ML20132B525

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Comments on Draft Seismic Analysis Research Plan. Seismotechtonic Program Requires Substantive Rev
ML20132B525
Person / Time
Issue date: 02/17/1983
From: Rolonda Jackson
Office of Nuclear Reactor Regulation
To: Knight J
Office of Nuclear Reactor Regulation
Shared Package
ML20132B198 List:
References
FOIA-85-363 NUDOCS 8303140673
Download: ML20132B525 (15)
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FEB 171953

'*meFt"OUM FCC:

James P. I'richt, i.ssister.t Director fnr Corpenents & Structures Engineerirn, DE FP01':

Rcbert E. 1achsen, Chief Ceesciences Branch, DE

SUBJECT:

CCf"'Et,'TS ON CRAFT SEIS!'IC ANAL.YSIS P.ESEARCH Ft.AR We have reviewed the draft plan and have provided directly to D. Gu:y, OFES, a marked up copy for his use.

It is our understanding that a najor rewrite is currentTy underway.

r'ur rvist substantive cc: Ment regarding the plan is that the "Seisr.otectonic Progran", as attached needs to be substantially updated to botter incorporate our current apprcach in cur now plen for ddressing the U.S.G.S. clarification regerdirg The Charleston earthouake. Ve also disagree strongly with bcth A. Thrdani (rcrorandue, l

A. Thedani to 2. Pes:tec:y, February 7,1923) and the draft Mr0 cements prepared by P. Williaes regarding the need fcr research effort on C~'

I seismogenic nochenisns. This research effort, preperly implerented will orevide direct usable inferretion in the short torn (3-F years}

which will Pave a strong influerce on the develeprent of scisric ha:ted curves. This infore.rtien centributet directly to how experts weigh varicus hypctheses cad haw credibilities should bo.assignecrin pec9 bilistic tenlysat. The cerr. ort that this work "cancot be er.pected to yi*1d results reccer.ab1v relever.t te regulatcry necdt during the

-remining operatir.g lifetire of rest current pencretion nuclore olents" is unfounded.

In fact, such ar. Observatice would represent a na.for i

reversal in NRR's previcus research recuests in this area. This work centributes directly te our ability to eveluate whether or not oresbilistic cerclu:ieas tre intuitivaly ressens.ble or whether inceitie

'urther attfer.s tre rects :ry ct ccrtair, citts.

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FEB 1 7 ;533 Tbc !!Pr; tra't cemrts, iter d., infers thct NRR's vievt of the l

scisretartoric precrcn is that it is not necessary.

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this ever hairg f3r.'s position.

Indeed, this would be inconsistent with l

cven11 Geesciences Jeanch planning and our current Charlesten plan, l

which relies heavily on this work in the next three years.

Original Signed by R.I.Jacksen Robert E. Jackson, Chief Geosciences Branch Division of Engineering l

l Attachrents:

(1) !!RP Cements l

(2) Thadani Menorendum, February 7,1983 cc: w/o ettachments l

T. Sullivan

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m o 2 1ssa MEMORANDUM FOR: Harold R. Denton, Director Office of Nuclear Reactor Regulation FROM:

Richard H. Vollmer, Director Division of Engineering

SUBJECT:

DIVISION OF ENGINEERING GEOSCIENCE PLAN TO ADDRESS USGS CLARIFICATION RELATING TO SEISMIC DESIGN EARTHQUAKES IN THE EASTERN SEABOARD OF THE UNITED STATES A plan for our proposed program to address the U. S. Geological Survey's

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clarification of position relating to seismic design earthquakes in the Eastern Seaboard of the United States is attached (enclosure 1). This plan elaborates on the outline provided as an attachment to a memorandum entitled, " Clarification of U. S. Geological Survey Position Relating to,

Seismic Design Earthquakes in the Eastern Seaboard of the United.

States", which was sent from the Executive Director of Operations to the Comissioners on November 19, 1982.

The plan is divided into two parts. Part one is a short term

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probabilistic assessment utilizing an extensive new seismic hazard study currently being developed by Lawrence Livermore National Laboratory.

Part two is a longer term deteministic assessment based prirr.arily on e long range ORES research with the possible need for utiMty sponsored investigations at some locations after an asseisment of the long tem research results. Additionally, we recomend that an industry sponsored seismic hazard study be solicited.

We estimate that the effort to establish the seismic hazard level for the sites and make appropriate comparisons will take approximately three years to complete, utilizing staff resources of about 2.5-3.0 SY per year, and 5300K per year in technical assistance funds. Que preliminary recomendations on which plants, if any, may need further evaluation should be completed in mid-1984 Because of the required research effort, the determini,s_ tic element will not be synthesized until 1985.

The proposed program will complement ongoing PRA reviews and the seismic hazard spectra which are developed can also be used for future SEP evaluations. This program, therefore, is basically a continuation, with modification, of our ongoing work. This program does not include resources to complete a reevaluation effort for plants for which design spectra may need to be reevaluated. We recomend that this contingency be considered and included in the operating plan for FY 84 This plan also presupposes that our interim position for licensing reviews (enclosure :) is f,und to be acceptable by ACRS and ASLB while we implement this program.

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There is evidence to support this assumption in the recent Appeal Board decisiononSummer(ALAB-710).

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.We have also assessed our abi ity to imp ement this plan under the existing regulation, Appendix A to 10 CFR Part 100. We have concluded that, although Appendix A itself does not explicitly recognize the use of probabilistic methods, as a minimum they can be used to assist in reaching detenninistic judgements (Seabrook Romand, CLI80-33).

It is not clear whether they can be used as the primary tool in setting '

appropriate ground motion levels. Therefore, we recomend that we implement a limited modification or clarification of Appendix A as previously planned in conjunction with ORES as a parallel, yet independent effort, along with the Charleston plan. This modification has been recomended in SECY-79-300 and endorsed by the Siting Policy Task Force in NUREG-0625 and is necessary to reflect the current state of art. This modification will require an additional' 1.0 SY per year for 2 years.

We reconsnend that you consider placing this effort equally under three resource areas - Operating Reactor Licensing Actions or Safety Technology, Systematic Evaluation program for older operating plants, and Casework for ongoing OL review plants.

This plan has b'ee'n' develop'ed' al a res' ult of extensive discussion CIRiri?

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the Geosciences Branch, NRR; and discussions with the Earth Sciences Branch, ORES; and the U. S. Geological Survey.

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Richard H. Vollmer, Director Division of Engineering

Enclosure:

As stated cc: w/ enclosure E. Case A. Murphy

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R. Vollmer W. Russell R. Mattson R. Bernero H. Thompson GSB Staff J. Knight Z. Rosztoczy R. Jackson P. Williams L. Reiter S. Broccum T. Sullivan L. Beratan R. Minogue F. Arsenault J. Scinto w

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j Recommended Plan Eastern U. S. Earthauakes Introductior On November 18, 1982, the U. S. Geological Survey (USGS) forwarded a letter to the Nuclear Regulatory Comission clarifying their past position with respect to the 1886 Charleston earthquake. The USGS letter states that:

"Because the geologic and tectonic features of the Charleston region are similar to those in other regions of the eastern seaboard, we conclude that although there is no recent or historical evidence that other regions have experienced strong earthquakes, the historical record is not, of itself, sufficient grounds for ruling out the occurrence in these other regions of strong seismic ground motions similar to those experienced near Charleston in 1886. Although the probability of strong ground motion due to an earthquake in any given year at a particular location in the eastern seaboard may be very low, deterministic *and probabilistic evaluations of the seismic hazard should be made for individual sites in the eastern seaboard to establish the seismic engineering parameters for <ritical faci.14 ties."

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We have evaluated the USGS clarification of position and have concluded that it can be addressed predominantly through existing programs at NRC with the possibility of additional requesti for utility - sponsored work. We recomend that a two part program be implemented which will address both the deterministic and probabilistic elements mentioned by the USGS.

Part 1.of.the. pronated. DIpgram_ is a _ shp,r,1._ tem probabi,1istic, ass,essment of plants in the eastern seaboard. This part of the plan is necessary l

because many of the current tectonic working hypotheses are not amenable to investigation by deteministic methods in the short tprm.

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I Part 2 of the proposed program is a longer term deterministic assessment of the causes of large earthquakes, such as the Charleston earthquake, in.the eastern seaboard. Specific areas of relatively high seismicity and tectonic structures are identified which we recomend be addressed through the ORES long range research plan.

Based on our evaluation of the research results, some applicants or licensees may be required to investigate tectonic structures which may not have been previously identified during the licensing procedure.

Part 1 - Probabilistic Assessment Discussion The November 18, 1982 letter from the USGS represents.-oct so much a new understanding but rather a more explicit recognition of existing uncertainties with respect to the causative structure and mechanism of the 1886 Charleston earthquake. Many hypotheses have been proposed as

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to the locale in the eastern seaboard of future Charleston-size earthquakes. Some of these could be very restrictive in location while others would allow this earthquake to recur over very large areas.

Presently, none of these hypotheses are definitive and all contain a strong element of speculation.

Traditional deteministic approaches such as that outlined in Section 2.5.2 of the Standard Review Plan are not generally designed to deal e

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3-with this situation. Probabilistic methods which allow for the consideration of many hypotheses, their associated credibilities, and the explicit incorporation of uncertainty are much better equipped to provide rational frameworks for decision making. The question that needs to be answered is:

Taking uncertainties into account, have licensing decis! ions for plants in the eastern seaboard (i.e., in the region affScted by the USGS clarified position on the Charleston Earthquake) resulted in acceptable levels of assumed seismic hazard (exposure to earthquake ground motion) at the individual sites?

One means for answering the above question is a probabilistic assessment of seismic hazard at all nuclear power plant sites east of the Rocky Mountains. Since adequate or acceptable levels of seismic hazard Rave-not been explicitly defined in probabilistic terms, it is assumed that the probability of seismic ground motion exceeding design levels implicitly associated with licensing decisions based upon traditional

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methods in other regions of the U. S. east of the Rocky Mountains is adequate; these other regions include areas such as the Central Stable Region and the Gulf Coastal Plain. The prime tool for carrying out this assessment is an updated version of the Unifom Hazard Methodology

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devel'o'p'ed 'for' ~the Systematic Evaluation Program by Lawrence L3e~more

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National Laboratory (LLNL) and its subcontractor TERA Corporation. This methodology relies upon the incorporation of diverse expert opinion with regard to the input parameters needed to make probabilistic estimates.

As such, it does not rely upon single hypotheses which de not account for existing uncertainties but rather attempts to incorporate the o

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hypotheses and their uncertainties into the computations.

Identification of plants (if any) in the eastern seaboard at which the probability of exceeding design-level ground motion is significantly greater than has been assumed at other locations may result in an integrated seismic evaluation and/or engineering reanalysis to assure the plant's ability to withstand a more severe earthquake. This study may also identify selected plants outside of the eastern seaboard whose design levels may be inappropriate, relative to other plants, with respect to the seismic hazard.

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In addition, we are also initiating, through a technical assistance contract, a study to better estimate ground motion from a large g.

earthquake the size of the 1886 Charleston event to gain a better understanding of how this ground motion should be represented.

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Major Activities - Probabilistic Assessment The probabilistic assessment portion of the proposed program is divided

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15to the following elements.

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1. January thru MT983 - Continue develop 5ent of LLNL study including expert opinion surveys on seismic hazard east of tne Rocky Mountains. This study (Seismic Hazard Characterization of the Eastern U.S.) is presently underway as a joint effort of NRR and w

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ORES. No additional resources above those already allocated are needed.

2. "; 1000 thm D::g i ti'Y Tan 19%Y TYl

_.,cr 1032 - Calculation of seismic hazard spectra by LLNL for all nuclear power plant sites (approximately

75) east of the Rocky Mountains. An estimation of the probability of seismic ground motion exceeding the design level at each site, taking into account specific site conditions, will be completed and provided as a report. An additional 2.0 SY is needed for LLNL and 0.3 SY for NRC effort durinp this period.

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3. k;y MFY Secrt:- 10S3 - Comparison of LLNL study with r

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existing probabilistic studies such as Algennissen and others (1982). An additional 0.2 SY is needed for LLNL effort.

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4. % a 365 - December 1

- Sponsorship by the utilities ttf-a-probabilistic estimation of seismic hazard for all nuclear power plants east of the Rocky Mountains. Thi,s study,-while not a requirement, is strongly recommended so as to ecmplement the LLNL

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study and provide another independent assessment of seismic hazard.

An additional 0.1 p;,needed for LLNL and 0.1 SY for NRC effort.

Mew MP 4 y il f'?f 5.. Rec..icr 10S: N. d ! " - Using LLNL and other studies, the NRC DecINY b Assesse4 staff will integrate this infonnation and make comparisons of the

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probability of seismic ground motion exceeding design leveTs in the oso/54 gg.g eastern seaboard with probabilities calculated at plants in the rest of the Eastern and Central U. S.

Comparisons will be made in

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several ways including comparison by region alone and by region and

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,,v plant vintage. Plants in the eastern seaboard (if any) that are pc I45f associated with significantly greater hazard than those elsewhere

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will then be identified. Other comparisons may be needed, but will be decided upon after review of initial results. An additional 0.7 SY is needed for NRC effort.

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Assessment of initial conclusions Eggr regarding hazard in light of feedback from expert opinion on b

original input. A final letter report will be issued w'ith a final recommendation on plants which need reevaluation. An additional 0.2 SY needed for LLNL and 0.2 SY for NRC effort.

7. January 1983-December 1983 - Ground motion estimates at different distances and site conditions from a large Charleston type earthquake. Both theoretical and empirical estimates using ~

data from recent earthquakes will be made. This study is presently being initiated through a technical assistance contract with LINT.7 No additional resources are required.

Status suninary reports of research into probabilistic estimates of

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seismic hazard funded by ORES will be needed by December 1983 so as to incorporate them into task number 5.

v implementation of Probabilistic Assessment Results

['f The I'm'plem'en't'ation of results'is outlined above in elements 5 and 6.

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NRR Staff and Cost Requirements - Probabilistic Assessment The additional effort required for this portion of the program will be 2l5SYforLLNL 9 in FY 8 0.6 in FY 84) and 1.3 SY for NRC (0.3 in FY 83, 1.0 in.FY 84). This staff effort can be accommodated with the currently available resources in the Geosciences Branch because this QISYL N Cric<rab O k ro c.

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program complements ongoing staff activities and may replace other staff activities for individual sites.-

This propram does not include resources to complete the seismic evaluation and/or engineering reanalysis which some plants may require as a result of the probabilistic elements.

Utility-Sponsored Study in Conjunction with the Probabilistic Assessment A recomended utility-sponsored study is outlined above in element 4.

Schedule - probabilistic Assessment The proposed schedule for implementing this plan appears in Table 1.

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Part 2 - Deteministic Assessment Discussion

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The deterministic portion of the proposed program is designed to better understand the causes of large earthquakesauch as the Charleston earthquake, in the eastern seaboard. This effort may require some expansion of immediate and long tem ORES programs. Increased understanding of the cause of seismicity in the eastern seaboard will

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allowareductionintheuncertaintyinestimatingtheseismichazard

'for nuclear power plants. The primary problem with seismic hazard characterization in the eastern seaboard is that no causative mechanism for seismicity has been identified to date and no surface offsets due to earthquakes are known. Although there are literally thousands of crustal structures known in the eastern seaboard, which, if they were active, could produce strong earthquakes, none have been demonstrated to have been active during the Quaternary (the last two million years) or I

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proved to be capable. The result is that, to date., there has been no generally accepted association between eastern seismicity and crustal structure.

The overall approach of the deterministic assessment is to study areas of relatively higher seismicity in the eastern seaboard to determine if tectonic features and processes responsibl for the seismicity can be identified and correlated. This will be pursued by crustal studies at hypocentral depths to determine if there is any correlation between

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crusta's structures at hypocentral depths and the earthquake hypocenters.

The primary tool for determining crustal structure at hypocentral depths

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will be the use of multi-channel seismic reflection profiles. The primary tools for locating the hypocenters will be the continued monitoring and analysis of earthquakes from the existing microearth'qtake nets. These nets will have to be maintained and upgraded in order to improve depth locations of hypocenters if there is to-be an improved ability to correlate between hypocenters and tectonic structures at depths of up to 25 kilometers.

This research will be contracted and monitored by ORES, and does not represent a radical departure from past programs.

Increased

' coordination between NRR and OR2S will be required, however, to better

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define the problems that are to be resolved in order to improve our understanding of eastern seismicity in the licensing context. This portion of the program is designed to improve our ability to assess the adequacy of the design of nuclear facilities on the eastern seaboard.

The result, in part, will be sunmary reports which will represent the current status of research including a review and synthesis of available e

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---. i data. These results will be used to modify, if necessary, conclusions drawn from the probabilistic studies and identify individual features, if appropriate, for assessment by utilities.

Major Activities - Deteministic Assessment The deterministic assessment portion of the proposed program is divided into the following elements appropriate to each region listed.

A. Charleston Region Since the causative mechanism of the Charleston earthquake of 1886 continues to be one of the primary unresolved problems in evaluating seismicity in the eastern seaboard, research in the Charleston area ~

should continue with the goal of testing the various hypotheses as to

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the cause of the earthquake.

In particular, emphasis should be pheed on determining if suggested features such as the Ashley River and

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Woodstock Fault zones constitute the source zones of-the Charleston earthquakes.

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May 1983

" Workshop on the 1886 Charleston Earthquake and Its

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Implications for Today" - the U. S. Geological Survey and the i

scientific community will present a summary and evaluation of the tectonics and seismicity at Charleston.

E0 eptember 1983 - ORES in consultation with the U. S. Geological l

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Survey and the scientific community should have a program in 6

G place to test the most likely tectonic hypothesis for 3

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3.

June 1984 - ORES presents the results of the program l

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of testing the highest-weighted hypothesis.

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January 1985 - ORES presents summary report describing the S#o results of the Charleston work testing the highest-weighted tectonic hypothesis.

B. Ramapo Fault Zone The Ramapo Fault Zone, a Precambrian fault zone that was intermitte dly active until the Mesozoic, is the northwestern boundary of the Newark Triassic Basin. Low level seismicity occurs in the area and may be associated with the fault zone, however, the seismicity in the region forms a band 40 kilometers wide. Detailed field work and limited trenching and core drilling suggest that the Ramapo Fault has not been" recently reactivated. The purpose of studying the fault is to establish r.,._ _

whether there is a causal relationship between Mesozoic or older fatrhs-such as the Ramapo Fault and current seismicity in this area by determining the location and geometry of these faults-at hypocentral depths.

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April 1983 - ORES initiates a new evaluation of the Ramapo Fault. The study should include multi-channel seismic

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reflection profiling and other geophysical techniques such as in-situ stress measurements and geodetic measurements to

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~~ deteiminethecurrentstateofstressathypocentraldepths.

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January 1984 - ORES presents preliminary results of the program (MNO!

to date, and plans for the coming year.

60 (3. January 1985 - ORES presents sumary report on this aspect of b

the Ramapo Fault Study including the identification and analysis of any seismic source zones.

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n C. Central Virginia Seismic Zone Recent work by earth scientists at Virginia Polytechnic Institute have suggested that there may be a relationship between the seismicity in Central Virginia and the northeast trending thrust faults and decollement of the Piedmont crust of the Appalachian Orogenic Belt. The purpose of this part of the program is to continue evaluation of tS

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relationship between the faults and the earthquakes.

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April 1983 - ORES presents a plan for undertaking the seismic reflection profiling, and applying other geophysical techniques

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such as geodetic measurements and in-situ stress measurements.

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January 1984 - ORES presents the preliminary results or g

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QU progress to d' ate, and plans for the coming year.

3.

January 1985 - ORES presents a sumary report on the

%%p #u gy, the Central Virginia Study includi_ng. the potential n

E identification and analysis of any seismic source zones.

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D. Giles County, Virginia The Giles County Seismic Zone is a northeast trending linear zone of seismicity which apparently is located beneath the decollement and

' thrust faults associated with the Valley & Ridge Province of the

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Appal'ac'hi$n' rogenic Belt.

It has been suggested that the seismic zone

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has occurred as a reactivated northeast trending nomal fault associated with the opening of the Proto-Atlantic (called the Iapatus) in the late Proterozoic and early Paleozoic (800-500 millionyearsago).

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April 1983 - ORES initiates planning for the proposed research,

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August 1983 - ORES initiates study of the Giles County W g#

structure using seismic r:flection profiling, j

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April 1984 - ORES presents preliminary results and plans for k

the coming year.

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April 1985 - ORES presents summary results of this phase of the Q h @jk research including the potential identification and analysis of any seismic source zones.

E. New England The research in New England has been underway for several years and will be continued. Increased emphasis should be placed on evaluation of the source mechanism for the New Brunswick and Gaza, N.H. earthquakes, the neotectonics of seismically active areas, and the orientation and magnitude of the stress field in the seismically active areas of thr-region. An in-situ stress measurement at hypocentral depths will be conducted at Moodus. Depending on the results of the--seismic re[lection studies described above, additional seismic reflection surveys may be conducted in seismically active areas of New England such as Moodus, Connecticut; New Hampshire; Massena, New York and New Brunswick, Canada.

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April 1983 - ORES completes plans for stress measurement at

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August 1983 - Conduct stress measurements at Moodus.

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April 1984 - ORES presents preliminary results of stress p

measurements and their relationship to the local seismicity and M

tectonics.

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January 1985 - ORES presents summary results of stress g

measurements and other studies described above.

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Implementation of Deterministic Assessment Results As the results from the deterministic studies become available, they will be evaluated, and, the effect, if any, on operating plants and plants in the Operating License stage of review will be determined. The need for additional evaluations of particular structures by utilities will be assessed as the infomation becomes available. Two problems. vill

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c be addressed by the deterministic portion of the program; (1) whether or not the deterministic findings warrant any reassessment of the conclusions drawn from the probabilistic stJdy; and (2) whether there are any particular tectonic structures which are associated with or similar to tectenic structures associated with seismicity which, bec'ause of their proximity to individual sites, should be analyzed by the r.,.-.

utilities. The above effort will take about two to three years (early 1985) to complete. The impact of this research on nuclear power plants

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will be detemined by the NRC staff with technical -assistance contracts, if necessary.

NRR Staff and Cost Recuirements - Deterministic Assessment This effort will require continuous communication among NRR, ORES and

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~the contractors. As research funds are limited and the amount of time

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infoStion required to allow a resolution of eastern seismicity.

It is

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estimated that one staff year per year for three years will be necessary for NRR to implement this deterministic part of the overall plan.

The research effort will be funded by ORES and technical assistance contracts will be funded by NRR.

It is estimated that for the 4

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deterministic assessment, $200,000 may be required to implement the NRR technical assistance program to determine the impacts of the findings on the nuclear facilities in the eastern U. S.

Utility-Sponsored Studies as Result of the Deterministic Asessment During FY 1983 no deterministic work by the utilities is currently recommended, beyond that necessary to pursue their normal efforts to

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continue to assess any hazards identified by them for their sites.

After the results of the research are available and if any source zones are identified which have particul.ar importance to specific sites or have impact on the probabilistic program, some utilities may be required

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to investigate structures in the vicinity of their plants.

Schedule - Deterministic Assessment

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e The proposed schedule for implementing this plan follows as Table 1. '----

Our ability to meet this proposed schedule may be somewhat optimistic and is contingent on implementing the appropria.te contracts. Wewiilbe-better able to assess this schedule when the work has been initiated.

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REFERENCE Algermissen, S.

T., D. M. Perkins, P. C. Thenhaus, S. L. Hanson, and B. L. Bender,1982, Probabilistic Estimates of Maximum Acceleration and Velocity in Rock in the Contiguous United States, United States Department of Interior, Geological Survey. Open-File Report 82-1033, 99 p.

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Calendhr Year Schedule'for Probabiilstic and Deterministic Seismic Hazard Program 1983 1984 1985 l

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Meet with ACRS to Meet with ACRS to Part 1 Short Tenn discuss Program to discuss Preliminary Recommendations

1. Update LLNL Seismic

+ Complete Methodology llazard Methodology i

2. Calculate Seismic !

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+ Report with Spectra llazard Spectra fo' Eastern Sites 3.ComparewithotheF

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+ Report with Comparisons available probabi'lity I

studies f

4. Initiation of Ind9stry-

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4 Production of Study Results

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Sponsored Seismic Ilazard Study l

Letter Report with

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Preliminary Recommendations 5.. Comparison of Sei inic

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+ Final Recommendations llazard at Sites

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Initate Feedback Assess Impact on

6. Assessment of Imp,ict of

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+ Previous Results Expert Feedback l

Initiate Tac with LLNL i

7. Charleston Ground! Motion

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+ Issue Report Study I:

f Table 1 i

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s Calendar Year Schedule for Protlabilistic and Deterministic Seismic Hazard Program j

l 1

1983 1984 1985 i

Meet with ACRS to Meet with ACRS to Part 2 Long Tenn discuss Program to discuss Preliminary Recommendations Workshop'-

Interim Progress Report on Results of i

Synthesis Hypothesis Testing Testing

1. Charleston Research

+

x x

xx-----

i l

Initiate Preliminary Summary Study Report Report

2. Ramapo Fault Research

(+

x x

xx-----

'I Initiate Preliminary Summary Study Results Report Report I

y.

3. Central Va. Research

+

x x

xx------

1 Preliminary Sununary Initiation RFP of Study Results Report l

l

4. Giles County, Va.

+

x x

x xx----

Research L

Stress Measurements.

Conduct Preliminary Summary Plan l

Measurements Results Report S. New England

~

+

x x

x

xx Seismotectonic Research Summarize Review l

Preliminary Evaluation Sununary of of Determinsitic of Resbits of kES Source Zones Work

6. Assessment of impact of

+

'x

[T x

+

Deterministic Studies j.

l on Sites

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1 Table 1 (cont'd) j.

i

7 Interim Position on Charlesten Earthouake

~-'

for Licensing Proceeoing

' ~

The NRR Staff position with respect to the Intensity X 1886 Char',eston earthquake has been that, in the context of the tectonic province approach used for licensing nuclear power plants, this earthquake should be restricted to the Charleston vicinity. This position 'was based, in part, on information provided by the United States Geological Survey (USGS) in a letter dated December 30, 1980 from J. E. Devine to R. E.

Jackson (see Summer Safety Evaluation Report). The USGS has been reassessing its position and issued a clarification on November 18, 1982 in a letter from J. E. Devine to R. E. Jackson. As a result of this letter, a preliminary evaluation and outline for NRC action was forwarded to the Comission in a memorandum from W. J. Dircks on November 19, 1985 -

~

C-The USGS letter states that:

"Because the geologic and tectonic features of the Charlestone region are similar to those in other r1gions of-the eastern seaboard, we conclude that although there is no recent or historical evidence that other regions have experienced strong earthquakes, the historical record is not, of itself, sufficient grounds for ruling out the cccurrence in these other regions of strong seismic ground motions similar to those experienced near Charleston in 1886. Although the probability of strong ground motion due to an earthquake in any given year at a particular location in the eastern seaboard may be very low, deterministic and

~

probabilistic evaluations of the seismic hazard should be made for individual sites in the eastern seaboard to establish the seismic

. engineering mamatars_ for critical heilitiac "

The USGS clarification represents not so much a new understanding but rather a more explicit recognition of existing uncertainties with respect to the causative structure and mechanism of the 1886 Charleston earthquake. Many hypotheses have been proposed as to the locale in the eastern seaboard of future Charleston-size earthquakes. Some of these 0

.7 y

7,...,_ -

~~

could be very restrictive in location while others would allow this earthquake to recur over very large areas.

Prt.sently, rene of these hypotheses are definitive and all contain a strong element of speculation.

We are addressing this uncertainty in both longer-term deterministic and shorter-tem probabilistic programs. The deterministic stud'ies, funded primarily by the Office of Research of the NRC should reduce the uncertainty by better identifying (1) the causal mechanism of the Charleston earthquake and (2) the potential for the occurrence of large earthquakes throughout the eastern seaboard. The probabilistic studies, primarily that being conducted for NRC by Lawrence Livemore National" Laboratory (LLNL) will take into acco'unt existing uncertainties. They m.,._

will have as their aim to determine differences, if any, between th't -

probabilities of seismic ground motion exceeding design levels in the-eastern seaboard (i.e. as affected by the USGS clarified positio[on the Charleston earthquake) and the probabilities of seismic ground motion

~

exceeding design levels elsewhere in the central and eastern U. S.

Any plants where the probabilities of exceeding design level ground

~

~

m6tions are significantly higher than those calculated for other plants in the Central and Eastern U. S. will be identified and evaluated for possible further engineering analysis.

Given the speculative nature of the hypotheses with respect to the recurrence of large Charleston-type earthquakes as a result of our limited scientific knowledge and the generalized low probability associated with such events, we do not see a need for any action for

m

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~

3 specific sites at this time.

It is our position, as it has been in the past, that facilities should be designed to withstand the recurrence of an earthquake the size of the 1886 earthquake in the vicinity of

~

Charleston. At the conclusion of the shorter-term probabilistic program and during the longer-tenn deterministic studies, we will be assessing the need for a modified position with respect to specific sites.

~

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N e

f S AINT LOUIS UNIVERSITY l

DEPARTMENT OF EARTH AND ATMOSPHERIC SCIENCES 3:17 LacLEDE AVENUE MAILING ACQmES$t SMxt Louil. Missoual 43:03 p.o. com eces. L AcLEDE ST Atl0N f

AiNT Louis, Missouai siise,

March 7.41983 The Hottbrable Doug Walgren

"~

Chairman. Subcotmaitte on Science, Research and Technology U.S. House of Representatives 2321 Ifaiburn House Office Building Washington. D.C.

20515 i

Dear Congressman Walgreat Enclosed please find 75 copies of my testimony to be given on t

March 15 at the authorizations hearings of your Subcommittee on

[

the National Earthquakas Bazard Reduction Prog' ram. At your request I have focused my statement on the earthquake problem in the

~

eastern United States. Also enclosed are 20 copies of a brief biographical sketch.

Thank you for inviting me to appear before yoIiir Subcommittee.

Sincerely yours,

b. w.ht.

t Otto W. Nutt11 Professor of Geophysics i

Cat:leh Enc.

l-x 7 n,A 7-l f

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TESTIMONY BY OTTO W. nun LI, PROFESSOR OF GEOPHYSICS, SAINT LOUIS UNIVERSITY 4

SUBtGTTED TO THE ROUSE SU3COMtGITEE ON SCIENCE, RESEARCH AND TECHNOLOGY MARCH 15, 1983 e

9

.p Mr. Chairman, I am pleased to appear before the House Subec==ittee g

on Science, Research and Technology and to discuss, at your request, the current activities of the, National Earthquake Hazards Reduction Program as it relates to earthquake problems in the eastern United States.

INTRODUCTION There are two principal points I wish to make in this te stimony.

'I The first is that earthquaks hazard i$ the United Stat.es is not res-tricted to the West, but also exists in varying degrees, in almost every state of the nation.

The second point is that work accomplished under

.t the Nazard Recuction Program has produced a number of significant accom-

{

plishments.

EARTHQUAKE BAZARD IN THE EAST Earthquakes do not occur regularly in t_ime.

Af ter great earth-

, uakes, there is a period of miative quiet until the ever-acting geo-q logical forces are able to produce sufficient strain to cause more large earthquakes.

The twentieth century has been such an interlude for catastrophic seismic activity in the eastern states.

Therefore, because t

there have been no major. eastern earthquakes in the memory of :ost of the people, the general populace is insufficiently informed about the earthquake hazard east of the Rockies.

Recently we have had several small reminders of this threat in the form of moderately damaging earth-quakes in New Brunswick, Canada and New Hampshire in January 1982, and of a 1980 Kentucky earthquake that was felt in fif teen states and in Canada and that caused several million dollars of property damage in Kentucky and Ohio.

In historical times structurally damagir4 earthquakes occurred in

~2~

' j-Alabana, Arkansas, Connecticut, Delaware, Illinois, Indiana, Kansas,

('

Kentucky, Maine, Massachusetts, South Carolina, Tennessee, Texas and Virginia.

For some of them, damage was also experienced in neighboring states, such as Georgia, Mississippi and North Carolina, Fortunately, the great eastern orthquakes occurred before the country was densely populated, and before the appearance of high-rise structures and the development of a sophisticated and vulnerable techno-logical society.

The 1886 Charleston, 3C earthquake, of magnitude 7.5, killed 110 people.

If it had happened 100 years later, the loss of life would have been at least ten times, and conceivably one hundred times, greater. Even more dramatic were the three, great New Madrid earthquakes o in the winter of 1811-1812, with epicenters in Arkansas and Missouri and magnitudes of 8.4, 8.6 and 8.7.

Ground shaking caused by them was felt I

in all of the United States east of the Rooki and perhaps farther to

~ the west.

Damage extended over most of the area consisting of the states of Missouri, Arkansas, Mississippi, Kentucky, Tennessee, Illi-nois, Indiana and Chio.

Other large nineteenth century earthquakes occurred in eastern Arkansas in 1843, in Charleston, Missouri in 1895 and in Giles County, Virginia in 1897.

From our studies of the New Madrid fault we know that enough energy is stored up along it to produce a magnitude 7.6 earthquake right cow.

This would cause damage over an area of 200,000 square =iles.

However, we are not yet able to predict when the r.ex t large earthquake will occur.

The longer the time that elapses, the larger the earthquake will be.

For the rest of the eastern United States we cannot be so specific about the seisimic potential.

Further data' accumulation and research s

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. /..

are needed to provide us this infor=ation.

C 4

SOME ACCOMPLISHMENTS FOR THE BENEFIT 0F THE EAST OF THE NATIONAL HAZARDS REDUCTION PROGRAM The National Science Foundation, the U.S.

Geological Survey, the Federal Emergency Management Agency and the U.S. Nuclear Regulatory Com-mission are the principal fedef al agencie,s that engage in earthquake-related activities in the eastern United States. Other important parti-cipant.s' are state and local agencies, universities, private industry.

and non-pMfit organizations such ~as the American Red Cross.

Significant acecaplishments under the National Earthquake Hazards Reduction Program span the whole range of goals of earthquake hazard mitigation. I shall limit my examples to those* with weich I have per-

~

sonal experience, and they will reflect my backgriund as a seismologist. ",

~

~

On the scientific level we are making progress in our ability to define the boundaries of the major earthquake source zones, to determine the frequency of occurrence of earthquakes within those =enes, and to estimate ib= largest earthquake that each area is capable of producing.

2 We also are acquiring quantitative infor=ation about the attenuation of

. high frequency seismic waves that produce. damaging ground shaking.

These kinds of information are needed to calculate the expected aucunt of grounc shaking at any selected site, which in turn is needed for the design of earthquake-resistant structures.

All of the seis=ic infor=a-tion comes frt the continued cperation of seis=cgraph networks, fro =

regional geological and geophysical studies, and from fundamental seismological research on the physics of the rupture process, the s

transmission of wave energy, and the geological structure of the Earth's e

e e.

crust.

The problems to be solved are especially difficult because f

eastern earthquakes, in general, do not rupture the Earth's surface (the faults can't be seen), the earthquakes occur relatvely infrequently, and the association between geological processes and earthquake occurrence is not as well known or understood as it is in the West.

Therefore a long-term research effort is required for a better understanding of the seismicity and tectonics of the fast, which*ocaprise the most fundamen-tal kinds of earthquake information.

In the past few years earthquakes in Arkansas, Kentucky, Missouri, New Brunswick, New Eaapshire and South darolina provided the first eastern strong ground-sotion records. These kinds of data are essential to 'the engineers who design structures. Also seismologists use them.to compare actual observations with those predicted on theoretical stu-

~

dies, to check oneir theory, and to determine sia1Tarities and differ-

~

enees with western earthquakes.

Until now engineers have relied upon modified western' data in designing seismic-resistant structures for the East, even though there is uncertainty as to how the data should be modified.

Strong ground-action data still are lacking for large sagnitude eastern earthquakes.

Continued operation of strong grouhd-motion instruments in the East is needed to cbtain these data.

Along with this, fundamental studies of earthquake source physics and of wave pro-pagation will enable us, to better " scale up" motions frca anall to large earthquakes, to speed the acquisition of this essential information.

From personal experience I know that the results of the aferemen-tioned studies already are being used by engineers in the design of e

O 4

%e nuclear power facilities and reprocessing plants, large dans and I

selected h15h-rise structures. It is gratifying that this NEHRP-derived 2.

knowledge is being used so immediately to reduce earthquake risk in the eastern United States.

In some cases ths is being done only because of

~

requirements of federal regulatory agencies, or because of the initia-

~

tive of individual engineers and architects who are responsible for the design of high-rise and/or dritical atttetures.

In general, there are no seismic building ocde requirements in most of the eastern United States. However, progress is being made along these lines also.

The U.S.

Geological Survey and the Federal Emergency Management Agenoy have taken the lead in bringing the earthquake hazard probles to the attention of state and local officials, structural engineprs, and agencies responsible for building codes, land-use planning, and for engineering response to disasters.

Well-dYtended conferences ad

~

workshops on these topics includes Knoxville, Tennessee workshop in September 1981, ' Preparing for and Responding to a Damaging Earthquake in the Eastern United States."

Saint Louis, Missouri workshop in May 1982, " Continuing Actions to Reduce Losses from Earthquakes in the Mississippi Valley Area.'

3 Charleston, South Carolina conference in May 1982.

Three additional workshops are to be held in 1983 in Charleston, South Carolina, Boston, Massachusetts, and Little Rock, Arkansas. These conferences are organized by the U.S.

Geological Survey, with support shared by the Federal Energency Management Agency, the National Science Foundation and *he U.S.

Nuclear Regulatory Ccamission.

The published proceedings of these conferences are

  • widely distributed and have received attention not only from techr.ical people and state and local

~6-officials, but also from the press, TV and radio, insurance underwriter h

organizations, school officials, and other getups of concerned citiness.

Because of these activities carried out under the NEERP, the eastern earthquake hazard problem is beginning to get the attention of the pub-lic' and of government officials responsible' for =itigating earthque.ke effects or of responding to earthquake disaster.

This educational pro-cess much be long-term and c6ntinuous 15 nature, it it is to achieve the desired goals.

At the state level, I an aware of some kind of governmental action regarding earthquakes in Kentucky, Massachusetts, Missouri, New York and Tennessee.

There any be more, of which I,as unaware.

At the local level ar experience is limited to metropolitan St.

Louis.

At.present there is an Ad-Hoc Commaittee on Seismic Risk of the St. Louis Section of

(,

the American Society of Civil Engineers, and a7entinuing concern of St'.

~

~

~ Louis County Civil Defense for educating school children for sate behavior during an earthquake, and also for planning their response to earthquake-caused emergencies.

I have attempted to cover the range of NEHRP-related activities in the East. There is one final point I wish to make. It concerns the need to continue the research efforts.

The members of the House Subcon=1ttee on Science, Research and Technology are well aware of the inherent values of research, so there is no need for me to spell them out to you.

But with regard to the National Earthquake Hasard Reduction Progra=,

there is a cost-effective reason which may not be obvious.

Critical facilities are designed to withstand the worst likely earthquake.

Because our knowledge is incomplete, this can result in overdesign.

As e

e

7 we better understand the earthquake hazard through the resese:b effort, r

we will find that for certain parts of the country, at least, the worst likely earthquake hazard' will be less than is presently assu ed.

This will allow for a less costly, but eq aally safe, design of the struc-tures.

The ex;ected savings in construction costs can conceivably be ordys of angnitude larger than the entire cost of the NEHRP.

In addi-

~ ~

tion, more precision and detail in ampping earthquake ha:ard will sake it easier to get local communities to adopt efffective ouilding codes, for the additional construction costs will not be so burdensome.

I I trust, Mr. Chairman, that my testimony will provide you and the members of the Conanittee on Science and. Technology with a fuller knowledge of the actions, resulting from the NEHRP, that have been a6d are being taken to mitigate earthquake hazard in the East, and of the i

need for continuing efforts in all aspects of the Program.

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