. f 1 various ground motion estimates are going to be used in the 2 analysis,--and we have felt that-this may be a weak point in~the 3~ study.that is interfaced between ground motion and engineering 4 analysis and soil structure interaction.
'S And we have set up a meeting to take place in May ir.
6 which we are going'to have all of our ground motion 7 consultants, our PRA consultants with the fragility consultants 3
8 and the. soil structure interaction people, and PG&Es ground 9 motion and~ engineering people to sit down and discuss just how 10 the, what is going to be used to simulate the ground motion and 11 how it is going to be applied in the plant.
12 DR. SEISS: If the PRA using these values showed that 13 the plant had an extremely low probability of core melt, or 2 14 that it could take a 50 percent greater input before it caused 15 any damage, would you have any concorn with these values? ?
16 MR. ROTHMAN: We have not as yet established tbc
- 17 magnitude of the earthquake to be used or for the grenad motion 18 studies.
19 DR. SEISS: I know that.
20 MR. ROTHMAN: If it showed that the ground motion 21 would be 50 percent higher than the--
22 DR. SEISS: You could show that it could withstand 23 the ground motion spectra increase by 50 percent.
24 MR. TRIFUNAC: Not likely.
25 MR. 11.OTHMAN: : don't think you are going to see--
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. )! l' the.incoherency review spectra.
2 MR. TRIFUNAC:' That's a separate issue. I am asking 3 you a simple question. That is -- buildings there, it's a free
- 4 field side. What do you consider an acceptable procedure to 5 convince you that this is okay to proceed with the design?
6 There must be something, otherwise if it is not specific there 7 is nothing we can see come to the end. You understand my 8 question?
9 MR. ROTHMAN: No, I don't understand your question.
10 DR. SCISS: No, let me. As I recall, the license 11 condition' simply says this shall be done. It didn't say 12 anything about what we're going to do about it when we get 13 through.
(,_ 'i
'- 14 MR. ROTHMAN: Well, I think it does. It says in the 15 fault part of the license condition, it says that these motions 16 will be accessed against the seismic margins as necessary, L. using deterministic and probabalistic methods. It was left 18 very general.
19 DR. SEISS: That's very, very general.
20 MR. ROTHMAN: That's right. Well, that's the way the 21 condition was written.
22 DR. SEISS: What does the staff expect to do after 23 they've gotten the final report on this in July 19897 24 MR. ROTHMAN: We'll write a review report, something 25 equivalent to an SER on this.
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.M 1 Oh. SEISS: Oh, I know'it may not be likely, but I'm 2 just trying to.see.
3 MR. ROTHMAN: I don't 29e thst. I couldn't answer 4 that.
5 DR. SEISS: It's a shame we can't start off with the 6 PRA and back up on these things, we may lind it. Any other 7 questions? Any other comments? Personally, I'll go with the 8 question. Yes?
9- MR. TRIFUNAC: I have a question ror ti.? SRC people.
10 DR.~SEISS: All right.
11 MR. TRIFUNAC: I still don't understand what we have 12 said as a decision basis, as a decision maker. Are you going 13 to ask them to simulate some scenarios and come up with k 14 different spectra at the site? Are you going to take some kind 15 of representative spectrum and work with that or are they going 16 to combine this into some kind c' informative spectrum type and 17 use that to go on? What is th. ultimasi accepting procedure 18 that you will consider?
19 MR. ROTHMAN: '911, we are trying to.use a multi 20 methenology. We are looking at the empirical ground motion to 21 see what that tells us about the estimates that were made. We 22 are looking at the numerical modeling to see how that compares 23 with the Hosgri reanalysis.
24 We are going to look at how the saw structure 25 interaction spectra corresponds to the tall review spectra and Heritage Hoporting Corporation (202) 628-4888
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I, 1 DR. SEISS: What will bo the basis-for your 2 evaluation of.part 100, of' severe accident safety goal,'what.
1-3- _ will you compare.this with?
4 .MR. ROTHMAN: We will compare ~-it against what-the 5 existing, what:the re-analysis that was done during the Hosgri 6 used to see if it-exceeds that, and if it does exceed it then 7 we will.have to look at the comparisons of the, implant 8 comparisons, to see'if there is anything. Weak' links.
9 DR. SEISS: So if anything.- the PRA won't be used 10 because there was no probabalistic basis for.the design of this 11 plant.
12 MR. ROTHMAN: Well, that will give us a handle for 13- looking at weak links within the plant systems that might-have O 14 to, that might contribute significantly to risk.
15 DR. SEISS: It sounds like the-IPE followed with 16 severe ax-- policy.
17 MR. ROTHMAN: I'm not familiar wAth that, so.
18 DR. SEISS: That's the problem with the staff, he had 19 three good - analyzing it (laughter).
20 MR. ROTHMAN: Possibly I'd like to speak to people ;
21 that are reviewing the PRA.
I 22 DR. KERR: No seriously, if you're going to be 23 talking about severe accidents, which is what would occur if 24 one had a major earthquake, shouldn't you be familiar with what 25 is being done about severe accidents by the NRC?
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228 t 1 MR. BAGCHI: Right now the IPE has none going to 2 external events.
3 DR. SEISS: That's temporary.~
4 DR. KERR: I am sorry, it is a clearly stated policy 5 of the Commission to consider external events.
6 MR. BAGCHI A generic state being prepareo !m that 7 we monitor the external events.
8 DR. SEISS: You're talking about the IPE, Dr. Kerr is 9 talking.the severe accident policy statement. The IPE is only 10 a partial response by the staff to the Commission's severe 11 accident policy statement.
12 MR. BAGCHI: You're right.
13 DR. SEISS: It's just what you'll be hearing for the
(,_)
14 next six months.
15 M3. BAGCHI: The policy statement is going to include 16 external events, and we are going to have to consider that.
17 DR. SEISS: But is this going to be considered under 18 the severe accident policy or is it going to go back and look 19 at it under the design basis.
20 MR. BAGCflI I personally suspect that it is so close 21 to meeting the severe accident policy, and it certainly is 22 going to encompass all the earthquakes that are likely to cause 23 severe accident type of scenario, that we are going to end up 24 with something more than what Pe.rk 100 would require.
25 MR. EDERSOLE: Fell I thought I heard that you were !
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')(,1 1 obligated-to considerJthe damagesto the containment in'the ,
2- Econtext that it may in itself-initiate a core-melt.' Whether or 31 not you?need the containment, it may trigger =a core melt by-
.4 . failing. 'And won't that.really; cover the sever accident 5- policy?
6 MR. BAGCHI: I think it.will cover the severe 7 accident. If the accident's condition really does not let us
-8 ~ get'into.that, some of-these things would have to be work'ed 9 out.
10 DR. KERR: Is it accurate to say that at this time 11 you do not know how you will decide what PG&E finally reports t
12 as acceptable? .
' 13 - MR.-BAGCHI It is fair to'say that we don't know 14 what vulnerabilities are going ~to be like. It depends very
.15 much on the vulnerabilities are going to be.
16 DR. KERR That's not the question I asked. I'm 17 asking how you will decide? Not whtt will occur, but how you 18 will decide whether what they come up with is acceptable? You 19 must, at some point, estcblish some criteria. You may not have
. 20 done so now, but at some point you will have to, and at this '
21 point you have not established the criteria for acceptance. Ie (
22 that an accurate statement? -
23 MR. BAGCHI: Yes, that's fait P 24 DR. KERR: What sort of mechanism are you going to 25 use to establish those criteria? !
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t 230-I[ 1 MR. BAGCh'It It would have to be the-PRA based.
2 Whether or not it has, how they think thht is the plant _ safety.
3 Whether or not the margins are'available.
4 DR. KERR1 What margins'are required by existing 5 regulations?
6 DR. SEISS: That's the problem, because you cannot go 7 back to Part 100 becauce the licensing condition said adequacy 8 of-seismic margins. And of course Part 100, the original 9 design basis did not address margins. It was the deterministic 10 approach calculate the stresses, compare them with the log.
11 So as soon as you bring in the idea of margins, you 12 are right back_to the Maine Yankee, seismic margin study and 13 'a'ny other seismic margin study. And this is just a very k' 14 ela5 crate seismic margin study.
15 HR. BAGCHI: That's correct.
16 MR. EBERSOLE: It occurs to me if you made it, you 17 didn't know when you went into Maine Yankee what was going to 18 be acceptable, right?
19 MR. BAGCHI That's correct.
20 MR. EBERSOLE: It occurs to me if you are lool.ing at 21 damage to the containment, just the context of that 22 precipitating a core melt, you may miss the fact, in the severe 23 accident case you have got to have an intact containment with a
24 the same release rate that it is supposed to have.
25 MR. BAGCHI Based on what I understand, they are Heritage Reporting Corporation (202) 628-4888
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- 1- looking into'the containment at pretty high levels, structural y
2- levels,-for failure.
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3= MR.1EBERSOLE: And I'm talking about no, not just 4 damage, a
Containment systems:I.think is a be'tter 5 DR. SEISS:
6 word.
7~ MR. BAGCHI Yes, that's a better word to say.
8 DR. SEISS: Containment structure itself I wouldn't 9 . worry about for more than a couple of seconds. But other 10 aspects to containment than the pressure containing boundary.
11 MR. BAGCHI I suspect when we get into the review, 12 PRA' review,~we are going to look at the containment system.
13 DR. KERR It would seem to me that at some point.
4 L([-)
~x 14 .soon you should be giving some thought to the criteria that you- t 15 are going to use to make a decision. Surely'it won't just be ,
16 ad hoc. 4 17 DR. SEISS: I think after they get there they.will 18 know. They will look at it and decide whether they are 19 comfortable with it. Wewilllookatitanddeckdewhetherwe 20 are comfortable with it, I'm sure PG&E will look at it and 21 decide whether they are comfortable with it. They've got a ;
22 fair investment down there. t t
23 MR. BAGCHI We say we don't have guidance from Part i 24 100, we certainly don't have little guidance from the policy
- 25. statement. [
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D. 1 .DR.LSEISS: You don't even know what did it with the.
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2 ' policy statement.
~3- MR. BAGCHIt. It's a very hard thing.- ,
4- DR. KERRt Indeed it is, and for.that reason it seems
'S to-me that we should' start.giving some thodght.to it. I doret:
6l pretend it's simple, I don't think it is. But it is.necessary.
-7 -DR. SEISS: For example,.I don't even know what -
8 criteria the staff'used to accept the Maine Yankee seismic '
1 9 -margin study. I don't even know whether that's a precedent or 10 not. You look atithat and nobody could really tell us, you ,
1 11- know, what was the basis for accepting it, much less the legal
- 12 basis. .I'd like to stay.out of that. :
13 .The. seismic margins end up being a feeling. How I)I 14_ comfortable you are with a margin. It's not something:you 15 could say it's go or no go. Nobody has defined whst is an 16 acceptable seismic margin.. !
17 MR. DAGCHI Going back to Maine Yankee though, there
. 18 were some staff studies which indicated that the SASSI value i
19 should be somewhere around .18 G, and with the seismic margin "
20 study the HCLPF value came out to be pretty high. [
21 DR. SEISS: After you fixed up the take. What was 22 the take, .187 And you weren't comfortable with it.
23 MR. BAGCHI: So that's why I wanted to emphasize that 24 the main thrust of it is understanding the vulnerabilities. If l
25 there aren't any, then we would know that the program has
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2' DR. SEISS: You know being comfortable with.something 3 is good engineering, it's just lousy regulation. (Laughter)
,4 aut until you_ decide on some sort of criteria, you don't_have H 5 ;any definition of vulnerability. At-what point is something 6' vulnerable?
~
7 MR. BAGCHI: The characterization of ground motion.at 8 the site. I think people have some judgment about that. If l
9 you asked me, I cannot characterize it right now.
1 10 DR. SEISS: Well, vulnerability is more of a bottom 1
11 line type thing. It's like what's a dominant failure vote?
12 That's what I saw as a definition of vulnerability in l
13 connection with the severe accident policy. Something that r"
(_)x 14 dominates:is a failure vote, even if it's 10'to minus 6, it's a I 15 vulnerability.
16 MR. BAGCHI Well, we wouldn't fix something that's 17 very, very low in probability.
18 DR. SEISS: PG&E will satisfy the licensing condition 19 when they have completed this work, and have provided a basis 1
20 for the seismic margir.s, whether the seismic margins are big j i
21 enough, somebody else is going to have to decide.
22 MR. BAGCHI That is correct.
23 DR. SEISS: Maybe we will be involved. Mr. Cluff, I 24 was hoping we might get through this soil structure interaction 25 today, and I'm willing to go until six o' clock. Do you think O Heritage Reporting Corporation (202) 628-4888
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-234' 11- we.could do onoughson'SSI-in 30 minutes _to;makecit. worthwhile? '
- 2- It will at-least-be 30 minutes:w9 don't have tomorrow-morning.
3 MR. CLUFF: 'Yes,'wofcan. .
'4L .DR.'SEISS: 'Okay. Let's start it,.and we willistop
'*S. 7 at the".en.1 of the' first slide af ter- eix o ' clock.
~
6 (Laughter) 37- I will ask-Bill. White,:#hol-is ch'arge of managing the SSI-to 8 -take over.
9 (Continued on followino oage) !
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(_)l 'l MR. TSAI (continuing): The numerical simulation 2 consists of a number of elements. First, we started at the 3 earthquake source. We did fault surveys of some area. We then-4 described that into fault segments and then summed the 5- contribution of'each segment to obtain the overall motion from 6 an extended-fault rupture.
7 Now, in this description of the source, one has to 8 choose the size of the sub-element, location of the cub-9 element. Also one needs to have a source function in terms of 10- time.
11 DR. KERR: Is this a distributed source, distributed 12 geographically?
13 MR. TSAI Yes.
(' >I 14 DR. KERR Vertically and horizontally. In two 15 dimensions?
16 MR., TSAI: This is a ground service over here and 17 it's downward, underground.
18 DR. KERR You are going to talk about the extent of 19 those dimensions later on?
20 MR. TSAI: Later on. Yes.
21 And then a wave is genorated here, propagated outward 22 to the side, propagated through the Jnter-meeting paths and 23 then of course it will be more defined by the site condition.
24 And so we, in the simulation, there are three parts. One is 25 the source, paths and the site contributions.
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(_) 1 Now, there are several important features in the 2I method we developed. First, in terms of source time functions,
'3 it meets the needs for some features which has to be~ accounted 4 .in the_ source time' function. And I will.be showing that in_the 5 'next figure.
6 Basically, it can account for the degradation of 7 radiation patterns at high frequencies. In other words, at low 8 frequency, a radiation pattern can be relatively reliably 9 predicted, but in high frequency, that prediction breaks down.
- 10. And so we need to account for that.
11 Then I will show you how the source functions are 12 selected, and the important part of that is to compare with our 13 site recordings. And then we correct for the propagation 1( )- '
14' -paths.
15 DR. KERR: Can you give me a brief description of 16 what you mean by the degradation of the radiation pattern?
17 MR. TSAI: Yes.
18 DR. SIESS: If you are going to do it later, just do 19 it in sequence.
20 MR. TSAI: Yes. Well, it's about time, since you 21 raised the question.
22 This is the S-wave radiation pattern. And over here 23 the data, the records shown are from a 5.1 aftershock of the 24 1979 earthquake. So one has recordings of different actions 25 and it is projected back to the earthquake ficors. As compared q
(_-
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182 1 to this pattern, those are theoretically predicted. And what 2 shows here is the upper two are two different components.
3 Radio component, transverse component. And then the upper two 4 are in filters, the whole records. The lower part is a low 5 pass filter, traces, in those high-frequency components. And 6 one can see down here, near the northern lines, the recorded 7 ground motion compared more closely to the theoretically 8 predicted, whereas the records which have high frequency 9 components don't show that clear correlation.
10 DR. KERR: So if I were naive, I could also interpret 11 this to mean that for low frequency, this model works and for 12 high frequency it doesn't work very well?
ym, 13 MR. TSAI: That's right. That's exactly what would
( I 14 be the extension of this.
15 DR. KERR: Okay.
16 MR. TSAI: But our job is not low frequency. Our job 17 in to predict the high frequency one.
18 DR. KERR: On that basis, that wave pattern, one 19 would not choose preferentially?z 20 MR. TSAI: That's right. So we cannot rely on this 21 theoretical representation, and since we are not really sure 22 how to represent it another way, deterministically, and so we 23 then go to the real records where it is there.
24 Now, the other feature is the site of the fault 25 segment. And there are several considerations. One is based q
%/
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183 m.
_) 1 on-area studies by Joyner and Boore, in terms of the 2 relationship between large earthquakes and smaller earthquakes.
3 Since we are summing a large number of small earthquakes to 4 simulate the large earthquake, how many of these smaller 5 earthquakes or fault elements do we need to sum is of 6 importance. And there is some concern of this.
7 Also, we need to consider the approximation, called 8 Fraunhoffer approximation. That is, near, very close to the 9 source, one uses, we are using wave tracing method. And the 10 need to satisfy this approximation, that is, we are looking at l 11 high frequency, and we need to have the source which is not 12 larger than the wave lengths we are looking at.
13 So there is a consideration needed to be made on the
- 14 size of the fault elements. And then we have some 15 observational basis to choose the segment size. And we did 16 perform some sensitivity study in terms of simulated ground 17 motion as function of different choices of segment size.
18 Then, we also consider fault heterogeneity. That is, 19 in that big fault, in case of a single large earthquake, the 20 amount of slip over that fault is not uniform. Some parts slip 21 more than other parts. And that is described in terms of the 22 special distribution in terms of the tug function of that slip 23 at a given location and also the extension or propagation of 24 the rupture starting at a new creation point throughout the 25 whole fault, and we also made some sensitivity studies with O Heritage Reporting Corporation (202) 628-4888
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,cx 1 MR. WHITE: Thank you.
2 I'm going to show a .few slides here to kind of set 3 the. stage. Then I would like to have Dr. Wen Tsing take over, 4 because my voice is going to poop out on me pretty quir.kly 5 here.
6 We' ll make the transition from the ground motion into 7 our actual studies.-
8 Before, we were talking about ground motion providing 9 empirical records and numerical records. We are taking both' 10 of those and combining this into structural analysis and 11 equipment response predictions and then this information is in 12 turn fed into our fragility analysis.
13- And in terms of what we are trying to do in the
/~'N 14 structure analysis, we are certainly directing our efforts
<)
15 towards support of the pRA. And when you get down to the kind 16 of calculations we' re making, even though it's a pRA, it is 17 very deterministic calculations.
18 We' re looking for forces in structural members, 19 deflections, accelerations, response spectra. We will get 20 around to equipment response. Again, we are looking for 21 response spectra and deflections. Very familiar kinds of 22 things.
23 Now, alcng with this, we are also looking for the 24 dispersion of the response, how much scatter are we getting.
25 And that's where the pRA part comes i n.
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w 236 i But most of the studies we are making are, like I 2- said, good, everyday engineering.
3 DR. KERR When you talk about response, are you 4 talking about stayinD within a linear range?f 5 . MR. WHITE: No. We were talking about in the pRA a L 6 very large' range of earthquakes. We are allowing the 7 structures and systems to go nonlinear.
8 MR. KERR: Thank you.
9 MR. EBERSOLE: When you say equipment response, are 10 you taking into account more than safety-related equipment and 11 system interactive aspects of equipment performance?
12 MR. WHITE: Some subsystem interaction.
13 MR. EBERSOLE: One of the big current flaps is the
('}
v 14 ef fects of fire protections systems going of f concurrent ly all 15 over the place.
16 MR. WHITE: Fire protection system is in the pRA.
17 In terms of the studies that were performed, we' ve 18 done an analysis to determine the median response spectra and 19 also the 84th percentile spectra. That's for the auxiliary 23 buildinD only.
21 And Bob Kennedy will talk about that tomorrow. The 22 next three items, Wen will talk about today -- the development 23 of a median response spectra for all the buildings and the 24 effect of the incoherent ground motion and also containment 25 uplift.
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237 1 And those are the three items that we' ll be talking
\ l' 2 about this afternoon.
3 In terms of how they fit together in terms of an 4 overall program, I' ve got a simplified flow ~ diagram that 5 summarizes this. We' ve got one that's much more complicated 6 that we' ve chosen to neglect.
7 But the three studies we will be talking about this 8 afternoon are these three portions here.-
9 This is response spectra, containment uplift and the 10 spatial incoherence. The time history stuf f we' ll be covering 11 tomorrow.
12 So, with no further ado, I don' t want to catch Wen in 13 the middle of a slide. Let's just bring Dr. Wen Tsing up and
(} 14 have him go through the detailed studies that we did for SSI.
15 DR. WEN TSING: This is the so-called more 16 complicated graph. I don' t intend to go through this in great 17 detail. But I Just will re-emphasize that there are three 18 parts we are going to talk about.
19 The first part is the so-called incoherent ground 20 motion input, and determining the SSI response for this ground 21 motion input.
22 And the second part is determining what is the 23 modification due to incoherence of ground motion.
24 And then the third part is kind of like a small 25 branching out. For containment structure, there was a question Heritage Reporting Corporation (202) 628-4888
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's 1 as to whether-the uplifting plane is high enough to warrant-a
')
2 modification of'the response. And we are usinD nonlinear 3- analysis 1to address that question.
4 Earlier on, when Dr. Tsai-presented the ground motion 5 . element of the. study, the input to SSI consists of' basically 6 three elements.
7 One is the site specific response spectra. And based 8 on this, this will be like a spectra prescribed at the plant 9 site, like at one point, a receiving station.. So there is no 10 spatial coherence, spatial variation information.
11 Then the second part of that coming from the spatial 12 incoherence function. And that spatial incoherence function 13 expands the point specification of ground motion in terms of f') .14 sitt specific spectra into a two-dimensional ground motion 15 variation within the foundation itself. 1 16 And then the third component of the time history 17 selected suitable for modification to fit the site specific -
18 spectra.
19 So I will quickly go through the first part of that.
i 20 That is the coherent response, response of the structure to 21 coherent ground motion. And this shows the median site- ,
22 specific horizontal spectrum that was determined from the >
23 empirical ground motion.
24 This spectra is for horizontal, 5 percent damping.
25 This is the same spectra that Dr. Tsai has shown I
() Heritage Reporting Corporation (202) 628-4888 ,
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^N 1 here. And this is the basis for us to - there is three sets i
2 of-actual earthquake records. Namely, the pacolma Dam, the 3 Tabas records and El Centra Station Number 4 records, where 4 chosen by the ground motion studies to be more suitable for-5 modifications to fit the spectra.
6 This shows the modified pacoima Dam longitudinal 7 component. And in order to make this spectra fit the site 8 specific median spectra we performed some adjustment to the 9 time history and after adjustment you can see the modified time 10 history median spectra fairly closely.
11 And this kind of time history adjustment, as you can 12 see, the upper one is the initial and adjusted time history and 13 after adjustment.
14 They are basically quite similar in chape, in (D'
15 phasing, except that it introduced a slightly higher high 16 frequency content to the spectra.
17 So essentially, the modified spectra still maintain l 18 quite realistic features as the initial time history.
19 We are doing this for two sets of time histories, the 20 Tabas records, three component, and the Pacoima Dam three -
21 component. And those are used for input to analysis for 22 cohere nt ground motion input.
23 Now in the coherent ground motion input , what we are ,
24 doing is basically the very conventional SSI approach.
25 That i s, we are assuming the ground motion arriving t
(- .
() Heritage Reporting Corporation l (202) 628-4888 .
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,1 1 at a site vertically, propagating wave, plane wave. There is
( ')
2 rx) special variation across the surface of the ground. So the 3 incoherence component in this particular study was not 4 introduced at all.
5 So using the model developed for the plant, there are 6 three power block structures. One is containment.
7 And this shows the containment model that we used for 8 the SSI study. Basically, there are two sticks. One 9 represented the outer shell and then a stick representing 10 interior concrete.
11 And for that we also developed a foundation model t
- 1. using the element approach, the SASSI computer program, and 13 carried this foundation model with the stick model just shown,
/~T 14 and run the traditional SSI analysis approach which gives us a b
15 representative spectrum, flow response spectra on this, at the 16 component in the top of the internal concrete.
17 And the two curves here are the floor expression 18 curve cominD from two time histories. For the north-south 19 modified Pacoima and modified Tabas. And as can be seen here, 20 the two spectra from two totally different time histories 21 really are quite consistent.
22 So the time history modification to fit the response 23 spectra did a good Job in matching the spectra and coming up L 24 with quite consistent response.
25 And in order to see, for this particular structure, Heritage Reporting Corporation ,
(202) 628-4888 P
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1 what SSI effect is, we also compute the same response, 2 assuming fixed base, and that his similar to what has been used 3 in the original design,-and the red-shaded curb indicates the 4 fixed base response.
5 It is also due to two time histories, so you can see
! 6 there are slight differences in shape to that and there is some I 7 drop of spectral peaks as well as CpA values, the maximum 8 serration response.
9 This clearly can be attributed to the SSI effect, la from inertia effect alone, because we have not considered the 11 special coherence and special variations.
la Then quickly we show the same, similar type of 13 response. This is a stick model, showing the two unit
'i 14 auxiliary building. Basically a symmetrical model with respect (O
15 to the center line of the building.
16 And for that we also developed a foundation model.
17 We only developed for half of the model, and using half of a 18 sugar structure stick model also.
19 This particular structure has some portions which are 20 embedded into the rock. The paper grate (ph) is at the 21 elevation 85 and there are about 25 feet imbedment for this 22 structure.
23 Applying the same ground motion as for containment, 24 it shows again one representative floor response spectra at 25 elevation 140, which is the operating deck of the auxiliary Heritage Reporting Corporation (202) 628-4888 l
4.
(
242 3 1 building, due to two time history inputs.
N) 2 Again, they are very consistent in response.
3 And to show the SSI effect for this particular 4 building, we also compiled a fixed base response with the SSI 5 response. The fixed base response showing as a lightly shaded 6 curve.
7 For this particular building one can see an SSI 8 effect produced much higher effect than the containment 9 structure as can be seen by reduction of maximum acceleration 10 as well as in the spectral peak of frequency.
11 And this probably is due to the imbedment effect of 12 the building which was about 25 feet of imbedment.
13 Then quickly for Unit 2 turbine building, this shows
(~)
%)
14 a foundation plan. The turbine pedestal here and two basically 15 north-south walls and two, three east-west walls.
16 For this particular building, the superstructure we 17 have used a more detailed finite element representation for the 18 superstructure, because of the more sparse distribution of the 19 walls.
20 It is more difficult to develop a single stick model 21 to represent the whole structure.
22 So for that, the foundation is also again composed of 23 a finite model and it is the finite model of the turbine 24 pedestal foundation.
25 Using this will show again representative floor Heritage Reporting Corporation (202) 628-4888
243 E
1 response spectra at the Wall Line A which is running in a
~
2' north-south direction. In the middle of the wall-line A the 3 floor response spectra.is due to a two time history input again 4 modified about Paeoima Dam method.
5 Again, they were quite consistent.
6 Then to see the SSI effect for this building, compare 7 the fixed base result with the shaking (ph) rate and the SSI 8 response. One can see for this particular building the-SSI
[
9 effect is relatively minor.
10 In other words, the fixed base response provides a 11 very good estimate of the response for this particular 12 building.
13 So these are the representative results for the so-
-Mj[) 14 called coherent ground motion input assuming a plane wave 15 propagating or approaching the site in vertical propagating 16 plane waves.
17 Now, again, the spatial variation part of it earlier 18 in Ben Tsai's presentation, the spatial variations were 19 described in the form like incoherence functions.
20 The incoherence functions can be represented for the 21 purpose of SSI analysis, into two components.
22 The first term of that represents the point 23 representation corresponding to the site specific spectra. And 24 this is described in power spectra density function.
25 So in other words, all have the response spectra Heritage Reporting Corporation (202) 628-4888
ll L 244 1 ' consistent power spectra density function and then brought up s -
2 with the incoherence functions which were determined from the 3 ground motion study.
4 The function is a frequency dependent as well as 5 separation distance dependant. And a product of that gives us 6 a so-called co-variance matrix that we can use as input to the 7 SSI analysis.
8 Now, since the specification itself is in terms of 9 power spectra density functions and so on, in the analysis we 10 have to depart from the traditional time history conventional 11 analysis.
12 So in order to use this information, we have used the 13 so-called stochastic or probabilistic type of approach in I" 14 getting the SSI response.
G}'
15 And the coherence function, the incoherence function 16 that had been determined from ground motion basically consists 1
17 of two terms. ,
18 One is the amplitude term and the face term. And 19 those are the expressions for the amplitude and expression for 20 the face. And the constants were determined from the 21 regression analysis dascribed by Dr. Tsai earlier. ;
22 Using this function and the spectrum comparable pause 23 propensity at the site, we made the process of getting to the 24 final response in the structure basically following these 25 steps.
() Heritage Reporting Corporation (202) 628-4888
245 t
(')
, i 1 I don' t intend to go through it in detail but 2 basically using the co-variance matrix, which is the product of 3 the power spectra density function and the incoherence 4 function, or getting the so-called scattur foundation motion.
5 Those are average foundation input motions.
6 Due to incoherence or spatial variation of the free 7 field motion, we will get an average foundation base motion in 8 six components. There are three components in translation and 9 three components in rocking.
10 Using this scatter foundation base motion and from 11 the SSI model, we would determine the transfer function from 12 the scatter foundation base rnotion to the specific structure 13 location where we need to determine response.
/"T 14 The process we are using, a convolution process, to Q) 15 obtain the response for spectra density function, and based on 16 the random vibration theory to go from power spectra to 17 response spectra, we can develop the floor response spectra and 18 the probabilistic floor response spectra.
19 Now, in this process, since we depart from the 20 traditional time history type of SSI analysis which we use for 21 the coherent part, we would like to sort of ratio out the 22 procedure itself.
23 So in order to obtain the pure reduction or pure 24 modification due to the incoherence itself, we use the same 25 procedure to also obtain the coherent ground motion input.
Heritage Reporting Corporation (202) 628-4888
4 246 1 So in the coherent ground motion input, the 4
2 incoherence function that earlier was developed by-the ground 3 motion was assigned to the unit, that there is no dependence o 4 frequency as well as distance.
5 And using the coherent.and incoherent ground motion 6 ' input simultaneously we can develop response at a particular 7 point in particular component due to these two types of input.
8 And we take ratio between the response spectra. That ratio 9 would then later on be used to modify the response spectra in 10 the coherent ground motion input.
11 So to show you a few response results, this again in 12 an aux. building. It will show a typical response at the 13 foundation base and the operating deck.
14 These are floor response spectra, the floor response
[].,
15 spectra obtained from coherent and well as incoherent input.
16 The upper curve coming from coherent input and the lower curve 17 coming from incoherent input.
18 Taking- the ratio of this we'll get a spectral 19 reduction factor. This is at the founoation base level, so if 20 we will consider as a spectral reduction factor in the sense 21 like a Tau factor, this is similar to the Tau factor, just due 22 to the spatial coherence, spatial variation of ground motion 23 alone.
24 Then doing similar things we will be able to get this 25 spectral reduction factor in any location in the structure.
Heritage Reporting Corporation (202) 628-4888
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247-
- 1 And this is the location in the operating deck, elevation 140,-
A J
2 in the aux.' building.
3 So the spectral reduction factor shows slightly 4' different behav, lor than the foundation base. And.ticiN is due 5 to contribution not only from the reduction in translation but 6- also due to the somewhat increase, due to rocking and motion 7 ' components.
8 And this can be illustrated by the composition of 9 those spectral reduction factors into different components or 10 contributions.
11 The lowest curve shows at the operating deck, if we 12 were only including the foundation average motion, due to a 13 horizontal translation alone, we are getting the reduction
() 14, 15 factor which is very similar to the foundation base at e levat iore 85.
16 Then if we are including the rocking component of the 17 motion, we will see that the reduction factor becomes smaller 18 at a particular frequency range, indicating the rocking 19 contribution to the response.
20 Then if we also include all components, that means 21 besides the rocking, the tortion and other components, then we 22 will come up with the final reduction factor.
23 So in this way we can see that the approach we' ve 24 taken will determine the spectral reduction factor or Tau-25 filter factor due to the spatial incoherence at different f
Heritage Reporting Corporation (202) 628-4888
248 s i points in the structure with different curves.
s, 2 MR. TRIFUNAC Can I ask you a question?
7 3 DR. WEN TSING: Yes.
4 MR. TRIFUNAC When you look at incoherent motion, 5 you are saying that you take the average value of the 6 disp),acements across the foundation and the average value of 7 rotation in order to put-that into the rocking.
8 What is the phase difference that you impose or that 9 you end up with between the rocking of the ground motion and 10 the average translation?
11 DR. WEN TSING: In the probabilistic type of force, 12 the phase is inherently included. In the incoherevice function 13 that was given to us from the ground motion study, it consists f'\-
s-)
14 of two parts.
15 One part is the amplitude reduction, the amplitude 16 function, which is the A part of the earlier slide I showed, 17 and the exponential part of phase.
18 And so whatever the phase contained in that model is 19 being included in the SSI.
20 MR. TRIFUNAC I' m sorry. You didn' t understand my 21 question.
- 22 l' m not talking about the phase of the ground motion 23 between two arbitrary points of the foundation. I' m talking 24 about this.
25 You have an average translation of the foundation and
,y
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249 1 you have average rotation of the foundation which you put into 2 your stochastic transfer function in the presentation.
3 DR. WEN TSING: Right.
4 MR. TRIFUNAC: Now, to get the response up somewhere 5 in the structure, I need to know what is the phase in time of 6 the average translation and of the average rotation of the 7 base? That is the phase I'm asking you about.
8 DR. WEi4 TSING: Okay. In the probabilistic,_these 9 phases are not considered explicitly. They are-integrated in 10 the process of convolution between the so-called scatter 11 foundation motion. They are phase, inherent phase in the 12 scatter foundation input motion.
13 MR. TRIFUNAC: That chase means that.the rocking and
'(~T 14 the translation responses are either added or subtracted from
%-)
15 each other or added in some vectorial fashion.
P 16 DR. WEN TSING That is correct. And by soplying the 17 incoherence model which is amplitude and also phase, and i
18 applying the, in a sense the traction vector coming from the 19 SSI, I mean the foendation, the founoation assumed rigid to be 20 on the surf ace of the foundation media (ph) there are certain 21 traction vectors at every point of that foundation beneath 22 that.
23 Using the traction multiplied to t e incoherence 24 model, that given by the ground motion, ' ,ha the scattered 25 foundation input motion itself contains tt inherent phase that r'
(%l Heritage Reporting Corporation (202) 628-4888 ,
250 7 -,< 1 is providing the ground motion itself.
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2 And this scattered foundation input motion then was 3 used to involve with the transfer unction. So I think the 4 phase part is included in the scattered foundation input-5 me
- ion.
6 MR. TRIFUNAC In other words, what you are saying is 7 that you are taking the compicx fourier transform input into 8 your transfer function to calculate say floor response spectra 9 and so forth?
10 D R. WEN TSINGs Right.
11 MR. TRIFUNAC: And you are taking that whatever it 12 turns out to be?
13 DR. WEN TSING: Right. *
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14 MR. TRIFUNAC: I understand.
15 DR. WEN TSING: Now, the third part of this is 16 considering the uplift potential for the containment structure.
17 For this we are looking at the same model as we used for the 18 coherent ground motion s*,udy, the same stick model used for SSI 19 analysis.
20 Now, for the uplift we are considering that the 21 foundation is supported on certain distributed soil springs 22 which has only compression capabilities. That means they will 23 be detached as soon as the dead load is exceeded.
24 Now, the schematic you can see that due to the 25 overturning moment that a ce'rtain port ion of the foundat ion, s
Heritage Reporting Corporation I
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> 251 1 theLtension will be dbveioped and when tension is developed, I l 2 the pre-ssure is being released and the geometry of the 3 -structure in contact with the foundation will be.-in partial 4 contact.
~5 Based on this model we can develop a non-linear 6 moment-to-rotation relationship to be used as the soil spring 7 barrier for the foundation in the SSI analysis.
8 For the Diablo Canyon containment structure, it is 9 'about 20 feet imbedment, abeut 12 to 14 feet. basement thickness 10 with a reactor peak. So they average about 14 feet imbedment.
11 For that imbedment we also incorporate the side soil 12 spring in addition to the foundation base spring which are 13 tensioned (ph) on it.
f')
a 14 For the side source spring we are using a linear 15 spring because when you rock on one side you have side source 16 spring from one side, rock on the other side, you have side 17 source spring from the other r;.de.
,18 So based on this model, then, using as the time 19 history coming from the ground motion study,-the three sets of 20 ground motion, the Pacoima, the Tabas and El Centro Number 4, 21 used as they are without modification in this case because it 22 was determined to be important that the actual phasing of the 23 ground motion is important so we directly used the groun'd
.24 motion, the recorded ground motion without modification to fit 25 the site specific spectra.
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7 Since uplift responseEis inelastic it is nonlinear.
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'10 Now, for the study, we are working to target spectra- i -
11 as a -ratio in two and a quarter .g's(ph) within the range of
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12 three and eight and a half hertz. That is the s ?ctral range 13 where earlier Dr. Tsai was showing the straight lineLof 2 ["'1 ' 14- - spectral acceleration.
- %,)
- 15 So we will take the average of these spectral values-
~16 .for the five percent damping witnin three to,eight and a half 17 - hertz range and adjust the. time history 1to'an average variable 18 of two and a quarter g's.
19 . MR. TRIFUNAC: Excuse me. How is the ground motion '
20 coming in?
21' DR. WEN TSING: The ground motion gives us three. sets i '22 of time history that are considered to be the most
.23 representative. And for the linear analysis earlier on we 24 adjust ~ them to fit the site specific spectra.
.25 MR. TRIFUNAC: No. That was obvious. I' m sorry.
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c6E l convention vertical. weight, the whole point being the same.
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"r ,7 MR. TRIFUNAC: So you'are minimizing'the effect of 18 separat ion by the _ nature . cf the input. -
9 DR.-WEN'TSING ' The intention here'is also to make a 71 0 < linear and a nonlinear analysis.
11 +1 R . TRIFUNAC: In either case, .you are minimizing
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-1 3 DR. WEN . 'NG: I think we'are usingsthe input c
q{g} 14 .because -- upl i f t is more-or:lcss caused by the inertial response; I, 15 of: the structure rather than incoherence'or out"of phasing.
<. 16 - ' And-the' inertial response itself I think-for the 17? vertical propagat ing wave, ' we are gett ing the; higher: response.
18' As'you'have seen-in the earlier showing for coherent 19 ground-' motion input. And that will give us higher inertial load and based on-high inertia load we should be getting higher
~
20 3 l
l -- . 21 - foundation overturning moment which should cause higher or L
22- conservative estimate of the base uplifting.
- 23 Now, we could reduce Lhe motion, and in the T24 meantime --
25 DR. KERR: Excuse me. Hew do you know what's n -
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254 c'T 1 conservative?
2 DR. WEN TSING: We have seen earlier that for 3 containment structures with vertical propagating wave, plane 4 wave of input, we are getting higher inertial load in the 5 structure.
6 DR. KERR I am simply saying, until you know what is 7 going to happen, it seems to me what you shor.1d look for is the a most accurate representation given resources and so on.
9 But I' m not sure, do you know initially what is 10 conservative?
11 DR. WEN TSING: Well, certainly it'a not, but at this 12 point in time since we are separating toe component motion into 13 several parts.
( 14 DR. KERR: I' m not being critical of what you' re 15 doing.
16 I am Just saying that it seems to me it may be 17 premature to label something as being conservative until you 18 know what the results are and what all the interactions are.
19 MR. BAGCHI: He's J ust looking to maximize uplift.
20 DR. WEN TSING: If you have the plane wave, vertical 21 propagating plane wave, versus --
22 DR. KERR: This is a very comp 1t,x system. This is 23 p3rt of the total analysis.
24 Until you know what the Fotal analysis is going to 25 produce, I' m not sure you know what's ev.1 servat ive on a n
k _) Heritage Reporting Corporation (202) 628-4888
k 255 1 component by component basis. Maybe you do. It is not obvious 2 to me that you do.
3 MR. TRIFUNAC: What you are doing is you are 4 minimizing the uplift. You are not maximizing it really.
5 because you are assuming that the ground motion consists of 6 vertically propagating plane waves, and the ground motion in a 7 real situation as you imply, by incoherence studies as well, is 8 not propagating like this.
9 So if you take a realist;c ground motion, you have in 10 fact imbedment, which is even helpin.) that effect further. You 11 have a rotation coming along with the SV, with the p and with 12 the ray (ph) lengths.
13 Only low (ph) *Javes and SH are not dcing the rocking.
j 14 And so by assuming a vertical are.aagation and a constant
['
15 motion of the base you are minimizing the effect of any 16 circumstances.
17 I' m not talking about what the building does. I' m 18 talking about what the ground does.
19 DR. WEN TSING: I think if you look in terms of the 20 input motion to the structure, then you are correct.
?1 By Just taking the vertical propagating waves, we are 22 maximizing the horizontal translation but minimizing the 23 rocking motion whereas in reality we do have scattered rocking 24 motion as well as translational motion, but there will be 25 reduction in the translation and there will be induced rocking
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.2 Now,~how can wefjudge whether we are~getting sort--of
/3- a;highcinertial load?
-4 .By looking'at.theLearlier' response, the' earlier-study-5- cin the incoherent ground motion input. If we compare,: for 6 example, ,at -the top' of internal concrete, the coherent input 71 -versus incoherent input, we are see'ing redu'c' tion of 8 acceleration response at that level of floor response spectra 9 as a whole.
10 But incoherence causes reduction in the floor
~
11 response spectra. So if we are using the coherent input,_then 12' we are using the_ higher acceleration or. inertial responne.i 13 MR. TRIFUNAC: -That is if the assumptions'that go 14 along with your incoherence model are correct. 15 DR. WEN TSING: Of course. Based on the current
'16 incoherence model. And based on the current incoherence model, 17 . we are seeing by vertical propaDating wave, we are maximizing-
-18 the inertial. response,: and likewise, the acceleration responce.
, '19 at various locations in-the containment structure. 20 And that's why I' m saying that by inputting vertical l 21 propagating wave, we are relatively conservative in these two h 22 particular cases. 23 DR. SIESS: That figure compares linear and 24 nonlinear. Do you heve something that shows me the effect of 25 basemat uplift? Heritage Reporting Corporation (2025 6do-40: 8
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7 1, [1 - > ~ DR.f WEN TSING:. This: has ' included basematiup1'if t. QJ ,~ -2 ' Flut ' then?.it' .is showing, . ' compare ' l inear, then, -- i f ; base L upl i f t /is X .
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, ,n4 'DR..SIESS: Linear _means'no.basemat up1'ft?- i 5' DR. WEN-TSING: . R i ght .--
- 6. D R. .SIESS: - Okay.
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- 7. DR. WEN TSING:' And this'is comparing at:the same.
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8' l ocat i on', and if we suppress, assuming uplift.does not occur,-
, L9 and : nonlinear f allowed . the . upli f t to occur, whatis the effect1 10 Lon the floor motion ir. terms of floor. response spectra.
11: So.this is one location.at the top of internal 4 12 structure, due to the Pacoima Dam records. 11 3 And we can also'-- I th' ink what we are doing is we'do
)~S 14 the.same_ thing for three sets of' time hisscry. - Wr are getting (m-)
15 some variation in the s'ame spectra. 16 ~Then we'will average out these three sets of input .
, , ~7' 1 results due to these three sets of input and get.an average.
v 18 MR. SEAVUZZO: One question.
'19 DR. WEN TSING: Yes.
20 MR. SEAVUZZO Did you get significant liftoff with 21 this comparison? 22' D R. WEN TSING: Yes. We are getting about 70 percent 23 liftoff in terms of very small displacement but showing' tension 24 occurred in the foundation buildifq.
-25 DR. SIESS: Tension over 70 percent of liftoff --
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. DR.',SIESS: .How much of.the-areaLis uplifted?.;
4,. .. 3-A i ::;; 14 L d ...- W E N . T S I N G : 70: percent.. , 5 DR. .SIESS 170. percent.- 6' " MR. :SEAVUZZO So there --is no .real' ef fecti. of.:that, 7 phenoinenon on .the, response as you calculated it?
?
g 8 DR.'. WEN.TSING:. Right,
'5I The intention is'if.there were a significantieffect 10 cwe will:use this factor to'adjustithe earlier response, j 1 1.. .incoherentJground motion SSI response'for~ input toffragility jl2 : -analysis. i
- 13 ' DR.ESIESS: Does that conclude your presentation?
14 Thank you. 15 I*m going'to defer further. questions'until-' tomorrow-16 morning. I' ll defer comments- from the staf f unt il; tomorrow . U .: 17 morning. 18 Would:anybody object to starting a littlefearlier-19 tomorrow morning?
- 20. (No response)
' 21 - Would that give any of the members or consultants a 22 problem? They are all staying at the hotel'.
23 Would it give you any problem getting in here? 24 (No response)
.25 Eight O' clock tomorrow morning.
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. Heritage Reporting Corporation (202) 628-4888 5
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3 1 1 1 CERTIFICATE
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s.- 2 3 This is to certify that the attached proceedings before the
.4 United States Nuclear Regulatory Commission in the matter of:
5 Name: ACRS:- DIABLO COAN"ON LONG TERM SEISMIC "ROFIW!
'6 7 Docket Number:
8 Place: Burlingame, California 9 Date: February 23, 1988 10 were held as herein appears, and that this is the original 11 transcript thereof for the file of the United States Nuclear 12 Regulatory Commission taken stenographically by me and, 13 thereaf ter reduced to typewriting by me or under the directior, 14 . of the court reporting company, and that the transcript is a 15 true and accurate record _of__th_e foregoing proceedings. 2-
'S
/S/ ,_ _-)o
'- n . ~ E, M 16 17 (Signature typed): Joan Rose 18 Official Reporter 19 Heritage Reporting Corporation 20 21 22 23 24 25 s .
Heri .a gt aporting Corporation (202) 628-4888 [
L*( O l l l l FEBRUARY 23, 1988 i NRC STAFF PRESENTATION ON DIABLO CANYON O SEISMIC REEVALUATION PROGRAM O i- 2
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-BACKGROUND 1 t
EARLY=1970's H0SGRI FAULTLIDENTIFIED 5.8 KM'FROM DIABLO
-CANYON WITH POTENTIAL FOR MAGNITUDE 7.5 EARTHQUAKE
[ < HOSGRI REANALYSIS PERFORMED WHIC'H REQUIRED MODIFICATION OF.S0ME STRUCTURES AND COMPONENTS _ IN 1978 THE ACRS RECOMMENDED THAT A SEISMIC REEVALUATION BE PERFORMED IN ABOUT-10 YEARS IN THE EARLY 1980'S NEW GE0 LOGIC- INFORMATION WITH DIFFERING INTERPRETATIONS OF-C0ASTAL CALIFORNIA TECTONICS BECAME AVAILABLE 4 g IN 1984 NRC STAFF PROPOSED OPTIONS.FOR THE REEVALUATION OF THE SEISMIC DESIGN BASES FOR DIABL0' CANYON COMMISSIONERS IMPOSED A CONDITION ON THE DIABLO CANYON UNIT 1 LICENSE REQUIRING A REEVALUATION PROGRAM I
-O L
3 , h
SUMMARY
OF LICENSE CONDITION EVALUATE RELEVANT GE0 LOGIC AND SEISMIC DATA AVAILABLE SINCE 1979 AND REEVALUATE EARLIER INFORMATION IF NECESSARY REEVALUATE MAGNITUDE OF. EARTHOUAKE USED AS SEISMIC BASIS REEVALUATE GROUND MOTION ASSESS SIGNIFICANCE USING PRA AND DETERMINISTIC STUDIES TO ASSURE ADEQUACY OF SEISMIC MARGINS o THREE YEAR PROGRAM PLAN SUBMITTED JANUARY 1985 AND APPROVED L BY NRC JULY 1985 L r l O
- . a
(1- . , c - UNDER THE DIRECTION OF THE COMMISSIONERS AND THE ACRS THE THE STAFF WAS URGED TO HAVE-A STRONG REVIEW AND INDEPENDENT PARALLEL PROGRAM NRC REVIEW AND PARALLEL PROGRAM TECTONICS AND GE0 LOGY EARTHOUAKE MAGNITUDE _ SEISM 0 LOGY AND GROUND MOTION ([) -S0IL STRUCTURE lNTERACTION DETERMINISTIC ASSESSMENT PROBABILISTIC RISK ASSESSMENT e i l u l
[ i b GE0 LOGY, TECTONICS AND GEOPHYSICS NRR REVIEW WITH RES STAFF SUPPORT TECHNICAL ASSISTANCE FROM USGS AND UNR SEISM 0 LOGY AND GROUND MOTION NRR REVIEW TECHNICALASSISTANCEFROMV5'GS AND LLNL PANEL S0ll STRUCTURE INTERACTION ([] NRR WITH RES STAFF SUPPORT TECHNICAL ASSISTANCE FROM BNL PANEL PROBABIllSTIC RISK ASSESSMENT RES WITH NRR STAFF SUPPORT TECHNICAL ASSISTANCE FROM BNL REVIEW TEAM ($)'
v . - i O WORKSHOPS, MEETINGS. FIELD TRIPS AND AUDITS GENERAL OVERALL PROGRAM REVIEW 2 GEOLOGV-TECTONICS-GEOPHYSICS 7
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' GROUND ' MOTION - 3 S0ll STRUCTURE INTERACTION 4 1
PROBABILISTIC RISK ASSESSMENT 4 [])
. DETERMINISTIC ANALYSIS 1 l
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40 ILOARD NOTIFICATION SPRING 1987 PG&E INFORMED STAFF 0F A NEWLY DISCOVERED CAPABLE FAULT IN THE SEA CLIFF APPR0XIMATELY 10 KM FROM THE PLANT AND THE POSSIBILITY OF.AN EXTENSION CLOSER TO THE SITE. ALSO, THE ACTIVE STRAND OF THE H0SGRI WAS FOUND TO BE ABOUT 4 KM FROM THE SITE-RATHER THAN THE PREVIOUSLY ASSUMED 5.8 KM. 10 THE STAFF INFORMED THE COMMISSIONSERS VIA A BOARD NOTIFICATION O
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DIABLO CANYON LONG TERM SEISMIC PROGRAM l ADVISORY COMMITTEE ON' REACTOR SAFEGUARDS SUBCOMMITTEE MEETING , .? . FEBRUARY 23-24, 1988 SHERATON INN - SAN FRANCISCO - 1177 AIRPORT BOULEVARD. BURLINGAME. CA 94030 0 AGENDA TUESDAY. FEBRUARY 23. 19M 8:30 a.m. - 9:15 a.m. Introductions
. ACRS
. NRC Staff
. PG&E 9:15 a.m. - 10:00 a.m. Background - PG&E
. The 1978 ACRS Letter
. The License Condition
. The LTSP Program Plan
. The LTSP Scoping Study 10:00 a.m. - 10:15 a.m. Break 10:15 a.m. - 11:00 a.m. Background-PG&E(Continued) 11:00 a.m. - 12:00 noon Current Status of LTSP - PG&E
^ . Geology / Seismology / Geophysics
. Earthquake Ground Motions
. Soil / Structure Interaction
. Fragilities Q . Probabilistic Risk Assessment 12:00 noon - 1:00 p.m. Lunch 1:00 p.m. - 2:00 p.m. Current Status of LTSP - PG&E (Continued) 2:00 p.m. - 2:15 p.m. Break 2:15 p.m. - 4:00 p.m. Current Status of LTSP - PG&E (Continued)
WEONESOAY. FEBRUARY 24. 1988 8:30 a.m. - 10:30 a.m. Current Status of LTSP - PG&E (Continued) 10:30 a.m. - 10:45 a.m. Break l'0:45 a.m. - 12:00 noon Closing Statements
. NRC Staff
. PG&E
. ACRS 1:00 p.m. - 6:00 p.m. Field Visit
. For ACRS members interested in visiting Olablo Canyon Power Plant
O BACKGROUND o Advisory Committee on Reactor Safeguards (ACRS) letter of July 14,1978 in which ACRS suggests "that the seismic design of Diablo Canyon be reevaluated in about ten years taking into account ap-plicable new information." O o ACRS Meeting to Review the Proposed License Condition
-- May 24,1984 - ACRS Subcommittee Meeting in Los Angeles, CA
- June 14-15,1984 - ACRS Meeting in Washington, D.C.
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i O BACKGROUND i o ACRS Letter of June 20,1984
. . . the elements outlined in the NRC Staff's proposal (license condition) will provide a suitable basis for the seismic reevalua-tion.
. . . It is appropriate for PG&E to take the lead in the seismic reevaluation and . . . the NRC Staff's independent evaluation can provide adequate review of the PG&E work. We recommend that the NRC effort include a significant support role for the USGS . . .
. . . we note that the seismic reevaluation includes the perfor-mance of a PRA. We believe that usefulinsight from the PRA would best be gained by PG&E if their personnel have an active O role in this work.
- We request that we be given the opportunity to review and com-ment on the PG&E program plan and schedule. We request also that the NRC Staff meet with us as appropriate to discuss their evaluation of the PG&E work.
o November 2,1984, Facility Operating License DRR-80, for Diablo Canyon Unit No.1 issued, including License Conditions which requires the Long Term Seismic Program. O
r DIABLO CANYON NUCLEAR POWER PLANT O LICENSE CONDITION g
- 1. PG&E shall identify, examine, and evaluate all relevant geologic and seismic data, information, and interpreta-tions that have become available since the 1979 ASLB hearing in order to update the geology, seismology, and tectonics in the region of the Diablo Canyon Nuclear O Power Plant. If needed to define the earthquake poten-l tial of the region as it affects the Diablo Canyon Plant, PG&E will also reevaluate the earlier information and ac-quire additional new data.
O I . L _ _ _-. _ _ _ _ - _ _ . . _ _ _- . __ _ -
IABL ANYON NUCLEAR POWER PLANT O LICENSE CONDITION l
- 2. PG&E shall reevaluate the magnitude of the earthquake used to determine the seismic basis of the Diablo Canyon Nuclear Power Plant using the informa-tion from Element 1.
O
- 3. PG&E shall reevaluate the ground motion at the site l based on the results obtained from Element 2 with full consideration of site and other relevant effects.
i O t i
IABL CANYON NUCLEAR POWER PLANT O LICENSE CONDITION
- 4. PG&E shall assess the significance of conclusions drawn from the seismic reevaluation studies in Ele-
) ments 1,2, and 3, utilizing a probabilistic risk analysis 4 and deterministic studies, as necessary, to assure ade-
- quacy of seismic margins.
i
, O Program Schedule LTSP final report to be submitted to NRC three years fol-1 lowing approval of Program by NRC staff.
l Program Progress
- Quarterly Progress Reports
. Meetings with NRC staff
- ACRS Progress Meetings
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O J BACKGROUND : o January 30,1985 - PG&E submitteA its LTSP Program Plan for review and approval by the NRC 4taff.
- LTSP Program Plan Geological invr d:gations d
Er.rthquake lugnitude Earthquake Ground Motion by Empirical Analysis Earthquake Ground Motion by Numerical Analysis O SoiuStructure interaction Seismic Hazard Analysis Fragility Analysis t Probabilistic Risk Assessment
- Dynamic Character of Long Term Seismic Program
- Program must be flexible to achieve successful completion of Program objectives.
J Elements of Program Plan must not be viewed as absolutes. To be successful, Program must be structured to accommodate l change. Program evolves as work progresses within framework of ap-Proved Plan. O
b O BACKGROUND - o PG&E/NRC Staff Meetings to Review Program Plan:
-- October 4,1984 - To discuss proposed geologic investigations
- November 15-16,1984 - To discuss proposed earthquake mag- ,
nitude and ground motions investigations December 11,1984 - To discuss proposed PRA
- January 10,1985 - To respond to NRC comments, and discuss NRC/PG&E Interaction during implementation of the LTSP O -- May 22,1985 - PG&E response to NRC Staff comments on the , Program Plan ,
1 l - June 24,1985 - PG&E/NRC field trip to review geologic features :
-- March 21,1985 - PG&E and the NRC Staff met with the ACRS sub- l committee to review the Program Plan !
- July 10,1985 - PG&E and the NRC Staff met with the ACRS to review the Program Plan :
-- July 30,1985 - The NRC Staff approved the LTSP Program Plan O
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O DIABLO CANYON LONG-TERM SEISMIC PROGRAM CONSULTING BOARD i Clarence R. Allen Seismic Geology and Tectonics Bruce A. Bolt Seismology and Ground Motions C. Allin Cornell Probability / Risk Assessment ; i 4 O Thomas M. Leps Engineering Cole R. McClure Geology ' i
- H. Bolton Seed Ground Motions and Soil /Struc-ture interaction l l
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1 0 ' BOARD FORMED OCTOBER 1984 TO PROVIDE ADVICE, GUIDANCE, AND REVIEW FOR: o PHASE I PROGRAM PLAN DEVELOPMENT
- o PHASE ll ACTIVITIES TO ESTABLISH PRIORITIES AND !
Q SCOPE OF WORK o PHASE Ill ACTIVITIES, CONDUCT OF WORK , l o FINAL REPORT L V O
O LTSP CONSULTING BOARD MEETINGS
- 1. October 25,1984
- 2. January 7,1985
- 3. January 21,1985
- 4. March 7,1985
- 5. June 12,1985
- 6. July 17,1985 :
- 7. September 26,1965 O 8. november ,, ,985
- 9. January 21,1986
- 10. May 1,1986
- 11. August 7,1986
- 12. November 14 and 15,1986 >
- 13. January 7,1987
- 14. April 29,30, and May 1,1987
- 15. July 2 and 3,1987
- 16. October 12,1987 k
I O NRC/LTSP REVIEWERS Staff Advisor for Geology / Seismology / Geophysics Dr. D.B. Slemmons, University of Nevada, Reno Ground Motion Panel Jean B. Savy - Lawrence Livermore National Laboratory Ralph J. Archaleta - University of California, Santa Barbara Steven M. Day - S - Cubed ' Kelti Aki - University of Southern Cailfornia , l Soll/ Structure Interaction Panel Q Dr. Morris Reich - Brookhaven National Laboratory : Dr. Carl J. Costantino - City College of New York Dr. Geogre Gazetas - Rensselaer Polytechnic Institute l i Dr. Andrew S. Veletsos - Rice University, Texas Fragility Panel 1 Dr. R. Fitzpatrick - Brookhaven National Laboratory Dr. Michael P. Bohen - Sandia National Laboratory Dr. James J. Johnson - EQE, Inc. ! Dr. M. Ravindra - EQE, Inc. ' PRA Advisory Group--Brookhaven National Laboratory : i Robert Fitzpatrick G. Bezoki ; O K. Allefendloglu ;
O LTSP PHASE ll SCOPING STUDY PURPOSE Develop Scope of Work for Phase ill i o Balanced I o integrated o Focused on important Topics O o cie., Sense or prioritie, o Realistic Schedule f i l l O l
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. PHASE 11 - DEVELOPMENT OF SCOPE OF WORK FOR PHASE 111 (SCOPING STUDY)
/~NECTIVES V
e Comprehensive response to-License Condition e Develop clearly defined Scope of Work for Phase III for each Program Element e Develop integrated schedule to complete project within allotted time. PROGRAM ELEMENTS GE0 LOGY / SEISM 0 LOGY / GEOPHYSICS , e Objectives
- To identify and address significant technical considerations relating to assessing the earthquake potential of seismic sources important to Diablo Canyon.
- Technical considerations include:
g- e Fault Location and Orientation e Fault length e Fault Type and Geometry , e Rate of Slip e Fault Segmentation e Earthquake Size s Earthquake Recurrence e Work Tasks Task 1 - Characterization of Hosgri Fault e Review Existing Data e Onshore Geologic Studies e Geophysics Analysis e Interpretive Maps Task 2 - Quaternary Studies . e Geologic Mapping e Fold Analysis O e Interpretation of quaternary oeformation i Task 3 - Seismology e Review and Analysis e Crustal Velocity , e 1927 Lompoc Earthquake
r - GE0 LOGY / SEISM 0 LOGY / GEOPHYSICS () e Work Tasks (Centinued)
~ ~
- Task 4 - Edna, San Miguelito Faults, San Luis-Pismo Folds e Review Existing Data ;
e Geologic Mapping e Offshore Geophysics Review Task 5 - Little Pine-Foxen Canyon Trend e Review Existing Data e Geology Mapping Task 6 - West Huasna, Rinconada Nacimiento Faults e Review Existing Data e Geologic Mapping e Geophysical Analysis Task 7 - Deep Crustal Studies e Review Existing Data ([) e Santa Maria Basin Region e La',a Integration and Interpret;sion , Task 8 .ectonic Model e Review and Synthesizc Fxisting Data e Integration of Additional data Task 9 - Seismic Source Characterization e Specification of Sources s Maximum Earthquake Assessments e Earthquake Recurrence Assessments O :
(]) GROUND MOTIONS e Technical Considerations: e Emrirical Ground Motion Models e Incorporation of Recent Earthquake Recordings e Evaluation of Dispersion, Truncation and Saturation Effects e Wave Propagation and Site Effects e Numerical Methods e Work Tasks Task 1 - Attenuation Relationships e Select Data for Rock Site e Refine Relationships with Recent Recordings Task 2 - Response Spectra e Select Spectra for Rock Site e Refine Spectra with Recent Earthquake Data Task 3 - Time Histories e Select Time Histories e ; e Generate Realistic Time Histories Rock Site - Assess Response Spectral Amplification Factor Task 4 - Site Effects e Assess Ground Motion Variability e Assess Wave Types and Spatial Coherency e Install Ground Motion Instruments Task 5 - Numerical Modeling e Evaluate Attenuation Relationships, Response Spectra and Time Histories e Assess Effects (Fault Types, Geometry, Rupture) ! e Assess Local Site Effects 4
~ ~
1 - (2) SEISMIC HAZARDS ANALYSIS ' e Objective e Develop Probabilistic Ground Motion Estimates ; e Work Tasks ' Task 1 - Evaluate Ground Motion Descriptions , e Peak Acceleration ' e . Peak Acceleration Plus Duration i e Spectral Acceleration i Task 2 - Seismic Hazard Analysis
)
e Develop Hazards Curves l e Sensitivity Analysis e Parametric Studies 1 P I r t i
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i O S0IL/ STRUCTURE INTERACTION e Work Tr.sks Task 1 - Assemble and Review Site Rock Data e Boring and Geophysical Data e Assess Rock Profile and Properties e Perform Simplified Sensitivity Analysis e Evaluate Response Sensitivity Task 2 - Free-Field Input Motions e Literature Evaluation - Spatial Coherenc ' s Sice Specific Free-Field Response Spectra e rree-Field Seismic Wave Incidence Characteristics Ta.ck 3 - Implementation and Testing of CLASSI and SASSI Programs e Verification and Documentation TasP 4 - Development of Scil / Structure Interaction Analytical Models O e o view Dvr.amic Modeis of Power Block Structures e Develop 3-D Structural Dynamic Models e Develop 3-D Foundation Models Task 5 - Correlation with Recorded Data e Analysis of Recorded Data i e Correlation Between Analytical Models and Recorded Data Task 6 - Parametric Studies e Reconciliation of CLASSI and SASSI Solutions e Basemat Flexibilities e Structural Embedment e Variations of Soil / Structure Interaction Properties e Variations of Input Motion Parameters e Soil / Structure Nonlinearities Task 7 - Soil / Structure Interaction Responses O
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t O FRAGILITIES e Work Tasks Task 1 - Reevaluation of Dominant-Contributor to Seismic Risk e Incorporate Results of Soil / Structure Interaction e Improve Phase II Fragilities Task 2 - Median In-Structure Response Spectra Task 3 Assess Lower Tails of Fragility Curves Task 4 - Improve Balance-of-Plant Piping Fragilities Task 5 - Assess Items Not Considered in Phase II Studies O l I i I O l
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l O l PRESENTATIONS AT PROFESSIONAL SOCIETY ! l MEETINGS o SEISMOLOGICAL SOCIETY OF AMERICA o GEOLOGICAL SOCIETY OF AMERICA '- o AMERICAN GEOPHYSICAL UNION lo : l l l l I i O
. , , _ . _ y __ _ _ _,.
EIGHTY-THIRD ANNUAL MEETING {v} -CORDILLERAN SECTION THE GE0 LOGICAL SOCIETY OF AMERICA HILO, HAWAII SEISM 0 TECTONICS OF THE CENTRAL CALIFORNIA C0AST RANGES I: GENERAL SEISM 0 LOGY AND SEISMIC REFLECTION Ina Alterman, Robert Brown, Lloyd Cluff, Richard McMullen, and Burton Slemmons, Presiding
- 1) D. Burton Slemmons: CAPABLE FAULTS AND TECTONICALLY ACTIVE FOLDS OF THE CALIFORNIA CENTRAL C0AST RANGES
- 2) Ray Weldon, Eugene Humphreys: PLATE MODEL CONSTRAINTS ON THE DEFORMATION OF C0ASTAL SOUTHERN CALIFORNIA NORTH OF THE TRANSVERSE RANGES
- 3) Thorx L. Davis, Kirk D. ficIntosh: a RETR 0 DEFORMABLE STRUCTURAL SOLUTION ACROSS THE SOUTHERN COAST RANGES AND IMPLICATIONS FOR SEISHICALLY ACTIVE STRUCTURES
- 4) Eutizio Vittori: STRUCTURAL ANALYSIS OF LATE CEN0 ZOIC DEFORMATION, SOUTHERN COAST RANGES, CENTRAL CALIFORNIA Cc
- 5) P. Dehlinger, B. A. Bolt: TECTONIC PATTERNS AND THEIR VARIATIONS ACROSS A PART OF THE CENTRAL C0AST RANGES OF CALIFORNIA
- 6) W. U. Savage, M. K. McLaren: RECENT SEISMICITY OF SOUTH-CENTRAL COASTAL CALIFORNIA
- 7) C. M. Poley, J. P. Eaton, A. G. Lindh: RECENT SEISMICITY OF THE CENTRAL CALIFORNIA REGION FROM SAN FRANCISCO TO THE TRANSVERSE RANGES
- 8) William U. Savage, Donald V. Helmberger: SOURCE CHARACTERISTICS AND TECTONIC ASSOCIATION OF THE 1927 LOMPOC, CALIFORNIA, EARTHQUAKE i 9) James K. Crouch, Steve B. Bachman: THE NATURE OF THE OFFSHORE HOSGRI FAULT ZONE
- 10) John W. Steritz, Bruce P. Luyendyk: HOSGRI FAULT ZONE OFFSH0RE SANTA MARIA BASIN, CALIFORNIA O
I. . 4 . A EIGHTY-THIRD ANNUAL MEETING V CORDILLERAN SECTION
, THE GEOLOGICAL SOCIETY OF AMERICA HILO, HAWAII SEISM 0 TECTONICS OF THE CENTRAL CALIFORNIA C0AST RANGE II: SAN SIMEON, PISMO SYNCLINE - SANTA MARIA BASIN Ina Alterman, Robert Brown, Lloyd Cluff, Richard McMullen, and Burton Slemons, Presiding
- 1) W. U. Savage, J. M. Howie, C. R. Willingham: INTEGRATED DEEP CRUSTAL STUDIES ONSH0RE/0FFSHORE SOUTH-CENTRAL COASTAL CALIFORNIA
- 2) David Cumings, T. A. Johnson, R. A. Gaal: STRUCTURAL GE0 LOGY, OFFSHORE SANTA MARIA RIVER TO POINT ARGUELLO, CENTRAL CALIFORNIA
- 3) K. L. Hanson, W. R. Lettis, E. L. Mezger, G. E. Weber: LATE PLEISTOCENE DEFORMATION ALONG THE SAN SIMEON FAULT ZONE NEAR SAN SIMEON, CALIFORNIA
- 4) Barbara Matz, D. Burton Slemons: REMOTE SENSING STUDY OF PISMO SYNCLINE AND SANTA MARIA BASIN, CENTRAL COASTAL CALIFORNIA O 5) Katheryn M. Killeen, D. Burton Slemons, Kirk E. Swanson: TIMING OF FOLDING AND UPLIFT OF THE PISMO SYNCLINE, SAN LUIS OBISPO COUNTY, CALIFORNIA
- 6) E. L. Mezger, K. L. Hanson, N. T. Hall, T. D. Hunt: EVIDENCE FOR QUARTERNARY FAULTING IN LOS OSOS VALLEY, SAN LUIS OBISP0 COUNTY, CALIFORNIA
- 7) Steve P. Nitchman, D. Burton Slemons: LATE PLEISTOCENE FLEXVRAL-SLIP FAULTING POSSIBLY TRIGGERED BY CRUSTAL UNLOADING, PISMO BEACH, CENTRAL COASTAL CALIFORNIA
- 8) John M. Coyle, N. Timothy Hall, James V. Hengesh, William R. Lettis:
QUATERNARY DEFORMATION ALONG THE SOUTHWESTERN MARGIN OF THE SAN l LUIS-PISMO SYNFORM, PISMO BEACH, CALIFORNIA l
- 9) K. *. Kelson, W. R. Lettis, G. E. Weber, G. L. Kennedy, J. F.
Wehmiller: AMOUNT AND TIMING OF DEFORMATION ALONG THE WILMAR AVENUE, PISMO, AND SAN MIGUELITO FAULTS, PISMO BEACH, CALIFORNIA O l
i O EIGHTY-THIRD ANNUAL MEETING V CORDILLERAN SECTION THE GEOLOGICAL SOCIETY OF AMERICA HILO, HAWAII SEISH0 TECTONICS OF THE CENTRAL CALIFORNIA C0AST RANGE III: FOLD-FAULT AND SLIP RATES Ina Alterman, Robert Brown, Lloyd Cluff, Richard McMullen, and Burton Slemmons, Presiding
- 1) Thom L. Davis, Martin B. Lagoe: THE 1952 ARVIN TEHACAPI EARTHQUAKE (M-7.6) AND ITS RELATIONSHIP TO THE WHITE WOLF FAULT AND THE PLEITO THRUST SYSTEM
- 2) E. A. Keller, R. L. Zepeda, D. B. Seaver, T. K. Rockwell, D. M.
Laduzinsky, D. L. Johnson: ACTIVE FOLD-THRUST BELTS & THE W. TRANSVERSE RANGES, CALIFORNIA
- 3) N. Timothy Hall: LATE QUATERNARY HISTORY OF THE EASTERN PLEITO THRUST FAULT, SAN EMIGDIO MOUNTAINS, CALIFORNIA
- 4) David P. Schwartz, Ray J. Weldon: SAN ANDREAS SLIP RATES: PRELIMINARY Q RESULTS FROM THE 96 ST. SITE NEAR LITTLER 0CK, CALIFORNIA
- 5) G. E. Weber, W. R. Lettis, K. L. Hanson: LATE PLEISTOCENE UPLIFT RATES ALONG THE CENTRAL CALIFORNIA C0AST, CAPE SAN MARTIN TO SANTA MARIA VALLEY l 6) C. R. Willingham, Douglas H. Hamilton: THE NATURE OF THE HOSGRI FAULT
- ZONE-PART I
- STRUCTURE AND EXTENT l
- 7) R. G. Heck, C. Richard Willingham, D. H. Hamilton: THE NATURE OF THE HOSGRI FAULT - PART II. EFFECT ON STRATIGRAPHY AND TIMING OF TECTONIC EVENTS
- 8) Douglas H. Hamilton: CHARACTERIZATION OF THE SAN GREGORIO-HOSGRI FAULT SYSTEM, COASTAL CENTRAL CALIFORNIA
- 9) Charles N. Branch, N. Timothy Hall: EVIDENCE FROM HIGH-RESOLUTION SEISMIC REFLECTION DATA FOR STRIKE-SLIP MOVEMENT ALONG THE HOSGRI FAULT ZONE, OFFSHORE CENTRAL CALIFORNIA
- 10) Douglas H. Itamilton, N. T. Hall: STRUCTURE AND TECTONICS OF THE SAN LUIS-PISMO-SANTA MARIA REGION, COASTAL CENTRAL CALIFORNIA
- 11) Frank R. Bickner, Patrick R. Vaughan: EVIDENCE FOR HOLOCENE ACTIVITY OF THE SAN SIMEON FAULT FROM DEFORMED FLUVIAL TERRACES NEAR SAN SINE 0N, C0ASTAL CENTRAL CALIFORNIA
-.5* SEISM 0 TECTONICS OF THE CENTRAL CALIFORNIA C0AST RANGE III: FOLD-FAULT AND SLIP RATES (CONTIN,UED)
- 12) N. Timothy Hall, T. Dwight Hunt, Patrick A. Vaughan, Frank R. Bickner, William R. Lettis: TRENCHING AND MAPPING INVESTIGATIONS OF THE LATE QUATERNARY BEHAVIOR OF THE SAN SIMEON FAULT, SAN LUIS OBISP0 COUNTY, CALIFORNIA
- 13) Tom K. Rockwell, Frank R. Bickner, Patrick R. Vaughan, Kathryn L.
Hanson: APPLICATIONS OF S0ll GEOMORPHOLOGY TO DATING AND CORRELATION COASTAL TERRACE DEPOSITS ACROSS THE SAN SIMEON FAULT ZONE, CENTRAL CALIFORNIA
SUMMARY
- Lloyd Cluff O
O
6 EDGE & RELATED SEISMIC PROJECTS (d' ONSHORE /0FFSHORE CENTRAL CALIFORNIA (S318) Presiders, M. Talwani, Geotechology Research Institute, and W. Mooney, USGS, Menlo Park
- 1) B. M. Page: GEOLOGY AND TECTONICS OF THE SOUTHERN COAST RANGES, CENTRAL CALIFORNIA: CURRENT MODELS AND MAJOR UNCERTAINTIES
- 2) David S. McCulloch: OFFSHORE GEOLOGY OF THE SANTA MARIA AREA, CENTRAL CALIFORNIA
- 3) Manik Talwani, Walter Mooney, William U. Savage, C. Richard Willingham, George A. Thompson, Alan Levander, and Anne Trehu: EDGE AND RELATED SEISMIC PROJECTS - ONSHORE, OFFSHORE CALIFORNIA ;
- 4) Anne S. Meltzer, and Alan R. Levander: INTERPRETATION OF DEEP CRUSTAL REFLECTION PROFILES OFFSHORE SOUTHERN CENTRAL CALIFORNIA
- 5) Kirk D. McIntosh, Eli A. Silver, and Donald L. Reed: SEISMIC EXPRESSION OF COMPRESSIONAL DEFORMATION OFFSHORE CENTRAL CALIFORNIA:
EDGE PROFILE RU-3
- 6) Douglas H. Clark, Douglas H. Hamilton, N. Timothy Hall, and Ronald G.
Heck: TIMING AND STYLE OF NE0 GENE DEFORMATION WITHIN THE OFFSHORE SANTA MARIA BASIN, CALIFORNIA
- 7) C. Richard Willingham, and Jan D. Rietman: DEEP SEISMIC AND POTENTIAL FIELD CRUSTAL STUDY ACROSS THE SOUTH CENTRAL CALIFORNIA BORDERLAND AND ADJACENT ONSHORE AREAS -
- 8) Anne Trehu, John Shay, Greg Miller, and Bob Brown: LARGE-0FFSET DATA RECORDED BY OCEAN BOTTOM SEISMONETERS ALONG PG&E LINE 1
- 9) John M. Howie, and William U. Savage: INITIAL CRUSTAL VELOCITY MODEL FOR SOUTH-CENTRAL CALIFORNIA C0ASTAL MARGIN
- 10) Alan R. Levander: INTERPRETATION OF A CONTINUOUS-0FFSET SEISMIC PROFILE IN THE CENTRAL CALIFORNIA MARGIN
- 11) Allan Walter, and Susan Sharpless: CRUSTAL VELOCITY STRUCTURE OF THE
.EUR-0BISPO (FRANCISCAN) TERRANE BETWEEN SAN SIMEON AND SANTA MARIA, CALIFORNIA
- 12) Carl H. Wentworth: IMPLICATIONS FR0 CRUSTAL STRUCTURE IN THE WESTERN COAST RANGES, CALIFORNIA, FROM STUDIES ALONG THEIR EASTERN MARGIN
- 13) Marica K. McLaren, and William V. Savage: RELOCATION OF EARTHQUAKES O OFFSHORE FROM POINT SAL, CALIFORNIA
e A i 7 U EIGHTY-SECOND ANNUAL MEETINC 0F THE SEISMOLOGICAL SOCIETY OF AMERICA SANTA BAO,BARA, CALIFORNIA, MARCH 25, 1987 STRONG GROUND MOTION David Wald, and Francis Wu, Presiding
- 1) M. J. Rymer: ASPECTS OF THE SAN SALVADOR, EL SALVADOR, EARTHQUAKE OF OCTOBER 10, 1986
- 2) Randall A. White: STATISTICS OF VOLCANIC CHAIN EARTHQUAXES IN AND NEAR SAN SALVADOR
- 3) David H. Harlow, Randy A. Whita, Martinez, Carlos, Alvarez, Salvador:
THE SAN SALVADOR EARTHQUAKE OF OCTOBER 10, 1986
- 4) A. F. Shakal, M. J. Huang, C. E. Ventura, R. Linares: PROCESSED STRONG MOTION DATA FROM THE SAN SALVADOR EARTHQUAKE OF OCTOBER 10, 1986 AND COMPARISON TO SOME EXISTING CLOSE-IN RECORDS
- 5) J. Anderson, J._Brune, J. Prince, S. Singh, R. Quaas: GUERRER0 ACCELEROGRAPH ARRAY-STATUS REPORT L D. Y. Papastamatiou, N. Mouyaris, V. N. Margharis, N. P. Theodoulidis, 6)
P. M. Hatzidimitriou, C. A, Pap 11oannou, B. X. Papazachos: THE XALAMATA SEPTEMBER 13, 1986 EARTHQUAXE IN SOUTHERN GREECE
- 7) Francis T. Wu: A TALE OF TWO COALINGA ACCELEROGRAMS
- 8) Wan, Peide, Wu, Francis, T: SYNTHETIC OF STRONG GROUND MOTION IN THE NEAR SOURCE REGION WITT, EMPIRICAL GREEN'S FUNCTIONS--YUNNAN, CHINA
- 9) D. Wald, P. Somerville, D. Helmberger: COMPATIBILITY OF ACCELER0 GRAMS OF THE 1979 IMPERIAL VALLEY EARTHQUAKE WITH SLIP DISTRIBUTION ASPERITY MODELS
- 10) A. J. Mendez, J. E. Luco: SIMULATION OF NEAR FIELD EARTHQUAKE GROUND MOTION BY A STEADY-STATC DISLOCATION MODEL IN A LAYERED HALF-SPACE
- 11) C. B. Crouse, B. Hushmand: EXPERIMENTAL INVESTIGATIONS OF SOIL / STRUCTURE INTERACTION AT CDMG AND USGS ACCELEROGRAPH STATIONS
- 12) A. Anooshehpoor, N. James R. H. Lovberg: SOIL / STRUCTURE INTERACTION AND TOPOGRAPHIC AMPLIFICATION IN FOAM RUBBERA
INTERNATIONAL ASSOCIATION OF SEISMOLOGY (p) , AND PHYSICS OF THE EARTH'S INTERIOR 19TH GENERAL ASSEMBLY, VANCOUVER, CANADA AUGUST 11, 1987 INTERPRETATIONOFSTRONGMOTIONWAVEFORMS(0RALANDPOSTER) CONVENOR: Dr. D. H. Weichert COCONVENORS: Prof. B. A. Bolt, and Prof. Lili Xie, Harbin CHAIRING: D. H. Weichert, Li-Li Xie, B. Bolt, and V. Schenk
- 1) John Boatwright: THE ACCELERATION RADIATED BY DISCRETE SUB-EVENTS EMBEDDED IN A COMPOSITE RUPTURE PROCESS
- 2) P. Somerville, D. Wald, and D. Helmberger: COMPATIBILITY OF ACCELER0 GRAMS WITH SLIP DISTRIBUTION ASPERITY MODELS
- 3) Kojiro Irikura and Keiiti Aki: SCALING LAW OF SEISMIC SOURCE SPECTRA AND EMPIRICAL GREEN'S FUNCTION FOR PREDICTING STRONG GROUND MOTIONS
- 4) V. Schenk: ANALYSIS OF STRONG GROUND MOTIONS IN AMPLITUDE
(] 5) DOMAIN--REVIEW AND APPLICATIONS V. M. Graizer: BEARING ON THE STRONG MOTION REGISTRATION PRINCIPLES l
- 6) D. M. Boore: STOCHASTIC MODELS FOR PREDICTION OF GROUND MOVIONS AND INSTRUMENT RESPONSE: A STATUS REPORT i
- 7) Edmund Reiter, Anton M. Dainty, and M Nafi Toksoz: NEAR FIELD ATTENUATION IN THE NORTHEASTERN UNITED STATES AND EASTERN CANADA
- 8) Bruce Bolt, and Shyh-Jeng Chiou: STRONG MOTION ARRAY ANALYSIS OF THE NOVEMBER 14, 1986 TAIWAN EARTHQUAKE
- 9) S. K. Upadhyay, and Sudhir Kumar: EARTHQUAKE SOURCE PROPERlIES AND WAVE PATH ATTENUATION CHARACTERISTICS FOR EARTHQUAKES IN HIMALAYA AND NORTHEAST INDIA
- 10) Jafar Shoja-Taheri: RUPTURE VELOCITY AND STRESS DROP OF THE TABAS, IRAN EARTHQUAKE
- 11) D. H. Weichert, R. B. Horner, and R. Baldwin: NAHANNI STRONG MOTION RECORDS
- 12) P. Suhadole, F. Vaccari, and G. F. Panza: THE RUPTURE TIME HISTORY AND THE MECHANISM OF THE 1980 IRPINA, ITALY EARTHQUAKE FROM COMPLETE SYNTHETIC MODELING 0F STRONG HOTION DATA
a ! i
~
('}' INTERPRETATION OF STRONG MOTION WAVE FORMS (ORAL AND POSTER) (CONTINUED) [ t I
- 13) S. Yoshikawa, T. Kitano, Y. Iwasaki, and M. Tai: THE SYNTHESIS OF die NEAR FIELD STRONG GROUND MOTION CONSIDERING RADIATION AND DIRECTIVITY
- 14) Li-Li Xie: AN INTERPRETATION OF THE VARIANCE OF GROUND MOTION IN A l SMALL AREA ,
- 15) Klaus H. Jacob, and Junho Um: STRONG GROUND MOTIONS OF THE Mw 8 EARTHQUAKE OF MAY 7, 1986, IN THE ANDREANOF ISLANDS, ALASKA {
INTERPRETATION OF STRONG MOTION WAVE FORMS I TUESDAY, AUGUST 11 POSTER SESSION
- 1) J. M. Churcher, S. M. Spottiswood, and D. Brawn: MINE TREMOR STUDIES AT A SOUTH AFRICAN GOLD MINE
- 2) A. Rovelli, M. DiBona, and G. Valensise: THE INFLUENCE OF LOCAL SITE ;
~
FREQ'JENCY-DEPENDENT AMPLIFICATIONS ON THE SCALING OF THE PEAK GROUND MOTION ; Q 3) Zheng-xing Yao, and Tian-yu Zheng: LULONG EARTHQUAKE STRONG MOTION MODELING FOR THE 1982 j k t i
?
t l I l'
I k G (d AMERICAN GEOPHYSICAL UNION 1987 FALL MEETING SAN FRANCISCO, CALIFORNIA DECEMBER 7, 1987 STRONG GROUND MOTION S. Seale, and K. Yomogida, Presiding
- 1) J. Hill, H. Benz, G. Schuster: A FINITE DIFFERENCE SIMULATION OF SURFACE WAVES AND RESONANCE EFFECTS IN SALT LAKE VALLEY, UTAH
- 2) 8. A. Bolt, S. J. Chiou: MODAL CONVERSIGN AND AMPLIFICATION OF STRONG GROUND MOTION BY ALLUVIAL BASINS
- 3) S. H. Seale, R. J. Archuleta: SITE EFFECTS AND SEISMIC AMPLIFICATION AT MCGEE CREEK, CALIFORNIA
- 4) J. A. Rial: EIGENMODES AND EIGENFREQUENCIES OF RESONANT THREE
. DIMENSIONAL SEDIMENTARY BASINS S) H. Kawase, F. J. Sanchez-Sesma, K. Aki: SITE AMPLIFICATION FAR BEYOND THE IMPEDANCE RATIO FOR INCIDENT SV WAVES
- 6) K. Aki, S. Steacy, M. Campillo, H. Kawase, F. J. Sanchez-Sesma:
SOURCE, PATH AND SITE EFFECTS ON STRONG GROUND MOTION DURING THE MICHOACAN EARTHQUAKE OF 1985
- 7) S. M. Day, J. L. Stevens: SIMULATION OF GROUND MOTION FROM THE 1985 MICHOACAN, MEXICO EARTHQUAKE - .
- 8) S. J. Steacy, K. Aki, M. Campillo: THE MICHOACAN EARTHQUAKE OF 1985:
DISLOCATION OR CRACK GROWTH?
- 9) K. Yomogida: DYNAMIC RUPTURE PROCESSES INFERRED FROM NEAR-FAULT OBSERVATIONS
- 10) 5. D. Ruppert, K. Yomogida: NEAR-FIELD SYNTHETIC SEISM 0 GRAMS FOR THE MICHOACAN, MEXICO EARTHQUAKE OF SEPTEMBER 19, 1985
- 11) A. Reyes, t.. Mendoza, J. Acosta F. Favela, R. Lopez, M. Diaz A.
Yazques, J. Otero: STRONG MOTION INSTRUMENTATION PROGRAM (STATE OF DEVELOPMENT)
- 12) D. J. Wald, P. G. Somerville: SEMI-EMPIRICAL MODELING OF RECORDED ACCELERATIONS FROM THE 1979 IMPERIAL VALLEY EARTHQUAKE ,
- 13) P. G. Somerville, J. P. McLaren, C. K. Saikia: FORMULATION AND nU VALIDATION OF A PROCEDURE FOR THE SITE SPECIFIC ESTIMATION OF SPATIAL COHERENCE OF GROUND MOTIONS CLOSE TO AN EXTENDED SOURCE
5 o () AMERICAN GEOPHYSICAL UNION FALL MEETING SPECIAL SESSION ON THE WHITTIER NARROWS OF OCTOBER 1, 1987 DECEMBER 11, 1987
- 1) E. Hauksson: THE 1987 WHITTIER NARROWS EARTHQUAKE IN THE LOS ANGELES METROPOLI1AN AREA, CALIFORNIA: OVERVIEW, LOCATIONS AND SEISM 0 TECTONICS
- 2) L. M. Jones: SPATIAL VARIATIONS IN THE LOCATIONS AND FOCAL MECHANISMS OF AFTERSHOCKS OF THE 1987 WHITTIER NARROWS EARTHQUAKE, LOS ANGELES COUNTY, CALIFORNIA
- 3) A. J. Michael: STRESS AND STRAIN IN THE WHITTIER NARROW AFTERSHOCKS
- 4) S. L. Salyards: THE WHITTIER NARROWS EARTHQUAKE AFTERSHOCK SEQUENCE:
FEWER AFTERSHOCKS THAN TYPICAL FOR SOUTHERN CALIFORNIA
- 5) P. A. Reasenberg: PRELIMINARY ANALYSIS OF SEISMICITY PRECURSORS OF THE 1987 WHITTIER NARROWS EARTHQUAKE
- 6) T. L. Davis: THE WHITTIER NARROWS EARTHQUAKE (M-5.9) AND ITS RELATIONSHIP TO ACTIVE FOLDING AND THRUST FAULTING ALONG THE NORTHERN MARGIN OF THE LOS ANGELES BASIN
- 7) J. Lin: C0 SEISMIC FOLDING DURING THE WHITTIER NARROWS, CALIFORNIA, (V3 EARTHQUAKE
- 8) E. M. Gath: THE WHITTIER FAULT IN SOUTHERN CALIFORNIA; PRELIMINARY RESULTS OF INVESTIGATIONS
- 9) G. Ekstrom: PRELIMINARY CMT SOLUTION OF THE WHITTIER EARTHQUAKE
- 10) W. W. Chan: SOURCE-TIME FUNCTIONS FOR THE WHITTIER NARROWS EARTHQUAKE OF OCTOBER 1, 1987 AND ITS AFTERSHOCK FROM MAXIMUM LIKELIHOOD MULTICHANNEL DECONVOLUTION
- 11) A. Brent: BODY WAVE MODELING OF THE WHITTIER NARROWS, CALIFORNIA EARTHQUAKE OF OCTOBER 1, 1987
- 12) 8. A. Bolt: EXTENDED REGIONAL BROADBAND WAVE RESOLUTION OF THE 1987 WHITTIER NARROWS, CALIFORNIA EARTHQUAKE
- 13) M. J. S. Johnston: STATIC MOMENT OF THE OCTOBER 1, 1987, WHITTIER NARROWS EARTHQUAKE FROM BOREHOLE STRAIN DATA
- 14) A. F. Shakal: STRONG-MOTION DATA FROM THE WHITTIER EARTHQUAKE OF OCTOBER 1, 1987
- 15) D. J. Wald: SIMULATION OF ACCELER0 GRAMS OF THE 1987 WHITTIER NARROWS EARTHQUAKE
.y.
AMERICAN GEOPHYSICAL UNION FALL MEETING SPECIAL SESSION ON THE WHITTIER NARROWS OF OCTOBER 1, 1987 DECEMBER 11, 1987 (CONTINUED)
- 16) O. Banamassa: DIGITAL RECORDING OF AFTERSHOCKS OF THE OCTOBER 1, 1987, WHITTIER NARROWS, CALIFORNIA, EARTHQUAKE
- 17) G. W. Simila: NEAR-FIELD ACCELERATIONS FROM THE AFTERSHOCKS OF THE OCTOBER 1, 1987 (M-5.9) WHITTIER NARROWS EARTHQUAKE
- 18) T. C. Hanks: THE MOTION OF MILLIKAN LIBRARY AT VERY SMALL AMPLITUDES
- 19) C.G. Bufe: SITE RESPONSE INFORMATION FROM THE WHITTIER NARROWS EARTHQUAKE AND ITS AFTERSHOCKS
- 20) J. P. Mutschlecner: INFRASONIC OBSERVATIONS OF THE WHITTIER' CALIFORNIA, EARTHQUAKE l 21) S. D. Oaks: THE OCTOBER 1, 1987, WHITTIER NARROWS, CALIFORNIA l EARTHQUAKE: A VIEW FROM CONGRESS O
1 O
4
\
l DIABLO CANYON LONG TERM SEIMIC PROGRAM PG&E/NRC MEETINGS
- 1. May 8,1984 PG&E/NRC - To Discuss Draft Ele- l ments of License Condition
- 2. May 24,1984 ACRS Subcommittee
- 3. June 14,1984 ACRS
- 4. October 4,1984 PG&E/NRC - To Discuse Proposed Geologic investigation
- 5. November 15-16,1984 PG&E/NRC To Discuss Proposed Earthquake Magnitude and Ground ;
i O Motions Investigstions
- 6. December 11,1984 PG&E/NRC - To Discuss Proposed PRA
- 7. January 10,1985 PG&E/NRC - To Respond to NRC ;
Comments, and Discuss NRC/PG&E interaction [ l ,
- 8. March 2122,1985 ACRS Subcommittee ,
- 9. May 22,1985 PG&E/NRC - Response to NRC !
Comments on Program Plan i
- 10. June 24 25,19P'^ PG&E/NRC - Fleid Trip O ,,. Juiy ,0-11,1P ^ ACRS Subcommittee & ACRS
? \
O PGE&E/NRC MEETINGS (CONTD) l
- 12. October 21,1985 PG&E/NRC - Soll/ Structure Interaction Workshop
- 13. December 12,1985 PG&E/NRC - Ground Motions Workshop i
- 14. March 11-12,1986 PG&E/NRC - LTSP Coordination ;
- 15. April 14-15,1986 PG&E/NRC - Ground Motions Workshop l
- 16. May 28-29,1986 PG&E/NRC - G/S/G Workshop O 17. August 15-16,1986 PG&E/NRC - Field Trip !
. l
. 18. August 20-21,1986 PG&E/NRC - PRA Workshop i -
- 19. October 21-22,1986 PG&E/NRC - G/S/G Workshop i ;
- 20. October 23-24,1986 PG&E/NRC - Ground Motions Work-shop
- 21. November 20,1986 ACRS Subcommittee
- 22. December 10-12,1986 PG&E/NRC - Soll/ Structure Interaction i l Workshop l I
- 23. December 16,1986 PG&E/NRC - Ground Motions l Workshop l O ,
i
t da O . PG&E/NRC MEETINGS (CONTD) l l
- 24. February 17-18,1987 PG&E/NRC - PRA Workshop l
- 25. May 5-8,1987 PG&E/NRC - G/S/G Workshop and Field Trip ,
- 26. July 15-16,1987 PG&E/NRC - Ground Motions Workshop
- 27. November 2-3,1987 PG&E/NRC - Fragilities Workshop
- 28. November 4-6,1987 PG&E/NRC - Soll/ Structure interaction l Workshop ,
- 29. January 14-15,1988 PG&E/NRC - PRA Workshop i
i , i l lO . 1 1
o's,- o ;
'v yc U ,g DIABLO CANYON LONG TERM SEISMIC PROGRAM PROGRESS GECL/SEIS/ GEOPHYSICS DATA ACQUISITION $P7# ff8 7[fff7 8 M 7/#7/ffffd 75%
ANALYSIS & INTERP !!$ #V fff/ 7//# M M 7/3 X#sii$$ 65% GROUND MOTIONS DATA ACQUISITION FV//7///#f; fin @WMJWFfffffffj 90% ANALYSIS & INTERP W/ 7/7/ f/ M Ff M J s P F 7 / W J fJ 70% SOIL /STR. INTERACTION ANALYS!S & INTERP Vf/27//#fMdijiii!!sjiMMfd 75% FRAGILITY ANALYSIS ANALYSIS & INTERP F # f7/ X W # f F # 7 #f/7//f M 80% PROB RISK ANALYSIS l ANALYSIS & INTERP F/###77//dilfF'/////47/////A 85% 0% 20% 40% 60% 80% 100 % l
.y , bd4f 3 l 4
O GEOLOGY /SElSMOLOGY! GEOPHYSICS WORK PLAN
-Focused
-Data-Driven O
l DATA ACQUISITION DATA ANALYSIS DATA INTERPRETATION SEISMIC SOURCE CHARACTERIZATION , l l
?' ;
l O DATA ACQUISITION LITERATURE REVIEW GEOLOGIC STUDIES
-marine and fluvial terraces
--age dating
--fault trenching i
!O OFFSHORE AND ONSHORE GEOPHYSICS
-COMAPS high-resolution near-shore study done by PG&E
-Digicon/PG&E deep crustal survey; includes Rice, HARC, USGS
-Additional proprietary Western and Nekton CDP lines
-Reprocessing of selected lines
--California State Lands data collected within 3-mile limit CENTRAL COAST SEISMIC NETWORK O
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'opographic feature of the Og'e,1985 (Southern Of fshore 4
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"- Mapped fault, dotted where concealed. Jennings (COMG),1975 Hall,1977 (Santa Maria River F. (?))
Os --- Trend of proposed subsurf ace fault. McCulloch et. al. (USGS),1980 (Santa Lucia Bank area) Sylvester and Darrow,19/8 g Anticlinal fold, expressed as (Santa Ynez River F. (?)) topographic feature of the Ogfe 1985 (Southern Offshore 4 sea floor. Santa Maria Basin) SANTA MARIA BASIN REGION
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b G **5 ~~' i - jilf 1ll@ Map Symbols Fault Data Sources
.*. Mapped fault, dotted where conc,:aled. Jennings (CDMG),1975 Hall,1977 (Santa Maria O - -.- Trend of proposed subsurface fault. McCulloch et. al. (USGS),1980 (Sar u Lucia Bank area)
River F. (?)) Sylvester and Darrow,1978 l g Anticlinal fold, expressed as (Santa Yner Rher F. (?)) j g topographic feature of the Ogle.1985 (Southern Of fshore Santa Maria Basin) sea floor. l SANTA MARIA BASIN REGION
\
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Map Syrnbols Fault Data Sources
.- Mapped fault, dotted where concealed. Jennings (CDMG),1975 Hall.1977 (Santa Mara O --- Trend of proposed subsurface f ault. McCulloch et. al. (USGS),1980 (Santa L.ucia Bank area)
River F. U)) Sylvester and Darrow.19 78 g Antichnal fold expressed as (Santa Ynez River F. (?)) topographic feature of the Ogle.1985 (Sc uthern Of fshore sea floor. Santa Maria Basin) SANTA MARIA BASIN REGIO *.
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1 O DIGICON DEEP CRUSTAL MARINE SURVEY SPECIFICATIONS DATE: November 1986 NAVIGATION: SYLEDiS Primary LORAN C Backup SHIP: ATLANTIC SEAL REFRACTION SURVEY SOURCE: 10,000 cubic inch tuned airgun array SHOT INTERVAL: 1 minute (approx.150 m) REFLECTION SURVEY SOURCE: 6,000 cubic inch airgun array CHANNELS:180 GROUP INTERVAL: 25 m SHOT INTERVAL: 50 m OFFSET: 241.5 TO 4716.5 m . l FILTER: 3 TO 80 Hz . RECORD LENGTH: 16 see SAMPLE RATE: 4 ms 1 O
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- )i l[ . 4 l i -- * ~ -~ ~~
Map Symbols Fault Data Sources O Mapped fault, dotted where concealed. Jennings (CDMG),1975
*" Hall,1977 (Santa Maria River F. (?))
--- Trend of proposed subsurf ace fault. McCulloch et. al. (USGS).1980 (Santa Lucia Bank area) Sylvester and Darrow.1978 6
Antictinal foid, expressed as (Santa Ynez River F. (?)) g topogr4Dhic feature of the Ogle.1985 (Southern Of fshore sea floor. Santa Maria Basin) SANTA MARIA BASIN REGION
~
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Q- : - - - * ~ , - Map Symbols Fault Data Sources ;
... Mapped fault, dotted where concealed. Jennings (CDMG),1975 Hall,1977 (Santa Maria River F. (?))
--- Trend of proposed subsurface fault. McCuMoch et. al. (USGS),1980 (Santa Lucia Bank area) Sylvester and Darrow.1978 g
Antklinal fold, expressed as (Santa Ynez River F. (?)) j topographic feature of the Ogte.1985 (Southern Of fshore sea floor. Santa Maria Basin) SANTA MARIA BASIN REGION
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- O O CENTRAL COAST SEISM L ,'
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PROCEESING
-s 19 STATIONS _
44 DATA CHANNELS %. : , SAN FRANC?SCO b
=
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CENTRAL COAST SEISMIC ACTIVITY 9/87 121.33 2/88 )- , _ 120.33 l oe?p OG 0 0
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1 O DATA ANALYSIS OFFSHORE GEOPHYSICS ANALYSIS
-Trend maps
-Structure contour and isopach maps ,
-Structural sections
-Fault surfaces ,
--Bathymetry FAULT BEHAVIOR ;
- O -Stratigraphic Correlations !
-Timing of fault and fold development
--Recency of faulting / folding
! -Slip / deformation rate , 1 SEISMICITY ANALYSIS l -Earthquake relocations
--1927 Lompoc earthquake O
l
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.,, ' SEISMIC OATA Geophysical Serv ces lac.1980 Line 97 -- !
s Location Map ' P. - e e.* , 4 oCe
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[ t b Leagth: 33 Km. (21mi) i Record Leagth:5 5ec. , Somote Rote: 4 Vs CDP 5f ACK: 4800'4 Wo.e Eovation Migration WELL INFORM ATION , s Chevron OC 5 P-060 1
* [
tocotion' j',dy,3.87 3 UT Drilled 1964 , f.D. 2445 m (8020 f t.) W.D.164m 1550f t-) I
- Projected 1463m. (4800f t) NW iato hae of sectioa Go.ty OC5 P 03951 !
tocation l.*dfje'ei UI Drilled 1963 _ T.D 2377m.(7800f t.) W D.236m (774 f t.)
~
Projected 610m (2000f e.)St iato leae of section
?
GEOLOGIC ' HORIZON I AGE
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-120-110-100-90 70 50 30 10 0 10 20 30 40 50 MODEL PG&E-3 OISTANCE (KM)
o O O' ' ASP 27 1105 l 1166 ASP 152 g COAST SP4 g SP5 SP6 SW 0 il.. r.liiiili...l 1 E NE
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-120-110-100-90 70 50 30 10 0
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B, DE ,D % / / o ' OF INT BUCHON a
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EXPLANATION vana . -- Scarp . __ \ 100 l ath: contour g
+
+ l,'01#2,"*'"*" -
LATE PLEISTOCENE STILL STANDS: 4 DEPTH: x 103yrs b.p. ! 4 3, 3,3 , O. s Q t8m s.s g- g, L
O SOURCE PARAMETERS OF THE 1927 LOMPOC l EARTHQUAKE i DATA: LONG-PERIOD SEISMOGRAMS AT DE BILT, NETHER- : LANDS; REGIONAL SEISMOGRAMS AT TUCSON, ARIZONA; BERKELEY AND MOUNTliAMILTON, CALIFORNIA ' APPROACH: - COMPARISON OF 1927 LOMPOC SEISMOGRAMS WITH SEISMOGRAMS OF THE 1969 SANTA LUCIA BANK AND 1983 COALINGA EARTHQUAKES, ! O WHOSE SEISMIC MOMENTS AND FOCAL : MECHANISMS ARE KNOWN. METHOD: COMPARISON OF RECORDED AND SYNTHETIC BODY WAVES: , P- WAVES S- WAVES 1 I l 1 O l [
--,n..,. ,e.- - , .. -.. -- - -- -- -_ _ _ _ . _- _. __ ____ - _
l i j Q 83/07/22 COALING A AFTERSHOCK 25 Mo .5 x 10 ergs 8ts ; I, .5, I sec SANTA LUCI A BANKS , Mo = .l5 x 10 26 ergs h = 8 km 8t s;I,!,I sec . COALING A MAINSHOCK 3 26 ergs kf Mo = .4 5 x 10 O ~T V h = 10 km 8t s ; l ', 3 , I s e e g P h LOMPOC . l p3 3 sec 1 f Mo = 1.0 x 10 26 ergs h = 10 km , 8ts ; 2,2,2 sec j O u i
.. 1 l
O l NOVEMBER 4,1927 LOMPOC EARTHQUAKE . Focal Depth: 10 km Focal Mechanism: Strike N23W, Dip 66 NE Strike N23W, Dip 23 SW Seismic Moment: 1 x 10 26 Moment magnitude: 6.6 O Surface wave uagnitude: 7.0 (eutenberg notepae) Long-Period Body-Wave Magnitude: 7.3 (Gutenberg notepad) , e i .I I
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O i POINT SAL MASTER EVENT LOCATIONS _n . . . . . - - - ,. ' l 1 i 35*- O, g*
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O O O' r POINT SAL MASTER EVENT LOCATIONS 4 H C 4 o- J t' - -J .. -
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O DATA INTERPRETATION OVERVIEW OF THE HOSGRI FAULT ZONE
-Northern termination :
-San Luis/Pismo reach ,
-Point San Luis to Point Sal reach 6
-Southern Termination ,
O SAN LUIS/PISMO BLOCK l
-Folding versus faulting
-Rates of uplift
-Other items? ,
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@ San Luis Sey feutt j
% 5teweteroNy tem,les reae A nettie.ashe trece ,
Atee of pre orved Pleistocene
.aer.no terraces B Olsen teoce 0.20 u,sitt ere in mm/ye .*6eed from ,
aior a. toeree. eievetieae @ t. s.,,e. c,.cture ( h Block Lake Ceavoa menocleae p
@ Ocenas fevit 0 10 Km '
('$l Pectie f evtt i I I
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Index map of the San Luis Pismo structural block illustrating distribution of marine terraces and uplif t rates derived from j marine terrace elevations, 7 I
O l SEISMIC SOURCE CHARACTERIZATION DEVELOP SOURCE PARAMETERS USING INTEGRATION OF MULTIPLE DATA SETS AND METHODOLOGIES
-Fault Geometry
-Magnitude
-Recurrenco O EVALUATE UNCERTAINTY ASSESS ALTERNATIVES 0 !
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O 10 20 30 mi g i i i l i i 1 0 10 20 30 km Honda,, N _ ,,,
~~
Fault Zone Slip Rate s
, 4
~
summmme > 10 mm/yr N 1 10 mm/yr $ c3 0.1 1 mm/yr 0.01 0.1 mm/yr SLIP RATES OF FAULTS IN COASTAL CENTRAL CALIFORNIA i
F SEISMIC SOURCE CHARACTERIZATION O PRELIMINARY RESULTS - 11 A4/86 o Onshore and near-shore geologic studies in San Simeon area are valuable to characterizing Hos,grl: sense of slip; near-surface geometry, slip rate, earthquake recurrence, displacement per event. o Offshore geophysics is helping to clarify lateral continuity, seg-mentation, structural relationships, history of slip. Promise for down-dip expression, crustal models, etc. o No "surprises" or significant findings have been identified that were not effectively included for source characterization in the Phase ll study. PRELIMINARY RESULTS - 2/23/88 Q o The LTSP Geology, Seismology, and Geophysics activities are em-phasizing data interpretation leading to seismic source
- characterizations that integrate multidisciplinary data sets and analyses, explicitly treat uncertainties, and address alternative source characterization niodels, o The San Miguellto and Edna faults are not capable according to Ap-pendix A criteria.
o Pismo synclinorium has not been subject to active folding for the past 700,000 years or longer and is subject to block uplift. The San Luis!Pismo block is bounded by the dip-slip Los Osos fault along : this northeastern edge. The Wilmar Avenue, Oceano, Pecho, and San Luis Bay faults lie southwest of the block and are discon- ' tinuous and have very low slip rates. The Hosgri fault zone bounds the western edge of the block. I o The November 4,1927, earthquake was a nearly pure dip-slip event having strike about N23W and had a focal depth of 10 km. The sels-mic moment of the earthquake was 1 x 10 26 , corresponding to a O moment magnitude of e.e. The surface wave magnitude was 7.0.
Les+ t O Jia):.0 Canyon _ang "erm Seismic 3rogram Grounc Mo': ion S:ucies 03lec:ives o una:e ':le grount mo': ion assessment
- or :le si:e a ]roVice grount ma': ion ca:8 or engineering ana:.yses A))roacles
- Com]i:.e anc use an u]Ca:ec s':rong O motion Cata Jase ;
- lse re*inec geo:.ogy/seismo:.ogy/
geo]1ysics in"orma': ion
- lse avai:.a):.e grounc motion recorcings a: :le si:e ;
- lse 30':1 em]irica:. anc numerica:.
made:.ing me':locs O . h
l O Curren: S~a:Us 0 3 3rounc Vo': ion S:ucies h Em]irica:. S':ucles
- Com]i:.a: ion 0" s':rong motion ca:a Jase
- le"inemen: 0" 3GA anc SA a:':enuation re:.ationsli]s 3rogress in si':e-s]eci"ic grounc mo': ion clarac':erization .
sumerica: Moce:ing Stucies i i O - Jeve:.o] men: o" tie semi-em]irica:. ;
; simu:.ation me': loc
- Ca:.i]ra': ion 0" :le Semi-em]irica:.
- simu:.a~: ion me': loc 3re:.iminary resu:.':s 0" simu:.a: ions Assessmen: 0" S]a':ia:. ':ncolerence l - Assessmen: 0" :le e" ects 0" extencet l
au:.': rul:Ure ! l
- Ana:.ysis 0" exis:in( site recorcings l
- 0] era: ion 0" a ree-field grounc ;
l mo':lon array O : t
O Grounc Va': ion :a:a 3rovicec :o ;a:e ;
- or Engineerinc Ana:.yses
- or Tragi:.i':y Ana:.ysis
.2 sets 0" em]irica:. acce:. era: ion
':ime lis':ories
.L sets o* simU:.a' ec 8CCe:. era: ion time lis:ories
- or Soi:-S:ructure ~:n:erac: ion Ana:.ysis
- Mecian si':e-s]eci'ic s]ectra:. sla]e O - Esets o' cancica:e acce:. era-ion ':ime lis:ories to ma:cl t1e site-s]eci*ic s]ectra: sla]e - S]a':ia:. incolerence unc': ions E
t o : l
\
O g.:ronc V0': ion :a':a 3ase 20m]i:.ec
~= ~
':le ::_ SJ 2
0P e 27 Sla:.:.ow 'ocus Crus':a:. Ear: 1cua<es e Namen: Magnituce Mw; rom L.6 :o 7./ e C:.oses': Jis:ance to r au:.': :;ur:ure Sur ace;;; rom :.': 0 300 <m :or 3GA anc rom :. :o 50 <m :or SA O e :oc< or :oc<-:.i<e ::ecorcing Sites ! e '.5/ :;ecorcings or 3GA : ! 65 :'ecorcings or SA i l l [ O 1 i i
.T3;:1 4: EARTHQUAXI.S PPCCU.... .;Ch S INCLUDED IN THE LTSP OA;a,as.5g EartMuak7 Name Date Rupt Mech darnitude h l
Helena. E (Main) 10/31/35 NM (19)' (5.613 (20): i Helena. W (AS) 11/28/35 NM (**)* (5 0) (20) x - Co ner. 0A 07/21'52 Rv (10> 7.4 O~ San Francisco CA 03/22/57 SS (12) (5 3) (04> (12) Parkfiel 4 CA 06/27/66 SS (13) 6.1 (14) Koyna. India 12/10/67 SS (54) 6.3 (04) Sorreso Mountain. CA 04/09/68 SS (15) 6.6 (16) Santa Rosa. CA 10/02/69 SS (55) (5.6) (02) Santa Rosa. CA 10/02/69 SS (55) (5 7) (02) Lytle Creek. CA 09/12/70 RV (53) 53 (06) San Fernando. CA 02/09/71 m (17) 6.6 (06) Hollister. CA 11/28/74 SS (53) (5.2) (56) Crov111e CA (Main) 08/01/75 NM (21) 59 (11) Croville. CA (AS A) 08/03/75 NM (**) (4.6) (22) Oroville. C.*. (AS F) 08/06/75 NM (**) (4.7) (22) Oroville. CA (AS K) 08/08/75 NM (**) (4.9) (22) ca 11. USSR 05/17/76 RV (23) 6.8 (04) Calipatria. CA 11/04/76 SS (25) (4.9) (45) Tabas. Iran 09/16/78 m (27) 7.4 (28) Coyote Lake. CA 08/06/79 SS (29) 57 (11) Imperial Valley CA (Main) 10/15/79 SS (30) 6.5 (32) Imperial Valley. CA (1331) 10/15/79 SS (**) (5 5) (50) Liversore. CA (A) 01/24/80 SS (33) 5.8 (33) Liversore. CA (5) 01/26/80 SS (33) 5.4 (33) Morse Canyon CA 02/25/80 SS (57) (5.3) (58) Mammoth Lakes. CA (A) 05/25/80 SS (36) 6.2 (11) i Mammoth t.akes. CA (B) 05/25/80 SS (36) 57 (11) t Mammoth Lakes. CA (C) 05/25/80 SS (36) 6.0 (11) l Mammoth Lakes. CA (C01) 05/25/80 SS (36) (5.7) (35) ! Mammoth Lakes. CA (CO2) 05/26/80 SS (36) (5 7) (35) Mammoth Lakes. CA (D) 05/27/80 SS (36) 6.0 (11) l O M i 11 v 11 r M 1 - westmorland, CA 08/o'/80 04/26/81 SS SS (37) (39) c8 4)' (5 6) (37) (38) l Coalings, CA (Main) 05/02/83 RV (41) 65 (59) Coalings. CA (AS03) 05/09/83 RV (41) 51 (42) Coalings. CA (AS08) 06/10/83 RV (41) 53 (42) Coalings. CA (AS10) 07/09/83 m (41) 5.2 (42) Coalings. CA (AS12) 07/21/83 m (41) 59 (42) Coalings. CA ( AS13) 07/21/83 M (41) 4.9 (42) Coalings. CA (AS14) 07/25/83 W (41) 52 (42) Coalings. CA (AS16) 09/09/83 RV (41) (5 3) (41) Morgan Hill. CA 04/24/84 SS (43) 6.2 (43) Bishop. CA - 11/23/84 SS (44) 5.8 (44) Nahanni. Canada 12/23/85 m (45) (6.93 (45) Hollister CA 01/26/86 SS (46) (5 5) (46) North Palm Springs CA 07/08/86 SS (47) (5 9) (47) Chalfeat Valley. CA 07/21/86 SS (49) 6.0 (49) porus:
- 1. (19) indacates reference near in rollo tas pasos.
- 2. " indicatu that af tershock ruoture mechartisa has toen interred to be stallar to the main shoca proceeding it.
3 A parentheets ( ) around a magnitude va.19e indicates that the % walue is being used ror M, al . A trocket ( ) around a eachtwde velve indicates that the N, value O se n.tre .d rer M, . l _
L- Iheye6 ena .eveese evente e = s trano et apentece s.cel e gue evente 3 , , , , . .
.i . . , , , ,
O
.J o o eoe 7 -
o o o e o c.oco s.co c. c. o o e e se o
- es a. cu. et. e e -
e o e e e ce esses e e W o o e gg - e em - w e ce o e e eso e 5 . . e .. . O e t e ee O o e e e o e
,o e e e e - l
- e e e e l
e o .e e ee o. en e o ceces e e e Se e 1 5 - * -
. e eoea e e
e 1 l . . . . . . . i . . . . . . ..i 4 1 2 5 10 20 50 100 200 300 : l Osatence R (keI . j FIGURE II-1. Scatter Diagram of Peak Ground Acceleration Dats for Rock-Site Recordings I I \ I l
O TheuC6 Cod PevePee evence Idl0888&tel e $ lethe etipen#Peelesellque evente 141g s f l aeo l 8 . . - , s J e a ea 7 - e e e e e e e m m ee eee e e
. ee e es use .
e e o e e e w o e Q 3 6 - * * - s N e se e Z o O 4 m e e e e e e e - e esu e e ; e as e e e a e 5 - * - e e s
- e e
1, { l
. . . . . ! . . . . . ..i j 4
20 50 100 20C 2;0 i i 2 5 10 Osetence R the1 FIGURE II-2. Scatter Diagram of Response Spectral Data for O R**. Site Processed <ccordings l v- m
l i I Rondomization Of Slip Time Function : I O I
. s f slip , ,
1 1 l , 1 I , I
, I i 8 !
- 8 e i I I l l
- 8 e I 1 ! 4 _
l ti i t; ) To time ti = To + ('i - I ) Te ; O : T tii _ t,i= a<ti,ii.i> l ( i = 1, nsre ) l h i i l i I Figure 9 l t : !O [ I i
O :egression "or 3GA Attenuation
- e:.a:ionsli3s l e Functional Form InlPGA; = Bi + B2XM + B3*ln R + C:M;E
+E where PGA = peak ground acceleration
! in g ; R = closest distance to fault rupture surface in km M = m ment magnitude . O E = random variable with zero mean , ClM; = B4*exp;B5xM; s Regression Procedure l Step i - Single regression for narrow l magnitude bands l l Step 2 - Multiple regression for all magnitude bands l lO l i i
9* +e=
-**** Dewa 5 -
O Mesesene <..n.eiese0..ee,me.s,,..ee.e O Coellnee,CAIMI.3/2/08.thewet.nes.3 ) ( '
@ gen Fsenende CA.2/0/71 Inevet.nv4 0,4800he f
'\ @ IV (MI,10/13/79 seethe slip.Me8 3 1
@ ateyne,Indle 12/10/Greelethe eiigemet.8 g . @ #seceege Min.eC4.04/09/08eeleite else.Mv8 6.4800he ]i ,
. . , , , ,CD ~,' ,,
1 - q) , , ,
.. ..., 'O, '
05 -
"'G ,'- 'N '
's, <
, s, , 'g . .
s s
' ,, s, Q 's,
, s s
% % g 02 -
e
; 's,a 's 1 ,4N,o
. - ,- p g e ', 93 sW
'o
- a. o,1 -
6 s, my s
'O 8\ -
s
'g \
s yg,\ . N ,g @gs - s s 0 05 -
\ 'A r
( s N', 3, 6'\ ,s -
. s \ s.>\
\ .
, h, \,\
0 02 -
'g \, \, -
\ sO, \,
s % k4 0 01 -
\Q s
-gs M -
, 'p 5 .
m - 0 005 -
\.
b d I (!!C-0 002 1 2 5 to 20 50 100 200 300 Diefence R thal r FIGURE IV-1. Regression Results for PGA for M=6.5 i Data Magnitude Range 6.3 to 6.6
, O- (Reverse / Thrust Attenuation Relationships) i
)
i
O Regression 'or SA Attenua: ion !
-8.8':lonS11]S e Functional Form for Spectral Shape In;SA/PGA;.=Bi'+82'*(8.5-M; -
+B3'NIn:R+CLM;;+E' i whereSA/PGA=normalizedresponse spectral acceleration :
R = closest distance to fault i rupture surface in km M = moment magnitude l E'= random variable with zero ! O mean C(M; = B4Xexp.;85xM , s Regression Procedure ! 1 Step i - Obtain PGA attenuation l l relationships from all data Step 2-ObtainSA/PGAattenuation i
- relationships from all data !
Step 3-CombinePGAandSA/PGA
- attenuation relationships, ln LSA; =1n lPGAL +1n (SA/PGA; l
10 l i
O e 4-s ... * - Iep Wily. M* *3
@ cool Melme M*6 3 )
A messeeli Vliv 9 6 4 , to , e a 4 1 1 5 1 1
., ~. 1
..,,,~,' ~,
2 - N,
% g A , , _.
- , - s, 1 s, a
,A , s .
- - . , - , , s
*g % %
05 - s , , 's ] N
, d,g 's, 's s -
s , e ge,,, gs, s, , m , s :
- s .
' ~
02 -
's r \ \
s g gg i s . ,
'N ' O\ j 01 - s
\ 'N .,
g \\ 4
*g5 i i 1
- s, s,
.\ \ 'i.
0 05 - s % s s g % -
% g %
j N. N '
\
- s, '
O.02 -
\\- s 4
. , ,.,,,i 1 .
m 0 01 - 200 1 2 5 to 20 50 100 Oi ience, a t we) 4 1 O FIGURE IV-4 Regression Results for Sa(T 0,12 sec) for M=6.5 ! Data Magnitude Range 6.4 to 6.6 (Reverse / Thrust Attenuation Relationships)
\
-C sa Fende. M*4 8
+ !ap Vitwe M*8'3 J e co., .. . ,....
A ne.steess vilW. M*8.4 iO . i , .
. t j ,
5 .
."- j
...,~.. . ,,' a
's ,
2 -
',, '\, I A
's, 's, Q
, sg 1 ,
- ,% s s. -
r.....,...~
~, 0 s. N, ,
, ..*. ,. ~,
A *
, Ns Ns .
05
- ' ' s' ~
','s :h4'g \
, s, 9 \g -
N ,0 '~, g os 'qa . l O a ' ,os 'a-s s s s 02 -
\s \ d '
s; .x c';s., \, _ , \ s 4 s s I
% g s g >
g ' s s l s s l 7 01 -
\
s
\\ s s
-~
i s s s , s s s . k s 4 s j
, , i 0 05 -
\ ,s s s '
1
- \\ g s
\
s l i s s ' i ; m\ \ 't J s s s % 0 02 -
\\ t s s e i s \
\\ %
0 01 ' ' ' ' ' ' ' ' ' ' ' ' 1 2 5 10 20 50 100 200 3: , 0:stence. R thal , FIGURE IV-5. Regression Results for Sa(T=0.24 sec) for M=6.5 i Data MMjnitude Range 6.4 to 6.6 ' (Reverse / Thrust Attenuation Relationships)
A 1
@ se Fenee, n=4 4
+ !as Vily, M*4*3 O O Cool Mein. M*4*3 l A movieels filye M*4 4 a
10 , i 5 D 2 s-..., ,
- c. , . ,
*., 's
% g 1 - A ',
's ' s y
..., , N ,
.., , s, a s , ,
s, r- 's \O 05 s+
, - N, NQ m ,
s, s
'g + 's
' ~
O : '.. . , 02 -
\
s, $, e s, h, '
. 4 ,
c , S. s l Ns +h s 's s i 01 - g s, s , g q ;
@ cts, \, \, \, i.
g 's, \ 'g i J 0 05 - s s
@r s s \
I l,
% % s g s s
- s s %
s g
%. r s
% g g r
- s s . I
% % s.
\
\,
0 02 - \, s\ ' s i ! g i s \ l s
\
0 01 1 2 5 to 20 50 100 200 3;: ! Dieeence. R thel ! FIGURE IV-6. Regression Rt.wlts for Sa(T=0.5 sec) for M 6.5 l O Data Magnitudt Range 6.4 to 6.6 (Reverse / Thrust Attenuation Relationsliips) 4 a
O Deve'o] men: o" Si:e-s]eci:ic
- es]onse S]ec':ra e Characterization of Site-specific Response Spectra
- Median
- Dispersion about the median e Site-specific Criteria
- Eartiqua(e magnitude
- Source-to-site distance
~
, -Sitecondition O - Style of faulting a Working Model for Site-specific
- Response Spectra l -Earthquakemagnitude~7
- Source-to-site distance ~ 4.5 km
- Rock site
! - The same :.ikelilood of strike-slip
- or reverse faulting i
)O l f
O A))ro,acles =or : eve o]ing :: 3 3
~
Si:e-sJeci ic Res]onse SJec:ra ! s Direct Statistical Analysis on SA of a Sufficiently Large Ensemble of Near-source Strong Motion Recordings
- 36 horizontal components
- MW 2 6.3
- R 1 20 km
- Rock or rock-like site condition
- Average of strike-slip and reverse faultingstyles O e Derivation through SA Attenuation Relationships from Regressions of All Available Rock or Rock-like Recordings
-308horizontalPGAvalues
- 130 sets of horizontal SA values
- MW = 4.7 - 7.4
- R = 1 - 300 km for PGA
= 1 - 50 km for SA
- Strike-slip and reverse faulting styles i
l l
o neck octo,a:verosancues tveneeseissisacol & e ! seen osse,sicew -elip/Noreal twenleteggittaed)
/i e
N = 6.25 l R = 20kg i 13 rock records t 2 o iA8 DHE ee i
? ~ i
.. t hN1 DN2 kNJ o e e e
,GAZ t
- $1l s eAc "t gap /
1N'. eee e e ; 00 e es se - t e"II e ' t o @ 0 id O o u6 e e - 6 o H l ' e se e a ! a : E e a o t o o e .l 4I
- i e e se e e \
e se o e e > t
=
i 5 - o a - e o e i t i i o > [ i o l i - 4 , i I i
, , , . ,,t ,t 4 , , . . .
i 1 2 5 to 20 50 100 200 Suo i O l Deseanco R temi ! i l FIGURE III-1: Summary of Ground Mot ton Data Used Fro:s Roci: Sites 4
. , _. - , . , . , - , , - - , . , - - . , , - , -,r,--,,-,,_,,,.,_.-,---n, ,, -,n., . - - . - _ . - . - . . - - - - . - - - - , , - - -~.-
- I s A Se a l Dele.Reveree /Theve t - Event el 4t e s t e sea l j A sei s cose. strike-e s ipener e t tvenieteien e s ses s j
.s . . . . . ..., . . . . ., ,
M = 6.35 ; R = 20km m 5 soil records A I. 7 . t CIO ,, , , , ,,, , , A A A o A ECSIC4 A OFA IILT A .A - A Aa, A AA A- -- f A & AJaha AA A A A N .te A A a . 3g-
. AA. 'A -+< .
i A MA A o , a E A A A A A Am i i
, I a, A -
[
- A AA 4 A l
5 A4 4 Ma M , 3 - A - I I I I i 4 i i i i 1 , i i i ! , , , ii 4 _
- 1 2 S 10 20 SO 100 20. - . :
1 D i e t rin c o R tkmi j i i FIGURE 111-2: Summary of Ground :tation Data Used From Soil Sites {
- w -, - -- , . . , , . . , . . _ _ _ _ - . . _ . _ _ _ _ - = - , . ,. . _ , . . _ _ _ , , _ - . . . . , . , . . . , . . , , , .,x,-~..r y ,
I i O S:rong,Mo': ion :ecorcings _sec or
- eve:.0]ing Si':e-sJeci ic S]ec':ra ,
Earthquake W RLkmL Fault Site fof l StyleCand. Rec. , 1967Koyna 6.3 3 SS Rock i 1971 San i Fernando 6.6 3-20 R Rock 5 1976Gazli 6.8 3 R Rock-likei l 1978Tabas 7.4 3-17 R Rock-like2 l 1980 Maxi-cali 6.4 9 SS Rock i ! . O 1985Nahan- , ni 6.9 6-16 A Rock 3 l 1 __________ 1979Imperi-al Valley 6.5 4-9 SS Soil 5 ,
. l
\ l l i io '
l l 3roCecu:e =or s:a:is:ica:. Ana:.ysis On SA o= \ ear-source Recorcings e Assemble a Large Ensemble of Near-source Strong Motion Recordings from Large Shallow Crustal Earthquakes eAdjusttheCandidateRecordingsto Meet the Site-specific Criteria for l DCPP
~
-Magnitudeadjustment :
O -Distanceadjustment :
-Adjustmentforsitecondition l l -Adjustmentforstyleoffaulting e Compute Average SA Value over Frequency Range of 3 to 8.5 Hz for EachAdjustedRecording a Compute the Median and Dispersion of f
! the Whole Ensemble of Recordings for ! i PGA and Averaged SA
- O l
l I I i i k _5
-5 7
f a~ e o e - f J d a 1 s a a 5 m a b e d 5 m y&
$1
+s
- E 1-O. o E
7 w k
+
5 f 4
- - + g l -
- b
\
.T 4
i
- i a i 3
~
l 1 e i t i e o e o o o ' e a A A A - (W 'W)V5d / (S* t'u'W)f54 30 011VW O
i O t 3.5 - - - i - - i - - . . - , Damping = 55 3.0 - - C g 2.5 - - 4 l 2.0 - O
- 1.5 -
1.0 - contretreeeeeac,(un) I seerte , Pelet 4 Pelet I Pelet C .i WS W C Reg. Golde 1.00 33 8 2.5 g,$ . WSBC EWE 4 0000
- 33 8 2.0 _
NOOM I Beeveleottee 33 8 2.3 Selected fee the present 33 1.5 3.0 LISP stedy
,..t .,f g,g . . , . . . . -
0.1 1 10 100 FREQUE EY (Hz) O FIGURE !!!-4 Basis for Selection of Control Frequencies
, 1 Ndtfied spectes .
Me 7 R = 4.5km ($4)3-8) Fault type a strike-slip Site conditions . rock 1r FA. vv Sa ) { l
}lI A N/V 2s 1
PGA 3.0 8.5 33 Frequency - hz (54)3-86 Mth : : 3 O sa 50th = 2 1 pg ERIEMEuni ~ Mth j 50th 3.0 8.5 33 Frequency - hr (5e)3 86 4 Sa l Mth 50th i i 1 , 3.0 8.5 33
- O rr a aci - a>
FIGuitC !!!-9. Schematic Presentation of Statistics of Site Specific
- Spectral Evaluation
u-a f 4 O !
'i 3.5
Ma 7 l [ R 4.5km i t 8 1 ROCK
$T-5LP
~
3.0 - - 4 Damping a 51 c i
~
2.5 - t f 2.0 - l L g 84th 1 = i 1,64 O
~
r l 50th 1 = l j 1.07 .
~ ; 1.0 - ;
O.81 ! 16th 1 = :
- 0.68 !
0.55 i 1
' ~ t O.5 -
0.37 4 i r ( (
, 0. 0 --
0.1 1 10 IM j FR(QIKleCY (M2) t
- i t
- FIGURE !!!-11. Estiested Spectra for Site Specific Criteria for { , a 5trike Slip-nodel :
; O i I !
i I
w o i O 3.5 - - - - >i - - i - 1 ,* , s , zI Me 7 ! i A = - 4. 5km l ROCK 50/50: ST-5LP/AV TH , 3.0 - Damping
- 55 2.5 -
2.0 - 84th 5 = 1.45
~
~
J. 1.5 - O Soth i = 1.18 __ , I 1.0 - 0.89 16th 1 = 0.75 0.60 a 0.5 - l .i r j 0.0 - ' O.1 ) 10 100 FREQUE O (Hz) FIGURE Ill 13. Estimated Spectra f or Site Specific Criteria for Equal Pr e dility Strike Sttp and Reverse Models
in U. 3.5 . - - ii
- 1 -
i - - . . . - M=7 R = 4.5km ROCK 50/50: ST-St.P/RV-TH 3.0 - Statistics of 36 camp
---- Regression results 2.5 -
~ ' ~
? - - -N - 1.95 3 /
1.85 3 /
/
1.5 -
/ -
/
/ . a.~_ _%
, ' l.33 N\
\
l /
%/ / l.18 's
*/ / g 1'0 -
' / x -
/ ,_ 0.41_ . N 0.89 g/ (16th 1) \ - gg .
f' O.15
,, 0.60 0.5 - ~
, -------- . O.42 l 0.40 0.0 * ' ' ' ' ' ' ' ' O.I i 10 100 l FREQUENCT IHz) 1 l f!GURE !!!-15. Estimated Site Specific Re:ponse Spectra from Statistics of Near field Ground Motions and from ! Regression Analyses l l
O An:ica:i.on o' sumerica:. 3rounc Vo: ion Simu:a: ion Ve':locs in ::_~SJ - e Purposes of Numerical Simulations
- To generate realistic acceleration time histories for engineering analyses by incorporating as much site-specificgeology/ seismology /
geoplysics information as possible
- To perform sensitivity studies on ground motion characteristics at the O site with respect to seismic source, ;
propagation path,and site properties a Simulation Met 10ds Developed in DCLTSP l - Empirical Green's function summation method -
- Semi-empirical simulation method on :
single empirical source function
- - Semi-empirical simulation method on !
mu:.tiple empirical source functions iO l l
--__---..--.-._,,,-----.__,,w -
s Fig '$.2 O ,
-e#
5 c 07 8* vj 1 d w a: d [p - I.- O . z 4 * - g a J r O Y 5 k ? =t E f z b,- l 3 a i a $. 2 g s O .J 4 9 ^ O a ', e % o h 'i I 2 $ -t 4 E % st ! N e k
- d' s ,
c!!
- a. 4( hl ut
.\\1 3 l s
s 1\\ t l\\\\\ '
- i. \\\\'\
{ 4 i j r i j i, l t
~ _ . - . --. ._ .- -- -
I' O Main ea:ures of :le le"inec l Semi em)irica:. Simu:.a': ion Me': loc e Source Time Functions
-Needsforempiricalsourcefunctions
-Degradationofradiationpatternat highfrequencies
-Selectionofsourcefunctions
- Comparison with site recordings l
- Correction for propagation effects i e Fault Segment Size ;
- Joyner and Boore constraint j
- Fraunhoffer approximation :
O
- -Barrierinterval
- Sensitivity study l l :
eFaultHeterogeneity
-Slipdistribution
-Sliptimefunction ;
- Rupture velocity ;
- Sensitivity study l
s Green's Functions j l -Computedbygeneralizedraymethod j
- Crustal model constrained by site l l~ recordings l
- Compared with f-k integration method !
O t l I l
i i O r 4 Needs jar Empirica:. Source unc': ions l s Source S]ec: rum
- recuency-c!epenc en: i - :1: ion I Ja':':ern l, e Near-source Sca':':ering
- e _nmoce:.ed 3ro]aga': ion Com]:.exi':y !
- Mu:.': ipa': ling O - Rever] era: ions ,
e Ane:.as':ic Absory: ion ;
- - 0 ?, r;
- e sear-si
- e Sca':':ering l 1 ;
i i r
,l ; r O !
I
Fig. 5.1 0 -
~
S WAVE RADI ATION PATTERN RADIAL TRANSVERSE
,{
MN
~
; 4 No 5
- x . ,i ,1.
-. -\h%
\ No 3 -
No 3 Unfiltered
-d
. b-v -
Dora j .N g 7 ,
\ HOLI
) '1 BNCR BNCR
'f
~/f N '2 sec' No 7 No 5
~
[N No 4 D3 Low- Pass Filtered
, y @go h3 X'N p Dato . Hotr f HOLT ex- up 1
0
O Se:.ec: ion o= m]irica:. Source ~unc': ions l e Subevent Size !
- Large enough for:
- Adequate signal-to-noise ratio
- Reliable seismic moment estimate
-Adequatesubevent/maineventmoment '
ratioLJoyner-Booreconstrainti
- Compatability with fault barrier interval-of the main event l
- Small enough for: '
- Fraunhoffer approximation to hold aRecordings
- Accurate location of subevent source
- Multiple recordings within about one
! sourcedepth
- Adequate sampling of the radiation l pattern e Selected Empirical Source Functions '
l
- 16 recordings of the 1979 Imperial .
l Valleyaftershock
- 12 recordings of the 1983 Coalinga j aftershock
.O 1
O
- Coolinga oftershock, overage of 12 recordings
...... Imperial Valley oftershock, average of 18 recordings
......... DCPP, average of 3 earthquakes, ML 4.7-5.4 0
10 7-------------------------------3 l WK l 4 10-' - i I I ,; 1
^
10-2 ,. O O
- s. . l A f?@ ij pg :
n - l'l ,, , j k h h;4lIrhY4t${hN
'h '
s 10~' F : l* i l ! l i jo-s . i : 10-' 1 --
, -----r-- - - -
I
~
5 'O 'S 20 25 O FREQUENCY (H:) 1 \ l
O ' s 100 _ , , i i , , ii,; , , ,
,,,,,l ~
- e occelerotion power spectro
- a geologic dofo .
O teleseismic P wave - m*~ r.,e 1.;. 0 p 10
#g 3
m ae %,a - cs.ui - 3 o9
- - V - .
I -
/ a c,. . .. -
'E O
#o Two O& one.=w -
- s.a 7.,%
O#aa Raw a r.ii.n
- f, n - , _
1 1
//
- g k ,,,.
- w. -
/
./ %,w 4
h 14 W e @i
/ in 6.wh
- p/ e -
4
/ -
1 4
- c. , i i i il i i e i , ,,i l i i iie ie i i
i 10 10 0 , barrier intervol in km l . Figure 11-1. Maximum fault slip versus barrier interval. ' l l
1 l O ~ rea: men: 0" au:': -eterocenei:y a S:a':ic S:.i] Jis':ri]u: ion
- G:.o]a:.y nonuni*orm
- Je:erminis':ic e S:.i] "ime Function 3rescri]ec':0^:a: rise ':ime
- G:.o]a:.y te':erminis:ic l ram];
_oC8:.:.y s':oClas':ic ; Gaussian e :,ur:ure Ve:.aci:y
- ur
- ure ini':ia':ing a': :.0wer Jar': 0"
- le au:':, :len ]ro]aga~:ing ou':Warc
- G:.o]a:.y ce:erminis:ic l0.8*Vs;
_ aca:.:.y s':oclas':ic l Gaussian; : O s
i ASPERITY MODEL OF 1979 IMPERIAL VALLEY EARTHQUAKE. CONTOURED (IN CENTIMETERS) ON THE FAULT PLANE FROM STRONG MOTION I g) ( AND TELESEISMIC VELOCITY DATA (PERIODS ABOUT 1 SECONO) Sinke Sho Arroy 18 Border w. f 5 mm j (- l l - A_ > o [ 2 g
- 12 27 0-w .4, , ,
@ i20
/ {
O -' 2 , 25 w .4, W- a ,Si ' 8-ot 20
^ -
) _
o a.
~ ~
~
O 4 8 12 l 6' 20 24 28 32 36 40
=
.10 .30 .60 .65 .90 .70 .50 .30 .40 .55
.02 .20 .80 1.10 1.60 1.15 .50 40 45 .50 0 .10 .55 1.65 2.05 1.88 .7d .35 .50 .58 0 .02 .10 . 30 .40 40 .20 .05 .10 .10 O SUBFAULT WEIGHTS FROM HART 2 ELL ANO HE ATCN 'n
-169- FIGU R E
Time (seconds)4 6
- X/6.30 8 10 12 0 2 n n a 0 s ; o i
/
j
/
I '
/ '-
' 2 5-1 j 551 1.82x10
( l SS2 7.66x10 0 j-10 - i { SS31.08x102 i /
/
4
} Ss41.14x102 j!
, 15 \
2 \\
' ' \- f
/
SSS 9.85x10 1 8e - l 20
'\p\
' SS8 8.20x10 1
E . ' O !-
=
l ( b',-- - s \ f yN 1
$ 25 SS7 6.55 10 f ,-
4,
" \ ~
SS8 5.75x10' N
~ -
i
\(-
3 t -- SS9 6.14x10 1 O 35 - 6
\ l $
1 1
\
( S105.36x10
^
y [ 40 - i a \' 1 h t S114. sax 10
'sE\. I. -
S124.37x10' 45 - I f f \.\ f % i s 12 g 6 8 10 0 2 4 Generalized Roy Tangenilal Velocity ei0uae 1.9 O .
O DCPP Strong motion quakes M 11/24/s5 M 8/29/83 1 6 M 12/ 7/86 O D@P W 11 M 5 s s N o Flou:t .
O , w o O 4 20 Jun 84 Santa Maria: Free Field Near Meteorological Tower
- Deck 5-4
, - 0.02 g g,gg33 , .i t j { L A .1. J . J -- La RJl2I4A IS'm L.A h .mta __ .__.m m. _m.m._ _m . . _-_ _ _m._a .__ _- - - - - m-- .- - . .y ~ ' ~ )
- ~
- , r v i g - ' ' ' ' ' ' ' - ' ~ ' ~
i i o.010e a 4 1 084 - 1 m. . . m .. k an d Ji hl u mn. d. i _ . . ___ _ ___.
.,_ _ '--__~~ = - ^
~ ~ - - ' - - - ~ '
,--,ir-~q ,
y , .. m ., - ' s r i
'r ' " -
l
-l ..\
0.010e a 364 - - - --
---- ---J
, ,,',.O .,, U,,E,.'"" '.- " " "- *.
--' -^ --
=^^= = - -- = -
n o C as 481 3 3 5 5 3 5 3 1 0 00 3.00 8.00 9.00 12.00 15.00 18.00 21.00 3 24.00 5 27.00 TIME (Sec)
i l 20.00 , , , ,
. i
- Observed data a5 km synthetics
- 49 km synthetics '
15.00 - tn "O A C O e O
$ 10.00 -
O t . (O 5.00 - _ s
.00 25.00 50.00 75 00 100.00 125.00 150.C0 Distance FIGURE .,.:
O
h o .,
,8;1]Pa:lon 0" ':,e -e 1nec Semi-empirica:. Simu:.a: ion Me: loc e Com]arison wi': 1 Ac:ua: :ecorcings 0" -
- le :.57E ::m]eria:. Va:.:.ey ear': 1cua<e
- Acce:. era: ion :ime lis':ories
- A':':enua': ion 0" 3GA wi': 1 cis':ance
- Acce:. era: ion res]anse s]ec:ra e ::m]or:an': incing le re=inec semi-em]irica:.
O simu:.a: ion me: loc is ca]a):.e of cenera':ing rea:.is:ic acce:. era: ion
':ime lis':ories W1ici can':ain <ey clarac':eris':ics essen:ia:. ':0 : C_~S3 engineering an:.ica: ions O
Fig. 3,1-0 l EL CBITRO STRGIG GR000 if;ilG1 APSAY ll5'45'w Il5
- 30'W
,, 33'00'N 8RAWLEY Array
- NO.1 fj BRAWLEY eNO.2 FAULT e NO.3 l
NO. eNO.4 6 ,NO.5 NO.7 e ' HOLTSVILLE ELCENTRO 4, Np.8 e 9o,9
- waoons e- \
NO.10 % ego,,, $ - 32'45'N O ~o ia e NO.i3 %<g *_*,"," O 10 km CALEXICO 4 . . . ,
' ' ' ' ' ' - ~ ~~ ~
u s A _ _ _' g _ _ . . _ - -~ ~~~ ~ ~0 E * \ C O vg (mu urnu. ue wAm. issa) I l
Time (seconds) 4
- X/6.30 8 10 12 0 2 6 o '
l l'jj
!! t l i
/
, / / SS14.13x10 I
' /
/ '
[ SS2 6.76x10' to - SS3 5.00x101 f /
, 15 M
i
'N
\
7
\ /
[ I j - SS4 2.57x10' i \. i
/ s 8e ~
r
- '2
[ - SS51.88x101 20 [\ /\
- Y E i !
O 9g ? ': l SS61.25x105 i' i I\ i I l \ 5 15 - L}M - SS7 8.98x100
/I 9 )) ' \ \
\\ ~
=-
hM ~d s,4[ t i' h\ r s SS8 6.19x100 S I I, \ O SS9 5.314100 35 - q k [
' ! \ l^
40 - f' k r i
! (\\\\?-
7 t I S10 4.97x100 H 1: I
,t '
\
\
S114.28x100 45 - \ \ - Mr lr L3 i S12 3.66x100 g f . 4 I f \.\ I 8
$ 1 10 t
12 O 2 6 Generalized Ray Vertical Velocity FIGURE 1.7 l0
O Randomization Of Rupture Velocity ;
, \,
4 L f oulf Se g rne n t deporting J(/ rupture i
\ ,- \_ front orriving \ , ,-
t \ t rupture # D f ront '\ to fa= R(ta,t b) i i Figure 2 i l O .
ROCW @/s) Q DENSnY (g/cm3 ) b3 i i s 42 ; f !_ 7 I i , - . --. - 1 . ya L, . 4 _. l . i ' 5-. - I . I
. . I
_. I . . I <
; I i '
10 - l L[ i S.. I i I - - 15 - - < . , . i _. I
< . . . I <
i I -
< . l . ,
i ' 20 -- I < I < i
- . . I m _.
- I ;
I
.3
_. i . i - 3_ . t_, .
. p 4
30 - I. _, 4 . 4 I 4 35 - l I, _.
- ggg -
]
. _. 4 4 1 ,
8 _. 4 4 I SI.b 4 SulI 4 .
' 1 .
50 --
; .
- 8 r 4
-- .- ----,---,------,n, ,,, , ,,,,,,,,,--,,,----,e,--,-, - , , ----,w - - - ,,---
n s. :.2 IMPERIAL VALLEY CRUSTAL STRUCTURE MODEL DENSOY (g/cm3) Va.0 CITY (km/s) g O_ 3 o i s . I f - ' 4 . 7 . e imo2 m . I I I f i 1 1 I I g
- i
~
1- _. t, . T, , 5 - 1 b i . .
-. ,, . . i 10 --
i - 0 -
. D
- . t i >
-b g : ' '
I 15 -. l ,
< - l
} ,
l I l
^ 20 - -
4 O~.5 - 4 D I*- -, S'lb 1 > a 25 - q > 1 emi > i 4 > 4 1 > 1 30 -- < - 4 > 1 Wai> 4 4 > 4 > eut> q , l 35 -- - , 1 b 4 > d , GBED
-> 9 a e i
1 > N a> Q 1 l - j j 45 -- . . 3 4 4
...-, .,,-, -- - , - , - - , . _ , ,,.-.~
Fig. 5.: 27 q i f^% .i O \ ' 24 l, l. ' .
?
a :, 21 N'r i it i ( r h n( e <,' I 4 ' 1 , , > Q 2 ' . 4, di
,s 18 *
' [l 1
I d d 4 g i
~
a f e m 8 a ,
< g' S #
. .% % /
_- r, 12 l a , y - Q G 3 1 E Z l w Z O a O a.O < O I T C 21 i, 23 1 p$ t' L < d 3' , b (' i' l Z ' O 15 .
' t 5
I
,P
'l 'b i
21 t <; ' i ,
- t J 4 > '
>- p <
( s <
, >, 5 ,
+.
O jg 2P j ' '
.i
.! < /q F o 4 .
, l * '
5 dE l[ 4f 5 t iL g o is s
~ <
- a,
/a
;p
/ >a - d e
r s1 .
'
- 3 12 .:S h
< wC 4 - 4r I t
= <
a a ? - i 9 F d- L a' <f
^ o. W I b M O O A f t- 9 Z l La Z
O V2 O e U O M N Sg v
- I )
18 , 1 i i < ,' I,,[ i " E ' a e < z 15 O N # 5 %
/
~ .****
2 2 12 :k
~
~
_w ' - G < t l y , h ' k 4 9 l n 4
'si -i2 -s -6 -s o a e $ 12 '5 O ow.- cu. - >
l l
l Fig. 5,;- i 1 1 Imperial Valley Main Shock 1979 l O 1 s
. - - - - - g - . , , , ,,, l l
4 1.0 -
~
l
- A ,
- A
. d g 9 y UAY 4 A
' t
[ X s
* +
m y . l 3 + Osn . 5 N 3o 0.1 _ Y
~
N - x - 8 - a. I t . I 0 01
.' H1 H2 I
Observed 4 A , Simulated X Y O , ,
, . . ..1 , . . .
1.0 t o, 1 oo,
, Distance (km)
I l
,\
G a
- w. =s we a,
. W
.s / .
4) M < d ql '*** . d a Q 5 % , E
\ , l N
1- s
\
= <
o Z Z NL Ne sie M O O w (8) avutKpr m3ds i m .
). EL we' we ers 4 g E :
( 1 J, t
, _j ;
d a a e> M _ d
~ s) , j e
1 7 a (\; , l {j{ o l 1 8: *Cuvv7TKev W 345
.. a
y we ws we we
,ew,
() ' i U W N *,,
,I d , -
j/ di i - g 5 7 . . 5 H I _- . - s ~~ ! 3 C5 w le I 7, . . e
- \.
Z NI Wb M WY O (6) a m w yg w O s x ~
> . .t.
E 4 e . p / y - n / 1 4 . 5 L N ~
?
~
5 3r 5 . t <' , 5 8
]
! ~. E
( Ap
]^" ,,
l@ . 1 83 9 t.
! \
O .. w, n,
,8) .<x m x m 3,s s
i l O 3re:.iminary Simu:.a': ions "or :C33 Si:e i o Magnitude 7 on Fosgri Fault Zone o 120 Cases Simulated
- 40 cases for strike-slip fault - 40 cases for oblique fault - 40 cases for reverse fault 0 14 Cases Selected for Fragility Analysis a Sensitivity of Ground Motions on Faulting Type o Comparison with Empirical Results O
FAULT MODELS - MAGNITUDE 7 O 3. FAULT TYPES - STRixE-SLIP (SS)
- OBLIQUE (08)
- REVERSE (RV) 7 RUPTURE LOCATIONS - SITE LOCATION RANGING FROM CENTERED TO OFF END OF RUPTURE 3 RUPTURE MODES - BILATERAL (BIL)
- UNILATERAL NORTHWARD (UNIN)
- UNILATERAL SOUTHWARD (UNIS) 3 ASPERITY MODELS - CENTRAL ASPERITY
- ASPERITY NEAR END OF RUPTURE O - DIFFERENT RANDOM NUMBERS 2 SOURCE FUNCTIONS - IMPERIAL VALLEY AFTERSHOCK (IV)
- COALINGA AFTERSHOCK (COAL) 3COMPdHENTS - VERTICAL (Z)
- PLANT NORTH (N) j
- PLANT EAST (E)
TOTAL OF 120 3-COMPONENT TIME HISTORIES 40 FOR EACH OF ! THREE FAULT TYPES l 1 O
E a r' (
, ,9 ?
M=7 Fault Models - Vertical Cross Section b ' Hosgri Site Foult 0- . . .O. -
.gs s.y:.;*, .
(....*...
- Approximate Incidence
\'- ',
- /
\ I Angle Ranges
\
N,,v/ ; 5- \ /,N - E -
\ t' '
' ,g, ,
.= \- ,
{',,' '.,
/ \ , ',
1 . 1 -
\ i.
.- \ : , .
o - e g -
. O IO- oe ,h.ypocenter \
'-{, hypocenter
- \ ,
- \
\ i n hypocenter
- \;
4 15 - OBLIQUE REVERSE STR IK E SLIP 60* dip 35' dip 90* dip FIGURE 2 '. O
l l 4 O - STRIKE-SLIP
' Plant North i.
',- (N23' W) w OBLIQUE I I ..., REVERSE
- i. I i l Fault i l Trace ' i l l I. l l e
I Site Azimuth l /...h. p.; g . .. . . . . . . . . , l Ranges
%:t 1 - .
l Note: Azimuth range for l O / l
..ii oe taoit is 3 0 ;
predominant range
! ' is shown.
/
- l .
...d.....l.......3 .
____i i
\ Surf ace Projections
/ Of Fault Planes l
l ) l l l i FIGURE.'.- I O ,
o M = 7 Fault Models Showing Segmentation
. . . . . . /.4 km T '
1 9 km Strike Slip _L i l'3km l 48 km ----l l
\
15 km Oblique
; 28 km -!
- S '^ ' ' " ' c ^ ' ' " S O _
18 km Reverse
! 2 4 k m --i l l l _l l I O 10 20 30 40 50 l km FrouRE _'.' -
O
do iro eUP- + OBUQUE + RTERSE, AVERAGE OF 120 CASES carnponent: E Damping: . o.os W W + Sig ....... r Wed - t WW - 5g . _8 2 . .
. . ...., . . . . . . . ., , . , , . . . . g i
ei 84
. f 6 g- : . . .
5 e # g ie g O 8 0 8 4 4 I
- g 4 .
n- , 3 , .
, s g 4 g- l ! s 8 ;
\ a
- . 1 s e I %
J %
/.% .
- ( ~
% ~
.i o
. .~ s >.
~.
i
- e// '
i
/ ..-
,e# * '
e 4 _ _ _ _ _a= =a8
- a e t e! A i e i i if f 8 8 i i 1 1 1 1 O O 0.1 1.0 10. 100.
M N W (Es) . O FIGURE 2.6 i
~ - - . . . . - - , _ _ . - - . . - _ _ _ _ - _ - - _ _ - - - _ - . . - .
TABLE 2.2 MEDIAK FEAK ACCELERATION PARAMETERS OF 120 SIMUMTED TIME HISTORIES () D FARAMETER COMBINED TAULTS STRIKE SLIP (40) OBLIQUE (40) REVERSE (40) s (120) la. Z 0.351 0.286 0.361 0.419
- 2. N 0.552 0.453 0.582 0.636
- 3. E 0.571 0.495 0.478 0.562
- 4. H 0.532 0.474 0.530 0.599
- 5. 2/H 0.66 0.60 0.68 0.70
- 6. H(TIFE) - 0.89 1.00 1,13 TABLE 2.3 MEDIAN SPECTRAL ACCELERATION PARAMETERS OF 120 SDIUMTED TIME MISTORIES PARAMETER COMBINED STRIKE SLIP OSLIQUE RIVERSE TAULTS (40) (40) (40)
(120) lb. Z 0.694 0.602 0.707 0.790
- 2. N 1.400 1.142 1.483 1.622
- 3. E 1.284 1.252 1.213 1.397 4 H 1.341 1.202 1.348 1.509
- 5. 2/H 0.52 0.50 0.52 0.52
- 6. H(TYPE) -
0.90 1.00 1.13 NOTES:
) la. breical median PGA
- s. W rtical median spectral acceleration (3), averaged from 3 to 8.5 hz.
- 2. Fitat north
- 3. Plant east 4 Average horizontal (N+E)/2
- 5. Vertical horizontal
- 6. Ratio of median horizontal spectral acceleration for individual fault types to that of for combined faults.
O
5 0 . Assessmen: 0" Spa':ia:. ::ncolerence 0" Ground Mo': ions e Development and Calibration of Spatial Incolerence Mode:.
- Effects of extended fault rupture
- Validation by El Centro Differential Array data of 1979 Imperial Valley main slock and afterslack ePreliminarySpatialIncoherence FunctionsforSail/ Structure .
O Interaction Analysis i e New Free-field Ground Motion Array at i DCPP Site : ? i : , r l i l
- O l
l
p W: p-:) , . - SOURCE AND WAVE PASSAGE O ; e DCPP a b Extended ad h d Source b- hg O PATH AND SITE DCPP a b n n n site s , f path M At ) Point Source i;jt~ l b l t At i O FIGURE 4,E
r l
.O .
Sm:ia:. ::ncolerence Voce..
- ncolerence Can':ribu': ion :an':ribu': ion 30 in':
E' eC': rom EX':enCec rom Source Source Wave 3assage Yes 1, sol2; 4 C s ': ' Source Yes s soI l O Ja': 18 Si':e so Yes Cp?; i Com]inec C P; = :s ?; X C] ?; i
)
- . ':nc:.uced ]y :a<ing zero-:.ag t corre:.a': ion !
2 Exc:.ucec by ':a(Ing Dea < corre..a:lan i 2 Assuming broadbanc 301n': s]ec': rum ! t O l i
- i
IABLE 4,3 VAllDATION AND ESTIMATION OF C0HEREilCE M_ IllC0HEREllCE EFFECT I.V. VAllDATI0ff DCPP ESTIMATION WAVE PASSAGE CS (F) DCPP LARGE Eo. S0uRCE SIMULATIONS I. V. MAINSHOCK SIMULATIONS PATH & SITE Cp (F) I.V. AFTERSHOCK DCPP EXPLOSION RECORDINGS RECORDINGS O COMBINED MODEL C(F) f 3(F) X Cp(F) C3 (F) X Cp (F) COMBINED EFFECT l.V. MAINSHOCK RECORDINGS O w.,
1 O 1
- _~S3 S3a:ia:. ::ncolerence Voce:. !
CL:,r;=A::,r;*ex)(i*3:: ,rD W1ere C J, r, is ':le com)..ex colerence UnC' 100 A;f,r;=ex]:-s+2*]i*M*':;Mrh . 3;' ,r; = 2*]iXB*' + :*r* sin l2*]ix
. E*';* sin;2*]i*G*'
': = 'requency in -z O
r = se ] ara':10n in me':ers , M, s, B, ), E, G = cons':an':s ce':erminec
]y ' i':':ing 0]servec ca':a ,
1 6 + h O I
~ . - . . . _ . . _ _ . . - - _ _ _ . ._- - - - - - - - - , . - - - - - - - , ,
1 115'30' 115'20'
" . I
/
9 i lo
-10' - - - 10 % i SRAWLEY
','/
e Yo e [j E06 FAULT
+
- 32'SO' ,d 1
- --2 o o 2 4 6m t__ i i i T
meters , N 305o0A6 i ,E MO, o -O '- ! 213 400A5 y . 10 " T&g'!& ' 3 s .
'j 128000A4 'N.,,
54 9"DA3 A Y
'$3l 76 OA CALIXICO 4 UNITED ,S1A.TES;,.20.-q
- 32'40' " -~
] - -
~
~ ~ TEXICO i
hex!cAu , Location of diffmntial array near the Imperial fault. Heavy lines rhow surface rupture suociated with the 1979 ewint. The inset shows the layout of the array elements and their spacing from , DA1. E06, EMO, and BCR are analog SMA.1 accelerometers which recorded the main shock. The star is the main shock epicenter o.' Archuleta (1982a) and the triangle and diamond are the epicenters of the 288 2319 aftershock umi by Smith et al (1982) and ourselves, respectively. The stippled lines are the surface outcrops of the planes we used to represent the Imperial and Brawley faulta, and the num:-s along them are a henzontal coordinate system. The 6NW-ISE refraction line is also shown. Source: Spudich and Oranswick, 1984. O FIGURC.l4.13
/
O IV MAINSHOCK SIM. PEAK COHERENCE, HOR. S WAVES l l g 3.75 Hz m=2.37x10-Sn =-2.38x10-4 g _.._ _ __ _ 7.50 Hz y _..._._. . . 15.00 Hz 1.00 w ," =m m= mm
- ~ ,
0.75 - g y " . s , ~. . ,y % T O + e Y..'..- S 0.50 - . d, !
- e i
M i 0.25 - 0.00 , , i i
- O 75 150 225 300 Distance in meters l
FIGURE 4.16 O , l
O IV AFTERSHOCK PEAK COHERENCE, HORIZ. S WAVES g 3.75 Hz m=1.74x10-4n=-3.74r.10-3 g - _ _. _ __ _. _. 7.50 Hz y - . . . _ . ._ . 15.00 Hz 1.00 g C g g 3 y f71 m s _
"g-m_R
\ g C 1 g -
hk 0.75 -
\ s*-
n s h O ! * *\
- t oa v
W k\ $ t'$s's*$ t ~ g m i M MN M % y' x mis * '~~,' 0.25 -
's,M y y -
s
's, -
0.00 i i i i O 75 150 225 300 Distance in meters l l O F1suRE4.17
s . O COMBINED I.V. PEAK COHERENCE MODEL, HO [g 3.75 hz g - - __ 7.50 hz ' 1.00 y-.... 15.00 hz
'\ K)=( 0.4000E-02 -0.2000E-03*w)*R
\N
\ N' 0.75 N m \, ' N T g N E
s !
\ N t s s 88 0 .50 s O b
\
s h Ns N ss W \* , I s s
- 0.25 \s N, s% .
i i. N s s'~~ . 0.00 s.~~. . ' i i - - - ' 0.0 75.0 i i 1 150.0 225.0 300.0 Distance in meters i i F1 cues 4.18 4 O l j i
O IV Mainshock Peak Coherence, Horiz. S Waves 1 g 3.75 Hz m=1.88x10-4n=-3.71x10-3 g __ _ ._ _ __ _ 7.50 Hz ! y __ . __ . . _ . . 15.00 Hz 1.00 - Ds3
\, g
\ N O g O U O.75 -
\ s :
s m A= *\5\ s s
- R m O 5
+ - 's " '
5 0.50 l
-W %
\
y'
's s -
T. m s kN s x
- g s , $~ s s
- l 0.25 -
's 's, g y%
s i
's.,
j 0.00 '
* *= . % , [ ' ' ' ' ' ' , :
0 75 150 225 300 Distance in meters i i O FIGURE 4.19 ;
s l I l O
\
ocep iocation map: scai.1 cm-5 km
-~2 r
E
, . t e i q
O ss.,. s t i . .\ 1 i . l f l .1 l l I { I i 10 km - i t I h l O I FIGURE 6 ' i I i
$w%eev@
WW F m.,m n a,ff m'l a\\.rh,!,'p
..i ,
^
Q . ';'-
.q , .. . , j k. ,
a
!{ 1 (u ;f.py; %
h!!1)!.lMh[hyj j' kfj ssu'\w\,d.C..yU
;))ff:Q v -
a m[.
! / -
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., ; .,, m. , ..
n
-. ~ .
/ _
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~
t- !
~
, . / ;'. .
- v. N&
.. ;%i:( , ., -
;-l,' ;'.:~ v
'b ,
p kN{6fu a , / r., ;
,. . y 's.. -
4.;I;& Q b .- 1. . j - p 7.
- .<: . .. Jr ,
/J 0g .
lf/h,fr.,&f l$hfjh- .
l l O + . 4 W i s 9 O I 4 o% 4 4 4 , p 4 e sE
- !4 l -I }* ; ' i l >
i ! 1 0 + A, i 1 1 l
i o Peak covariance vs. Distance Diablo Canyon Power Plant Site SHOT 3 111, 112 INSTRUMENT VERT
)
t 1.75 SEC WINDOW FILTER ORDER 3 PASSBAND=0,5 0F VfD FREQUENCY
- u. .
s, Agn @ya% - - 1- 6 l-qWh e o~
~ .u r g, a -
a'~4M&d & 5~
!-1%Mne l~; M; .. m o y a
JNM Wh o a'
!-4Mb e jE~;wp
.a ; a .
Lee (seeene7 s ; a- =$$0% j: %g
;, fqp ew ~ .u wa
~
i , 1.o , . . . o.s - l j . 1 o if7ly ' a.o o a a a .e ,- 1 Dhstem:e ( W )
O ; DCPP Shot 3 Time Dom. Coherence, Vert. P Waves a 3.75 Hz m=2.00x10-7 n= 1.80x10-3
................................ 7.50 Hz
, ............... 15.00 Hz 1.00
. E s
o
- 0.75 -
s.
... ,,+
... ' '- 4 m
a: *
+ .
N. .,.
+ **... , ... .~ . ..
O y .. . g .
~
.t 0.50 i .
l
- w *.,
- 1 , .
4 . J o ' s
- 0.25 -
0.00 i i i i 0 75 150 225 300 Distance in meters O
- O DCPP SIMULATED ZERO-LAG COHERENCE, HORIZ. S WAVES g 3.8 Hz m=0.874E-04 g _ _ _ _. _. _ _ 7.5 Hz n= .102E-02 g _..______.._. 15.O Hz 1.00 sN $ $ $
N's e e3
\ jN 0 0
-l 0.75 _ N
's 'g #WM k s' g
+
5 0.50 Mg g #@ 4 sgg 1 *'s (N h s ) 's, l !
- 0.25 _
M 'N- N
~Y ' '
M O.00 I I I I 0.0 75.0 150.0 225.0 300,0 DISTANCE IN METERS I i ! O ; i l :
I O DCPP COHERENCE MODEL, HORIZ. S. WAVES [9 3.75 hz g - . ._ __ _ _. __ _. 7.50 hz y . _. _. . _. . _. . 15.00 hs 1 00 in(x)-(-0.soo0E-03 -0.asoor-04%)=a
'N
\'N %
\ N s
0.75 _ N
\, N
's s O 5-x s 88 0.50 _
\\ N N
l s N N O \
'N, s's g
y 0.25 _ N, N
' N ,~~
ss *
's,s
~
.~-._
0.00 l I I I , 0.0 75.0 150.0 225.0 300.0 i l Distance in meters t 1 i ! lO l 1 I I
, - - - , , - -. - - - - - - - . . - - , - - - - - . - - - - - - - - - - - - - - -,n e -----w
, y; ., c -
O x NS8524.ht/ E 12 G20 79 l N 56273.39 E ll00s,23 N 402tl. 2(, . ~-
~
C //2 00,7+ r~' l 0 -
; z_
TURBINE BLOGL
, .I c
- NS98I1.89 g E 9538 93 L OCA TION OF /NS TRUMENT SITES E,F, H 4 I O
i
7 4 4 1 E r"%
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)g y)./ \ g g , ,, Wh ,o .
a ; gc.. w[
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,i i/
l/ I
~
t 6 r
O . .
,counc a Mo: 1on _a:a or
~
ragi:.i':y Ana:.ysis . e :.2 Se':s 0': Empirica:. "ime -is':ories
- Roc < or roc (-:.i<e si:es
- 1.0 <m
- H 1 6.5
- - S'
- ri<e-s:.ip, 03:.icue, anc reverse au..':Ing meclanisms e :t Se':s o': Simu:.a:ed "ime -is:ories l O
- JC33 si':e !
- - -osgri ':au:.': zone l
-H=7 l
- S':ri<e-s:.ip, 03:.icue, anc reverse !
l "au..':Ing l
- .ni:.a': era:. anc ]i:.a': era:. ru1:Ure ,
over cieren': segments 0' - ostri ! i ; i l I
- O l i
t
! f 4 !
Ug g. ; I O ! N EMPltlCAL TIME alliotill FOR FRAGILITT ANALT818 e etcomo IAtinouAKE MAGulTUDE OfSTAhCE(km) FAULT TYPE
'l
, TASAs 1978 TASAS 7.4 3 AEvtt$t OAYN00K(M00.) 1978 TASAS 7.4 17 Rtyttst
$1TE 1 1985 NANAhMI 6.9 4 Riviest i KARACTR Poluf 1976 CA2LI 6.8 3 etVtest !
a PAC 0lMA DAM 1971 SAN FlanANOC 4.6 3 Atyttst
- LAKE MUGuts :#12 (MCe.) 1971 SAs flanAm00 6.6 20 afvttst
( CA$fAlt (M00.) 1971 $AN fitmANDO 6.6 25 RivtRSE . OlFFEttNTIAL AntAT (M00.) 1979 IMPitl AL VALLif 4.5 5 stalKr. SLIP EL C!Niko 84 (M00.3 1979 IMPitlAL VALLET 6.5 6 sitigt.st!> PLEASANT VALLif PtseP sf Aflou 1963 COALimCA 6.5 to Blytest ($W1TCNTARD, M00.) . i C070ft LAKE DAM (M00.) 1944 MORGAN MILL 6.2 0.1 Staltt $ LIP r , Tim 0 LOR (MCs.) 1964 PARKFitLD 6.1 10 tititt SLIP L j i
! i h
i i 1 .
- O !
i - i I i l
, i SIMUIATED TIME HISTORIES For Fragility Analysis No. Mach Rup Md Asp i Ran i Source Loc Comp
# i i sa bil 2 8 CL 2 N l E
D 2 sa bil 2 8 IV 3 N i E
\
D , 3 as unin 2 8 IV 9 N ; E ! D 4 ss unis 5 6 CL 6 N E D 5 ss unis 5 6 IV 6 N : E D . , 6 ob bil 2 8 CL 4 N l
- E l D
I 7 ob bil 2 8 CL 5 N E
+
D 8 ob bil 2 8 IV 7 N , E' O 8 == uain 2 8 ct s = E [
, D i 2
10 ob unin 2 8 IV 6 N E D i i 11 ob unis 5 6 CL 4 N ! E D < 12 ob unis 5 6 IV 1 N
- E D
13 rv bil 2 8 CL 1 N .I' E D l 14 rv unin 2 8 CL 2 N l E : D ! k i I 2 ; I
- i i
d i ! i O . r i
SUMMARY
OF SPECTRAL ACCELERATION VALUES OF THE TIME HISTORIES FOR FRAGILITY ANALYSIS, AVERAGED OVER THE FREQUENCY RANGE FROM 3 TO 8.! Hz
.n. 4 . . . ...,.i - . . . . . .
.i . . . ,,.n
'v 3.5 3
2.5 Tebes Lake Hughes No.12
- 3. 2 - Coyota Lake Dem,NAQ(gl{ -
Pesoise Dam,Catais.
-' Piemant Valley Pump Station 1 . .
I
- ~
1.5 Differential Array l Dayhook l Katakyt Point Tomblee El Centre No. 4 3 05 - - l l O O.1 0.2 0.5 1 2 5 to 20 50 100 FREQUENCY O FIGURE 2 AVLiviv L Asi is Average cf 2 riodzontal . 'mpon:nta Domping: ' o.oe i u.4 + so ....... ! u.4 . _ _ . Ued - Sig
,4 . .
. . . . . . , . . . ...., 8 a
$- -3
.s .
l- 's , , -l
.l.' I ..
O : n-R. l ' 8 3 ' E 3-l 7.,f~ ', s -3 Q . . - ._g ,
! - \.
l %.s. .8. lM. , a t j i _____ .. ., D..... a ...: , , , . ....i . . , . ..., a L .e to. ice. Q O FMQUECY (Hz) FIGURE 3,31 __w- wm - -
O 3rounc Vo: ion ::a':a 'or Sa'i:./Struc':ure ::n:erac': ion Ana:.ysis e Si e-speci"ic Acce:eration Response Spectra
- R ~ t.5 <m
-M~7
- Site condition: rock
- faulting type: compositeofstri<e- ;
slipandreversefaulting '
- Components: larizontalandvertical
-Dampings: 2%, 5%, 10%
O - Level and slape: median : e 3 Sets of Candidate Time Fistories .
-PacoimaDamrecordof1971 San Fernando earthqua<e ;
- -Tabasrecordof1978"abas l eartigua'<e (
! - Adjusted i:. Centro #4 record 0" :.979 l l Imperial Va:.:.ey Eart1 quake ; s Spatia: ::ncolerence Functions l I 4 O ; l t l i
~
.i b
c 3.5 - i F--.; ,,,,I , , _ , , , , -
's t )T t
'1. .- 1
Domping = 2 X "
Demping = 5 % l 3 ~ Damping = 10 % _ i t L 2.5 -
. l l
s i 2 -
~
1
'S w i 0 ~
/
l \ 1.5 -
/ ,
\ _
l 0- -
/
f
/
,~
, ,,--,g
=
/ # % *
/ %
/ # ;
3
/ // !
-- w \\ !
\ % \ "
l
/ / s \\N\ ;
s e / '
-/ / NNk ,
,/ / \'q\ !
! / ~
.5 ~. ,/,!/ -
t'
/l /
spf'
/*'/r / .
t g# ' .- 0 - '
' ' m A -- ' '
4 l ' ' ' ' ' ' ' '
.1 2 ' .5 1 2 5 to 20 50 100 Frequency (Hz)
FICURE 1. Horisor;al Response Spectra Uwd for SSI Analyses O
- Iw at N
.s .t :.
F b
.r ~, . . *r
, i
< 1 1 .
l L
. _ (
_ _ w n o 0 0. O Q. E r . . I J . r . O o g, o q o w U l O < U Co C
~
2 W. 2 uj >- - 3
<m e m gg ,
0 N ,-4 i Laj 4 m . M $ . > . E < ' O , . U <
,w w
, _ _ _ n
.4 W4 23 J' l u
~
Ho < , 22 1' $ ! 08 g :"" *
< s 4 4 l h
m< s w mw Wm 4< d l _ _ n e e4 H n -g =m yn , W
- i
( K <> 86 ,
- 4
(
- N t;2
- y% .
p i=
=
t Zgg M p .. . y == ww --
=.mc ' _"F _" e E
Ez M n-
=-
e i
. p 2 TMiG 0$
g,
- r 4_ .
s . , n g* g W c r &-m gO '-
-~
'"**-*TW of e i U
o Dh __: t.
'4 m:t-i
< -c br- a t
W .
<w . -
s,> g b b a __
*A = = = = =
~ w m 2% R f
P- M~ -c t-5- .
. ;4 .
??= s-sc
.-w p e.
v I
- t i IF 1 I . I i t , g- i I . t .lP'
, t .
n W e4 d v4 n* e4
** W O + e .4 n O
- t .4 n O *
- O
- Q
- O Q l O : O 6 (D) 33W (01 33e t01 330
-20 FIGURE 3
r i n U f . - 3 - -t
*"y""r
* . .g -
., ,4 e-8 8 0 2 9
C:" C O
- p M
2 g O =$ 0 U
- w "R - =J - >
~
o 3 kW mc -g - b . m9 - =r-Eii 2. Ec -
% ~ n p -
O$ % - -- A-
$4 M @I
(-
- g3 a
~
$ e
$0 d Yt W- 0 t-- ::
!m!
c# , h m gi' =
-k. .
5h-E 1gg - e e
<m co y
o;>p . a 3 ,
< h -
[ - 3 [.
< )3 4 5-S L 1
r [
- 1 h .
w
, C
, ,t 1 -
= r '
g I
, i 3
I I I 1 1- ! I f t i ,
" O a e e O
- M Q o. , i O
o' C. o i e
- n. o n. : i 6
0 . o a ! e t03 00V t01 309 P (01 030 (
\ r
-26 FIGURE 9 ;
t
O O O ACCELERATION TIME lilSTORIES FROf.1 TiiE EL CENTRO NO.4 RECORD OF. Tile If.1PERIAL VALLEY EARTiiOUAKE. MODIFIED FOR SITE CONDITION 1 - 05 - 230 COMP O ~ # #dbiiY j .' ('N 4 "^ ^ - ^ " - - - - -
-o.5 -
. i . i . i 1 . i . i , i , i . 1
_1 1 - o.s - 140 COMP e 0 -4INiN 1 h^'^ /#-~"+t^ -# -# ^#- ^-- ^# " - ^
' = - - '
~
-0 5 -
i i i - i i i ,
. . . . . . , , . i
_1 1 - o.5 - VERT COMP
. ,NS "AUV^/.i- ^, , Ole . O ^ *-a '
0 - ,VO I l g .
-0 5 -
3 - i t i i i i i i
@ _1 ' O 3 6 9 12 is 18 21 24 27 m
E TIME (SEC)
h vat 4F S- l l l
-g O
GROUND MOTION ) l i EMPIRICAL NUMERICAL RECORDS RECORDS . O ' STRUCTURAL and EQUIPMENT RESPONSE 1 o i FRAGILITY l EVALUATION r l l l'
- l. t O -
i O ANALYSIS HAS BEEN l TAILORED TO SUPPORT PRA ;
- REQUIREMENTS
- O STRUCTURAL RESPONSE ;
e FORCES IN STRUCTURAL ELEMENTS e DEFLECTIONS ; e ACCELERATIONS e RESPONSE SPECTRA ! EQUIPMENT RESPONSE e RESPONSE SPECTRA i e DEFLECTIONS l DISPERSION OF RESPONSE ; I O . (
i0 o STUDIES PERFORMED: e DEVELOPMENT OF MEDIAN and 84% FLOOR RESPONSE SPECTRA-AUXILIARY BUILDING e DEVELOPMENT OF MEDIAN RESPONSE SPECTRA - O Att suiLDiNas e EFFECT OF INCGHERENT GROUND WOTfDN o EFFECT OF OONTAINMENT BASE UPLIFT I I l
- O
4 O GROUND MOTION ENSEMBLE OF SPATIAL VARIATION TIME HISTORIES COHERENT OF GROUND MOTION GROUND MOTION AUXILIARY BLDG SITE SPECIFIC RESPONSE SPECTRA RESP NSE SPECTRA
^
O ALL BUILDINGS 50% RESPONSE SPECTRA CONTAINMENT BASE UPLIFT I TLANT FRAGILITY ! EVALUATION I l O ! l l l l
i Ground Motione Ground Motione (Empirical + Naseericag) (Emipirical + Nemestical)
- I i
y 4
. 1r Parasnoter Effect Spatial Verlation i Coherent Ground tiotloca p SeneitivitY of Groesnd Motion Enseenbee of 7 tate Historlee (Emp8t ical) (Nasnotical) (Nemnotical)
', Esastrical - 12 Sete i Nusnotical - 14 Sete
- Traveling Wave -
l l >VerticaNy Procegating VI*** M *
- Path and Site 1'
3r qp
- Extended Source .
60% & 84% Groemed Spectra Conelatency Check I h Wfk gw Tisne History Enseenble on Median Spectra M8 incoherence Ground Motion PSOF Matrix ~ 8 elect 3 Sete of
- Tiene Histories
. Tiene History Scanne .Matchine Spectra .Tlate Hielory Scaling 1r Latin Hy,,.. _ _! : Tiene SiwHfled y y History AsM "
SSI Model w Austenary essadlas 0 ;; 808. W containsnont Upstt 88s Anasynie (84anonM Model) esoing SA8SI Nonlinear Analysis isonne CLA883 & PROSPEC if ' " u Floor htra ,Coneletency Check, Floor Roeponse Spectre Modification Factore Micet t es 60% and 84% " on Aux. Building
# # *I due 2 h Mitig .
Spatial Verlation
Response
i i u c Overall Plant Responses 3r for Key Parasnotere Plant Fragluty Analyste __ _ _ _ _ _ _ _ _ _ _ _ _ _ ._ _ -_. , _ . . - _ :n_t
; m 1 , k' i duatnt #lo n 'w)
PART I SSI RESP 0tlSES TO C0HERENT GROUND MOTION INPUTS (VERTICALLY PROPAGATING PLANE-SEISMIC WAVES) CONTAItmENT STRUCTURE AUXILIARY BUILDING TURBINE BUILDING UNIT 2 O .
^ . ,
a h 3 i i O 4 )I Ground Motione (EW4NtWel
- Mustorkel) 1 l
1r , Parameter Effect 3,.gjeg wien Coherent Ground Motione p SonettivitY (Emioitical) of Ground Wetton (Numeetical)
, (Nummerical)
. Traveeng Wave
- %f t6calty Propeesting Plano Wevee
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