ML19254D663

Safety Evaluation Input for Show Cause Proceeding Re Geologic Faulting Near Getr

ML19254D663
Person / Time
Site:	Vallecitos File:GEH Hitachi icon.png
Issue date:	09/06/1979
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML19254D659	List: ML19254D658 ML19254D663 ML19254D672 ML19254D678
References
NUDOCS 7910290323
Download: ML19254D663 (35)

Text

__.

P **

.d Show Cause Proceeding Geosciences Branch Safety Evaluation Report Input GE Test Reactor Site /Vallecitos Nuclear Center Septemoer 6, 1979 I.

BACXGROUND In July 1977, the Gecsciences Branch was requested to perform a review of the geology and seismology aspects of the General Electric Company's application 'to renew the Operating License of the General Elec:ric Test Reactor (GETR) at Pleasanton, California. As part of the documentaticn for the license renewal application, the General Electric Company (GE) submitted reports on the geolsgy and seismology of the site and vicinity (URS/ John A. Blume, 1973a; URS/ John A. Slume, 1973b; Engineering Decision Analysis Company, Inc. (EDAC), 1976).

Preliminary review of these reports caused the staff to become concerned that a potentially serious safety situation existed at the site which had not been adequately defined in the licensee's submittals.

Specifically, the staff recognized that the GETR is located within an active tectonic environment about. 2 kilcmeters east of the Calaveras fault zone, is about one kilometer south of the Williams fault as macced by Hall (1958) and, as shown in the licensee's report (URS/ John A. Blume, 1973a), a lineation passed directly through the plant site. The existence of the lineation caused the staff to become concerned that a potential existed for fault offset beneath the GETR structures. We met with GE on August 4,1977 and made them aware of our preliminary findings anc of the scope of investigation that we then considered would be necessary

o conservatively evaluate the earthcuake and f ault hazards at the site.

045 20 3

.l910290 r

t t

. On August 22, 1977, NRC received a copy of the U. S. Geological Survey (USGS) open-file report number 77-689 (Herd,1977) which contained an interpretation of the geology of the Livermore Valley, California including the area of the Vallecitos Nuclear Center. A new geologic map which accompanied the report placed a fault (the Verona fault) immediately adjacent to the GETR. The position of the Verona fault as mapped by Herd (1977) coincides with the position of the lineation shown in the GE license renewal submittal (URS/ John A. Blume, 1973a) and is about one kilometer south of the Williams fault as mapped by Hall (1958).

USGS personnel met with the NRC staff and GE and its censultants on August 31, 1977. At that meeting Dr. Herd reviewed the geologic evidence on wh'ich he based his interpretation of the Verena fault. In response to that meeting, GE excavated two trenches across the trace of the Verona fault as mapped by Herd (1977). On October 21, 1977 GE reported to the NRC that its geological consultants had identified evidence of faulting in both trenches. Mr. Hofmann and Dr. Jackson of the NRC and Mr. Morris of the USGS inspected the trenches on Octater 22, 1977. Our inspection confirmed the existence of a icw angle plane of movement across wnich near-surface beds are offset. We c:ncluded that this plane could be a low angle thrust fault which, based on the evicence then available, could be capable within the meaning of Apoendix A to 10 CFR ? art 100. As a result of these findings and in consideration of the potential for a large earthcuake on the nearby Calaveras fault which could cause grouno =ction

~ exceeding that for which the facility was designed, an Order was issued by the Acting Director, Oftice of Nuclear Reactor Regulation on October 24, 1977, which directed that, pending further order, the facility be placed and main-tained safely in a cold shutdown condition and GE show cause why the suspension of activities of the facility should not be continued.

GE responded on November 11, 1977 with a report which argued that an ancient landslide is present, that the landslide accounts for the icw angle shear planes observed in the trenches and that the existence of the Verona. fault is therefore unsupported by the available data. After reviewing that report we met with GE and its consultants and infomed them that the report did not adequately explain the evidence for offsets near the GETR. We stated further that we believed an extensive investigation and aoproximately 18 months to two years of review and interaction would be required to completely assess the geology, seismicity, and geotechnical engineering aspects of the GETR site as would be required for renewal of the license. We also indicated that investigations would be necessary to detemine whether or not the proposed Verona fault exists near the GETR and, if so, whether it should be considered capable within the meaning of Appendix A to 10 C.:R Part 100. GE was also provided with several requests for additional infor.ation.

On Oecemoer 16, 1977, (letter, R. W. Cartmizel to V. Stallo) GE took the following position with respect to the Show Cause Proceeding:

"while we (GE) strongly believe that the Verona fault does not exist, G.E. has agreed to base our analysis and modifications on two non-mechanistic conditions which are: a) ;eak ground acceleration of 0.8g from the Calaveras fault b) a surf ace offset of 1.0 meters as a result of a hypothesi:ed low angle thrust fault near 3ETR."

i MS 291

Since that time, GE has continued to acquire data and modify the existing mapping and geologic interpretations of the site area and region. In August,1978, the Geosciences Branch had reached a tentativeconclusionthatGEhadnotundertakenthenecessarvinYesti-gations to resolve whether or not the offset features were due to tectonic (earthquake) faults or landsliding. On August 18, 197E (letter R. Darmitzel to C. Nelson) GE submitted a proposed program for additicnal investigation of postulated Verona fault.

curing a meeting on August 24, 1978 between General Electric Ccmpany, the Nuclear Regulatory Ccmission, the U. S. Geological Suchey, AdYisory Comittee on Reactor Safeguards, and the California Division of Mines and Geology, a program for resolution of the potential for surface faulting at GETR was discussed.

During the period of August-December, 1978 G.E. undertock a major geolcgic expic-1 tion program designed to respond to outstanding NRC questions, herein referrad to as Phase II investigations.

Thisprogramincluded,forexample,abcut13,000feetoftrenchexcaYations, detailed geologic logging of trenches,'radiocarbcn age-dating, geologic mapping, and gecphysical exploration. The results of these investigations were submitted to NRC in a report entitled, " Geologic Investigations - phase II, General Electric Test Reactor Site, Vallecitos, California (letter, R. Carmitzel to V. Stello, February 23,1979). In this letter, GE concluded:

1.

The origin of the low angle (15-25 ) shear-like structures observed in trenches 3-1, 3-2, 3-3, H, H-1, and H-3 cannot be absolutely determined. It is the consicered cpinion of GE and its consultants that the most procable origin is large-scale lanosliding.

It is possible that these structures could also be the result of tectonic f aulting.

1345 292

_ _. ~

D

~.

2.

No offset was obserhed on any plane, which if extended, would

~

break the surface beneath the GETR indicating that no faulting has occurred in the foundation area of the reactor for at least 1 million years.

3.

ThereisnoehidenceofanyconnecticnofthepostulatedVerona fault with the Pleasanton or Calaveras faults to the northwest or the Las Positas fault to the east.

4 No surface displacement or " offset" has occurred in the vicinity of the Vallecitos site in the past 8,000 to 10,000 years. A maximum " offset" of 3 feet has occurred in.he past 10,000 to 20,000 years and 3 to 9 feet prior to that but since the last 70,000 to 125,000 years. The latter maxirum total movement is the result of several occurrences.

5.

Measurements indicate that the average rate of strain relief over at least the last 70,000 to 125,000 years is extremely. low ( 0.002 inches / year). This rate of relief is at least two orders of magnitude lower than for systems such as the Hayward,'Calaveras, Bue'na Vista and San Fernando faults.

We and our adhisors, the USGS and the U. S. Army Corps of Engineers (COE),

~

accompanied by personnel fr'em the California Division of Mines and Geology (CDMG), have made a number of hisits to the site and hicinity to examirie the results of investigations.

In additien, we hahe received letters frem the USGS (letter, P. Hanshaw to W. Ga=ill, January 30, 1978; letter, H. Coulter to E. Case, March 31, 1978; letter, J. Devine to R. Jackson May 4,1979 and letter s, H. M'enard to H. Denton, September We have also r'eceived memoranda from the COE (letter, 5 & 19, 1979).

T. Krukjian to J. Stepp, January 10,1978); frca the COMG (letter P. Amimoto to J. Stepp, October 29, 1977; letter P. Amimoto to J. Stepp, December 29, 1977; and letter J. Dahis to R. Jackson, August 16,1979) and frem our censultant Dr. Oavid 3. Slemmens (lettar, 3. Slemmons to R. Jackson, January 7,1979 ; le::er, 3. Slemmens to R. Jackscn, August 3, 1979; ano letter,J. Slemmens to R. Jackson, August 9,1979).

1345 293

~-

.~

• In addition to the field trips and meetings at the site and at the NRC Sethesda office, we hahe receihed a number of reports and addenda from GE relating to its investigations of the geological, geotechnical and seismic aspects of the site and vicinity. These reports are:

(1) " Seismic and Geologic,Inhestigations for the Ge'neral Electric Test ReactorFacility," July,1973,URS/JohnA.BlumeAssociAtes; (2) " Seismic Analysis of the Reactor Building for the General Electric Test Reactor Facility," July,1973, URS/ John A..Blume Associates, Engineers; (3) "Ehaluation of General Electric Test Reactor for Operating, Enviroa-mental and Postulated Accident Conditions," June,1976, Engineering Oecision Analysis Co. Inc.;

(4) " Response to NRC Order to Show Cause dated 10-24-77," Nohember 11, 1977, General Electric Company; (5) " Seismic Criteria and Sasis for Structural Analysis of Reactor Building,l Attachment 1," Cecember 15, 1977, Engineering Decision Analysis Co..

Inc.;

(6) " Geologic Investigation General Electric Test Reactor 'lallecitos, California, Preltminary," January, 1978, Earth Sciences Associates; (7) "GeologicInhestigationGeneralElectricTestReactor'lallecitos, California," February, 1978, Earth Sciences Associates;

- (8) " Geologic Investigation General Electric Test Reactor 'lallecitos, California, Addendum I," April, 1978, Earth Sciences Associates; (9) " Landslide Stability, General Electric Test Reactor Site, 'lallecitos, California", July, 1978, Earth Sciences Associates; (10) "Oraft Seismic Risk Analysis for General Electric 'luclear Center

?leasanton, California," Cece.cer 5,1977, Tera Cor;oraticn; (11)

'0eterminacion of 'libratory Loads to be Combined.vith Fault Jis-clacement Loads, March 1,1973, Engineering Cecision Analysis 1345 294 Oc. :nc.;

i

. /-

(12)

" Geologic Evaluations of GETR Structural Design Criteria Reports 1, 2, and 3," March,1978, Earth Sciences Associates; (13)

" Geologic Inhestigation, Phase II, General Electric Test Reactor Vallecitos, California," February, 1979, Earth Sciences Associates; (14)

" Evaluation of Seismic Hazard at the General Electric Reactor Site, California," February,1979, Richard H. Jahns.

(15)

" Probability Analysis of Surface Rupture Offset Beneath Reactor Building, General Electric Test Reactor," April 12, 1979; (16)

" Response to Comments Raised by NRC staff and Consultants ConcerningGETRGeologicInhestigationsatMeetingof3-20-79,"

letter R. Darmitzel to V. Stello, March 27, 1979.

(17)

" Response to Questions Raised Regarding the Geological Investigation-Phase II, General Electric Test Reactor Site,"

letter R. Darmitzel to R. Reid, June 25, 1979.

We and our consultants and adhisors hahe reviewed the data prohided in these reports submitted up to and including the June 25, 1979 submittal.

Our conclusions and the supporting bases contained herein represent our assessment, based on currently available data, of the earthquake vibratory ground motion, faulting and landslide hazard at the GETR site.

II. Current Staff Position The information available at the present time leads us to conclude that:

(1) Tnis evaluaticn represents our findings with respect to the Show Cause Proceeding. Theinformationdehelocedforthissitedoes not comaletely meet the investigatiEe recuire.ments of Accendix A to 10 CFR Part 100. Additional inhestigations whicn will be neeced during a license renewal effort are not saecifically adcressed in 1345 295

.nis evalua: ion.

t

-8 (2) Geologic data indicates that the GETR site is located within a zone of faulting (the Verona fault) which is at least 2000 feet wide based on current trench exposures.

(3) Since the Verona fault displaces Holocene (less than 10,000 years old) soils it is a capable fault within the meaning of Appendix A to 10 CFR Part 100 and, therefore, poses a potential for surface faulting near or beneath the reactor site.

(a) Although future displacements have a higher likelihood of occurring along existing fault breaks rather than between them, this likelihood cannot be quantified for the Verona fault zone based on current geologic observations. The concept and study of "new faulting" (initiation of new fault breaks) is in an infantile stage and observations to date in-dicate that paths of surface displacements within and adjacent to fault zones during earthquake events are not predictable.

(5)

Two and a half meters of reverse-oblique net slip could occur beneath the reactor along a fault plant which could vary in dip from about 10 to 60 degrees provides a conservative description of surface displacement on the Verona fault zone during a single earthquake event.

(6) Maximum vibratory ground motion at the GETR site would result from a magnitude 7 to 7 1/2 earthcuake centered cn the sector of the Calaveras fault nearest the site. Acceleration peaks at the free-field surface could be sligntly in excess of Ig. Tnis conclusion is based on seismological princiales and does not incorporate factors decendent On soil-structure interaction or the cenavior of the structure.

1345 296

(7) Tne horizontal Yibratory ground motion at the GETR site resulting frcm an earthquake of magnitude 6 to 61/2 centered on the Verona fault could contain acceleration peaks as high as ig. Howeher, the cherall lehel and duration of shaking would be less than for a magnitude 7 to 71/2 earthquake centered on the Calaheras fault approximately 2 kile=eters from the site.

(8) Combined loads caused by fault offset at the surface and peakhibratorygroundmotionmustbeconsideredtoact simultaneously because there is no reasonable way to forecast:

a) The location of rupture initiation, the made of rupture propagation and the potential source area for radiated seismic energy.

b)- T he location of possible fault asperities or other localized bedrock inhomogeneities which may control peaks of strong ground motion.

c) ThesequenceofpossibleinteracticnamongtheCalaheras, the Verona and the Las Positas faults.

In view of the above and the hirtual absence of near-field records of strong ground motion for larger earthquakes, there is insufficient evidence to supcort the proposition that peaks of a strong ground motion and offsets from surface rupturing will be separated in time.

1345 297

. (9) While it is the staff's position that the evidence strongly supports tectonic origin of the offsets observed in the trench exposures at the site, there is a' Iso evidence for a potential landslide hazard at the site (See pp. 26-28).

This is based on location of the GETR within a shear zone at the base of a hillside, evidence for repetitive displacements on these shears before and during the Holocene, characteristics of the Livermore Gravels, and the topographic relief adjacent to the site. There exists a potential landslide hazard for the GETR. Landslides often occur as a result of seismic events, and therefore, the landslide hazard is considered to be part of the overall geologic and seismic hazard to the GETR site.

In the absence of a definitive evaluation, we must make the conservative conclusion that the GETR coulo be impacted by a landslide. The dimensions of such a slide cannot be estimated at this

tim, III.

Discussion 1.0 Geolcay 1.1 General Thestaff'sgeologyrehiewhasbeenconcernedwithdefiningthe earthduake sources in the site hicinity and ehaluating the potential hazards of faulting and landsliding at the site. The GETR site is located in a hignly active tectenic environment (Bolt and others, 1977; Lee and others,1971). Physiographically the site is within the Vallecitos Valley section of the larger Livermore Valley. Geologically both of these valleys lie within the LiYermore syncline and the central part of the Coast Ranges structural and gecmorphic province. The Coast Ranges are structurally related to the San Andreas fault system, a transfam fault which foms a major sector of the boundary between the North American and Pacific lithosoneric plates ex-tencing frcm Cace Mendocino to the Gulf of California (Ancerson, 1971). Differential movement across the lithoseneric plates across 1345 qgg c

this boundary is accarently occuring it accut 5 cm/ year with

~

11 the Pacific plate mohing northward relatihe to the North Anterican plate. This mohement results frcm a regional orientation of the maximum principal stress that is approximately north-south horizontal (Andersen,1971).

The sector of the San Andreas fault system in the' vicinity of the San Francisco Bay consists of the main San Andreas fault and two, perhaps three other major members. The easternmost of these is the Calaveras fault zene which passes about 2 kilometers west of the GETR site. Geologic and geodetic data (Regers and Nason, 1971; Radbruch,1968; Thatcher,1975) indicate that the Calaheras fault is moving in a right slip sense (rock mass on the west side of the faulting being moved northward relative to rock mass on the east side of the fault). We censider the Lihermore syncline and the major structural elements therein, including faults, to owe their existance to cohement across the Calaheras fault. The faults significant to our review which we ccnsider genetically related to the Calaheras are the las Positas fault, which trends approximately northeast-scuthwest across the Liver-. ore syncline, and the Verona fault, which as interpreted is a low angle thrust within the southern flank of the syncline. The Greenville fault, which may also be considered a member of the San Andreas fault system, li'es about 16 kilcmeters east of the GETR site (Herd,1977). Thetectonicdehelecmentandneotectenicsofthe Livermore Valley region is not well understcod at the : resent time. Recent geologic macping (Herd,1977) and a major new geologic and seismic studybeinguncertakenbyLawrencaLiYercreLaboratcry 1345 299

- 12 l-(Department of Energy,1979) also serve to illustrate the geologic ccmplexity of this regicn and the limits of our current knowledge.

1.2 Verena Fault Since the Show Cause Order dated October 24, 1977, GE has submitted a number of geologic reports. The report entitled, "Geolcgic Investigation of General Electric Test Reactor Site, Vallecitos, California," dated February 1978, and Addendum I dated April 1978, complies GE's investigations and summarizes ir.for-mation gathered; up to that time.

In the report, GE sets forth its position regarding the existence of the Verona fault and the potential for surface faulting in the site area. The staff's conclusion, which differs from that of GE in several significant respects, is set forth later in this section.

GE position With respect to the existence of the Verona fault and the* potential for surface faulting in the site area this report concluded that:

"This investigaticn has disclosed several lines of evidence.which indicate that neither the "Vercoa fault" nor any other active or capable fault exists in the vicinity of the GETR."

This conclusion by GE is based primarily en the following interpretations:

(1) Evidence presented for the existence of a fault is either errcneous or can be explained more easily by other geologic pr: cesses.

(2) The thrust offsets or shear features observed in trenches 1 and 2 and in the large diameter borehole result frca large scale land-

~

sliding.

(3) Continuous mappable stratigraphic units around Vallecitos Valley preclude the existence of north-or northwest-trending faults wnich ::ostdate de:osition of the Livermore age graveis.

(4) A north-s1ce up thrust fault is inconsistent with the structurai 1345 300 and stratigraphic relationshios in the Livermore Valley.

. (5) The regicnal tectonic framework indicates that the Livemore Valley region is in an extensional stress environment which argues against development of, or movement on, a thrust fault.

(6) The similarity and continuity of landforms and erosional surfaces between the Livemore Valley and Vallecitos Valley preclude significant faulting in the cETR site area.

As a result of additional NRC questions and outstanding concerns, GE undertook a major trenching and investigation program primarily to evaluate the cause of linear features trending across the site area, demonstrate the location of the headscarp of the proposed massive land-slide, and evaluate the presence or absence of faulting away from potential landslide areas. On February 28, 1979, GE submitted a report enti.tled, " Geologic Investigation-phase II, General Electric Test Reactor Site, Vallecitos, California," which sumarizes information acquired to that date and modifies earlier conclusions. With resoect to the geologic characteristics of the GETR site GE concludes:

1.

The origin of the icw angle (15-25 ) shear-like structures observed in trenches 3-1, B-2, S-3, H, H-1 and H-3 cannot.be absolutely determined. It is the considered opinion of GE and its consultants that the mosc probable origin is large-scale landsliding. It is possible that these structures could also be the result of tectonic faulting.

2.

No offset was observed on any plane, which if extended, would break the surface beneath the GETR indicating that no faulting has occurred in the foundation area of the reactor for at least 1 million years.

aAS W

. 3.

There is no evidence of any connection of the postulated Verona fault with the Pleasanton or Calaveras faults to the northwest or the Las Positas fault to the east.

4.

No surface displacement or " offset" has occurred in the vicinity of the Vallecitos site in the past 8,000 to 10,000 years. A maximum " offset" of 3 feet has occurred in the past 10,000 to 20,000 years and 3 to 9 feet prior to that but since the last 70,000 to 125,000 years. The latter maximum total movecent is the result of several occurrences.

5.

Measurementsindicatethatthea$eragerateofstrainreliefoverat least the last 70,000 to 125,000 years is extremely low ( 0.002 inches / year). This rate of relief is at least two orders of magnitude icwer than for systems such as the Hayward, Calaveras, Suena Vista and San Fernando faults.

In view of the above findings and the detailed analyses su corting these findings, GE submits that a zero offset design criteria for the reactor building and a value of no =cre than three feet in a plane 15-25 degrees from horizontal on observed shears are conservative criteria for adoption by the NRC staff in addressing issue No.1 of the Show Cause Order.

NRC Staff position We conclude that the investigations accomplished to date by GE and their consultants support the existence of a Verona fault zone projecting through the GETR site area. This conclusion is based on the following observations:

1) Reverse fault offsets were observed in trenches 7-1 and T-2, 3-1, 3-2, 3-3, H and H-1.

The fault ~ offsets observed in trenches 3-1 and 5-3 confirms that the offsets previously cbserved in trenches I-l and T-2 are continuous and extend along the case of hillfront aporoximately 300 feet northeast of the GETR site. The shear :enes observed in these trenches are about 55 feet wide and consist of at least fcur

rominent faults. 3ased on coservations cf buried caleosols (ancient soils) and ca

eacia hcri:ans, :nere nave been multiole movements on

nese snear sys:ams :uring at leas: :ne las: 70,0C0 years. The younger 1345 302

. (estimated 8,000-17,000 years old) horizons are displaced approximately 3 feet with older horizons being displaced 10 to 11 feet thus indicating recurrent movements on the fault system.

A number of shears spanning approximately 50 feet wereobserhedintrenchB-2,about1300feetsouthwest oftheGETRinthehicinityofaprominentairphoto lineation. Themainshearobser$edinthistrench offsets the youngest paleosol horizon about 3 feet andalsoprovidesevidenceofrecurrentmohements.

Trenches H, H-1, H-2 are located about 2500 feet south of GETR, at the base of a small hillfront in the hicinity of building 102 coincicent with a prominent airphoto lineation. Observations in these trenchesindicatethepresanceofarehersefault which has a left lateral oblique slip component.

The LiYemore GraYels are offset a minimum of 29 feet at this location with younger horizons displaced a minimum of 3 feet in trench H-1.

The overall appearance, parallelism and similar recurrent actihity of these three main shears spanning 2500 feet in front of the hill-front strongly succort a tectonic origin for this fault system.

1345 303

s (2) The trench investigation (trench series D, F and G) undertaken in the hills northeast of GETR failed to reveal any major pullaparts and/or shears that are associated with the headscarp of a major landslide. Such major pullaparts and/or shears would be expected to be found at the headscarp of a major lanoslide of these proportions.

The vertical normal shears identified are in the vicinity of recent surficial slides and none of the observed shears were extensive enough to account for the displacements noted at the hillfront.

These observations further support a tectonic origin for the shears near the GETR site.

(3) To the southeast of the GETR, the geologic log of the La Costa tunnel (California Department of Water Resources,1966) suggests low angle faulting and folding in an area through which the Verona fault wculd pass if projec' ed eastward.

In the t

same general area there is a major abrupt change in the stratigraphic secticn above the middle conglomerate unit of the Livermore gravels when c: cared to the section to the ncrth of the GEU. This change can be explained either by the presence of a thrust fault, by an unconformity,or by c mplex structural geology related to the intersection of the Verena fault and the Las positas f ault wnich is also in the area Of the Jilliam's fault

('dall,1953)-La C sta tunnel intersecticn. 'Jnderstanding 1345 304

. this relationship beccmes important in attempting to synthesize a tectenic model for fault development and fault movement in the Livermore valley. Areas of intersection or merging of faults can be in' a transitional stress state which usually leads to the development of fault patterns wnich are geologically complex such as en echelon faults rather than a single planar fault surfaces. The licensee has excavated trenches A, A-1, A-2 in this location with discovery of a major fault zone coincident with a deep colluvium (reworked recent soils). GE indicates that this fault strikes N65-70 W, dips 70-75 NE and represents a fault which projects northwesterly to the northeast side of the hills adjacent to the GETR.

It is our conclusion that this fault also has reverse slip associated with it in addition to the observed strike-slip movement and the dip of the fault mere realistically ranges frem 15-75.'IE.

The discovery of a major ccmolex fault zone at trench A locatien supports the probable projection of the '/erona fault into this area, therefore this fault is limited to the northeast only by its intersection by or merging with the Las Positas fault.

(4)

Existing geologic maos and texts of 'lickery (1925),

Hail (1953), Prince (1957), URS/Blume Asscciates (1973),

and mere recently Herd (1977) succor the existence Of the 'lenna f ault and other f aults in the 3ETR si a area anc vicinity.

n acciticn, Oc the nortnwest of One x.n

~

1345 305

. site and along the general northwesterly projection of the Verona fault is the northwest-trending Pleasanton fault which is identified as a potentially active fault on the California Division of Mines and Geology Special Studies Zones Map, Dublin Quad-rangle (Slosson,1974). Several authors (Burkland and Associates,1975; Judd Hull Associates,1977; Carpenter, 1977) have assigned various locations to the Pleasanton fault. In addition, recent gravity profiling and interpretation by Griscom and others (1979) indicates the presence of anomalies at a location near Pleasanton along the northwesterly projection of the Verona fault.

In order to determine the projection of the Verona fault to the northwest of GETR, GE proposed to excavate trench C at a prominent topographic escarpment. As a result of difficulties in obtaining procerty access, GE excavated a trench at an alternate and scmewhat less desireable locatien-Trench E.

Althcugh no young faulting was noted in trench E, questions remain as to whether or not this trench crossed the projection of the Vercna fault. At the present time, it is reasonable to concluce that the Pleasanton fault may be a continuation of the Verona fault.

}3kb

(5) Recent seismological studies of earthquake fault plane solutions indicate that reverse slip movements in the Livermore Valley region are occurring and therefore this area is in northeast-south-west compression (Simila and Somverville,1978) and not extension as argued by the licensee. Moreover, this indirect observation of the stress direction is consistent with the highly active regional tectonic framework. Northeast-southwest compression would support development of, and continued movement along, a northeast-dipping thrust fault such as the Verona fault.

If extension were occurring in this area, stresses would not be likely to cause the development of, or movement along, a northeast-dipping thrust fault.

O e

l.3 Surface Fault Offset GE and the NRC staff (including its consultants) continue to disagree on the amount of surface fault offset to be assumed on the Verona fault zone. The respective positions of the two parties are set forth below.

GE Position On December 16, 1977 (letter, R. W. Darmitzel (GE) to V. Stello (NRC)), GE stated that a hypothetical offset displacement at the grcund surface of 1.02 meters on a 15 degree shallow-dipping shear plane would be used to analyze the effects of surface rupture on the GETR structure. This hypothetical fault displacement is based on an empirical relation of maximum surface displacement to total length of surface rupture (Earth Sciences Associates, 1978).

The licensee assumes 8.2 kilometers for the total length of the Verona fault.

Utilizing data frem Slemons (1977), the licensee deYeloped a plot of surface displacement versus rupture length for kncwn faults.

Utilizing a maximum rupture length in a single event of one-half the total maoped length or 4.2 kilcmeters for the Verena, a maximum surface displacement of 1.02 meters was estimated. As a result of the more recent Phase II investigations (ESA, 1979) GE indicates that the Verona fault is limited in length and that the assumed 8.2 kilometer length is conservative.

In addition, GE c:ncludes that measurements of offset soil stratigraohic ::arkers c:nfirm that the maxirum amount of offset that has occurred on any single shear surface within the last 20,000 years is less than 1 meter, and that an asrS.ed offset of 1 meter is c:nservative.

1345 308 EC Staff :Ositien de c:nclude based on our site visits and revlew Of :.e licensee's recort (e.g.

ESA,1979) :nat :here have been rec.:rret,. movements On the order of 1 meter on

21 -

r the observed shears and that some of these movemar.ts took place as recently as during the Holocene. Due to the abance of clearly recognizable and correlateab soil stratigraphic markers for older time horizons (i.e., deeper in the trench) we conclude that movements of as much as a few meters could have occurred along any shear.

In addition, cumulative total displacement on all the cbserved shears en the GETR site could have cccurred during a single earthquake event.

Since these shears are probably splays of the sa=e fault at depth, this cumulative displacement might occur en any single splay cr between them.

We conclude that a postulated 21/2 meters of reverse-oblique net slip along a fault plane which eculd vary in dip frem 10 to 50 degrees provides a conservative description of surface slip en the Verona zone during a single event. Our judgement is based, in'part, en our understanding and evaluatien of observations of faults offsets made folicwing the 1971 San Fernando, California carthqu;xe (Barm and others,1973).

Tne Verena fault, including its northwest erly projection alcng possible splays of the Pleas % ?cn fault, has an et timated surface length of 12 kilo-meters (Herd, 1977; Earth Sciences Associates, 1972b). This fault is either truncated by cr Serges with the Calaverts fault to the northwest and joins with or is truncated by the Las Positas fault in the ;eneral area of the La Costa tunnel. de believe that utili.:ation of the tan Fernando data is a reas'nable basis for ;cstulating the amount of of# set that cculd occur en the Verona fatit near t5: GETR because af general sinilarities. The length of observed surface rupture during the San Fernando event was abcut 12-15 kilo-metars. '4cvement was predcminantly in a thrust sense with a substant'ai hori: ental ccmpenent. AssEing the Verena fault ruptures along its estimated trace, it would have a rupture length of abcut 12 kiicmeters. Based en Observaticns cf a reverse thrust movement in the trench excavations near GETR 045 309

- 22 and ragicnal stress censiderations which would support crustal cc=pressien

('_ee and others, 1971), we would anticipate the Verona fault to undergo reverse movementasdidtheSanFernando$reafaults. In addition, due to the crientaticn of the regional stress, the Verona fault shculd be expected tohaheahorizontalcomponentofmovement.

In supccrt of the judgement we obserhed that Bonilla and others (1971) calculated slip h' ctors alcng an assumed fault plane in the Orange Grohe e

Avenue and Eighth Street of San Fernando that sustained surface rupture during the 1971 San Fernando ~ event. These calculations indicate that 2.4 meters of net slip displacement took place. Itisalsonotedthatherticaldisplacement for this location is distributed across a zone of breakage 2C0 meters wide which is complicated by a zone of shearing and thrusuing and a zene of extension.

D*

D

• D.S

=

ew e

In order to prohide further information en possible fault displacerent, we used the aaproach of Slemons (1977) and EDAC (1977) which relates maximum surface displacement to length of surface rupture. For purposes of this analysis the Verona is assumed to be a reverse thrust fault with a rupture length of 12 kilcmeters as discussed prehicusly. Slemons (1977) performs. an analysis which develops a best straight line fit to fifteen cata points of reherse and reherse-cblique-slip faults. Fcr a rupture length of 12-15 kilcmeters as observed after the 1971 San Fernando earthquake,thisrelationshipwouldpredictamaximumnet-sliphalueof 1.56 to 1.33 meters. Actual net-slip caserhaticns at San ernando indica:e that the maximum net slip was about 21/2 meters. This fault-length versus offeet relationshio based on historical observations wculd not have accurately credicted the arount of offset obcarved during the 1971 San ernando earthquake.

1345 H 0

s.

Itisclearthatthisworldwidedatasetforreherseandreherse-oblique-slip faults is very small and has a wide hariation in halues.

Because of this fact, these observations cannot be used in a rigorous We do beliehe, howeher, that they do provide further support sense.

of our judgement.

Based on the above considerations, we conclude that 2 1/2 meters of reverse-oblicue net slip at the surface along a fault plane which could dip 10-60 degrees provides a reasonably conservative description of the magnitude of offset that might be anticipated as a result of movement on the Verona fault during a single event.

The USGS indicated in their letter of January 30, 1978 that censidering the fact that the San Fernando earthquake produced 2.4 meters (7.9 feet) of net sl.ip, the one meter of net-slip" movement postulated by GE dces not seem to provide adequate conservatism. The USGS has also indicated in their letter of September 5, 1979 which is attached as Appendix A to this report, that the next slip that could occur en the Verona fault zone could greatly exceed the one meter proposed by GE.

Dr. David 3. Slemons, acting as an expert consultant on fault behavior to the'NRC staff indicates in his letter of August 8,1978, attached as Appendix 3, that the 2 1/2 meter net slip value is reasonable for a fault with a length of between 3.2 and 12 kilometers and the obser$ed 1 meter affset of the modern scium and it is consistent with the discersien of data shown on the worldwide cata for earthquake magnitude to c.aximum displacement relations.

The CCI'G has been an interested participant in the geologic discussion and site visits.

Its report is attached as Appendix 0.

1345 311

. 1.4 Surf ace Fault Offset Beneath Reacter In support of the position that a zero offset design criteria should be used for the reactor building, GE submitted a study entitled, " Probability Analysis of Surface Rupture Offset Beneath Reactor Building General Electric Test Reactor."

GE's Probabilistic estimates are based on the assumption that the future occurrence rate will be the same as that in the past and on the validity of the 128,000 years datum as the actual age of non-offset materials beneath We requested that Dr. David Slemmens, review the validity of the reactor.

In his review, Dr. Slemmons the geologic assumptions contained in the report.

states in his letter of August 9,1979, attached as Appendix C.

"I believe that the basic seismologic cycle that appears to occur en many faults involves progressive strain, earthquakemicro-earthquake build up of activity at times with smal4er faulting.

events or creep, a main shock, a decay period of decreasing. activity.

Earthquake sequences on adjoining or connecting faults may vary the cycle. This is a deterministic process and the ;rebabilistic approach used in this report may not adequately represent the risk. In addition, the numerical values used for the probabilistic analysis, although they are listed with three significant figures, are based mainly on assumed ages of older soils, on scattered radio-metric ages of the modern solum, and en limited field data. The over-all effect is that the results are presented with an aura of scientific accuracy and precision that may be misleading.

Although probabilistic methods generally can be utilized fcr I

assessing the likelihood of occurrence of specific e/ents, we conclude that such metheds cannot be used with any level of confidence to specifically predict the location and likelihcod of fault offsets within this active fault cne which is pooriy understcod. This view is succorted by Dr. Slemens' review report which indicates a probabilistic accroach anich assumes a Poissen distributien may not be accrocriate far risk analysis Of the :ctential for surf ace rupcuring. In addition, 1345 312

the state of kncwledge of the geological-seismological cer:cunity regarding the concept and study of "new faulting" is in an infantile stage.

In a recent report by M. G. Bonnilla (1979) entitled, " Historic Surface Faulting--Map Patterns, Relation to Subsurface Faulting, and Relation to Fre-existingFaults",thebehahiorofsurfacefaultingisassessedbased on worldwide cbservations. Bonnilla concludes that:

"Although historic surface faulting has typically followed pre-existing faults, it has been selective, following one fault for a distance, then stepping over as much as 6.5 kilcmeters to another fault. On a more detailed scale, displacement has occurred on one fauli: in preference to another as close as few meters away.

One can speculate that the choices among available paths deoends on orientation of the pre-existing faults with respect to stress and their relative strengths."

Dr. Slemons also notes the possibility that "short cut" faults may deYelop between existing faults. The USGS concludes in their September 5,1979 review report that the potential for surface faulting beneath the GETR reacter cannot be eYaluated properly with the infomaticn curfently ahailable. This conclusion is based en the young age of unfaulted gravel horizons nhserved in the trench nearest to the GETR which could obscure faults at death. The USGS further concludes that:

"Even if there were no known faults directly beneath the GETR, the possibility of new surface faulting beneath the reactor vessel cannot be discounted. The GETR lies within the center of the wide Verona thrust fault zone, and could well experience surface faulting along a new break which could form in the zone. All faults are new at some time."

As discussed earlier, the GETR is bounded both to the northeast and southwest by faults which have had substantial amcunts of relatiYely recent movements alcng them. Based en cur current evaluation, the initiatien of "new faulting" between these offsets shculd be c:nsidered

ossible.

In sucmary, we conclude that, although future disalacements have a higher likelihood of Occurring alcng existing f ault breaks rather than between them, this likelihood cannot be cuantified for

}3kb M3

s j

-2 theVeronafaultzonebasedoncurrentgeologicobserhations. In addition, the concept and study of "new faulting" (initiation of new fault breaks) is in an infantile stage and obserhaticns to date indicate that paths of surface displacements within and adjacent to f ault zones during earthquake events are not predictable. Accordincly, surfa:c dis;:ia:eme-t beneath the GETR could occur anc must be censiderea in determining the proper seismic and geoi:gi: desig, bases for the facility.

2.0 Landslidino ThissectiondiscussestheeYidencefortheinterpretatienofalarge landslide complex northeast of the GETR site and the stability of the The discussion postulated landslide complex against future movement.

of the relative merits for landslide versus tect:nic origin of the shears is presented elsewhere.

Tne crest of the northwest-trending hills (Rocky Ridge) im.ediataly northeast of the major building complex at GETR is at an elevatten of The toe of the southwest facing hillside is at about about 1,200 feet.

Near the GE R, the drop in elevatica from the ridge elevation SCO feet.

(elevation 1200 feet) to the tee (elevation 500 feet) is typically Tne hori: ental distance from the ridce to the t:e varies fr m 500 feet.

With a vertical dr:o 2,300 feet to *,3C0 feet and is typically 3,5CO.

of 500 'se: and a hori::ntal distance of 3,5C0 feet, -he average sicpe is 5 heri::ntal to 1 vertical.

045 M4

The detailed topographic map, Figure 14 of the Geologic Investigation byEarthSciencesAssociates(1978b)fortheGETRprohidestheconfiguration of the hillside slopes adjacent to the GETR complex.

Three separate slope conditions can be identified from the ridge crest down to the toe of the hillside. RelatiYelysteep(1.7Horizontalto 1 Vertical) amphitheater scarplike areas can be identified between about elevation 900 and 1,100 feet. The central portion of the slopes is characterizedbyarelatiYelyflatbenchareatypicallybetweenelehation 900 and 950 feet. The toe of the hillside benches below elevation 900 feet consists of moderately steep sicpes, typically 3 horizontal to 1 vertical. The horizontal length of each of these areas is typically 1000 feet.

Evidence that suggests the southwest facing hillside north of the GETR site contains a large landslide ccmplex can be identified on hign altitude and low altitude air photos (Earth Sciences Associates,1972b) of the hill front. The high altitude photos shew a scarp-like feature two-thirds of the way up the southwest f acing hillside and the low altitude photos show a scarp-bench-toe configuration frequently associated with large landslides.

Shear plans and low angle thrust features were identified in the T, 8 and H series trenches (ESA, 1979) and borings (3H-1, BH-2 and SH-3) located near the base of the hillside (Ref. Fig. 7, Earth Sciences Associates,1973b).

In addition, subsurface materials observed in trench T-2 were jumbled and sheared. These features are typically observed at or near the toe of a landslide.

5

. Two additional important items that bear on the landslide issue are the recurrent nature of the movement and the age of last movement.

Thefieldehidenceindicatesmultiplemovementsduringthelast70,000 years and the youngest movements displace Holocene-age soil.

The stability of the landslide complex northeast of the GETR site dependsonthedriYingforceduetotheweightofmaterialswithinthe hillside cceplex (plus any seismic loading), the strength of the geo-logic materials, and the influence of the groundwater conditions en both the resisting and driving forces. Only a qualitative evaluation of the stability of the complex based on assumed data can be made at the present time. To provide a quantitative evaluation of the hillside stability a detailed investigation and complete geotechnical analysis must be performed.

The Landslide Stability (ESA,1978c) repcrt does not adequately define the slip surface, shear strength or groundwater pressures required to evaluate the safety factor for the slopes north of the GETR. Therpfnra, based on the young age and recurrent nature of movement en the shears the staff can only conclude that there exists a potantial landslide hazard for the GETR site.

GE has argued (GE, June 25, 1979) that performance of additional extensive geological field investigations and engineering analyses at this juncture would be unnecessary for the development of seismic design bases. The staff, hc 4 aver, concludes that these investigations and analyses are required to define the appropriate seismic and geologic design bases for the GETR.

1345 316

3.0 Seismolooy 3.1 Seismic Desian Basis TheseismicdesignhazardsfortheGETRsiteincludehibratory ground motion, fault offset at the surface beneath the unit and vibratory ground motion combined with surface offset caused by postulated movement on the Verona fault. Tne licensee has provided an evaluation of these design hazards in reports by EDAC (1976, 1977) and has provided additional supporting discussion in a report by Earth Sciences Associates (1978d). The staff has reviewed these reports but has relied on the review of the USGS and Dr. Slemmons as well as detailed discussions with them in preparing Section 3.

3.2 Vibratory Ground Motion The GETR site is located in a complex fault environment 2.3 kilcmeters east of the Calaheras fault within the Verona fault zone and within 3 kilometers of the Las Positas fault. Thelicensee'sehaluationof vibratory ground motion at the GETR site is gihen in ECAC (1975 and 1977).

Tne evaluation considered both recurrence probabilities of earthquake intensity at the site and maximum earthquakes on the San Andreas, Hayward and Calaveras faults (EDAC, 1976). The licensee concludes that a value of horizontal ground acceleration of 0.56g is the appropriate effective value to be used to scale Regulatory Guide 1.50 spectra as the seismic design basis vibratory ground motion at the GER site. Tnis conclusien is based in part on an assumed maximum earthquake of magnitude 5.5 cn the 1345 317 ok

. Calaherasfault. In a later report the licensee adopted a seismic designbasisYibratorygrcundmotiondescribedbyaresponsespectrum haYingtheshapeofRegulatoryGuide1.60,butwithamplification factors scaled to 0.8g for the GETR site (EDAC, 1977).

We consider that the potential earthquakes sources that are important in assessing the vibratory ground motion hazard at the GETR site are the Calaveras fault and the Verena fault. Earthquakes occurring on these faults could have magnitudes of 7 to 7 1/2 and 6 to 6 1/2, respectively. A magnitude 7 to 71/2 earthquake is estimated for the CalaYerasfault. Strike-slip faults subsidiary to and connected to theSanAndreasfaulthaYegeneratedmaximumearthquakesofmagnitude about 7 to 71/2 based on the data of Coffman and Von Hake (1973). As previously discussed in the geology secticn, the proposed Verena fault probably exists beyond the bcunds of the area mapped by Herd and could merge with the Calaveras fault. This assumption yields a total length of aceut 12 kilcmeters.

The Verona fault could be structurally connected to larger faults, and a major portion, and possibly all, of the 12 kilcmeters length could rupture during a single earthquake. It is our conclusion, therefore, that it is reasonable to consider the San Fernando earthquake of 1971 as an earthquakesimilarinsizetoapotentialeYentontheVeronafault. A larger earthquake (magnitude 3 to 31/2) could occur on the main San Andreas fault, but due to its distance from the GETR site, a: proximately 50 kilcmeters, such an eYent would result in less sericus ground motion at the site than would be caused 'cy the cotential eYents described abcYe.

1345 318

TeGETRsiteislocated2.3kilcmeterseastoftheCalaheras h

fault, about 3 kilcmeters west of the Las Positas fault and within the Verona fault zone. The le' vel of ground motion hazard from the Las Positas is considered enveloped (due to its greater distance frcm tha GETR site) within the ground motion hazard from the Calaveras fault and is not considered further herein. The USGS concludes, due to the absence of the Verona fault zone, it is not possible to arrive at reasonable estimates of the earthquake size and resulting ground motion that could originate on the Verona and Las Positas faults.

However, they note similarity of the Verona and Las Positas fault to the then poorly known fault system which generated the 1971 San Fernando earthquake that had a magnitude of 6.6 and produced grcund motion in excess of Ig acceleration Eery near the fault break. Dr.

Slemmons concludes that a potential magnitude of 6.510.5 for an earthhuake generated by faulting that is limited to the Verona fault zone.

The lehel and duration of acceleration near an earthquake source have been evaluated based en the aYailable data by Page and others (1972).

Their study indicates that peak horizontal near-scurce acceleraticn for a magnitude 7 to 71/2 earthquake could exceed lg and that the total duration of strong motion could be between 25 and 40 seccnds. The staff considers these values accropriate for describing the vibratory grcund motien hazard at the GETR site due to a magnitude 7 to 71/2 earthquake centered on the Calaheras fault at a distance of 2.3 kilcmeters.

045 319

. Because of the presence of the Verena fault zone beneath the site, ccmbined loading must be censidered frcm both surface offset and the peaksofhibratorygroundmotion. While it is possible that the peaks of strong ground motion may subside prior to the enset of surface rupturing, it is our conclusion that these two kinds of earthquake effects must be treated simultaneously. This is the case because of our inability to.for.ecast the source area of radiated peaks of seismic energy, and the possible interaction among the faults near and under the site. Hanks (1974),

for example, considered, based on a streng motien record for the 1971 San Fernando earthquake at Pacoima Dam, that the breakcut phase indicatihe ofnear-surfacerupturingoccurredduringthetimeinterhalofthe strengest ground motion.

The lic'ensee argues (Earth Sciences Associates, 1978d) that streng ground motion will travel at shear-wahe helecity and that rupture will prcpagateatabcut70percentofshear-wahehelecity. Because of this velocity differential there wculd be a delay time at the site of seheral seconds between the arrihal of the streng.:otion and -he cropagating rupture. While these assumptions are not unreasonable, there exist many uncertainitiessuchasthosedescribedatchenotenccmpassedbythisline of reasoning. It is cur conclusion that sufficient justificaticn dces not exist for separating in time the effects of strong grcund motion and offsets of surface rupturing.

045 320

References Anderson, D. L.,1971, The San Andreas Fault, Scientific American, V. 255, No. 5, pp. 53-66.

Barrows, A. G., Xahle, J. E., Weber, F. H., Jr., and Sault, R. B.,1973, Map of Surface Breaks Resulting from the San Fernando, California, Earthquake of February 9,1971; in San Fernando, California Earthquake of February 9,1971, U.S. Department of Comerce, Washington, D.C.

Bolt, B. A., Stifler, J., and Uhrhamer, R.,1977 The Briones Hills Earth-quake Swarm of January 8,1977, Contra Costa County, California, Bull.

leismic Soc. America, V. 67, No. 6, pp.1555-1564 Bonilla, M. G., Buchanan, J. M., Castle, R. O., Clark, M. M., Friz: ell, V. A., Gulliver, R. M., Miller, F. K., Pinkerton, J. P., Ross. 0.C.,

Sharp, R. V., Yerkes, R. F., Ziony, J. I.,1971, Surface Faulting in the San Fernando, California Earthquake, February 9,1971, Geological Survey Professional Paper 733, U. S. Geological Survey and National Oceanic and Atomospheric Administration, U.S. Department of Interior, U.S. Department of Connerce, Washington, D. C., pp. 55-76.

Bonilla, M. G.,1979, Historic Surface Faulting -- Map Patterns, Relation to Subsurface Faulting, and Relation to Preexisting Faults, Preprint from: Proceedings of Conference VIII Analysis of Actual Fault Zones in Bedrock.

Burkland and Associates,1975, Geologic and Seismic Hazards Investigation, Pmposed Restaurant and Office Remodeling Site for Mr. Vic Lund, Jr.,

Prepared for City of Pleasanton, 27 p.

California Department of Water Resources,1966, Final Geologic Report on the Construction of La Costa and Mission Tunnel. OWR, Division of Design and Cgnstruction, Project Geology Report C-10.

Carpenter, D. W.,1977, Geologic Investigations for Master Plan Formulation, Santa Rita Property, Prepared for Alameda County Board Supervisors,17p.

Coffman, J. L., and Von Hake, C. A.,1973, Earthquake History of the U.

S.,

U. S. Department of Comerce (NCAA), Publication 41-1, 208 p.

Earth Sciences Associates,1975, Fault Investigation, Library Addition.

Amador Valley High School, Pleasanton, California, Prepared for Amador Valley Joint Union Hign School District, 10 p.

Earth Sciences Associates,1973a, Geologic Investigation General Electric Test Reactor Vallecitos, California (Preliminary); Prepared for General Electric Co., Pleasanton, California.

Earth Sciences Associates,1973b, Geologic Investigation General Electric 7est Reactor Vallecitos, California; ?repared for General Electric Co.,

Pleasanton, California.

1345 321

2-Earth Sciences Associates,1978c, Geologic Investigation General Electric Test Reactor Vallecitos, California, Addendum 1; Pr1 pared for General Electric Co., Pleasanton, California.

Earth Sciences Associates,1978d, Geologic Evaluations of GETR Structural Design Criteria, Prepared for General Electric Co.,

Pleasanton, California.

Earth Sciences Associates,1978e, Landslide Stability General Electric Test Reactor Site, Vallecitos, California, Prepared for General Electric Co.,

Pleasanton, California.

Earth Sciences Associates, 1979, Geologic Investigation Phase II, General Electric Test Reactor Vallecitos, California, Prepared for General Electric Company, Pleasanton, California.

Engineering Decision Analysis Company, Inc., 1976, Evaluation of General Electric Test Reactor for Cperating Environmental, and Postulated Accident Conditions, Criteria and Bases Summary for Structural, Piping Systems, and Components; Report for General Electric Co., San Jose, California.

Engineering Decision Analysis Company, Inc.,1977, Seismic Criteria and Basis for Structural Analysis of Reactor Building, Attachment 1; Prepared for General Electric Co., Pleasanton, California.

Engineering Decision Analysis Company, Inc.,1978, Determination of Vibratory Loads to be Combined with Fault Displacements Loads; Prepared for General Electric Co., Pleasanton, California.

General Electric Co.,1977, Response to NRC Crder to Show Cause Dated 10/24/77; General Electric Co., Vallecitos Nuclear Center, Pleasanton, California.

General Electric Co., June 25, 1979, Response to Questions Raised Regarding the Geological Investigation Phase II, General Electric 7est Reactor Site -

Docket No. 50-73.

Griscom, A., Roberts, C.W., and Holden, K. D.,1979, Gravity Data and Interpre-tation of Detailed Gravity Profiles in the Livemore Valley Area, California, U. S. Geological Survey Open-ftle Report 79-549.

Hall, C. A., Jr.,1958, Geology and Paleontology of the Pleasanton Area, Alameda and Control Costa Counties, California, California University Pubs. Geo'.

Sci., V. 34, No. 1, 53 p.

Hanks, T. C.,1974, The Faulting Mechanism of the San Fernando Earthquake Journal Geophysical Research, Vol. 79, No. 8, pp.1215-1229.

Herd. D. G.,1977, Geologic Map of the Las Positas, Greenville and Verona Faults, Eastern Alameda County, California, USGS Open-File Report 77-639, 25 c.

Judd Hull and Associates,1977, Geologic Investigation for Procosed Civic Center Additions, ?leasanton, California, Prepared for City of Pleasanton, California, 21 p.

Lee, W. H. K., M. S. Eaton, and E. E. Brabb,1971. The Earthquake Sequence Near Danville, California,1970, Bull. Seism. Soc. Am. V. 61, p.1771-1794.

Prince W. S.,1957. Earthquake Considerations at Proposed GETR Site, General Electric Ccmpany, Atomic Power Equipment Department Report, GEAP No.1050.

Radbruch, O. H.,1968, New Evidence of Historic Fault Activity in Alameda, Contra Costa, and Santa Clara Counties, California, in Dickinson, W. R., and Grant:, Arthur, eds., Proceedings of conference on geologic problems of San Andreas fault system: Stanford Univ. Pubs. Geol. Soc., V.11, p. 46-54.

Rogers, T. H. and R. D. Nason,1971, Active Fault Displacement en the Calaveras Fault Zone at Hollister, California, Seis. Soc. America, Bull., V. 61, No.

2, pp. 399-416.

Simila G. and Somerville, N.1978, Seismicity of the L.vemore Valley, California Region (Abstract), Earthquake Notes V. 49, c. 27.

Slemons, D. B.,1977, State-of-the-Art for Assessing Earthquake Hazards in the United States Report 6. Misc. Paper S-73-1, United States Amy Corps of Engineers, Waterways Experiment Station, Vicksburg, Mississippi, May 1977.

Slosson, J. E.,1974, State of California, Special Studies Zones, Dublin Quadrangle, California Division of Mines and Geology, Sacramento, California.

TERA Corporation, Inc.,1977, Draft Seismic Risk Analysis for General Electric Nuclear Center, Pleasanton, California; Prepared for General Electric Co.,

Pleasanton, California.

Thatcher, Wayne, 1975, Strain Accumulation of the Northern San Andreas Fault Zone since 1906, Journal of Gecphysical Research, Vol. 30, No. 35, pp. a873-4880.

United States Department of Energy,1979, Transcript of Public Hearing on Lawrence Livemore Laboratory Environmental Impact Statement, April 12, 1979.

URS/ John A. Slume Associates, Engineers,1973a, Seismic and Geologic Investiga-tions for the General Electric Test Reactor Facility, Report for General Electric Co., Vallecitos Nuclear Center, Pleasanton, California.

URS/Jonn A. 31ume Associates, Engineers,1973b, Seismic Analysis of the Reactor Building for the General Electric Test Reactor Facility; Report for General Electric Co., Vallecitos Nuclear Center, Pleasanton, California.

Vickery, F. P.,1925, the Structural Dynamics of the Livemore Region, Journal of Geology, V. 33, p. 608-628.

045 523

Appendix A l g%$7 United States Department of the Interior

.:E GEOLCGCAL SURVEY RESTON. VA. 2:09 In Reply Refer To:

Mail Stop 905 SEP 5 1979 Mr. Harold Centen Ofrec:cr of the Office of Nuclear Reacter Regulations U.S. Nuclear Regulatory Ccmission Washington, D.C.

20555

Dear Mr. Centen:

/

Transmitted herewith, in response to the request of your staff, is our review of the geologic and seismologic data relevant to the General Electric Test Reacter at 'tallecitos, California.

This review was prepared by Earl Ersbb, Darrel Herd and Jatt:es F.

Devine. Assistance was provided by Robert H. Morris.

Sincerely ycurs,

~

t(

-Me t., ySO b

,e t H. W1111am'Menard Director Enclosure M

DUPLICATE DOCUMENT} } /[ b 3 2 4 f.}

Entire document previously 0 " #"" #'d Y' entered into system under:

1*.

ANO

.N.. _ _

No. of pages:

s

//

q l'pg1 United States Department of the Interior 1 -,.f GEOLOGICAL SURVEY s

RESTON. VA. 22092 In Reply Rafer To:

Mail Stop 908 EE.* 1

'3l9 Mr. Harold Denton Director of the Office of Nuclear Reactor Regulations U.S. Nuclear Ragulatory Cet=ission Washington, D.C.

20555

Dear Mr. Denton:

The enclosed supplement should be added to the U.S. Geological Survey status review dated Septe=ber 5,1979, of the General Electric Test Reactor Facility Dociet No. 50-70.

Sincerely yours,

//

l'r*je.u'jlv J

l'

'H. William Menard f

DL :ector Enclosure

'go

1. " 4. u 1345 325 N 0 'i t

s

.2 x

]

j \\

)

One Hundrel Years of Ear:h Science in :i:e Puclic Senice

.,. =

w:&>.

7 ouseso473 y

D '

' M9 5

.JH L

a

s General Electric Test Reactor Vallecitos Nuclear Center Vallecitos, California Docket Number 50-70 Supplement to Status Review The letter frem R. W. Darmitzel, General Electric Company, to C. Nelson, NRC, dated July 12, 1979, raises Obe point that USGS Professional Paper 943 does not show either the Verona nor the Las Positas faults and that this point should be considered along with the applicant's data regarding the geology of the Liver = ore area.

Professional Paper No. 943 " Flatland Deposits -- Their Geology and Engineering Properties and the Importance to Comprehensive Planning" vas published in 1979, and therefore post-dates the publication of Open File Map 77-689 (1977)'in which the Verona and Las Positas f aults are shown. Although PP 943 was published in 1979, the authors manuscript was submitted in 1976 and received approval March 2,1977. Data in the report thus pre-date Open File Map 77-689 and omission of the Verona and Las Positas faults as described by Hard becenes understandable.

Furthermore PP 943 is principally a study of Pleistocene and younger strac1graphie units and the acce=panying maps plates 1, 2 and 3 were not intended to show all faults in the areas depicted. For instance the Hillside fault, Miller Creek fault, Cull Creek fault and Bolinger fault are exa=ples of the many others not shown.

The apparent emission of the Verona and Las Positas faults from maps in FP 943 therefore provides no basis f or emphasis, pro or con, in the review of geologic data pertinent to the Vallecitos GE!1 site.

t

.