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/ o,, UNITED STATES*
8 NUCLEAR REGULATORY COMMISSIONos j WASHINGTON, D, C. 20655
\...../NAY 0 81985
Dr. J. Carl Stepp
Electric Power Research Institute/ 3412 Hillview Avenue
k P.O. Box 10412Palo Alto, CA 94303
Dear Carl:
In response to your letters of April 11, 1985 which discuss the
comparativeevaluations cf the LLNL and EPRI seismic hazard studies,
it may beappropriate to review our basic perspective on this issue.
As part of NRC'sresponse to the USGS clarification of its position
with respect to theCharleston 1886 earthquake, the staff included a
short-term probabilisticassessment of seismic hazard at all nuclear
power plants east of the RockyMountains. This assessment, an update
of a more limited LLNL study, hadbeen initiated prior to the USGS
letter but took on greater importance aspart of the so-called "
Charleston Program." The earlier version of the LLNLseismic hazard
study (begun in 1978) had been used very successfully indetermining
seismic reevaluation criteria for 9 sites in the
SystematicEvaluation Program and in several licensing safety
reviews. It underwent
; intensive staff, utility, ACRS and peer-panel review and was
consideredfavorably in several licensing-board hearings. While
there were individualutility studies, there was no coordinated
response that could allow a,meaningful comparison to the LLNL study
in the manner in which it was used.As a result we recommended in
the " Charleston Program", that a unifiedutility study be conducted
so as to allow such a comparison. - We were verypleased with the
positive response by the industry in initiating the ongoingEPRI
study. We are also pleased that the approach taken by EPRI is
somewhatdifferent than that taken by LLNL. The-present status of
seismic hazardevaluation at low probability levels is sufficiently
uncertain such thatdifferent perspectives on the same problem are
needed. Our aim, as in thepast, is to make decisions primarily
based on relative estimates of,
i seismic hazard.
As a result of our meeting with the Executive Director for
Operations (EDO)on November 7,1987, it was decided to delay
calculations at most of thesites until the EPRI results 9 for test
sites could be compared to the LLNL
: calculations at the same sites. This meeting was an important
meeting and Iam enclosing a subsequent memorandum from the EDO
which includes a short istatement on this delay.
The comparison with the EPRI results is an important part of
ongoing 1comparisons with other seismic hazard studies. In the LLNL
report (to be ipublished in May) final results are presented for
the 10 test sites alongwith comparisons made with the SEP studies,
individual utility studies, USGScalculations and historic hazard
analysis. These, plus additional studiesi
: being carried out by the USGS, and of course, EPRI will allow
us to make the
I 8601170370 851205PDR FOIABELL 85-535 PDR
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best use of seismic hazard calculations. Towards the end of the
1985, afterj we have seen the EPRI results, and the analyses of
differences (if any)
between the two studies, we will decide whether and to what
extent repollingof the LLNL panels is necessary before calculating
the hazard at theremaining 65 sites in the central and eastern
United States. We view theUSGS/NRC-sponsored conference on seismic
hazard to be a very important -element in the comparative
evaluation process. We are looking forward to
4
LLNL, EPRI and the USGS presenting results of their studies at
this meeting.'i Additional studies by EPRI and the USGS will be
considered concurrently with
the LLNL calculations at the 65 sites. All available seismic
hazard studies! will be considered by NRC in determining how to
apply the results to the
" Charleston Issue."
I I might add that we are already using the LLNL studies outside
the contextof this issue. The LLNL studies have been very helpful
in reviewing severalseismic PRAs, operating license applications
and in a seismic reevaluationprogram. In one case (Hope Creek),
which was not one of the 10 initial
| sites, the applicant chose to use LLNL data and the LLNL
methodology to: calculate hazard at the site and presented the
results to the Advisory
Cemittee on Reactor Safeguards. With respect to schedule we see
threeimportant meetings:
1. First Comparative LLNL/EPRI Evaluation Meeting, June. 18,
1985. We hope1 that by this meeting LLNL will have completed
calculations for 9 sites
using the LLNL methodology with the EPRI ground motion model and
theEPRI lower bound cut off. This will allow a direct comparison
ofresults. We also hope that as part of this meeting EPRI will be
ableto present a short tutorial on its methodology and results.
2. Second Comparative LLNL/EPRI Evaluation Meeting, November
5,1985. Atthis meeting the bulk of the LLNL and EPRI comparative
evaluationswould be presented along with any the USGS has
performed.
3. NRC/USGS Seismic Hazard Conference, November 25, 26, and
27,1985 inSan Francisco. Presentation and discussion of comparative
LLNL/EPRI
, evaluations, in the context of general seismic hazard
evaluation, toi the larger seismic hazard comunity.
We expect LLNL, EPRI and the USGS to come out with separate
reports andcomparisons. It has beer our experience that in seismic
hazard evaluation,as in many other areas of the earth science, the
most robust conclusionsthat NRC can effect come about through the
encouragement of separate andindependent analysis. Whether and how
these analyses will appear in onevolume is one of the items that
needs clarification,
j With respect to the National Academy of Science / National
Research CouncilPanel or seismic hazard evaluation, we view this
NRC initiated effort as a
: longer range view of what the capabilities are and where we
expect to go inthe future. We do not expect this panel to recommend
particular
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methodologies although they have expressed a keen interest in
receivingcopies of both the LLNL and EPRI studies and participating
in the NRC/USGSconference in November.
In conclusion, NRC views the LLNL, and EPRI studies as playing
importantroles in resolving ongoing seismological problems. We do
not expect work inthis area to stop with the publication of these
and other studies.Additional updated methodologies and calculations
will undoubtedly be neededas our understanding increases.
I would be happy to meet with you again to discuss any
additionalcoordination that you feel is necessary. I look forward
to hearing from
,
you.
Sincerely
Leon Reiter, LeaderSeismology SectionGeosciences Branch
cc: w/ enclosureP. SobelG. Giese-KochJ. KnightSherwood H. Smith,
Jr.Ruble A. ThomasJohn J. Taylor EPRIWalter B. Loewenstein, EPRIIan
B. Wall, EPRIJerry King, EPRIDon Bernreuter, LLNL
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United States Department of the Interiori=# GEOLOGICAL
SURVEY
# RESTON, VA. 22092
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In Reply Refer To:Mail Stop 905 May 17,1985
Memorandum
To: Keiiti Aki, University of Southern CaliforniaTed
Algermissen, USGSDon Bernreuter, LLNLKen Campbell, USGSKevin
Coppersmith, Geomatrix Inc.Allin Cornell, Stanford UniversityA. Der
Kiuregian, University of California, BerkeleyRobin McGuire, Risk
Inc.Chris Mortgat, TERA Corp.Otto Nuttli, St. Louis UniversityDavid
Perkins, USGSMaurice Power, Geomatrix Inc.Leon Reiter, NRCHaresh
Shah, Stanford UniversityBurton Stemmons, University of NevadaCarl
Stepp, EPRINafi Toksoz, MITDaniel Veneziano, MIT
From: Walter Hays, Chairman of Steering Committee
Subject: Workshop on "Probabilistic Earthquake llazards
Assessments,"San Francisco, California, November 25-27, 1985
On behalf of the steering committee, I am inviting you to
participate in thesubject workshop cosponsored by the U.S. Nuclear
Regulatory Commission and theU.S. Geological Survey (USGS) .
We are requesting that you prepare a "draf t paper" of at least
8 pages on thetheme identified by-your name in the enclosed
preliminary program. Pleasefollow the format of the enclosed
example. You will have 60 days af ter the
meeting to finalize your paper before publication as a USGS
Open-File Report.
We will reimburse non government participants for their travel
costs inaccordance with current government regulations. Please let
me know within 30days if you can participate in what promises to be
a very interesting andvaluable meeting.
Enclosure
cc: Joe Berg
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WORKSHOP ON PROBABILISTIC EARTHQUAKE HAZ,ARDS ASSESSMENTS,
Fisherman's Wharf Matriott HotelSan Francisco, California
- November 25-27,,1985
Sponsors : U.S. Nuclear Regulatory Commission and U.S.
Geological Survey
Objectives: 1) To review the methodology and results of recent
studies toassess earthquake hazards probabilistically, and 2) to
identifypractical and innovative ways to improve the overall
state-of-knowledge.
Preliminary Program
(Note: The program will be refined to incorporate suggestions up
to the dateof the meeting.)
Monday, November 25
1-1/2 hrs. Review of Methodology--Studies conducted by Lawrence
LivermoreNational Laboratory KLLNL) and Electric Power Research
Institute
1 (EPRI) will be featured. Differences will be identified and;
discussed.
| --Carl Stepp, EPRI (will organize presentation)--Don
Bernreuter, LLNL (will organize presentation)'
BREAK
1-1/2 hrs. Discussion of Methodology--Two participants will lead
the initialdiscussion of the methodologies used by LLNL and EPRI.
Everyonewill take part.
--Haresh Shah, Stanford University--Otto Nuttli, St. Louis
University
LUNCH
1-1/2 hrs. Review of Results and Comparisons
--Don Bernreuter, LLNL (will organize ~ presentation)--Carl
Stepp, EPRI (will organize presentation)
1-1/2 hrs. Discussion of Results--Two participants will lead the
initial-discussion of the results obtained by EPRI and LLNL and
theircompa risons. Everyone will take part.
--Maurice Power, Geomatrix, Inc.--Ken Campbell, USGS
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Tuesday, November 26
1 hr. Historical Seismicity and Tectonic Information--What is
the roleof historical methods of analysis versus zonation
methodologiesnow being applied in the Eastern and Western United
States?
--Daniel Veneziano, MIT--David Perkins, USGS
1/2 hr. Discussion of Presentations--One participant will lead
the initialdiscussion of this issue. Eieryone will take part.
--Chris Mortgat, TERRA Corp.
BREAK
4 hrs. Problems Associated with Describing Seismic Source
ZonesProbabilistically--A series of presentations focusing on
currentproblems of interest and concern. Discussion .to clarify
issueswill be permitted during presentation.
(Note: Lunch will be taken midway in the session.)
Type of Faulting, Subduction Zones, etc.--Kevin Coppersmith,
Geomatrix Inc.
Earthquake Frequency Distribution, Characteristic
Earthquakes,Non-Poissonian Models, Attenuation, Seismic Gaps,
etc.--Robin McGuire, Risk Inc.
Directivity, Finite Faults, Complex Descriptions of Ground
Motion,Uncertainty, etc.
--A. Der Kiuregian, University of California, Berkeley
Maximum and Minimum Magnitude Estimation, etc.--Burton Slemmons,
University of Nevada
1/2 hr. Additional Discussion of Presentations--One participant
will leadthe initial discussion of these problems. Everyone will
takepart.
--Nafi Toksoz , MIT
Wednesday, November 27
1 hr. Where do we go from here?--Two presentations suggesting
innovativeways to increase the state-of-knowledge needed to make
significantadvances in probabilistic hazards assessments.
--Allin Cornell, Stanford University--Ted Algermissen, USGS
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1/2 hr.- Discussion of Presentations ,,
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BREAK
2 hrs. What are the present capabilites, limitations, and the
appropriatenext steps?--A panel discussion describing where we are
now and
i suggesting practical plans or proposed actions to increase
thecurrent state-of-knowledge.
--Keiiti Aki, University of Southern California'
--Robin McGuire, Risk Inc.--Carl Stepp. EPRI--Don Bernreuter,
LLNL--Leon Reiter, NRC--Ted Al germissen, USGS
1/2 hr. Closure -
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INCREASING BAZARD AWARENESS AND PERSONAL PREP WESS
by' Os ?- $p +
#Risa I. Pale o tf#"Osiversity of Colorado 4N#f g j
Boulder, Colorado 80309 Og# /e4
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IETRODUCTION d**b o|o' 0o 0p
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00q 7* O| The title of this session suggests that there is an
association between f#0 ,*oi increased hazard awareness and
increased personal preparedness. In this
paper, th'e extent to which such a linkage exists will be
discussed, as well asthe implications of this relationship for
public policy particularly public
education campaigns.
At the outset, it is important to determine both the current and
the optimumlevels of-awareness of the earthquake hazard in the
Virgin Islands. Althoughthe Virgin Islands have experienced
numerous earthquake.s, the level of
1
i awareness of such earthquake susceptibility by either the
resident or visitingpopulation is not known. However, one suspects
that resident awareness in the
Virgin Islands is less than that observed in a state such as
California with a
history of major damaging earthquakes and an extremely active
program of
; public and private efforts to increase awareness and
mitigation behavior. Theadoption of mitigation acasures directly
related to the Virgin Islands
'
earthquake hazard could also be assumed to be less than the
level observed for'
California - which means that it is highly likely that only a
minority of the
papulation have earthquake insurance policies on their horses,.
and few peoplehave taken preparedness measures related to the
earthquake hazard.
COMMUNICATION CHANNELS<
What sorts of campaigns should be taken then, both to increase
generalawareness of the earthquake hazard, and more importantly, to
induce personalpreparedness?
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#" 'o UNITED STATES~ , ,,E NUCLEAR REGULATORY COMMISSION* g*; y
WASHINGTON, D. C. 20555
' ' . . . . * DEC 2 41984.
MEMORANDUM FOR: Chairman PalladinoComissioner RobertsComissioner
AsselstineComissioner Bernthal .Comissioner Zech
FROM: William J. DircksExecutive Director for Operations
SUBJECT: PROGRESS REPORT AND SCHEDULE CHANGE IN NRC PROGRAMPLAN
RELATING TO CLARIFICATION OF U. S. GE0 LOGICALSURVEY POSITION
REGARDING SEISMIC DESIGN EARTHQUAKESIN THE EASTERN SEAB0ARD OF THE
UNITED STATES
For the purpose of licensing nuclear facilities in the
Southeastern U. S.,the NRC staff has taken a position, based
primarily on the advice of theU. S. Geological Survey (USGS), that
any reoccurrence of the 1886Charleston, S.C. earthquake would be
confined to the Charleston area; thatis, the Charleston earthquake
is assumed to be associated with a geologicstructure in the
Charleston area. The effect of this position is thatnuclear power
plants in the region east of the Appalachian Mountains areusually
controlled in their seismic design, according to Appendix A to
10CFR Part 100, by the maximum historical earthquake not associated
with ageologic structure. This controlling earthquake is typically
a ModifiedMercalli Intensity (MMI) VII or VIII whereas the
Charleston earthquake wasa MMI X. Since 1974, the NRC has funded an
extensive research project togain further information on the
causative mechanism of the Charlestonearthquake.
In a letter dated November 18, 1982 from James F. Devine, USGS
to RobertE. Jackson, NRC, the USGS~ clarified its position
indicating that:
"Because the geologic and tectonic features of the Charleston
regionare similar to those in other regions of the eastern
seaboard, weconclude that although there is no recent or historical
evidence thatother regions have experienced strong earthquakes, the
historicalrecord is not, of itself, sufficient grounds for ruling
out theoccurrence in these other regions of strong seismic ground
motionssimilar to those experienced near Charleston in 1886.
Although theprobability of strong ground motion due to an
earthquake in any givenyear at a particular location in the eastern
seaboard may be very1cw, deterministic and probabilistic
evaluations of the seismichazard should be made for individual
sites in the eastern seaboard toestablish the seismic engineering
parameters for critical ,facilities." |
Contact:R. H. Vollmer, NRR492-7207 f$ M 7 L
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In a Comission Paper dated February 5,1982 (SECY-82-53), we
informed theComission of the possibility of modification in the
USGS position and ina memorandum dated November 19, 1982, the USGS
clarification was forwardedto the Comission along with an
assessment of significance and a pre-liminary plan to address the
clarified USGS position. This plan wasdiscussed with the Comission
in its November 19, 1983 meeting and a jointNRR/RES program was
initiated. The joint program consisted of a shorttem probabilistic
program that has as its core a Lawrence LivermoreLaboratory (LLNL)
estimation of seismic hazard at all nuclear power plantsites east
of the Rocky Mountains, and a long term deterministic
programthrough RES to determine the causes of large earthquakes,
such as theCharleston earthquake, in the eastern seaboard.
With regard to the short term probabilistic program, final
calculations by -LLNL are almost complete for 10 test sites. As a
means of comparison werecomended in our original program plan that
a utility sponsored studyalso be carried out. The utility study,
being conducted through theElectric Power Research
Institute.(EPRI), is currently scheduled forcompletion in April
1985. We have decided to defer LLNL's estimation of;the seismic
hazard at the 65 remaining eastern sites for approximately 1year so
as to await completion of the EPRI program and allow a
thoroughcomparison of EPRI and other seismic hazard estimates to
be.made. Theoriginal plan called for this comparison to take place
concurrent withLLNL's calculations, however, we believe this change
to be useful in lightof the rapidly evolving technology of seismic
hazard estimation. As aresult the probabilistic portion of the plan
to address the clarificationof the U. S. Geological Survey's
Position on the 1886 Charleston Earth-quake will be available at
the end of 1: 96, instead of in 1985 asoriginally scheduled.
The long term deterministic program is also progressing. Most
signif-icantly, several teams of investigators, mainly funded by
NRC, have foundevidence. of paleoliquefaction in the Charleston
area. This is the firstindication of large to moderate earthquakes
in the eastern seaboard inprehistoric times. It is possible that a
seismic recurrence interval for
~
large earthquakes in the Charleston area may be developed and
that adetemination can be made whether or not this area is
seismically unique.These conclusions await further investigations'
and assessment.
~ '
(SignsiD William J.Dirck
William J. DircksExecutive Director for Operations
cc: SECYOPE
OGC-
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