ML19308B392
| ML19308B392 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 07/27/1976 |
| From: | Hofmann R, Rolonda Jackson Office of Nuclear Reactor Regulation |
| To: | Gammill W Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML19308B393 | List: |
| References | |
| NUDOCS 7912300176 | |
| Download: ML19308B392 (11) | |
Text
.
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O JUL 2 71976 50- %9 i.
l DSE William P. Cammill, Assistant Director for Sits Techno o I
Thru:
REPORT ON SITE VISIT - OCONEE/ LAKE JOCASSEE DAM l
13, 1976 for the purpose of gathering
)
i inity of A site visit was made on Julyinformation reisting to the earthquak Lake Jocassee during past months.
ultants, Law Duke Power Company and their geologic and seismologic cons d
presentation Engineering Testing Company (LETCO) and Dr. T. Long ma e a Info:mation on past earthquake activity, geologic mapping, l
An outline of the topics discussed
{
to the staff.
and dam construction was presented.
It was indicated to us that i
was provided by the utility and is enclosed.
Commission, has j
a board of consultants, approved by the Federal Power d review geologic reconomended that Duke gather data on the earthquakes anDr. P J
been consulted by the mapping of the area.
l and the South Carolina State geologist have a so f July 1, The representatives of Duka Power indicated that as o been withdrawn j
1976 the 4-7 portable seismographs that were being used had utility.
i i ity of Jocassee l
and one portable instrument was installed in the v c nDu i
as part of the permanent South Carolina network.
j t to the north dam.
is located in the vicinity of the proposed Bad Creek pro ecAft l
of the general i
i Dam as well as several miles north of the dam where a v ewThe staff ad of Lake Jocassee.
l ff avaluation.
valicy area could be observed. discussing the earthquake acti i
l Robert, Jackson, Geologist Coology and Scismology Branch l
Division of Site Safety and Environmental Analysis I
Renner 11ofmann, Seismologist Geology and Seismology Branch i
Division of Site Safety and Environmental Analysis 1
Enclosure:
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An ainicd I
OFFICE P
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W u. s. sovEnnesENT PRINTING OFElCES 4974.e44 464 912 306 h 6 Feces ABCats (Rev. 9-53) ABCM 0240
l William P. Ga:=till _
Enclosure 1.
List of Attendees 2.
Proposed Presentation Outline 3.
Press Release 4.
Incident Report i
cc:
H. Denton D. Haller K. Coller G. Zeech W. Cannill C. Stepp L. Hulman R. Hofmann W. Bivins R., Jackson F. Miraglia NRC PDR i
DISTRIBUTION:
CENTRAL FILES NRR RDG DSE RDG GSB RDG
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o.re w Form ABC )ls (Rev. 9 53) AECM 0240 W u. e. sovannessur Paimisme orrects se74.eae. tee I
l
LIST OF ATTENDEES l
NAME COMPANY S. B. Hager Duke Power Company P. Talwani U. South Carolina R. E. Jackson USNRC R. Hofmann USNRC Leland Timothy Long Georgia Tech - LETCO George P. Sower Law Engineering Bob White Law Engineering G. H. Fogle Law Engineering D. C. Holt Duke Power Company M. S. Tuckman Duke Power Company Clay Sams Law Engineering E. H. Gladden Duke Power Company L. C. Dail Duke Power Company R. S. Bhatnagan Duke Power Company Donald Stuenson Univ, of South Carolina I
i
i e
PROPOSED PRESENTATION OUTLINE JOCASSEE - NRC MEETING Illustration Outline M 7V t a rY Yet IV G.O
' J)uc c l-4 ~nL. -
c A.
Regional Geology P.
B.
King 1954 1.
Geologic provinces and general rock types a.
Piedmont - Paleozoic metamorphic rocks - some local intrusive bodies Overstreet and Bell 1965 b.
Blue Ridge - Early Paleozoic schist, gneisses and amphibolites c.
Brevard Zone - Mainly schists IIatcher and Grif fin 1969 2.
Structures in area a.
Brevard - Dips southeast beneath reservoir and dam b.
Tectonic slides Georgia color IR photos, 3.
Linears in area ERTS photos, Bad Creek reports, U.S. Agricul-a.
Brevard ture Department photos b.
Warwoman 4
c.
Others llatcher 1971 B.
Local Geology Ca'xea,$ 1961-1962 1.
Henderson Gneiss Roper and Dunn 1969 a.
Site area prior to construction b.
Outcrops available and mapped Miscellaneous Jocassee c.
Maps of dam vicinity photos and maps of geo-logic data d.
Structural map of vicinity e.
Geologic sections l
f.
Photos of dam foundation
GL I
2.
Brevard Zone a.
3.5 miles of northwest of dam Area Drainage Map 3.
Drainage pattern in area a.
Joint control Historical Earthquake C.
Local Earthquake History Prior to Filling Epicenters at Jocassee prior to impoundment 1.
Started filling Jocassee April 1971 2.
3 VI mms a.
1916 (1) and 1957 (2) 3.
V mms - 8 4.
< V MM - 20 5.
Total within 60 miles is 31 earthquakes 6.
Most recent local earthquakes were:
a.
1969, V MM, 11 miles northwest b.
1971, IV MM, 11 miles south Jocassee Reservoir D.
Local Earthquakes after Filling Filling curve 1.
July 13, 1971, IV MM, il miles, south 2.
No other in region of > M=3 or felt prior to November 1975 3.
August 12, 1973, felt small event 3.5 miles northeast of dam E.
Events at 'Jocassee since October 1975 October 18, 1975, 1.
October 18, 1975, M=2.5 Intensity survey Intensity survey i
2.
4 - 7 Portable Microearthquake recorders MEQ 800, Georgia Tech, USC, USGS 4 Sinc % ormw s~1D"o+-17 "a" values, "b" values, 3.
Activity and lake levels and lake levels l
h u.sc h 4.
LETCo - Data gathered and analyses
[pc[7ec a.
"a" and "b" values b.
Hypocenter-locations
[c.
Fault plane solutions y/Jg5?O' d.
-Correlation with other paramaters -
including lake levels Case histories of reservoir induced
\\e.
l seismicity
\\
f.
Earthquake mechanisms g#
-g. - - Meximum ;isa%umke-he*F Oe. ik wwi
- 0. (),$C
.c7 em:*&
)'%,PiedmontEarthquakeMechanismsandMicro-earthquake Activity 1.
Recent concepts 2.
Proposed mechanism a.
Stress concentrations at crustal inhomogeneities 3.
Microcarthquake activity
/
"a" values, "b" values y
Conclusions on "a" Values and lake levels 1.
Definition - number of events per day
.)4" duration
(>
.5 sec.) (magnitude :-2) 2.
Peak January 13, 1976, for period Octo-ber 1975 through June 1976 3.
Possible slow decline in "a" values Janu-ary 13 to present (t1 I
Conclusions on "b" Values Log (Ne) = A-bM 8
M e Log (duration) 1.
We have used a maximum likelihood esti-l mator of "b" using magnitudes computed from durations of events.
l
4.
2.
7-day moving average 3.
Possible correlation between "b" values and lake levels ff Lake Levels vs. Other Parameters 1.
H.
K. Gupta reports An increase in lake level is followed a.
by an increase in frequency of shocks, and rapid changes trigger larger events 2.-
Possible correlation of Jocassee "b"
values with lake level Epicenter Location Map
}f Conclusions on Hypocenters 1.
Occur mainly between surface and 3 km below sea level 2.
Occur in a roughly oval area, maximum diameter about 10 km Local geologic cross-3.
Some hypocenters may be located within section Brevard Zone rocks Chronological Epicentral 4.
Area of hypocenters expanding with time Areas 5.
Hypocenters becoming shallower with time K.
Conclusions-on Fault Plane Solutions 1.
Introduction a.
Traditional use b.
Composite fault plane solutions for i
small shallow events 1
i
'i c.
Stress field derived from a fault l
plane solution l
l
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tr^
2.
Results of fault plane solution work j
Summary of fault plane solutions and Stress Field Maps (6) a.
resulting stress field orientations (1)
Stress field varies in time and location with local exceptions (2)
Below 1 km (below msl) stress field is extensional generally in a north-south direction b.
Comparison with (1)
Regional stress field results (2)
Local stress field measurements (Bad Creek)
L.
Maximum Earthquake at Jocassee Hypothesized Fault Plane for Maximum Maximum fault plane determined by hypo-1.
Earthquake center locations and fault plane solutions 2.
Stress drop estimated 3.
Using Randall's relationship, maximum earthquake determined Converts fault plane size and stress a.
drop to magnitude (5. 53 - 5. 8) 4.
Determine maximum intensity and associt.ced acceleration a.
I
= VII MM o
b.
a = 0.12 g Intensity-Acceleration Relation-g, g, g
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j ship
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KEOWEE COURIER 3-3-76 e.
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ALSO:
Westminster News 3-3-76 Spartanburg Herald 3-4-76 Duke Power To Study Earth Movement In Area WAbilALLA. Duke Power an area within 50 miles of permanent seismic station near Company said that it is joining Jocassee Dam.
the Jocassee reservoir with N.
with South Carolina authori ies To assist in the studies. Duke K.Olson, South Carolina's state
- t in a thorough study of mild has retained iaw Engineering geologist.This station would bc carth movement activity in the Testing Company, a firm noted a part of the Soutli Carolina vicinity of its Lake Jocassee in for its expertise in ' seismic seismic network.
Oconee and Pickens Counties matters.
The first tremor was felt at near here.
Duke Power also is dis-Lake Jocassee on October 18.
A series of " micro earth-cussing the establishment of a 1975, and on October 20 and 21 quakes" which began in Dr. Taiwani installed three October, 1975, are being seismographs. Another small studied by Duke engineer-tremor was recorded on scientists in collaboratiori with November 6. and even smaller Dr. Pradeep Talwini, Geology "aftershocks" on November ~
Department of the University 6-8-9.
of South Carolina, and David E.
A larger tremor was Itawell. Division of Geology. S.
recorded on November 25 C. "tala llevelnpment floard.
reaching a magnitude of 3.2 on A battery of six seismo-the Richter Scale. Other minor graphs has been installed tremors have been detected around Lake Jocassee, and over the past few months, the these extremely sensitive latest on February 16.197G.
instruments are charting any The Jocassee dam and activity on a 28. hour basis, powerhouse, designed for much in addition, the University of larger seismic events, has South Carolina has installed undergone a detailed inspection -
I by Duke Power and found to four instruments known as -
" strong motion accelerographs" have suffered no ill effects from to gather data for detailed the tremors.
analysis of any larger move-The geologists and seismo-ments that may occur in the logists involved in the current study are seeking reasons for future.
9.he tremors. A number of Moderate earthquake activ-theories are now under I vesti-O ity is not uncommon in the Piedmont area. During the last gation and all agree that several additional months of 100 years, at least nine mild earthquakes were recorded in study may provide answers.
i i
The Jocassee dam impounds l
a reservoir of 7.565 acres and serves as the upper pond for Duke's 610.000 kilowatt hydro.
electric pumped storage opera.
tion it became fully operational in May.1975. ( wR 3plx, wun n Tile )(tioWEE Gov. cia 3/31'7G l
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October 18, 1975 - 12:30 AX i
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Subject:
Jocasseo *iydro S;,ation Earthquake Conditions Prior To Inciden,:
Friday October 17 i. rained 23 inches at Jocassee Hydro Station fro. 6 AX to 5 PX. Friday October 17 i rained 5 3/4 inches at Bad Crook fro 4 AX to 2 ?X. Jocessco Hydro Station was not oper-ating.
Incident:
At 12:30 AX Sar. Burton, operator on duty, heard a loud noise and sta ion vibrated for riva (5) seconds. Modo inspection of station, could find no new leaks or cracks in walls. Inspected top deck and rock walls near station, everything soc =ed normal.
Inspected Jocasseo main da: and dikes 1 and 2. Could find no now leaks or shifting in rocks or soil. A'so inspected all Xeoweo dar.s and everything normal.
7&lked with various peoplo in the arca and listed are the cor.~.ents, Charles McSwain:
Lives 5 r.iles fror, station.
i Thought he heard a sonic boom and a lot of shaking for a few seconds.
Terry Patterson: Lives 3 =iles fror, station.
Heard loud noise and dishes fell frc= shelves. No cracks in wall and could find no damago.
X. W. Abercro. bio: Lives 10 miles from station.
Heard a noise that sounded like explosion. Xinor shaking, O. M. Rumfelt: Lives about 10 miles from station.
Did not hear or feel anything.
Jocassoc Recording Rain Chart:
At 12:30 AM recording needle =oved 1/8" and then returned to nom.al position.
Bad Creek Recording Rain Chart:
F No =ovement of recording needlo.
I i
i i
U Freeman Service Station: About 5 miles fror, station.
Heard loud r.oise - something like thunder. Another man lives about 1 Zi10 from Gervice statior. thought so3Cor.0 slaZ%Cd a Car door.
Town of Sale :
9 miles fro station.
Talked with 6 people and no one heard or felt anything.
L'alhalla Police Departr.ent: 19 miles from station.
No report of noise or. vibration.
~
Seneca Police Departnent:
21 miles fro: station.
No report of noise or vibration.
Clemson t'eather Station: 26 miles from station.
No report of noiso or vibration.
Oconee Nuclear Station:
16 miles from station.
J Has accelerometer mounted in the tendon gallery to detect any vibration and will alarm at vated.
.05 g's. Alar. was not act.1-University of South Carolina:
i Geology Lepart=ent has detectors at Parsons Xountain and Jenkinsville, S.C. The seis=ograph regi-I stored 2.5".
Cause of the Incident:
A small earth quake.
Co:nont:
Notified the Departr.cnt of Geolotar at the University of South Ct.rolina. Talked with Dr. Pardeep Talvani he asked permission to como to Jocessee an,d set up te=porarydep instz c.cntation to detect any further carth trc= ors. A slight trer.or was recorded Monday night and the center of activity was esti=cted to be 3 =ilos up stroa of the Jocassee Da=,
fh b'd$
E. H. Gladden Plant Superintendent EEG/dd I
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(2)
-