ML20052A786
| ML20052A786 | |
| Person / Time | |
|---|---|
| Site: | Vallecitos File:GEH Hitachi icon.png |
| Issue date: | 10/20/1977 |
| From: | Kelleher J Office of Nuclear Reactor Regulation |
| To: | Stepp J Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20052A734 | List:
|
| References | |
| FOIA-81-483 NUDOCS 8204290176 | |
| Download: ML20052A786 (1) | |
Text
v s.
., : : o 3 3. :.,
[*e
..'k is'UCLC All 1:CliUt AI0:lY Cifi.".'Gr.10tJ T/
((/)
,{,
, j.. *}
r.r. ;i nric t ute, o. c. m.. s
..* *d [. : 4, A / d
/,
i j' GCT 2 0 mi e...*
HD!ORANDIP.! FOR:
J. Carl Stepp, Chief, Geosciences Branch, DSE FRO {:
John Kellchcr, Geophysicist, Ccosciences Branch, DSE
SUBJECT:
CE'IR t.'UCLEAR FACILITY
'Ihc purpose of this merorandum is to express my concern about the -
seismic hazard at the CETR nucicar facility posed by the Calaveras fault zone.
The Calaveras fault zone is a capable fault within the meaning of Appendix A to 10 CFR Part 100 and, at its closest point, is within one or two miles of the CETR site.
It is reasonable, in my opinion, to assume that an earthquake of magnitude about 7.0 to 7.5 could occur at any time on this fault and at any locatio*n along the fault.
Such an carthquake, therefore, could occur at any time within one or two miles of the plant site.
The resulting ground motion generated at the plant site by the postulated carthquake would S'
almost certainly be severe and peak ground accelerations would be among the higher observations to date.
The probability of such an event occurring within any specific time interval cannot be esticated in a quantitative manner at, the present time because there is not any reasonable evidence to establish a recurrence time.
Attempts to determine such a recurrence interval on the basis of seismic data from other fault zones are, in my opinion.
hiChly speculative, and should not receive consideration in determining
(
the hazard posed by the Calaveras fault none.
In a qualitative sense it is reasonable to state that the inninent occurrence (within several weeks to several months) of a major, carth-quake along the Calaveras fault zone is very low.
My basis for this assessment is the knoun seismic record of the Calaveras fault zone.
l It is unlikely that extensive future investigations will modify this assessment in any siCnificant manner.
ikw
.d.i.ll:y Johi} Kelleher, Coophysicist Geology and Seismology Section Ccosciences Branch, DSE U
1 O
8204290 M a