ML20237L576
| ML20237L576 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 08/06/1987 |
| From: | Thompson G STANFORD UNIV., STANFORD, CA |
| To: | Seiss C ILLINOIS, UNIV. OF, URBANA, IL, Advisory Committee on Reactor Safeguards |
| References | |
| ACRS-CT-1898, NUDOCS 8708280158 | |
| Download: ML20237L576 (1) | |
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M STANFORD UNIVERSITY h$ DYAf l SCHOOL. OF E ARTH SCIE'NCES MITCHELL BUILDING 101 Offue of the Dean STANFORD, CALIFORNIA 94305 2210
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(415) 723 2544 i
August 6, 1987 7
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" rA fil',iD., ; %i yd USNAC.
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Dr. Chester P. Siess i
3110 Civil Engineerin6 Building rNJGJ2R9 i
University of Illinois i
Urbana, Illinois 61801 I
Dear Chester:
l I
I attended the P.G. & E. workshop cri their Long Term Seismic Program in
-San Francisco on July 15 I was not able to be there on July 16.
The focus of the meeting was grounc motion, but. included were summaries of their pro-gress on the geology, seismology (including source mechanismo), a world-wide ocupilation of grounc motion as related to known fault rupture, and attenua-tion.
l They showed rather convincingly (again) that the Hosgri Zone is the main i
l concern at Diablo Canyon, despite the numerous other faults that have become better known from recent studies. They choose to model the Hosgri In two al-ternative ways (thrust or strike-slip) to avoid interminable debate about its c harac *.er. Their evidence suggests that the eastern fault of the Hosgri Zone is a vertical strike-slip fault and that the western part of the Zone is a thrust dippin6 about 35' toward the plant; these studies are still in pro-I gress.
1
.j They seem to have the best data base on known faults and strong motion l
that has ever been compiled, and they are proceeding to model ground motion l
l numerically.
I was favorably impressed by the competence of the people, the I
thoroughness of the approach, and the robust, resilient methodolo6y, which al-lows for introduc* ion of new data at any time.
Sincerely, l
a George A. Thompson or cc:
E. Igne l
l I
l l
l 8708280150 070006 PDR ACPS PDR CT-1898 DESIGNATED ORIGIIAL l
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