ML20204A137

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Summary of 860418 Meetings W/Usgs & Util Re Progress on Geology/Seismology Confirmatory Issues for Plants.Attendance List Encl
ML20204A137
Person / Time
Site: Perry  FirstEnergy icon.png
Issue date: 05/05/1986
From: Sobel P
Office of Nuclear Reactor Regulation
To: Liaw B
Office of Nuclear Reactor Regulation
Shared Package
ML20198D542 List:
References
NUDOCS 8605090402
Download: ML20204A137 (3)


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+ pa asog#o, UNITED STATES 8" [ 7. NUCLEAR REGULATORY COMMISSION

/cj WASHINGTON. D. C. 20555

%,, - / MY 5 1986 Docket No.: 50-440 MEMORANDUM FOR: B. D. Liaw, Chief Engineering Branch Division of BWR Licensing FROM: Phyllis Sobel, Geophysicist i

Engineering Branch Division of BWR Licensing 1

SUBJECT:

MEETINGS WITH USGS AND CEI TO DISCUSS PROGRESS ON. GEOLOGY / SEISMOLOGY CONFIRMATORY ISSUES FOR PERRY PLANT In the morning of April 18, 1986, the U.S. Geological Survey (USGS) reported their progress on studies related to the January 31, 1986 earthquake near the Perry plant. An attendance list for that meeting is attached.

1 Charles Langer of the USGS summarized historical seismicity in Ohio. He has located the aftershocks of the January 31 earthquake and found no definitive fault plane suggested by the data. The aftershocks occurred at 5 to 6 km depth.

Craig Nicholson calculated fault plane solutions for the af tershocks l from USGS data and all other available data. The fault plane solutions

. of the two largest aftershocks are mostly strike slip with an ENE P-axis.

i Not all the aftershocks show the same focal mechanism; some show mostly 1

oblique slip.

l' Roger Borcherdt found some indication of lineation in aftershock locations based on USGS data using GEOS instruments. The GEOS 4

instruments are able to record ground motion at higher frequencies than other systems. Energy from the aftershocks was recorded out to at least 70 to 80 hz. He found for station 1, which is next to the Perry plant site, there were anomalously high amplitudes recorded for the aftershocks, especially energy at 5 to 10 hz and 20 hz. He suggested the till layer underlying the instrument has 20 hz resonance. The Perry plant, where 4 and 20 hz energy was recorded for the main shock, is founded on rock.

The difference in site conditions between the Perry plant and station 1 will be investigated further by Borcherdt.

Rob Wesson reviewed the possibility of induced seismicity in northeastern J Qhio. One model of stress as a function of distance for the deep waste injection wells suggests an increase in stress of a few bars at a

) distance of 12 km and a depth of 2 km after 15 years of injection. A few bars of pressure change predicted near the recent earthquake suggests the wells are not a major factor in triggering the earthquake.

C m tact: P. Sobel X-27592 ~ ~

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MAY 5 1986 i B.O. Liaw i 1

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i Wesson has also considered solution mining for salt as a source of i

  • seismicity. Solution mining began near Cleveland in 1889 and there were  :

earthquakes that may be associated with solution mining in 1906 and 1932 (both maximum intensity V), but the association is not clear.

In the afternoon of April 18, the USGS presented a summary of their work to CEI, the Perry utility. Borcherdt suggested a site investigation at i

some of the USGS stations would help assess if the 20 hz energy observed

] at station 1 is a site effect. Dick Holt of Weston Geophysical, a CEI i consultant, suggested that the 20 hz energy observed at station 1 could i

be due to resonance in the till layer. CEI will provide a velocity

{ profile for station 1 to the USGS.

~I:s j Phyllis Sobel, Geophysicist i

Engineering Branch

< Division of BWR Licensing 1

l

Attachment:

Attendance

! cc w/ attachment:

l i

R. Bernero J. Stefano t

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l G. Lainas S. Stern

! W. Butler R. Savio i F. Congel L. Reiter, L. Beratan I. Alterman i

A. Murphy A. Lee

, R. LaGrange G. Geise-Koch

R. Hermann R. Rothman i N. Anderson R. McMullen j P. Sobel l

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DATE A/S /86 4/ /86 -

1 l OFFICIAL RECORD COPY J

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NRC/USG3 MEETING APRIL 18, 1986 N_,8{

J. Stefano L. Reiter P. Sobel I. Alterman A. Murphy R. Savio R. McMullen USGS R. Wesson C. Nicholson C. Langer R. Borcherdt NIRS L. Bloom I

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