ML19242D917

Early Site Review for Facilities

ML19242D917
Person / Time
Site:	Crane
Issue date:	02/10/1977
From:	Office of Nuclear Reactor Regulation
To:
References
PROJECT-558A NUREG-0171, NUREG-171, NUDOCS 7909040223
Download: ML19242D917 (50)

Text

{{#Wiki_filter:N U REG- 0171 Early Site Review Report for the Sundesert Site San Diego Gas & Electric Company Reported by the Office of Nuclear Reactor Regulation 3 3 Project No. 558 i U. S. Nuclear Regulatory Commission TNashington, D. C. 7 g .7 i :. '. o.'i February 1977

Available from N, tional Technical Information Service Springfield, Virginia 22161 Price: Printed Copy $4.50, Microfiche $3.00 c- ,e Jvd / J 1 i/1 UDl 3

NUREG-0171 Fetiruary 10, '977 EARLY SITE REVIEW REPORT BY THE OFFICE OF fiUCLEAR REACTOR REGULATION U. S. NUCLEAR REGULATORY COMMISSION IN THE f1ATTER OF SAN DIEGO GAS AND ELECTRIC COMDANY SUNDESERT SITE PROJECT NO. 558 ,.r j j ,) l e 4, ? i VUL

TABLE OF CONTENTS PAGE 1.0 INTRCDUCTION AND GENERAL DISCUSSION. 1-1 1.1 Introduction. 1-1 1.2 General Description of the Site... 1-2 1.3 Identification of Agents and Contractors.. 1-5 1.4 Summary of Principal Review Matters... 1-5 2.0 SITE CHARACTERISTICS.. 2-1 2.1 Geography and DemograpFy....... 2-1 2.2 Nearby Industrial. Transportation, and Mi?itary Facilities. 2-6 2.3 Me teorol ogy. 2-9 2.3.1 Regional Meteorology. 2-9 2.3.2 Local Meteorology. 2-10 2.3.3 Onsi*e Meteorolog ;al Measurements Program. ?-10 2.3.4 Diffusion Escimates. 2-10 2.3.5 Conclusions. 2-11 2.4 Hydrology. 2-11 2.4.1 Hydrologic Description. 2-11 2.4.2 Flood Potential. 2-12 2.4.3 Cooling Water. 2-13 2.4.4 Low Water Considerations. 2-13 2.4.5 Groundwater. 2-13 2.4.6 Conclusions. 2-14 2.5 Geology and Seismology 2-14 2.5.1 Regional Geology 2-15 2.5.2 Tectonic Province and Regional Tectonics. 2-18 2.5.3 Site Geology 2-20 2.5.4 Surface Faulting 2-11 2.5.5 Regirnal Seismicity. .f. 2 21 2.5.6 Design Basir Earthquakes. 2-23 2.5.7 Conclusiens. 2-26 -3 4 r- ~ ' ~7 ,t i 0J f av/ 1

TABLEOFCONTENTS(Continuedl PAGE 3.0 DESIGN CRITERIA FOR STRUCTURES, COMPONENTS, EQUIPMENT, AND SYSTEMS 3-1 3.7 Seismic Design 3-1 3.7.1 Se i s. nit Input 3-1 18.0 REVIEW BY THE ADVISORY COMMITTEE ON REACTOR LAFEGUARDS 18-1 21.0 CONCLUS10% 2I-I J k Y J I g.

APPENDICES PAGE APPENDIX A CHRCNOLOGY OF LIMITED EARLY SITE REVIEW FOR SUNDESERT SITE. A-1 APPENDIX B REPORT OF THE U.S. GE0 LOGICAL SURVEY. B-1 APPENDIX C BIBLIOGRAPHY. C-1 LIST OF FIGURES PAGE FIGURL 1.1 GENERAL SITE LOCATION SUNDESERT SITE. 1-3 FIGURE 1.2 AREA WITHIN 20 MILES OF SITE. 1-4 FIGUPE 2.1 AREA WITHIN 10 MILES OF SITE. 2-2 FIGURE 2.2 LAND CW'iERSHIP - SUNDESERT SITE. 2-3 FIGURE 2.3 CUMULATIVE POPULATION DISTRIBUTION (1980). 2-5 L 2 y J 6 g i t.i :)

1.0 INTRODUCTION

J O GENERAL DISCUSSION 1.1 Introduction The purpose of this report is to present the Nuclear Regulatory Conmission's (Cornis-sion) evaluation of several of the matters relating to the suitability of a site (Sundesert site) near Blythe, California, on which the San Diego Gas and Electric Company (applicant) proposes to build a nuclear facility, identified as the Sundesert Nuclear Plant, Units 1 and 2 (plant or facility). The Sundesert Early Site Review Report was submitted on April 16, 1975, in support of a request by the applicant to have the Corriission evaluate the suitability of the proposed site with respect to (1) demography and geography, (2) consideration of nearby industrial, military and transportation activities, (3) hydrology, including certain hydrologic design criteria, (4) geology ano seismology, including seismic input criteria, and (5) site meteorology. Initially, the applicant requested that the Sundesert Early Site Review Report be reviewed by both the Comission's staff and the Advisory Conmittee on Reactor Safeguards. Subsequently, in September 1975, the applicant requested that the U.S. Geological Survey also pa-ticipate in the review of the report with regard to geology and seismology. This report sumarizes the results of our technical evaluation of the suitability of the proposed Sundesert site for a nuclear power plant and delineates the scope of the technical matters comidered in evaluating the suitability of the site. Additional details as to the scope and bases used by the Commission's staff to evaluate the radio-logical safety aspects of proposed nuclear power plant sites are provided in the Nuclear Regulatcry Connission's Standard Review Plan For The Review Of Safety Analysis Reports for Nuclear Power Plants, NUREG-75/087 (hereinafter also referred to as the Standard Review Plan). The Stendard Review Plan is the result of many 3 ears of experience by the Connission's staff in establishing and promulgating guidance to enhance the safety of nuclear facilities and in assessing Safety Analysis Reports. The applicant also tendered an application on December 8,1976 for construction permits to build two light water reactors, each rated at approximately 978 electrical megawatts, on the proposed Sundesert site. The applicant submitted the Environmental Report with the application and plans on submitting the Preliminary Safety Analysis Peport in March 1977. The nuclear steam supply system for each unit will be a three-leop system to be supplied by the Westinghouse Electric Corporation. /) 1: 5, k (' L j e 1 l-1 7 4 d / ! J i

During the course of this early site review, we and our acvisors, the U. S. Geological Survey, held several reetings with the applicant and visited the site on three occasions. During our evaluation of the information contained in the Sundesert Early Site Review Report, we requested the applicant to provide additional information. The additional information was provided in Amendments 1 through 12 to the Sundesert Early Site Review Report. The report and its amendments are available for public inspection at the U.S. Nuclear Regulatory Ccxvission Public Document Poom, 1717 r Street, N.W., Washington, D.C. 20555, and at the Palo Verde Valley District Library,125 West Chanslorway, Blythe, California 92255. A chronolcgy of the srircipal.ctions rolated to our review of tre Sundestrt Early Site Review Report is included as /prendix A to this report. The U. S. Geological Survey's evaluatico of the geology and seismology for the proposed Sundesert site is anclosed as Appendix B. The bibliography for our report is enclosed as Appendix C. 1.2 General Descr_iption of the Site The site for the prcposed Sundesert Nuclear Plant is located on the "esa in the Palo Verde Valley in the southeastern corner of Riverside County, California, as shown in Figure 1.1. It is lccated approxin3tely 16 miles sou thwest of Blythe, California (1970 population of 7,047), and 2.5 miles west of Palo Verae, California (Iopulation less than 300). It is also aporoximately 50 miles north-northwest of Yuma, Arizona (1970 population of 29,607) which is tf e closest population center of greater than 25,000 persans. The land un the mesa is substantially controlled by the U.S. Department of Interior, Bureau of Land Management. The airst ice above the site is currently overtlown by low level and high level military fliqhts. The site is located on the mesa adjacent t; the flotd plain approximately two miles west of the Colcrado River flood clain, as shown in figure 1.2. The site area encom-passes approximately five square miles The :iule Mountains lie approximately five miles west of the site, and the Palo Verde Mountains lie approxinately six riles southwest of the site. The ground surface ranges from approximately 350 feet above mean sea level on the eas+ side to 400 f eet above mean sea level cn the west side. These elevations are 100 to 150 feet above the level of the flood plain. Groundwater level is approximately 240 feet above mean sea level. The site is situated within the Sonoran Cesert physiographic and geologic subprovince of the Basin and Range province. The geology within a 25-rile radius of the site is characterized by mountain ranges which are relatively short, irregular, and stand sharply above broad alluvial-ti' led basins Rocks of the mountains vary from deformed crystalline rocks of Precambrian age to volcanic and sedinent=ry rocks of middle Tertiary age. Pliocene marine aposits, Pliocene to Pleistocene alluvial deposits, and Holocene alluvium fill the broad basins Faulting within the site area is restricted solely to the bedrcck and basement complex. Thrust faulting, confined to the basement rocks, is associated with the Lar vnide orogeny. High-angle f aults, including both strike-slip and norral faulting, postdate ~, 1-2 n ~ ' r;,

I 6 b I P 4 el N Sacramento C San 4 + Fra n cis c o ( C i V k ,4 90 Fresno o' o g 4 Los l D 4 OVeGoS n Bakersfield 4 o WCH AVE COUNT Y -n Santa Barbara Sen J Los Angeles O B ernardino _ _ _ c-Parker O O CD -r-~~ s," 6'R i v e r s id e Blythe ARIZONA , - -o'. Santa Ana ,'s,c _ _.- ',,0 R I V E R*;lC E C ' SITE O C R A N i. E C O S AN DIEGOr Oi P Y YUM A COUN TY count < l Yuma c. San s Diego :- e M E y O 5:a.F-la FIGURE 1.1 GENERAL SITE LOCATION SUNDESERT SITE ' ', )- 1-3 /3 r . n. t - . t. U O

DT 0 l T ,r lin vv ~0o _ mt.1 a sii.:4 t o r!st**o m og k l i i a j! g jilil! t!U: > s: (J + - 4. - <---t - s ., g s l -aa.. ghb gV 5-~mse l s "l k ' '\\ fk f_ ys b4(% %'?, W-g w \\ / )r~~.' g ~ r .~ '/ vg cye

,;. e $

,b 'A O s 1 ~ d I.' O C A,[. %]j%[> ~ \\ I 4 e ( " O3 - "_ aN J U z c V .,,/ O' n i p ,,c/2 's., C'). IO S4_.,.I ] 3: r,_ c c.,'~ 3 i T. 1 a, %/ t s { l g 2 [/ / b n\\ g JV ,5c i ~ RW, k .gl' N Q 8 ,,=. a.y v w u .m l / , ~f I., ' N' !s U ? e u+ l 9 e =# ' y'p)n$ l

• l j'$ (

l fl,f ~ '%s'f'?" I d4

,7;

• e e m

su.n \\ -,#[fW4 s ' D!'s, W ,t O .- P P .] o ,e-V $ 0h

• _f h

4:.<.. ,/l 3. %[MI s .jk, b5 f7 H / fi O f E E N /,'. O m N- /;s27 '\\, 1t .2 v m s m / j ', /' \\ (1'~~

1&

vY ) w n / "> 7 [y ~ >f is l ' [;? f / 5< 8, }i u 1 I l f9 v-J\\ f f) g J l J s 1-4 (,.) /

the thrust faulting and disrupt both the tedrock and the baserent complex. Pliocene to Holocene sediments are flat-lying and undef ormed throughout the site area. The most significant tectonic structure in th' vicinity of the site is the San Andreas f ault system. The applicant has chosen the Sand Hills fault, which is 35 miles fron the site, as the closest member of the Si i Andreas f ault system to the site, even though the Sand Hills Tolt is clearly not the see kind of master tnro"gh-going feature as the San Andreas system. Foundation soils at the site consist of approximately 3E0 feet of dense granular soils underlain by a thick derosit of hard clay. 1.3 Identificatinn of Anonts and Contractor 3 The San Diego Gas and Electri: Company will be responsible for the design, construction and operation of the proposed pla it. At the present tire the San Diego Gas and Electric Company is tho only participant in the proposed Sundesert Nuclear Plant, but broader ownership may he included when the freliminary Eafety fc.alysis Percet is submitt?d. The Stone and Webster Engineering Corporatino has been selected as the architect-engineer and constructor for the proposed plant The following consultants were retained ty the applicant to perfom investigations and studies for tre preparation of the Sundesert Early Site Review Report: (1) Fugro, Incorporated, Lonsulting Engineers and Geolegists (2) EDS Nuclear, Incorporated, Consulting Engireers (3) Buckman-Edmonston Engineering, incorporated, Specialists in Later Pesources (4) WESTEC Services, Incorporated, Environmental Censulting Firm 1.4 Sumary_of Princio_al Review Patters Our e"aluation included a +echnical review of the infceration and data submitted by the applicant with emphasis on the following principal matters (1) Wa evaluated 'he exclusion area, lcw peoulation zone and population density in the site environs to determine that these characteristics were in accord 3nce with the Cemission's siting criteria in 60 CFR Part 100. (2) We evaluated the land use characteristics of the site environs and the 'mysical l l i sharacteristics of the site, including reteora eay, hydro ogy, gec ngy, and seismology to determine that these characteristics had been adequately descrited and were given appropriate consideration to Jeterr.ine the significant site-related raramete?, fcr the design of a nuclear plant, and that these site characteristics were also in accordince with the siting criteria in 10 CFR Part 100. q n Q_.rp---h'td _,,c 15 ~ ' * .E I L J\\ 0

(3) We evaluated the nazards to a nuclear power plant which could result from ran's activities near the site environs, such as petroleum extraction, mining 3ctivity and trcnsportation accidents to determine whether special design considerations would be required, because of trese activities, for a ruclear power plant to be located on the proposea site. During the process of performir:a our evaluation of the above principal natters, we have identified the additional inforrution that we will review when the preliminary Safety Analysis Peport i s s t,bm i t teri, to complete our de' ailed review of these s ite cha r ac teris t ic s for a construc t ion permit aprlica tion. J i _, _. i 1-6 'i

) ',' 1

/ I t

2.0 SITE CHARACTERISTICS The scope of the Sundesert early site review does not include the design paraneters for a specific nuclear power plant design. This information will be provided by the applicant at at future date in the Preliminarj ~afety Analysis Report in accordance with the requirements of 10 CFR Part 50. Hevever, the Sundesert Early Site Review Report and this early site review report have established an envelope of reteorological, hydrological, geological and seismological conditions for a n; clear power plant design. These conditions provide an indication, in advance of the develcprEnt of a specific nuclear power plant design, of site-related design requirements for a nucle. r power plant at the Sundesert site. 2.1 Geography and Denography The 7,040 acre Eundesert site is located in the extrere southeastern portion cf Riverside County, Calif ornia, about 5.5 niles west of the Colorado River. The site is located on the Palo Verde Mesa, 9.5 miles southwest of Ripley, California, 1C miles southwest of Blythe, California, and 50 miles north-northwest of tuma, nrizona. The Unit 1 containment will be centered at 33 degrees, 27 ninutes, 7 seconde north latitude and at 114 degrees, 47 minutes, zero secords west lcngitude. The Unit 2 containment will be located 600 feet due east of Unit 1. Figure 2.1 identi fies the site location and characteristics of the area within 10 miles of the site. The applicant has defined a site bcundary and exclusion area radius of 3,200 feet as shown in Figure 2.2. The applicant proposes to acquire land (sho,.n as Parcel No.1 ir Figure 2.2), cor.sisting of about 6,560 acres, from the U.S. Departrent of Interior, Bureau of Land Management through an in-lieu property exchange. To tnis end, the uureau of Land Management has designated lands, in the Coachella Valley region in California, which it is interested in acquiring by exchange. The applicant has op-tioned the lanc; designated by the Bureau of Land Management for the prop 9rty exchange. Based s the Bureau of Land Management's land excnarge practices, the applicant will acquire 100 percent of the mineral rights in about two-thirds of the land to be acquired from the Bureau of Land Maragement. However, the applicant will acquire from the Bureau of Land Management 100 percent of the mineral rights in all the lard within the exclusion area. The applicant has optioned, with the exclusive right to purchase, the land sho,in as Parcel Nos. 2, 3, 4 and 5 in Figure 2.2. The options to purchase held by tte applicant include 100 percent of the mineral rights, except for Parcel No. 2 (which is n9t in the exclusion area) where the optionar has reserved 50 percent of the mineral rights An option to purchase the land shown as Parcel ho. 6 in Figure 2.2 bas been. tendered to the Cwner, who declined to enter into an option agreement. The parcel is YCt 'within the exclusion area and therefore control, including mineal rights, is not' req 6 ired. 2-1 ~ 1I .p y V,L i j0 t U s I n s

x v \\ J~T~\\ J\\,)N } KQ ,) x t q + '; ,( W h @ NNW /,< Eiini$9 A ' N Y NNE,f T5 Blythe

e o/o /

/ y 42/s2 1252 E 43/ / WN S / x(7efE,/ C A L I F O' R M E A ~ ( f-Riplev ( CH U c KW A LLA 7 3/\\0

/ 2 2s/274 WNW h 7 E( x '

NENE qct{p9 'I AL 9-p. d \\ - i}/ VERDE cW 5 0j / '/ PROPOSE 0 o 9 5 y i' SITE p'.~ oloj RIVE R SI D E CO. _,. ~ gg O E w id u. s 4 i 155/ ,/ 3 IMPERIAL CO. p' x / d p%' 0/0\\ [ \\/ 'd Y U/M A C O. \\ b \\.\\ - \\ p A a N E p, \\ \\ fd 'WsW d!o[- \\ Nry'uT7s/27 E \\ ? ?f% PROVIN G %v, GROUNDS EAST s i '242/435 0 M P E R 0 A I_. . 3 / 8 S W o/0 G SE ~ /28/ss ?, ARIZONA 2 3 SSW i2/24v SSE LEG E N D 8 s E 8/ /A g U NIN CORPOR ATCO PLA C E - --- 7 Blythe INCORPOR ATED PLACE PA3KE3 CE NSUS COU N TY OM 510N -- YUM A CO. COUNTY \\ NOTE: 1970/2020 SECTOR POPUL ATIONS O, 5 3 S C A LE - WI L E 5 mo F! CURE 2.1 f AfiEA WITHIN 10 MILES OF THE SITE o[p g~T F-2 i U[U 4 jl ;(d) , A i _a ~.T

A r s W 9 i,k

==a- . ~ v . seur. I l'?ajN

• y

.y - ;: e ia s

,

?.: :

.: 8 . :.,.,a +, 1 - 3.. =,, : : : .<, m d $ a, a..; 1., .0 3 i* s ~$' i 9', ms' -n+ ..n& inn mom D 0 i =.,..-e...m. co i j e,s _ T p lll 0 3 b c u J a F *?dQ, e h d oi M i d a Wd 6 4,hr:s.,s sp-w m,,,, U "I M@%.r-TJrovasseumsp'. l D%R D $, fs%. % 2 $,- 0. A,% T lEf7 4,.,. p,m m.,a, _ a, q, .. y. c g., m,.- f..>, ,. g

u. a

,,.; m..; g %,(',

1. ' l 'I 1m

-c YL., '\\ ' I. d 7 L3'4 f$' i IF3i - V' ' a eI d._ k' u*. U-) e u.a t,u ua'd ? t ) e 3 Q_ Jhp~,.C.' G 7 g. 54 - T7,'n{ i g3 my ~Q jp. ;..4 . am c..st u i * -~ . I y ds, 4J. L!j. A.n 4 *%; s. s, 77Q.A.,7 7 y. m hj p; il J M O gif,ybd d.$,Q n;m ,,,,5 g pe - 7r - g 's. ~~rqf;. I g ~ g,J

.3n

-Q- >p.,, s q. Dt1 ,I=neg cggl:"w=pciJ.39 k z ^ !A. 4 ,..,J S y '. g ;- Q-%

• ._ ' g;

+ w _.n. :.... _ __x.a_ e_7,';q;g[.,giE.C .........J..~:,.s 7-- g m. T ~ ~ 9 i C.. ' - ' Q '.n,(l'4 m.- a > y - -g., t g. j,,3 y y. + - - .u y , M)., ?., o .., ~ n- _p.- s s ',_,. :/... p w., . L_.__. , g,', ' <o ~ e ~ 3 %1 d m = 2- ~ ~ : ? / 'Su f an I. 1 s ~ gW,i, M' ), ] j.! .,L ) ,.s W. 1," / 8 > ::* 't f .w C} W 'p ! l l a, I. p,. o 0 f i l ,, qJc a ic 'f S 4 yr FJ ,t_ _ a W' I s E q L _ ___ / n ~, e,& j l\\ 3 );, j/ ' I< .,,' #' Q',. {-(- l y a

\\

y -s >q: p.,.4, %,a :.. w i. ~-- ~w e e ,...,, mi - 4:. :y y, 7~

t..;',-

'v~ ra& i p*t *.i ga h, ,f,, y. f ', l /# -/ ($ .3 5 i, e . 0 l ,. 5-1 .w;s '. fjg ;* E,';'o)g 'y !~j h;Q[,,,=5,l d f' k 's .v, ,jg,' f gj? j. :l ' ?? ] ' r .e -, j,.- 4 c., u m, A,. glo.,j /-4l #

• ly, { s'g '

e s .t f,m', a f p ' (

• G, $,,

j

w....

g,' c #< # 4 #s N;. &', && {p N T: g.,I ' .s a ~ ,?+ ?.Y.._,y;Irf } m/. h W L A I 'i W ':W's,' s,g : (, o.la.li ) e... 1. y,' . b,,.Q.'1 .lrv W:.(0.' s.& l [a s, I t, : y: f H, 37 r.? l+. d, }' '* },.. cY,,:fIW.") ','.,v $...'t? ' S ~n. y), L, 'Qh ^ x{<?, r , " J. Q j**., %' ', '* - - " u , ~.., Y* f

• ' ' "b.s,. fir J

('. $ Kj.,, av,

. - -g., ', %.j-V' 4, f.7-e -

% qe yL e ..y

• ~

+ 0s J %b .f [h,Y i ,U,QJ / (fa',',F n y, ' WY;3p +;\\ sS$0_:l$$f h)L' ' I ,f e,plf hm[._ _ waV m

.f Y

^ -i y'_- g' g - - ,r I l' ,3

• +

r' e 0 1 l v

The applicant has specified a low Dopulation zone of three ciles radius. The 1980 population within the three-mile low population zone is estimated by the applicant to be 18 persons. The 1980 population within five miles of the site is estimated to te 463 persons and within 10 niles is estirated to be 1,131 persons. Tre estimated cumu-lative population distribution within 50 miles of the site for the year 1930 is shown in Figure 2.3. The applicant states that the population center, as defined in 10 CFR Part 100, closest to the proposed site area 4ith a population of Fore than 25,000 persons, is tre city of Yuma, Arizona. The 1970 population of Yuna was 29,C07 and its location is approximately 50 miles south-southeast of the proposed site. Population projections' do not irdicate that any other area within 50 mile s of the site will attain a population etceeding 25,000 by the year 2020, the app'oximate end-of-plant life. Therefore, the distance fron the outer boundary of the three-mile low population zone prop 0 sed by the applicant is well in excess of the minimum population center distance of one-ana one-tnird times tne low population zone radius, as required by 10 CFR Part ICO. Two distinct types of transient population are attracted to the area within a SC mile radius of the proposed Sundesert site. The first type involves people pursuing recrea-tional activities who visit the area primorily during the winter season. The second type involves transient farm workers erployed en the area's irrigated farm lands. Major concentraticns of desert transient recreationists are located south, west, and east of the proposed site. Major concentraticns of river-oriented transient recrea-tionists occur along the Colorado River Valley extending north by northeast, to south by southeast f rcr the site. The section of the Colorado River Valley extending to tre southeast contains the largest fraction of transient recreationists. The estimated mean seasonal day recreational population within a 50-mile radius of the site is 4,'d2 for 1930 and 14.172 for 2020, the estimated end-of-plant life. During the lifetime cf the proposed plant, however, there are no known plans for recreational activities that would result in transient recreationists within the three-mile low population zone boundary. Agricultural areas within a 50-mile radius of the proposed Sundesert site contain more than 300,000 acres of irrigated f armlands The 1974 peak transient work force in the area w3s estir:ated to bc approxiTately 3,500. During the lifetime of the proposed plant, however, there are no known plans for agricultural activities that would result in transient agricultural workers within the three-mile low population zone boundary. In acccrdance with 10 CFR Part 100, offsite dases fron postulated design tisis accidents are to be calculated at the exclusien area and the low population zone on the bases of the site meteorology, recctor therral power level, and the safety features that are to be engineered into the ruc' ear power plant. Regulatcry Guide 1.4 " Assumption Used for Evaluating the Potential Padiological Consequences of a Loss-of-Coolant Accident for Pressurized Nater Reactors" specifies the allowable radiological consequences for the construction perrit review. Since the required information fcr the evaluation will rot be available until the Pre!iminary Safety Analysis Report is sJbmitted, we are unabla to ".onclude on these matters a t this time. ,1 i e a 24 _l 1.r ,>\\U >; 9 a

7 10 ,/ / / / / / / 6 10 j l ~ / 500 PEOPLE /SOUARE MILE / / / / / 0 / Qa 2 / / 5 10 m f 5 i / 30 / / / 4 10 9 - p - SUNDESERT 8 - 1 4 7 - 6 -f 5 - 4 - 3 - I l 1 3 10 10 20 30 49 5t, DISTANCE FROM PLANT, MILES FIGURE 2.3 CUMULATIVE POPULATION DISTRIBUTION (1980) 2-5 f 3.- n,,, r) 'a

_d

,i

Fowever, based on past experience, we have found t at a minimun exclusion area distance of 640 reters (0.4 mile), and a low population zone distance of 4000 reters (three miles), even with unfavorable atmospheric dispersion characteristics, usually trovides assdrance that engineered safety featurcs Can be provided to maintain Calculated doses from postulated accidents within the guidelines of 10 CFR Part 100. This will t,e verified during cur review ct the Preliminary Safety Analysis Peport when t'e design features of the plant are availatle. The practicability of evacuation, as an emergency protective moasure, of persons within dnd beyond the lCw poDulation zone is perforred during the review Cf the applicant's proposed emerlency plans. The emergency plans are evaluated to determine th3t they rueet the requirements of the Ccnnission's emergency planning critcria in Appendix E to 10 CFR Part 50. Since the propased er.ergency plans will not be available until the Prelimirary Saf ety Analysis Report is submitted, we are unable to conclude on this matter at this time. However, based on past ex;)erience, we have found that wpropriate emergency plans can te developed for the e mected [opulation levels in the vicinity of the site. The practicability of evacuation, as an eviergency protective r,easure, of persons within and beyon'. the low populat ion zone will be verified during our review of the proposed eme - gency plans af ter the Prelirinary Safety Analysis Peport is submitted. On the basis of the 10 CTR Part 100 def initions of the exclusion area, Icw population zone, and popuiation tenter, we conclude that exclusion are, low population zone, and ppulation center distances for the proposed Sundesert si te can r eet the requirerents of 10 CFR iart 100. The tCllowing dreas will be verified curing our review of the Preliminary Safety Analysis ?eport in order for us to cor.pleto our evaluation of site gec.)raphy and deFography. (1) The at:ility of the exclusion area t.oundary to meet the dose limitation guidelines of 10 CFR Part 100 in the m ent of a postulated accident. (2) The practicability of evacuation, as an erergency protective Imasure, of persons within and beyond the low ecpulation zone. - 2 Noa r by _I n du s_t r i a l, T ran synr tj_t i on_, and fi l_i t_a ry_ Fac i l i t i es There are no industrial f acilities, pipelires, railroads, or comercial or rilitary airports within five Liles of the site. The rearest of these facilities is an industrial area located in Ripley, 9.5 niles northeast of the site, a s"all airfield also in Riples, nine miles metho3st of the site; 3nd two 30-inch natural gas pipelines, rated at a preswre of 307 "ound; ;er squire inch, which parallel Interstate Highway 10 about 10.5 riles ncrth of the site. There is also a maller natural gas distribution lire, located one mile south 01 the two rajor lines, with a two-to-four inch varying 7/ h/ ~ .n n b b, r J N a' f $ {.) U 'l I

diameter and rated at a pressure of 30-40 pounds per square inch. There is a private airstrip about three miles northeast of the site on the Norton Ranch with two Cessna 411s based at this field. None of these facilities would have the potential for adversely affecting the safe operation of the proposed plant. There are six mines within five miles of the site: Coon Hollow Mine, a " rock-hound" mine located five miles west of the site; a sand and gravel quarry located four miles southeast of tue site, and a rock quarry locatad three miles north of the site, both operated by the Eureau of Reclamation; Roosevelt Mine, an inactive gold mine located 4.5 niles north by northeast of the site; and an inactive manganese mine located five miles south of the site. None of tnese mines would have the potential for adversely affecting the safe operation of the proposed pit.1 t The nearest Highway is California State Highway 78, a north-south two-lane .ad connecting Blythe and Brawley, located about 3.25 miles east of the site. because of the distance of this road to tne site, no type of transportation accident on the ro3d would have the potential for adversely affecting the safe operation of the proposed plant. The onlv major waterway near the site is the Colorado River, which is 5.5 miles south-east of the site at its closest point. The river is daared north of the site at Parker Dam and south of the site at Irperial Dam. No locks exist at these dams, and thus there is no commercial shipping on this portion of the river. Since there are no hazardous caterials transported on this section of the river, there would be no impact on the safe operation of the proposed plant. The airspace above the site vicinity may be conveniently divided into three general vertical levels: below 1,500 feet, between 1,500 and 18,000 feet, and above 18,000 feet. This airspace is virtually bounded, to the east and west by large areas restricted to military aviation, and by major east-west aerial routes that cross through the region over Blythe to the north and Yuma to the south. Within this area, airspace below 1,500 feet is currently used by local general aviation and military low level training routes. A Ifne connecting navigation aids operated by the Federal Aviation Administration near Blythe and Yuma passes 3.5 miles ecat of the site, and defines Federal Airway V135. Above 18,000 feet there is a traffic pattern associated with a military ba'a to the south of Yuma. The applicant has submitted an analysis, using an acceptable ethod of estimation, which concluded that the risk of aircraft impact from present traffic on the low level nilitary training routes, where they ire now located, is less than 4 x 10-8 er year per unit. By agreement between the Nuclear Regulatory Commission and the Department of Defense, however, a directise exists (Department of Defense, Flight Information Publi-cation, AP/lB) that such military trair.ing routes te rsted prior to reactor operation, such that th?y are clear of nuclear power plants. The clearance specified is suf ficient 50 that accident' that might occur involving aircraf t flying those routes could not credibly be etpectec to impact these plants. se J L. 2-7 n-p i-

Crashes are extremely rare for aircicf t while flying in traf fic separation scheres of Federal airwiys. Dorestic air carriers have accumlated only one occurrence of such an accideat in 2 x 10 revenne niles Miles flown by all other aircraf t in Federal airways is unknown, but we Ny take ten times the dorestic air Carrier crash rate as a conservative estiNte of the total Crash rate for all airnay traffic, which computes 0 to an accident rate of 5 x 10 er aircraft rile. If it is further assuned that 30,000 flights per year occur along Federal Airway Vi35 (about twice the current traf fic), and that crash irpacts are restricted to a ten-nile wide corrider, then an impact rate of 2 x 10 per year per unit is predicted for flights in this airway. Because of this s irpact rate, we ccrclude thet the propcsed site is suitable for the con;truction of a nuclear powe ula[t witnoJL the need for decial desiqn considera-tiens for postulated cc r ercial al traf t accidents in Federal Airway V135. About 1,400 military flights per yeir, sure fraction of which carry live ordnance, overfly the site a c altitudes in excess of 18,000 feet. Overall training missien loss rates fur aircraf t of the general tHe used in this traf fic are about 5 x 10 per mile. ' wever, a search of Department of Defense records for tre years 1965-1975 5 hows tha t m military crashes in the Yu a-Slythe ccrridor were recordad caring that period. Again assumirg a IU-rilt wide nrpact cert idur, the present traffic leads to an estinated irpact rate of 10 per year per unit fcr these military flights. The

enterline for this flight path, the Yura Marine Corps Air S+stion Standard Instru ent Departure, passes about cre nile trcr the prLpo5ed site.

"ence, it wo71d be ccrserva-tive to assume a one -ile wide ira t corridor, yieldin'; a conservative impact rate estin3te of 10 w r jear per unit for tre flights. The criteria to t'e satisfied for excluding, as a aesign basis, the cap 6bility to mitigate the consequences of a postu-lated accident involving a nuclear tower plart, are (1) an atticent f requercy of a bra t 10' per jear cer unit cr les', as dcter-ired by tre Ns t realis tic estirate available, and (2) Pn accident freq3pncy of less than abcut 10 " per year per unit, a s deterrined by conc 'ive estimates. As demonstr ated in thn absve analyses, the proposed site for t:. p., nt ~ eets these criteria f or military flight accidents. It shculd be noted that nilitary regalations, a;.plicable to an aircraf t in the Standard InstrLrent Departure flight path which t eca'e unairworthy, wculd require the pilot to direct the aircraft towards the Nutta Provina Grcands to tre east or toward the Cnocolate Mountain Gunrery P3nge to the west, prior to abandonnert. At an alti F de in excess of 18,000 feet, suf ficient glide f ath is available to perfcrn tnis rareuwer. Thoretore, both of the abose estirates tantain an additieral nrquartifiable consorvatism. We ccnclude that, with the c urrent "ili ta ry tra f fic es tima tes, t he propcsr d si te is stai table f or tne c ons tr,.Clinn o f ' nucle 3r power p l an t wi thCJ the need for speCidl design considerations for - il i ta rj ai rc ra f t in pa-t. To provido agains* ar y future thanges in nilitary asiatico rid cver tN service life of any plant at the proposed site, we will re mire that the applicant cbtain an agree"ent !ct " location of ' ' present Yva Mar 1re Corps Air Staticn Standard Instrurent Cecarture route rorth at Yura to assure that af ter a plar.t cn this site is ready for oceration, r3 aircraft carrying live nrdnanu will ov er fly wq t h10 five -iles of the site 2-8 y.- -n l ) s s~ /

The nature and extent of the other activitle, at nearby industrial, transportation, and military facilities have been evaluated and we ccnclude that currently, with regard to these consideraticns, there are not activities in the vicinity of tie Sundesert site which have the pctential for aMrsely af f ecting saf ety-related strut are_ of any nuclear pow"r plant whicn n'ay be prcposeJ for the Sundesert site nor which would require special design ccnsiderations for any plant proposed for tLr site. 2.1 Meteo_rclogy Information concerning the atmospheric dispersico characteristics of a proposed nuclear power plant site is required in order that a deterrination riay be rade that postulated accidental, as well as routine operational, releases of radio)ctive uterials are within Corrission guidelines. Furthermore, regional and local clin.atological information, incitiing extrenes of climate and severe weather occurrences which ray af f ect the safe design and siting of a nuclear plant at a proposed site, is required to assere that safety-related plart design and operating bases are within Cor:r,i5sion guidelines. The design basis meteorological characteristics of a proposed site are determired by the Corrission staf f's evaluation of r.eteorological infernation in accordance with the procedures presented in Sections 2.3.1 through 2.3.5 of the Standard Peview Plan. 2.3.1 P gional Petecrolooy The southeastern ccrner of California, which in;ludes the proposed site, is typified by a desert-type climate. Surrers are long and hct with af ternoon ;.erperatures aver 3ging 100 degrees Fahrenheit f ron June into september. thi st air f ro-' the Gul f of Lower California is drawn into the area resulting in higner Fumidities than wculd normally be expected to occur in a desert clim. ate. Winds from the south-southeast prevail du-irg the suser months and f rom the north-r.ortheast during the wirter ronths. Temperatures ray be expected to reach 30 degrees Fehrenheit or higher, on about 169 diys a year, 32 degrees Fahrenneit or lower on about tnree days a year and would not he expected to fall to zero during an average year. Arnual average relative hunidity is 30 percent-Local thunderston" activity is responsible for rest of the severe weather activity in this regian. No tornadoes were reported during the period 1955 through 1967 within a one degree latitude lengitude square containing the site. During the same time interval, storms with winds of 58 miles per hour or greater were Eeported on twa days The " fastest mile" wind speed reported at Yura, Arizona (about 50 miles south-southeast of the site) during the 24-year period ending in 1974 was EG r les per hour (August 1973). i Thunderstorms in Yuma nay be expected to occur on approxirrately seven days on an annual average. Climatic records indicate that icing is not a prcblem in this area. aEn l j

s) 2-9 l

t ,. r s j {j

Design and operating bases for tornadcs and sustained fastest mile wind speeds have not yet been determined for the Sundesert plant. We will require that these values be provided in the Preliminary Safety Analysis Report. 2.3.2 Local Meteorolon Long-term weather records f rom Yuma, Arizona, show that an extreme maximum temperature of 116 degrees Fahrenheit occurred in June 1974 and an extreme minimum temperature of 24 degrees Fahrenheit occurred in January 1971. Annual temperature extremes of 123 degrees Fahrenheit (September 1970) and 22 degrees Fahrenheit (January 1937) have been recorded elsewhere in the site area. Maxirrum 24-hour precipitation, totalling 2.42 inches, was recorded at Yuma in September 1963. For other areas in the locality of the site, a 24-hour maxirwm precipitation of 4.01 inches was reported in August 1909. Maximum 24-hour snowf all recorded in Yuma is a trace. The area has an avetrage of one day a year with heavy fog tvisibility reduced to one-fourth mile or less). Wind data collected at the 33-foot level of the ensite meteorological tower during the period of June to November 1975 show predominant wind flow was from the southwest with a f requency of 13 percent. Winds from the east-southeast were least frequent, occurring 2,5 percent of the time during that period. 2.3.3 Onsite Meteorological Measurements Program The onsite meteorological tower for the Sundesert site became operational in June 1975. Measurements have and are being made from e instrumented 260-foot high tower. Wind speed and direction are measured at the 33-foot, 190-foot, and 260-foot levels on the tower. The vertical temperature gradients are determined by v asurerents between the 33-fott and 190-foot levels, and between the 33-foot and 260-foot levels The dew point is measured at the 33-foot level. The meteorological measurements program conforms to the recorrendations of Pegulatory Guide 1.23, "Onsite Meteorological Programs." The applicant has provided six months of onsite data for the period of June 1, 1975 t hrough November 30, 1975. We will require that the applicant provide one full year of representative onsite meteorological data, with at least a 90 percent recovery for each set of data, in the Preliminary Safety Aralysis Report. 2.3.4 Diffusion Estimates A preliminary analysis was conducted of the onsite data submitted for the period June 1, 1975 through November 30, 1975, using a straight-line Gaussian mndel and desert dispersic1 parameters. This evaluation indicated that dispersion at the Sundesert site, during the indicated six month period, is comparable to another site in the area (Palo Verde Nuclear Generating Station, Units 1-3, Docket Nos. STn' 50-523, STN 50-529 and STN 50-530) which has previously been evaluated. However, data in the Sundesert analysis included or.ly two seasons, winter and spring, when dispersion is 2-10 _- 7 j. .77 ,,J 'Jl s

expected tc be relatively good at the site. 'rerefore, we will roev31u3.te the site dispersion characteristics w v n a tJll year of re; res(ntative onsite retecrclogical data is sub-itted wit h the Prelinirary Saf ety Analysis Report. 2.3.5 Cceclu M ns based un our revlea of the retcorological inf orr a tion preser.ted tj t t e applicar.t. we conclude tr at the r etcorologj for the arci will not preclude a fasorable finding with regard to ito suitability. We alsa ancluje that t he onsite reteoro ogical l measuren ents pre ;rar, t eing conducted in a ranra r that is consistrnt with the recomendatiens of Pe9ulatnry Gaide 1.33. The follcaing addition 31 inforrvnion will be revi N ed during the review of the Frelinirary Saf ety Anaiysis F( port to covlete our evaluaticn of W site meteorology: s anj " fastest mile" wind speeds for the (1) Design and operatirg tase< fo r t o re s Sundesert plan? site based on one full year of representative (2) 01ftusion t_stinates 'or tr o cnsite data. 2.4 Hj d r_o l_ojy 2 2.1 Hydroloaic Description i h. proposed site for t he Surdesert 7,uclea r Plant is located approximately 5.5 niles west of the Cclorado River cn the Jalo Wrde W sa overlooking the Colcrado River flood Plain knowr, lecelly as tre Palo Verde Valley. The proposed plant grade will be a[proxiNtely 375 feet atuve rean sea level. The Colorado River in the vicinity of the sita is atout 1 R 6 et belcw the pre;;csed plant grade. The site is located within the Colorado Iiver crain3ge basin of which approximately 182,000 scsare.iles are upstream of tFe site. Numerous drs for nater supply, irrly tion, cc er and flood contral are located upstrea of the site. The tt largest ard ret significant ores are Glen Canycn 03o and Hoover Can. Colorado Risce water belcw No',er Car,s cc itted to water users in Southern California, Arizona a+J " nico. Diversions are presently rade at Farker C ra, Headgate Pock Dam, Palo Verde Car, Pperial Da, and Moreles Dam Major fut = diversions are planned fer the U.S. Euren of Recla ation's Central Arizona Prc ect. s The loca 7.5 square-mile drair. age basin, within the Colorado River drainage basin, to the west and upstrear cf the site is characteristic of desert area tasins. It consists of very steep, t,arren ncuntains with rany canjons terninating in alluvial fans. IMse f ans tnen rergo form rg a bajada that is crossed with neercus dry channels Tne pecposed site, located abo;t 'ive miles from the %Ie Mountains, is on this alluvial plain and is c rossed by 'aj dis tritatary channel s .,>s - n l 2 li (. ' e G

The site is subject to flooding erigir.ating in *he local 7.5 square-mile drainage basin. Although there are no records of floods at the site, records for similar d rea s in the so Jlhw",t show that they are subject to rare but very intense precipitation that causes flooding. However, it is not unusual for several years to gu by without any runoff. Groundwater at the site is directly related to the Colorado River level. The water table has been lowered only in the area of intense well developr+nt to the north on the Palo Verde Mesa (northwest of the toan of Slythe, California). 2.4.2 F l orid. Po.t en t i a l The applicant has cvaluated th" flood potential at the site due M (!) penulai.ed dan failures, (2) t he ;'robabie ma ximum flood cn the Colorado River, and (3) the probable maxinun pr"cipitation on the local drainage basin. Alttough tr ere are n;Terous dams upstreem of the proposed Sundesert site, there are only two rajor structures whose failure could adversely affect the plmnt. These are Glen Canyon Dam, located near the Arizona-Utah border about 500 miles upstrean, and Hoover La located anout 150 miles to the north on the Arizona-Nevada border. The applicant cchcludes that plant grade at the site will be above the maxirum water level that could be reached by the f ailure of any of the dans on the Colorado River, including the Glen Carjon and Hoover Dar>, tecaus+. the site i', about 150 feet above the flood plain for these postulateJ failures, and because of the large an'ount of storage available in the flood plain. We have perf urned an inde;,endent water level c ar-pu ta t i o n f ur these postulated f ailures and concur with the applicant's conclusion. The applicant his also evalu tted the ef fccts of a probable ruximum flood on the Colorado River anJ has concluded that such a flood woulo not result in the design basis flood level for the proposed site. We concur with the applicant's conclusion sin ( o the flood control storage available for the Colorado River wuuld reduce the probable raximum flood dischirge to a value that is less than the discharge that would result f ecm a postulate l da-f ailure. The applicant has determined the probable ra;iirum precipitation on the local drainage t.asin using the c ettods defired by the National Oceanic and Atr,ospheric Administratir1 in " Probable Marirum lhunderstorn Estirates for the Southwest States ' The applicant then used this protable maximum precipitation to calculate that the runof f f roni the local dralrage basin cnJld reach 33,000 cubic feet per second. We have performed an independrnt aralysis of this postulated event and concur with the applicant's value of est ic ated runof f f rom the local drainage basin. s concludc that the probable mairum flood analysis for the site meets the recorrenda-tions of Regulatory Guide 1.59, " Design Basis floods for Ibclear Power Plants." h ver, the au,iicant has not yet determined the nethod of protection for tne proposed 2-12 _.' ) r-() O 'J / vQ ,1r 7 i Jwl i

plant f ron the rurof f that would result f ror the probable ruimum precipitation on the local draina je bcisin. We will %f re that this inforration t'e provided in the Frelimina y Safc ty Analysis Ecport Uc will evaluate both uie ano.p '. level reniting f rom this postulated flood and the proposed flood protection for the site d;rin i cur review of the Preliminary Safety Analysis Report. 2.4.3 Coolig Waj er Althcugh 'he plant cooling w3ter requirements have not been finalized, tt e applicant est " *, that approxirately 17,000 acre-feet per year will t;e used f or each unit. The applicant prcroses to supply the approximately 17,000 acre-feet per ycar for Unit No.1 (an average flow of 23.5 cubic feet per second) with irrigaticn return nater, which is relatively high in salt content, from the Palo Verde Irriqation Ulstrict's outtall drain by pu" ping it up to the site. This water is the recainder of irrig3 tion water ottatrma up,<, car f mm the Colorado River and which would te returned to the Colorado River downstream In order to raintain tre wote, aii m pt fcr the Jawnttrca: users, the applicant has acquired 17,000 acre-f eet per year from the Metropolitan Witer District of Southern Calif ornia', allotrent to the California coastal plain which it obtains via the Colorado River aqueduct. Instead of actually acquiring it, this amount of additioral water, having a lower salt content th3n the irrigation return water, will be allowed to pa s, through Parker Can do n the Colorada Piver. For Unit No. 2, '.he applicant proposes to reduce tr e irrigation allotrent of the appllCdnt'" farn lands v.ithin the Edlo.erde Irrigation CistrlCt by a sufficient amont to provide the 17,C00 acre-feet per year needed for nakeup. The applicant e tates that thc plant rakeup water syste, including the proposed purping f acilitle* in the Colorado River flond plain, will not be saf ety-related. 2.4.0 Lew Water Con *,iderations Makeup water for norNI plant o;; ration and cooldcwn will be supplied from the Colorado Ri ver. The ability to safely shutdcan tre plant is not related to the probable minir un flow rate and leul resultirg from the nast severe drought en the Colorado River since the ultimate heat sirk design will ret rely on this cource of water during postulated accident. However, tha applicant nas not yet defined the ultimate heat stra design for the proposed olant. As a result, an evaluation of tre ability of the ultimate heat sink design to provide adequate cooling for a r-inimur of 30 days under the c ost severe environr' ental corditions has not been perforred. We will require that this analysis be included in the Preliminary Safety Analysis Report. 2.4.5 G roo r dwa te r. The witer table at the site is directly related to the Colorado River, unich is approximately 150 feet telcw the surface. The only areas of "xtensive groundwater 2-13 - 3 p D,' i i O 't r-t oc Y

use are rear Blythe, where dcrestic water is d+> rived f rom wells, and on the Palo ..v e u me n u t o!ytr e, wrer e ea tei,sive use is me et wells ter _,..s irrigation. The nearest irrigation well to the site is r,n the Palo Verde Mosa about 10 riles to t ht nortn. ine nearest curestic well 15 three riles east of the site ir the tcwn of Palo Verde. The evaluation of the res altant contagination of ground or surf ace water due to postulated accidental releises of liquid effluents from the plant will be performed during our review of the Prelinirary Lafety Analysis Peport when the design f eatures of the plant are available. % ever, w. >>pect that the resultant contamination from t hese releases would be t elow 10 CFR Part 20 limits t.ecause (1) the existing ground 'a ter le vel is about 150 feet t;elow the surface, (J) the nearest dw.estic well is U, e:e miles f rom he site, and (3) the nearest downitream surf ace water user (irrperial Dam) is about LO niles away. 2.4.6 Conclusions Based on our review of the hydrological inforration presented by the applicant, we corclude that, subject to establishirg the requirer ents for th? ultimate heat sirk, the hydrology for the area will net preclude a f avorable finding with regard to site suitability. We also cerclude that the p rota bl e r'a x i n um flood analysis for the site reets th recomendatient of Regulatory Guide 1.53. The followirg additicnal i n f o rr.a - tion will b( revicwed during the review of the Preliminary Saf ety Analysis Report in order inr us to complete our evaluation uf the site hydrology: (1) The proposeJ flood protection fer the site f rcr: the rtnoff that would result from the prcbable maximum pncipitation on the local 7.5 square-r.ile drainage basin. (2) The ability of tM ulti~ ate teat sirk dasign to provide ade wate cooling for 30 days under t he "os t se vere envi ronr enta l condi ticns (3) The resultant conta-iration of crcund er surf ace water due ta postulated accidental releases of liquid ef fluents. 2.5 Geology and Seismology Our review of the Surdesert Early Site Review Repcrt addressed tre safety-related geo;ogic aspects of the proposed site, including the geologic histcry of tte region through analysis of physiogsphic, lithologic, stratigrauhic and tectonic settings, and the subregioral and site specific goology and seismology, and seisnic design basis. In addition to reviewing data subm.tted by the applicant, wa visited the site and its ensirons on three occasions During those visits we exatired the regional geology, tedrock exposures, and excava'M + recc % c b c-31 o conferred with local geologists, the applicant's consultants, Pologists from the California Division of m - 2-la s 'J ,u "? 1 g sl

Mines and Geology, and with our advisors, the U.S. Geological Survey. The U.S. The rain Geological Survey evaluation is attached as Appendix B to this report. ef fort in reviewing this site was to resolve specific site and regional geological and seitnological issues which could pose a potential hazard to the safe operation of a nuclear power plant at this location ond/or impacted on the seisaic design for the proposed plant. These issues were (1) capability of several subregional faults, (2) potential for local surfar.e faulting, (3) definition of regional tectonic environrent of the site, and (4) determination of the safe shutdown earthquake. 2.5.1 Regional Geology The Sundesert site is located in the Sonoran Desert subprovince of the Basin and Range geologic and physiographic provin.e. Basin and R6nge type structural geology and the San Andreas fault ystem (including subparallel major fault zones with similar characteristics) provide the distinguishing geolegic characteristics of site region. Within 200 miles of the site are located parts of the Great Basin and Mexican Highlands Transition zone subprovinces and parts of the Colorado River Plateau, Saltnn Trough-Gulf of California, Peninsula Ranges, and Transverse Ranges provinces The Sonoran Desert province includes the Mojave Desert of California and the Gila Desert of northwestern Mexico. This province is characterized by subdued rountain rangos, usually less than 4000 feet in elevation, trending nurthwest, north and northeast. This subdued relief suggests a relatively stable crust. The Basin and Range geologic province was involved in several orogenic events ranging in age f rom Precambrian to Tertiary. The most rECent diastrophism to affect the 5ite region was the Laramaide orogeny which began in late Cretaceous and continued into Tertiary time. A good description of the orogeny during the Tertiary time is presented by the applicant on pages 2.5-46 and 2.5-47 of the Early Site Review Report under the heading Late Tertiary. Igneous activity, including volcanism and plutonism, was widespread in the Sonoran Desert and Mexican Highland-Transition Zcre during the Mesozoic. Volcanism occurred in the Central Sonoran Desert Region, the Western Mojave, the Colorado Plateau, and the Salton Trough during Quaternary tine. Continued crustal spreading along the San Andreas fault system is evidenced by extensive Quaternary and Holocene f ault displacement which can be related to rovement of the Pacific Plate relative to the North American Plate. The San Andreas fault system is the tectonic first order feature in Western North America. The closest approach of tnis system to the site is approximately 40 miles. The San Jacinto, Whittier, Elsinore, Garlo;k, and the Death Vailey-furnace Creek fault zones are approximately 75, E0,170, and 200 miles, respectively, from the site. Quaternary deformation is coatinuing in sore areas of the site region. As a result, a numter of active fault zones can be found in the region. All of the active faults within the 200 miles radius of the site are not discussed here due to the dominant influence of the San Andreas fault zone and sore smaller t aults closer to the site on the deternination of the safe shutdown earthquake. kln,0U q 2-15

1. lE l

l t u av

The r;eologic evolutien 31 d tectonic irplications of the San fodreas f ault syster have been discussed estrosivel v by rany autt ors In trese discussions, tnly its relation-ship to the site aroa is addressed. Iho San Andreas faul t syster is a; prox ima tel y 100 r iles lung and es tends f rom tP 9 N @ ciro Escarpu nt to the Ca f of California. in Central California, the feult is basically a single, linear break displaying richt lateral strib e-slip displace ent. Further to the southeast, tre San Andreas fault br> several clerent> Still further to tre scuth, the San Andreas zone aLprors to torninate. As tr e aLplicant dc scritzcs, " At the south erd of the Salton Sea, tre San Andreas f ault appear s to te rnirate at an actis spreading center, transferring ration within tre Sin AnJreas sy ste" to t he Irrerial ard San Jacinto f aul ts. Although the %n J Hill; and Al ;odones faalts lie alcing tFe projection of tte San Andreas ' t scultea tward from the Salten Sea, they do ro. appear to te active ele ents of tho rescnt San Tadreas faslt syster. A #evcr, the applicant nas con-servatively assad tre Sand Hill fa21t to be the eler. tnt of the can Ardre as f a;1 t system clou st to the site. Nurorcus < 7111 t al t s wore f ound in the site region. Tte applicant cond;cted an intensive Wog;c lnwstig ttian of ill such features which were identified. None of the faults within E O "' i l o, of t Fe site, with tre exception of tFose of the San Andre n f ault syster, b n e bcen a ucc ia ted wi th hi s toric sei s".ici t y, al th%gh scr e show geologic e,idt ece vf fjuaterrary diepia:+ rent. Tre fFuckwalla Pourtair, Salton Creek and Sheep t' ale f aul t; and ttc Blythe Gr aten are considered ta te capabie faults In addition to t%e fdJlts, "Aien51se inVestinations were Ccrddied by the arplicant along tre Lc t Tri p fault and in tre Crocolate Mcuntairs wnich lie adjacer.t to and r:crthej;t of the Salton trough and San Andrels f ault tor t The Chr6 walla N untiin f wlts trced nort N est for several riles. The closest approach of tre faults ta the sit" is about : s riles ar d they are i antified primarily as linears which parallel c tror drairages. Cre of tFe lirears aligns with an east-west trending f L it which juxta;o irderated Iertiary densits with interbedded e clay, silt, and sand dercsit, 0.erlying vo.nger alluvial fan surfaces and deposits ap; ear un disturt ed, but field rclaticm hips are not definitive cncugh to preclufo Quaterrary faultinc Tre east-west trerding Salton Cre"E fault separates the Orocopi) Mountains frc~ the Crocolate tantairs a t i s marked t'y a r ajor c hacq_ i rl geol ogy t et.voen the two areas. Icrtiary allusial deposits are ofIset by tre fault e,nich has a rs;ed length of 12 nilm and is located 38 miles frcn the site, TFe Sheep Hole fault, whico trends rortreast along the Geep Fsle Mountains, disrupts 'uaternary formtice E3 tension of this fault to the scutheast is based on gravity data. f4 few earthc 1Les have boen located near tre rcrthern end of this fault. It> length is abeut 40 miles and it> close>t apcroach to the site is 41 miles ihe Blytt e Gruaen is a set of two parallel normal f aults s;: aced about 300 feet apart. It is a srall arcuate si.ructure which strikes approxinately northwest, tas a 4 j ,d I 2-16 r, \\,I-) e y

traceable length of 3-l/2 miles, and is 22 riles northeast of the site. The faults of the Graben of f set Quaternary units and last novertnts nost likely occurred t.etween 6,0% and 3';,000 vears ago. At present, t!e grabe' can be seea as a topographic depression in the alluvial surface. This structure is located to the scuthwest of the Big Maria Mountains and on strike with the gereral trend of the structural front of both the Big Naria and Little Mria rountains. The Blytne Graben coincides with a steep gravity gradient along the Lit tie Maria and Big Maria ro;ntains. Altncugh available data are in uequato to establish a direct structural relatienship tetween the gravity gradient and the Blythe Graben, the coincidence of stribe and locaticn recuire that it be assur.ed that such a relationship r.ists This gradient and another pacallel to it, about f our and a hal f to seven miles southeast of it (22 and 15 miler respectively f ron the site), are interpreted as faults with iarge vertical separatien. These faults would delineate a ncrthwest treniin] subsurf ace basin approxirately coincident with McCoy w3sh. To t M south"ast in the Done Pock Mountains (approximately 30 niles frun the site) are several nert%est-trending f aul ts which indicate separation up to two niles. These faults do rat appear to disturb Plio Pleistocene alluvial fan uterials The steep gravity gradients noted in McCoy wash do not cut tne dome Pack roantains. To the northweit, faulting was observed coly in the older Tertiary f analonerate, ba(ed field reconnaissance and inspection of aerial photogra;.hs of the r'alen P3ss area, on tat r.o capable f aulting was found. The Lost Trigo fault zare.s a zone approxim tely 1,000 to 2,000 feet wida containing nu+erous call f aul ts, so.e of which are en echelon and others indicatin) dips both to tN east and wost. This zone nas a ;eneral i crth-south strike, ha3 been traced f or seven and a half r iles ard is located 15 miles scutreast of the proposed Sundesert site along the western rargin of the Dore Pock re.ntains. Geologic evidence indicated that this feult is not capable. The fault e goied in Hart Mine wash offsets the Pliocene Scas> Forr.ation, 1 Plio-Pleistocene alluvial fan d" posit, and a Plio-Pleistocene fluvial dsosit tut is crosscut by an alluvial fan deposit which is ridJ1e Pleistecene in age (estinated to be 510,000 to 1,C00,000 yea rs old). The Chocolate Mountains of Califcrnia are irrediately adjacent to and east of the Irterial valley-Salton Trough and San W roas Fault Systen. To tra north ar d south of this rang' are the Orocopia and Cargo L craco Ma ntains, re vectively. Previous rapping of this area, the Salton Sea Sheet, Geologic Map of California (Jennings, 1967) and the Prelirnnary Fault and Geolugic M3p of California (Jennings,19t7) traicateo th( preserce of n eerous northwtst-souttwost and sore east-wes+ t rend i n; faults S o m, of tre northwesterly trending f aults were inferred to tm continuous for tens of k ilor+ters Sone flults were shoan to ef f u t Quaterniry units Eecauso of the presi ity to tbg 9n f M reas tault syst ", the pcta1cial existerce n f a l a r';e throughgoin] northwest trendir:q faalt ohitn might be d: ectly related to the San Andreas syste and closer to the site than the % nd H1 ls fault, w3s assetsed. 1 ;r qr,, 2-17 I \\ b 9

The genlogy of the Chocolate Mountains is not well known partly due to limitations on ground and aerial access to large areas of the Chocolate Mountain Aerial Gunnery Range, which is an active military practice range. In order to cbtain more detailed mapping of this area, the applicant undertook a reconnaissance geologic mapping study utiliz.ng newly acquired Landsat iriagery and black and white aerial photographs. This reconnaissance study was supplemented by ground field checks and extensive consultation with numerous experts cn the geo!ogy of this rer11on. As a result, the applicant has been able to generate a new updated map of this area. As a result of our review of this updated mapping, we conclude that the northwest trending Tertiary or Q;aternay f aults in the Chocolate Mountains region southeast of the Salton Creek fault are discontir uous structures which cannot be directly related to the presently active San Andreas fault zone. Althouq~ there is evidence for the existence of sor"e small capable faults along Salton Crcek and on the western flank of the Chocolate Mountains, they have no influence on the determination of the safe shutdown earthquake or the Sundesert site. 2.5.2 Tec tonic Province and Regonal Tectonics The proposed Sundesert site is located in the Basin and Range tectonic province. As described by Eardley (1962), this province is characterized by an extensional stress regime which has resulted in block faulting with the rountains and intervening alluvium-filled valleys correspor. ding to up-lifted and down-dropped blocks respective-ly, ihroughout nach of the province, the faults wnich mark the tourdary between the up-lif ted and dcwn-dropped blocks are now buried under alluvium eroded f ron the receding rountain f ronts which rakes their identification dif ficult. The rain tectonic event responsible for the development of the Basin and Range struc-ture began in niddle-Miocene time and continued into Pleistocene time (Eardley, 1962). However, a tensiond stress regime corducive to strike-slip and/or normal faulting 3p;'arently persists to the present time in some parts of the province. The Sonoran Desert region of the Basin and Range province, in which the Stadesert site is located, is characterized by broad and deep alluvial valleys and low-altitude nountains which are ccrsidered to be evidence that the 3rea has experienced relatively little orogenic E tivity since the earlier stages of Basin and Range development. Northwest-trending right-lateral strike-slip deformation and northebt-ti ending lef t-lateral strike-slip deforration appear to be present in rany parts of the western and southern portions of the Basin and Range province. Most of this deformation was apparently initiated in Mtorene time and is conterpuraneous with the tectonic activity generally thought to be responsible for the formation of the typical Basin and Range structural pattern (Hamilton and Mjers,1956). A limited numt>er of earthquake focal rechanism, displacements observed in historical surface faulting and observations of strain accumlation indicate that the present stress regime in the western and scathern portions of the Basin and Range province correrponds to extension oriented northwest-southeast to east-west. g W s 2-18 .I (V / {,

If strike-slip faulting is the dominant rode of tectonic activity in tte western and southern portions of the Basin and Range province, recent f aulting could be nore dif ficult to recognize tu n if norral faulting is dominant. Fowever, if dip-slip displacerent accompanies strike-slip covement, as is expected for nost f aults in the region, recogni-tion of recent f aulting would be facilitated. Several faults have been identified by geologic investigation in the general vicinity of the site. As discussed in Section 2.5.1 of this repnrt, soc.e of these f aults, such as the Chuckwalla Mountain fault, the Salton Creek fault, and the Blythe Graben, show geolcgic evidence of Quaternary f ault displacement which is regarded as indicative that these faults are capable. Ho wver, the Chuckwalla Mountain fault, Salton Creek 'ault, and Blythe GraLen are not reccgnized to have associated seismicity. The nearest of these f aults to the Sundesert site is the Blythe Graben approximately 22 miles north of the site. West and southwest of the site the tectonics are more strictly controlled by the interaction between the Pacific and North American plates. This interaction rainly is represented by right-lateral strike-slip neverent along faults in the San Andreas f ault systen, associated high seismicity, and relatively recent (Quaternce") surface displacenent. The southeast portion of the San Andreas fault system, where the fault systen has its closest approach to the Sundesert sitt, splays into several strands which are in rest areas buried under tnick alluvium in the Salton Trough. As noted in Section 2.5.1 of this report, the ar-licant has indicated that the San Andreas fault appears to terrinate in an active spreading center at the south end of tne Salton Sea which transfers motic.i within the system to " ore active strands further west in the Salton Trough. This spreading tenter would align with, and represents a ccntinuation of, a series of such centers linked by transform f aults which have been described further south in the Gulf of California (Atwater, 1970 and Anderson,1971). The existence of a spreading center and nultiple stranding of the San Andreas fault system in the Salton Trcugh tend to distinguish this region from areas further to the northwest where rost activity is confined to a ruch narrower zone and where the largest earthquakes have occurred. Within and bounding the Salten Trough, several northwest trending fault strands are recognized including principally the Irperial, Calipatria, Brawley, Superstition Mountain Superstit'un Hills, anJ San Jacir,to f aults ard, closer to the site, the 54 Andreas, Algodones, and Sand Hills faults Based on seitmicity, the nost active of these appear to be the San Jacinto fault ard the Ir:perial fault. Northwest of the site, the Mojave Blcck is identified as an area bounded by the Garlock fault, part of the San Andreas f ault, the eastern Transverse Panges, and on the east by a less well-def ired boundary, tre Soda-Avawatz f aul t zore (Gu f unkel,1974). The Mojave Block includes several northwest-trending, right-lateral, strike-slip faults which have undergone displacement in Quaternary tine, such as the Pelendale fault, the Lockhart f aul t, the Lerwood f aul t, the Car.p Rock faul t, the West Calico fault, the Pisgah fault, and the Blackwater fault. fhese faults apparently do not represent through-going struc-tu es and do rot extend beyond the boundaries of the Mo p ve Block. Garfunkel (1974) .,r l ~ - 'p u

suggested that this f aulting has been produced by a distortion of the overall shape of the Mojave Block to accorrodate latcral variations in crustal spreading betneen the area tast anJ the area soutnwest of the Mojave Block. Because seismicity and faulting in the Mojave Blcck is lower in m.agnitude and rate of activity than in the San Andreas fault system, and because the Mojave Block cones no closer to the site than the 5ar. Andreas f ault system, the larjest earthquakes associated with the San Andreas fault system are expected to produce !arger ground motions at the site than earthqu3kes in the Mojave Block. 2.5.3 Site Geology The proposed site is located in the western part of the Palo Verde Valley on the Palo Verde Mesa west of the Colorado River in Eastern California. The site is flanked on the weit by the Pule Mountains, to the south by the Palo Verde Mountains, ano on the east by the Colorado River and the Dor.e Rock Mountains To the north of the site is the continuation of the Palo Verde Valley and Pesa. In the site area (five mile radius), the Palo Verde Mesa is composed of a series of broad, gently sloping alluvial fans and fluvial terrates which slope 40 feet per mile to the east. The proposed site is situated on an alluvial fan surf ace and partly on a flat surface of the 70-fuut terrace, one of two terraces above the present Colorado River level. A north-south trending linear wash exists along the Febble Terrace part of the Palo Verde Mesa. Feconnaissance geologic rupping by the Califcrnia Division of Mines and Geology noted this lineation as a fault, but trenchirg of this feature revealed un-disturbed sedirentary stra'a across tne trerd of the lineation. The lireation is due to a dif ference in erosion rate of the fluvial raterial and, therefore, is not a f ault. The section unJorlying the site has teen inve >tigated direc tly by boi ings and surf ace mapping and indircctly to basement rock, by gravity and nagnetic analyses, by seismic ref raction and by projections of units f rom surf ace rapping. lhe subsurface investi-gation program included Si drill holes with depths f rom 140 f eet to 900 fe et. Thirty-four of these drill holes were used for geological investigation while the others were used for foundation engineering assessment. Subsurface continuity of strata w)s based on correlation of drill logs and geephysical data, such as radiaticn logging, resistivity and potential reasuremerts. The section beneath the site area consists of C etaceous plutonic and netarerphic baseren' rocks, overlain by Tertiary volcanic and f anglomeratic beJrock. These units are oveilain by the Couse forr.ation which is a P;iocene Marine sad 1 rent. Surficial deposits 6t the sitt are Pliccene-Pleistocene alluvial deposits of the Colorado River, s.nl Polocene alluvial and fluvial deposits and enlian sands Structure contour ard isopach raus de esoped f or the site area did not indicate the presence of any faulted stratigraphic units. Good correlations can be rad < in the site area using seven units, a silt lens, and four intra-unit clay horizons To the east rf.d avutheast, correlation beco"es nere di f f nuit as the alluvial f aq pinches r 2-20 / 'l 3 J JJ J ,f[ d/l a gi

out. Lateral variation within the units is corron even over shcrt distances so correlation of detailed sub-units is not feas1 Die. Elevation charges are to be roted but no consistent anomalies are Evident. The applicant's seismic ref raction survey, and gravity and nagnetic surveye indicated no evidence of ' alting. Displacoment of sediments caused by vertical or lateral 'aulting could create sharp breaks or discontinuities to appear on the profiles, isonetric drawings, and structure contour and isopach maps. The absence of such discontinuities is strong supportive evidence that there is no faulting beneath the site. No evidence of ground subsidence has been noted in 'te site area. lhere is no petroleum extraction and no mining activity or other man r J e activities which would have any effect on the site. 2.5.4 Surf ace faul t'n3 We have found no evidence to indicate that a potential exists for surface faulting at the site. The closest known capable fault is the Blythe Graben which is located 22 miles from the site and is discussed in Section 2.5.1 of this report. 2.5.5 Regional Seisnicity The Sundesert site is located in an arca of the Basin and Range province which apparer,tly has experienced a relatively low leval of historica' seismic activity. It must be recognized, hov.ever, that the historical record in this area is short cor: pared tu most areas of the United States, arJ that the population density in much of tne Sonoran Desort area has historically been very low and remains low. A limited instru-rental detection capability tcr earthquakes in this area has t xisted since the earliest seismograph stations were established in svuthern Califorr ia in the late 1920's. The applicant estimates that the instrumented detection threshold since 1945, for earthquakes with epicenters in tnis a ma, is about magnitude 4. (The size of earthquakes in the Western United States is typically classified by the units of magnitude nn the Richter scale.) This detecticn and location capability has improved sub>tantially in the past few years with ir.sta s iation of a dense seismograph networn in the eastern Mojave desert, such that the current threshold level in the area is estimated to be as low as Dagnitude l.0. Much of the earthquake activity in the Basin and Range province is contentrated r. ear its eastern and western margins as evidenced by the earthquake epicenters along the Wasatch Front and those in western Nevada and extending southward into California jest to the east of the Sierra Nevada batholith. Comparable zones of high seismicity are rot apparent in tt e southern po-tion of the Basin and Range province in which the site is located. Excl sive of the Fort Yuma earth-quake, which is discussed in detail below, the earthquake reported nearest to the site occurred in 1943 about 30 miles southwest of the site and has an estimated ragnitude fron 4 to 4.5. The earthq;akes reported rearest to the site, which are of ragnituS 6 and greater, were associated with the San Andreas f ault system which ncroaches the site no closer than 35 mile 2. The largest earthquake in the historical record associated with c- ~! 2-21 l \\v JU ]/ j r {3 ( ; 's

these southern splays of the San Andre 3s fault systen was the Imperial Valley earthquake c.f 1940, which had a nagnitude of 7.' and occurred on the Irperial fault approximately 60 miles southwest of the site. During the course of our review, several questions were raised regarding an earthquake which occurred in the vicinity of Fort Yuma in 1852. Because this earthquake occurred so early in the history of southern Califcrnia at a time when the area was virtually unde-veloped, detailed information regarding this earthquake was not easily attainable. The main questions raised were with regard to the date, location, and structural association of the Fort Yu'ra earthquake, Conflicting reports regarding these points exist in the published accounts for this earthquake. lnis is a problem which is generally encountered when one attempts to obtain information aDout earthquabes which occurred in a region prior to or during its early development. Specific informaticn to unequivocally deter-mine the location of such an earthquake and demonstrate its structural association is usually not available. In this case, the applicant ccndJcted a careful literature search and was able to identify the primary sources for the published report; on this earthquake. These sources consisted of diaries kept by te military of ficer; stationed at Fort Yuma, a report published in 1861 on the Colorado River expediticn of 1857 and 1858 (Ives,1861), and two newspaper accounts of ef fects felt at large distances In addition to the literature search on the Fort Yuma earthquake, the applicant investigated reports of sirilar nhenonena observed during more recent earthquakes in this area of the San Ardreas fault systen, such as tho 1940 Imperial Valley earthquake, two earthquakes in 191b and one in 1934 located in the Salton Trough. The applicant aryd that geyser activity, g-ound cracktrg and lique-faction, which occurred southwest of Fort Yuna during the 1852 earthquake, should be regarded as the primary indicatcr of proximity to the epicenter. The anDlicant further contended that the roc k f all at Chin ney Feak (Picacho Feak ), which occurred at the tire of the earthquake, should be discounted tecause tha ec:thered condition of the Peak rade it susceptible to rock falls at relatively icw levels of notion. As a resu't of e lysis of data gathered in the literature search and consiceration of the history e' 5 quake activity in this area, the applicant ccncluded that: (1) The Fort Yur'a earthquak e occurred cn Novec ter 29, 1852 at approxi 3tely r: con. (2) The epicenter of the earthquake u s located in the Salton Trcugh. (3) The magnitude of the earthquake is estirated to have been beteen 6 and 7. As a result of our review of data on the f ort Yu a earthquake and krcwledge of seisrcicity and tectonic; in the area, we have concluded that-(1) The date for the Fort Yuna earthquake deterrined by the applicant is accarate. (2) It is reasonable to assur that the Fort Yum f artg3ke wa. associated with struc-7 tures of the San Andreas fault syste-js/ ,.o e

(3) The Fort Yuma earthquake was probably no larger than other earthquakes which have occurred in this area of the San Andreas fault system. Besides the arguments provided by the applicant cited above, the prime data sup-porting these conclusions are (1) the relatively high seismicity in the Sclton Trough and virtual absence of seismicity to the northeast of this area, (2) the existence of sever 11 faults with Quaternary displacement within the Salton Trough and relative scarcity of evidence for recent fault displacement to the northeast of this area, and (3) the existence of major, plate bourding faults in the Salton Trough and lack of similar features to the northeast of this area. 2.S.6 Design Basis Earthquakes As already noted in Section 2.5.5 of this report, the historical record of seismic activity in the southern portion of the Basin and Range province is poor. Because of this, it is necessary to rely primarily on the recognition of active faulting in estab-lishing the safe shutdown earthquake for the Sundesert site. The majority of earthquakes which have occurred in the 9asin and Range province can be reasonably associated with mapped f aulting. In particulur, what was probably the largest earthquake in the province, the Owens Valley earthquake of 1872, produced surface ruptures at the tire of the earthquake (Slemmons,1967 and Bonilla,1967). Many of the other large earthquakes in the province, such as the 1887 earthquake in Sonora, Mexico, the 1915 earthquake in Pleasant Valley, Nevada, and the 1954 earthquakes at Fairview peak and Dixie Valley, Nevada, also are repoi ted to have produced surface displacements. Because of this association between earthquake actis ity end faulting, according to the criteria of Appendix A of 10 CFR Part 100 it is not necessary to assume that earthquakes in the Basin and Range province can occur closer to the site than the faults with which they can be reasonably associated. In connection with our geology and seismology revicw of the Palo Verde nuclear power plant site, it was determined that the largest earthquake in the Basin and Range tectonic province, which could not reasonably be associated with faulting, had a magnitude of 4. The applicant f or the Sundesert site has conservatively assumed a magnitude 5 earthquake could occur near the site, at a distance of five miles, in establishing the safe shutdown earthquake. Extept for the Sundesert site area and a few other scattered areas, only reconnaissance geologic m pping has been conducted throughout much of southeastern California and most of the western half of the State of Arizona. The applic " t has conducted state-of-the-e art geologic investigations in the vicinity of the site. dased on the applicant's investigations and the results of reconnaissance mapping in the region, the f, ult nearest the sit' which is considered to be capable is the Blythe Graben, 22 niles from the site. As discussed in Section 2.5.1 of this report, the Blythe Craben has a traceable length of three and a W f miles but can be inferred to be longer based on gravity measurerents. Based on interpretation o' the gravity data, the Blythe Graben has been inferred to be on 2-23 7 - q/jr aqi !n -4 j ss ux ia U< r

the northeast side of a structural trough about 25 miles in length, whose southwest side is about 15 miles northwest of the site. Though the southwest side e' the structural trough may be inf erred to be relatcd in the mechanism of its origin to tne northeast side, the southwest side has not been assured to be apable becau;e of the lack of evidence of Quaternary f ault displacement on the southwest side of the trough. The applicant assumed a magnitude 6.5 earthquake could occur on the Blythe Graben 22 miles from the site. Given the relatively short length (approximately 25 niles) of the struc-ture and lacking eviderce of associated seismicity, the applicant's assessnent appears conservative when ctrpared to existing correlations between earthquake ragni tude and fault leagth. Capable faulting is known to exist in tre area of the San Andreas fault system southwest of the site. The San Andreas faJ1t systea extends fron tre Gulf of California on the southeast to Cape Mendocino on the northwest, a distance of about 700 miles. The length of the southern San Andreas fault system from the bend near the Garlock fault to the Gulf of California is about 300 miles. The southern part of the system has several splays. The largest earthquake which has occurred on the San Andreas fault system was the 1906 San Francisco earthquake with an estimated ragnitude of 8 3. An earthquake of estimated magniture 8 occurred in 1857 at Fort Tejon near the intersection of the Garlock fault and the San Andreas f ault, producing surface displacements ncrth and south of this intersection. This earthquake has been associated with the northern portion of the San Andreas f ault system since the geologic characteristics of the fault system near this intersection and tho characteristics of the Fort Tejoq earthquake are core repro-sentative of those associated with the northern San Andreas fault system. The largest earthquake 3 on the southern San Andreas fav't system were slightly larger than nagnitude 7. These include the 1915 Ba;a California earthquake, the 1934 Baja California carth-quak e, and the 1940 Ir perial Valley earthquake, all of ragnitude 7.1, and the 1903 Baja California earthquake listed as ma;nitude 7 plus. The f ault strands in the San Ar.dreas fault system closest to the site are about 35 miles to the southwest in the Salton Trough. The applicant assumed a ragnitude 8.5 earthquake could occur on these structures 35 miles from the site. This assumed earthquake is larger than any reported for California. Based on relat ons between ragnitude and length of surface fault rupture i dur ng earthquakes, a magnitude E.5 corresponds to a surface rupture length of about 300 i miles. Based on these considorations, an earthquake producing surface rupture along the entire lengtn of the scutrern San Andreas f ault syster; i.e., f rom the Gulf of California to the bend near tre Garlock f ault cculd reascnably be expected not to exceed magnitude E.5. Considering that (1) earthquakes in the historical record for the southern San Andreas f ault system have not had cagnitudes extceding about 7.1, f. ) the largest earthquake in the historical record anywhere on the S3n Andreas f ault system had a ragnitude of 8.3, (3) total off s t in the San Andreas f ault system uy be distributed over rultiple strands in the southern San AnJreas system, and (4) the nare active strancs within the Salton Trough are fur ^ her to the soJthwest, the assu-ption of a magnitude 3.5 earthquake on northeast strands of the San Andreas f ault system 35 miles from tre site appears conserva. '7r 7 tive. - s - 2-24 -r,- p,

The applicant has proposed to use the response spectra defined in Regslatory Guid<. 1.60, " Design Response Spectra for Nuclear Power Plants. ' to define the characteristics of th2 safe shutdown earthquake. Our evaluation of the proposed design response spectra is presented in Section 3.7.1 of this report. The horizontal response spectra are to be normalized te 0.35g, and the vertical response spectra are to be normalized to 0.23g. Several dif ferent scenarios were evaluated in assessing the adequacy of a horizontal acceleration level of 0.35g for the safe shutdown earthquake: (1) A magnitude 5.0 earthquake was assumed to occur near the site, beyond the region of intense geologic investigations conducted within five miles of the site. Based on empirical relations between magnitude, epicentral distance, and acceleration, the peak acceleration due to this earthquake would be expected to be betwecn about 0.07g and 0.15. 9 (2) Historical earthquakes associated with mapped faulting in the Basin and Range province were assuned to occur on ' hose faults at their closest mapped positions to the Sundesart site. All such earthquakes hid magnitudes less than 8.3, the e5 timated magnitude of the Owens Valley earthquake of 1872, and the associated aul'.s are suf ficiently distant from the site so that the peak accelerations rLsulting at the site from such earthquakes would be expected to be less tnan 0.36. 9 (3) A magnitude 6.5 earthquake, associated with the Blythe Graben, was assumed to occur 22 miles f ron the site. The peak accelerations calculated from acceleration-ragnitude-distarce relationships for this event are between about 0.lg and 0.25. 9 (4) A nagnitude 8.5 earthquake, associated with the San Andreas fault, was assumed to otcur 35 miles from the site. Peak accelerations for this event calculated from acceleration-magr.itude-dis Lance relationships are between about 0.199 and 0.35g. (5) Effec s at the site due to potential earthquakes in the Mojave Block were also considtred. As discussed in Section 2.5.2 of thi; report, peak accelerations at the Sundssert site from earthquakes in the Pojave Block are expected to be less than that for earthquakes associated with the San Andreas fault system. Therefore, the horizcntal acceleration level preposed for the safe shutdown e rthquake is as great as, or greater than, the peak accelerations which would be expected to result at the site due to any of the postulated earthquakes. Trifunac and Brady (1975) developed empirical relationships between eat thquake inten-sity and reak acceleration for both horizontal and vertical components of rotion. By a corparison of the rolationship for peak horizontal acceleration to the relations ^ip fcr pef. vertical accelzration, the peak vertical acceleration is seen to be somewhat less than two-thirds the peak horizontal acceleration. Based on this comparison, the vertical acceleration level of C.239 proposed for the safe shutdown earthquake is as qm 2-25 74 r ~ q

great as the peak vertical acceleration which would be expected to occur at the site from an earthquake producing a peak horizontal acceleration of 0.35, i.e., a r,agnitude 9 8.5 earthquake occurring 55 miles from the site. Therefore, we conclude that the applicant's proposed horizontal and verticrl dccelera-tion values of 0.359 and 0.23g, respectively, for the safe shutdowa earthqu3ke are acceptable for the Sundesert site. As an additional check on the adequacy of the proposed safe shutdown earthquake, the applicant developed response spectra fron strong rotion time histories for four earth-quakes recorded at firm-soil sites thought to be nost representative of the conditions at the Sundesert site. For each of the earthquakes; i.e., the 1952 rero County earthquake recorded at Taf t, the 1940 frperial Valley earthquake recorded at El Centro, the 1933 Long Beach earthquake recorded at Vernon, and the 1971 San Fernando earthquake recorded at Whittier narrows, the horizontal and vertical components of strong rotion were scaled using accelerasion-magnitude-distance relationships. The response spectra were determined and compared to the response spectra in Regulatory Guide 1.60 scaled to 0.35g (hcrizontal) ard 0.239 (vertical). In general, the response spectra in Regulatory Guide 1.60 envelope the response spectra for the real earthquake records with the exception of the El Centro spectra which slightly exceed the spectra in Regulatory Guide 1.60 at a few f requencies. The vibratory ground acceleration values for the operating basis earthquake, which are taken to be one-half the vibratory ground acceleration for the safe shutdown earth-quake, are consistent with the guidelines of Appendix A of 10 CFR Part 100. Therefore, we find them acceptable. 2.5.7 Conclusions Based on our review of the geology and seismology for the proposed Sundesert site, we conclude that (1) there are no geological structures that would tend to localize earthquakes in the innediate vicinity of the site or cause surface faulting at the site, (2) there are no known geologic features at the site ahich ceuld represent a potential hazard due to solution activity and/or subsidence, ard (3) the seismic design bases are appropriately conservative for the eartharake potential at the site. Therefore, we conclude that the proposed Sundesert site is accestable with reg 3rd to geology and seismology considera'. ions. I J s 2-26 p a l' t' ) I

3.0 DESIGN CRITERIA FOR STPUCTURES, COMPONENTS, EQUIPMENT, AND SYSTEMS 3.7 Seismic Design 3.7.1 Seismic Input The seismic design response spectra to be applied in the design of seismic Category I structures, comperents, equipment, and systems comply with the recorrendations of Regulatory Guide 1.CO, " Design Response Spectra far Nuclear Power 'lants." The specific percentage of critical damping values to be used in the seismic analysis of seismic Categury I structures, components, equipment and systems are in conformance with Regula-tory Guide 1.61, " Camping Values for Seismic Analysis of Nuclear Pow er Plants." The synthetic time history to be used for ;eismic design of seismic Category I plant structures, components, equipment, and systems will be adjusted in amplitude and frequency conter.t to obtain response spectra that envelop the response spectra specified for the site. Conformance with the recorrendations of Regulatory Guides 1.60 and 1.61 assures that the seismic inputs to seismic Category I structures, components, equipment, and systems are Jdequdtely defined so as to for, a conservative basis for the design of such struc-tures, co:rponunts, equipment and systems to withstand seismic loadings. We conclude, therefore, that the seismic input criteria are acceptable. 7 4 r - ' ') l } l' l-l ~1 1 n,n e [.*U 3-1

18.0 PEVIEW BY THE ADVISORY COMMITTEE ON REACTOR SAFEGUARDS The Sundesert Early Site Peview Report is expected to be reviewed by the Advisory Com-nittee on Reactor Safeguards. We intend to issue a supplement to our early site review report af ter the Comittee's report to the Comission, relative to their review, is dVallable. The supplement will append a copy of the Comittee's report and will address corm ents made by the Committee, and will also describe steps taken by the Connission's staf f to resolve any issue raised as a result of the Conmi. 's review. 7 Ij }j J 'n J '[} '! i' ~' / i 18-1

21.0 C07.CL U",10% Based on our evaluation of the site characteristics presented in the Sundesert Early Site Review Report, we have reached the following (onclusions, subject to the applicant establishing the requirements for the ul timate heat sink (Section 2.4.6), witn regard to these site characteristics. (1) The applicant has described, analyzed and evaluated the proposed Sundes>rt site to establish tho occeptat.i:ity of the site for tne construction and operat ion of a nuclear power plant. This descriptien and our evaluation have included a definition of site parameters w'

h we v.ould find to be acceptable for a nuclear power piant at the prepo'.ed Sundesert site.

(2) C r, the basis of tne foregoing, we conclude that the Sundeiert site is acceptable under the guidelines of 10 f f R Part 100 for tre construction and cperation of nuclear power plant of the general type and size being proposed tur the Sundesert site. ~a (- . o e l r

+

! h / / 's i.^n l \\ ']

' l - 1 W

APPENDIX A CHR0'iOLOGY OF THE LIMITED EARLY '.ITE REVIEW E SUNDESERT SITE October 29, 1974 Meeting with representatives of San Diego Gas & Electric Company (applicant) and its consultants to discuss plans for the proposed Sundesert Nuclear Plant and an early site review. March 4-5,1975 Site visit by Commission staff, applicant and its consultants to in.pect geologic fec'.ures. April 16,1975 Submittal of a 4-volume Early Site Review Report for review by the Comnission. May 27,1975 Letter to applicant advising that the Early Site Review Report is acceptable for continued review and requesting additional information on exclusion area control, regional and site a ea land use, population projections, turbine-generator missiles, and statistical independence of three earthquake ccmponents. June 12,1975 Letter to applicant transmitting a review schedule for the Early Site Review Report. June 13,1975 Letter to applicant req;esting additional information on geology, seismology, and soils structure interaction analysis. June 25,1975 Submittal of Amendment No. I to the Early Site Review Report, consisting of responses to request for information dated 5/27/75. July 23, 1975 Letter to applicant requesting a description of aircraft activities in the vicinity of the site, and recalculation of the probable maximum flood. July 25,1975 Submittal of Amendment No. 2 to the Early Site Review Report, consisting of responses to request for information dated 6/13/75. July 30,1975 Meetir.g with applicant to discuss round one que;tions and ceneral progress of the review. ] ., 3 r -s ., g '_ _ h.- ~ t J A-1

August 11, 1975 Submittal of Amendment No. 3 to the Early Site Review Report, consisting of additional responses to 5/2 /75 request f or informa tion. August 20, 1975 Letter to appli: ant requesting additional geological infornation. August 22, 1975 Submittal cf Arendment No. 4 to the Early Site Review Report, consisting of res;,anses to request for information dated 7/?75 with tne exception of infornation on aircraf t act. .ies. August 27, 1975 Meeting with applicant to discuss its response on aircraf t activities in the vicinity of the site; arplicant's deci-sion to raquest U.S. Seological Survey participation in the review; and hydrology qJestion 321.1. September 12, 1975 Submittal of Amendnent No. S to the Early Site Review Report, consisting of responses to reqJest for information dated 8/20/75. September 19, 1975 Meeting with appiicant, its consultants and U.S. Geological .,vey to discuss seismology and geology of the croposed site. Septeccer 30, 1975 Sutrii stal of Arendment *.o. 6 to the Early Site Review Report, consistinq cf responses to request for Vorrk-tion on all aircraf t activities in the vicinity of proposed site. October 7, 1975 Meeting with applicant to discuss antitrust natters. October 15, 1975 Letter to applicant requesting additional information on reteorological data reduction technique and on faJlting. November 3, 1975 Subli ttal of Amendment No. 7 to the Early Site Peview Report, consisting of responses to request for information dated 10/15/75. Dec mber 2-4, 1975 Meeting with applicant, its consultants, U.S. Geological Sorvey and the California Energy Conmission to discuss nydrology, geology and seismology and to inspect the site. January 16, 1976 Letter to aoplicant requesting add'.ional geological i n f orna ti o n. January M, 1976 Submittal of Arenci ent No. 8 to the Early Site Peview Report, consisting of revisions to the analysis of local flooding, as a result of 12/2-3/75 meetings r february 9, 1976 Letter to applic3nt requesting addi.ional gealogical J' l' / s .v i n f orma t i on. ,n j j L} l06 A.2

March 1, 1976 Submittal of Amendment No. 9 to the Early Site Review Report, consisting of partial responses to request for information dated 1/16/76. March 2, 1976 Meeting with applicant and its contractors to discuss the status of the site review. March 11,1975 Letter to applicant forw?rding U.S. Geological Survey draft report on the geological review of the site. March 18,1976 Letter frcm applicant submitting first six months of onsite meteorologica) data. April 7, 1976 Letter tc applicant transmitting a revised review schedule. April 9-11, 1976 Meeting with applicant co discuss geology and to inspect areas where exteneive geologic studies have been conducted in response to Commission and U.S. Geological Survey questions. Apr'l 20, 1976 Submittal of Amendment No.10 to the Early Site Review Report, consisting of responses to requests for information dated 1/16/76 and 2/9/76 addressing geotechnical aspects of site. May 20, 1976 Meeting with applicant its consultants, U.S. Geological Survey, and California Division of Mines and Geology to discuss the geology and seismology of the site environs. June 8, 1976 Letter to applicant transmitting staff position on aircraf t impact risks. Junc 15, 1976 Letter to applicant transnitting a revised review schedule. July 7,1976 Letter from applicant requesting reconsideration of our posi-tion on aircraf t impact risks os it pertains to applicant's agreement with U.S. Marine Corps. July 14,1976 Submittal of Amendnent No.11 to the Early Site Review Report, consisting of responses to all questions posed at the S/20/76 reeting. July 21,1976 Meeting i ith applicant tc discuss the acceptability of incorporating the Site Report by reference into the construc-tion oermit application. August 4,1976 Letter to applicant forwarding the revised staff position cc eircraf t impact risks. U[- - l.j A-3 1 r-

August 31, 1976 Letter to applicant forwarding corrected revised staff position on aircraft impact risks. Oc tober 20, 1976 Meeting with applicant, its consultants anc U. S. Geological Survey to discuss " Status of Review" report prepared by The U. S. Genlogical Survey on Sundesert. November 2, 1976 Letter from applicant regarding the Sundesert seismic design response spectra. Noicnber 10, 1976 Letter to applicant requesting additional information con-cerning the 1852 Fort Yuma Earthquake and transmitting the " Status of Review" report by the U. S. Geological Survey. November 18, 1976 Submittal of Amendment No.12 tc the Early Site Review Report, consisting of responses to request for additional information dated 11/10/76. December 9,1976 Letter h applicant concerning Sundesert seismic design response spectra. December 15, 1976 Meeting with applicant, its consultants and U. S. Geological Survey to discuss Amendment No. 12 to the Early Site Review Report concerning the 1852 Fort Yuna Earthquake. December 23, 1976 Le ter f rom applicant transmitting Errata to Amendment ha.12 of the Early Site Review Report. r ~ q ,U / A-4 ,,g; I '/

APPENDIX B r$,, ' s 'f \\ United States Department of the Interior L ,e GEOI.OGICAI RVEY R ESTON, VIRG L.. A 22091 %., e In Reply Refer.0: Mail Stop 905 JAN 1b M7 .e,e. r; 3 NY kC[l'4t0 ~/ + -<a Mr. Benard C. Rusche V Director of the Office of Nuclear j/38 m dC Reactor Regulation lt "^, g,,,,m [ U.S. Nuclear Regulatory Comission cg Washington, D.C. 20555 5 s 'N

Dear Mr. Rusche:

TO Transmitted herewith, in response to a request by your staff, is a review of the geologic and saismologic data relevant to the Sundesert Nuclear Plant, Units 1 and 2, (NRC Docket No. 558) as presented in the Early Site Review Reports and Amendments. This review was prepared by W. J. Carr, D. D. Dickey, M. G. Hopper, and S. R. Brockman. We have no objections to your making this review part of the public record. 5.;,cerely yours, <T O Y k Acting Director Enclosure qoLUTioq 'O, g j!:

J 'i g

.,.7 c 2 We.# B-1 Ti C-i ' .)

San Diego Gas & Electric Lv.gany Sundesert Nuclear Plant, Units 1 and 2 Riverside County, California NRC Project 558 The U.S. Geological Survey hereby provides a review of the geology and seismology of the Sundesert site and surrounding region as presented in the Early Site Review Report (ESRR), Volumes 1 through 4 and Amendments 2, 5, 7, 10, 11, and 12. In addition, the Geological Survey has participated in three field examinations (December 1974, December 1975, and April 1976) of the Sundesert site area in company with representatives of the applicant and with several geologists of the California Division of Mines and Geolcgy. We also attended two conferences on the Sundesert site in Denver, Colorado, and examined several trenches near Blythe, California, which were dug across the Blythe graben, the only known capable fault in the area. Geology During the past several years tne reviewers have been mapping in detail the Vidal area about 50 miles (80 km) nnetheast of the Sundesert site. This area is also adjacent to the Colorado River and is similar geologically. Much of the initial work by consultants for the power companies, in particular Southern California Edison Company, was done for a proposed nuclear generating station near t.oal west of Parker, Arizona. On the basis of the similarity of the two areas, and our work 7 .i , i v B-2 bi; ~' ' / i

in the Vidal site region, which has led to a general familiarity with regional geologic problems, plus our review of the Vidal site ESRR, it is reasonable to extrapolate this experience to the Sundesert site. The Geological Survey reviewers concur with the general pologic conclusions reached by consultants for the applicant, San Diego Gas & Electric Company, but, as in the case of the 'lidal site, we disagree with some aspects of the stratigraphy and tectonic history of the region, as presented in the ESRR. These structural and stratigraphic problems are not easily resolved with existing techniques, and as most of them involve the pre-Quaternary history of the area, probably are not critical to site safety. These problems will be discussed below. The Sundesert reactor site is located about 15 miles (24 km) southwest of Blythe, California, about 4 miles (6 km) west of the Colorado River, and lies within the Sonoran Physiographic and geologic subprovince of the Basin and Range Province. Geologically, the site is on an old Colorado River terrace that is locally veneered with younger alluvium and under-lain by Plio-Pleistocene sands and silts, largely Colorado River deposits, and clays, silts, and sands of the Bouse Formation of late Pl'ocene age. Bedrock in the adjacent Mule and Palo Verde Mountains consists of meta-morphosed volcanic and sedimentary rocks and granitic plutons of Mesozoic age, overlain unconformably by mafic to silicic 1 ,os, tuffs, volcani-clastic rocks, and fanglomerate of middle Tertiary age. Late Cenozoic deposits of the site area have been divided by the consultar.ts to the oower company into seven units, the oldest of which are probably of Pliocene age. In addition, three Holocene units are distinguished on the large-scale geologic site maps. The younger Colorado River deposits are overlain in the immediate site area B-3 71~ }Q7 c-i

2 (about a square mile (3 km ) by a thin veneer of Recent alluvium (probably less than about 10,000 years old), so that drill hele infor-mation and geophysical nieasurements have been heavily relied upon to substantiate claims of unfaulted deposits beneath and adjacent to the site. Within a 2-mile (3 km) radius of the site only about 50 percent of the surface area is mapped as older than Holocene. The rapidly changing, largely fluvirl character of the deposits above the Boese Formation makes correlation by neans of drill hole sampling difficult. Therefore, the evidence is largely geophysical--in-hole logging and surface seismic, gravity, and magnetic surveys. The substantial data acquired provide an adec;uate basis to demonstrate that large capable faults are not present in the immediate site area. However, it is our position that capable faults of perhaps as much as 10 feet (3 meters) of vertical displacement cannot be completely ruled out in the immediate site area. The assuned absence of such small capable faults at the site is predicated partly on their probable absence in the surrounding area. Dating of the deposits of critical age, chiefly those of middle Pleistocene age, has been accomplished in part by extrapolation from the Vidal area where earlier work established a relative sequence of deposits based on geomorphic and soil development, supplemented by U-Th dating of caliche. Magnetostratigraphy ef the fine-grained river deposits and a few supplemental dates from the Blythe-Sundesert . ;,0 ov B-4 . ~ } 3 r-

site area seem to adequately support the extrapolation. The reviewers feel that the correlJ ions between Quaternary units at Vidal and Sundesert areas are reasonable, although reservations expressed on the dating problem for Vidal (Carr and Dickey,1976) apply also to the Sundesert site: basically that the older Pleistocene units in particular are not precisely dated. At and near the Sundesert site very few faults have been found in rocks younger than the Tertiary volcanic rocks (approximately 15-30 m.y.). One of the few, the Lost Trigo fault, does not appear to offset rocks younger than the Bouse Formation. The only capable fault found near either Vidal or Sundesert is the Blythe graben about 20 miles (32 km) north of the Sundesert site. It is topographically expressed and clearly offsets unit Qfc, which, on the basis of soils and U-Tn dating, is thought to be between 50,000 and 200,000 years old. U-Th dates from similar deposits in the Vidal area averaged about 80,000 years. The apparent relative scarcity of post-volcanic faulting in the Sundesert area as compared with the Vidal area can be reasonably exclained by the lesser aerial exposure of the Bouse Fomation anc Helstocene units in the Sundesert area. Although the Vidal anJ Sundesert areas are quite similar geologically, there are several fundamental differences which help to maintain a relative perspective of the structural settina: (1) The Sundesert area lies in a region of relatively much stronger geophysical anaralies, both r3gnetic and gravity; the Vidal region is characterized by very weak geophysical anonalies with diverse trends and very few steep gradients that might indicate buried B-5 n c i.; ; I ().. l l - Jv J l

large faults, whereas the B.ythe-Sundesert area has several strong gravity gradients, as pointed out in the ESRR. The reviewers believe these gradients are best explained by faulting that probably involves late Pliocene age or possibly even early Pleistocene aae deposits. (2) The Sundesert site is only about 35 miles (56 km) from the nearest seismically active areas to the southwest--twice as close as Vidal. (3) Mountain ranges in the Blythe area tend to be distinctly more linear than those in the Vidal-Parker area, including some definite northwest trends; this linearity suggests younger faulting than in the Vidal region, but such faulting, if present, may not necessarily be capable. (4) The Vidal site region has an areally areater proportion of exposed critical dating units (Q2 or Qfc and oldcr), so that estab-lishment of the absence of active faulting seems to be on a sliahtly firmer basis than at Sundesert. (5) The structural style of the Sundesert-Blythe area appears to differ somewhat from that of the Vidal-Parker area in that the latter is characterized by a major low-angle detachment fault of Tertiary age, and the structural grain of northwest-trending faults developed in the upper plate of that fault seems to be largely extensional and dip slip in character, whereas such a detachment fault has not been recognized in the Sundesert-Blythe area, and the northwest-trending faults, particularly in Arizona, seem to have a greater component of strike-slip displacement.

• 0 B-6

'1 r 7 1 / l., Jv 't

It should be pointed out that much of the area in the Trigo Mountains on the Arizona side of the Colorado River within 25 miles (40 km) of the Sundesert site has received little geologic study by the applicant. Thus, it represents a geoloqic "blindspot" in the site region. In the reviewers' opinion, the most important site safety consideration at Sundesert is the character and recency of faulting (1) along the northwest side of the Vule Mountains, (2) along the northeast side of the McCoy Mountains, and (3) along the southwest side of the Big Maria Mountains. These locations are discussed below. (1) An extremely steep linear gravity gradient is present along the northwest side of the Mule Mountains, indicating a steep contact and sharp density contrast between the bedrock of the hills and the valley fill, which is probably Bouse Formation and fine-grained Colorado River deposits. The evidence tends to support the conclu-sion that the gravity defined scarp is not an active fault. The mountain front is not strikinaly linear and the buried scarp is not w ry close u the mountain front, and although much of the trace of the fault is buried by Holoce.ie deposits, several small areas of Pleistocene alluvium apparently are not faulted. (2) A linear gravity gradient along the northeast,Me of the McCoy Mountains 10-25 miles (16-40 km) north of the site is less pronounced but similar to the gradient along the Mule Mountains in that it lies a mile or so (about 2 km) from the mountain front. According to the applicant, 77r If I B-7 ~/ 1 q I l J JJ

photo study of the area has revealed no evidence of faulting in what appear to be largely Pleistocene age alluvial deposits along the northeast flanks of the range. Existing information, therefore, seems to indicate that neither the MH e Mountains nor the McCoy Mountains frontal faults are a site safety problem. However, two things should be pointed out with respect to possible faulting in that area; first, Nicholls Warm Springs, a warm water well near the Blythe airport, is located almost precisely at the projected junction of the two faults just discussed, but according to available informa-tion, the water from this well is only very slightly warmer than that from some other wells in the general vicinity of Blythe; second, a low drainage divide exists in the area between the McCoy and Mule Mountains. With a few exceptions, all alluvium-filled valleys that lie between ranges immediately west of the Colorado River and between Las Vegas and Yuma drain into the Colorado River. Just west of the Colorado River drainage system are several closed, internally drained depressions--the Salton Sea, Ford Dry Lake, Rice-Danby dry lakes, and an unnamed dry lake about 10 miles (16 km) southwes+ of Boulder City. Ford Dry Lake lies a few miles ".orthwest of the Mule Mountains. These closed depressions relatively near the Colorado River drainage are regarded by the reviewers as sensitiva indicators of possible Quater-nary fault activity. (3) The McCoy Wash art a southwest of the Big Maria Mountains is the site of a pronounced negative gravity anomaly elongated northwest-sout'heast parallel to the fronts of the Big Maria and McCoy Mountains. .c - c, / !5 U s B-8 l

A 31/2-mile-long (51/2 km) capable fault, called the Blythe graben in the ESRR, has been identified which coincides closely with the northeast side of the anomaly. Consultants for the applicant have been reluctant to directly relate the Blythe graben to a subsurf ce structure defined by the gravity gradient, whereas it seems very reasonable, almost compelling, to ~do so. It is significant to the reviewers that this elongate linear gravity anomaly is the only one known to cross the present Colorado River Valley between Needles and Yuna. Further-more, it is on line with northwest-trending faults mapped by the applicant in the Dome Rock f<ountains east of Blythe, and with a major gravity low west of the Kofa f tountains in Arizona. Even though the mapping in the Dome Rock fiountains indicated no faulting of Pleistocene deposits, this does not preclude such offsets in the Blythe-McCoy Wash area. The applicant attempts to show that the Bouse Forration is not at greatly different altitudes in wells in the Clythe-!!cCoy Wash area, but the reviewers believe that the well logs on which the conclusions are based are not adequate to eliminate the possibility of important structural displacement o# the Bouse in this area. The Blythe graben cuts alluviun possibly as young as 50,000 years; rough scarp slope angles measured by the reviewers suggest an age of between 100,000 and 1,000,000 years, using curves developed by R. E. Wallace of the U.S. Geological Survey. Very recently the reviewers detected an additional sall, short fault scarp with a ncrthwest trend about 4 niles (6 kn) scutheast cP tnc previously rioted Blythe f; ult, ena about : M les (13 imi norin of E t s. AlthoJ9h the two ljC ]jJ7 Us ,,7 / iJ J/

faults have the same trend aad general relation to the Big Maria Mountains and the gravity-topographic trough, the Blythe graben has a curved trace and therefore the two do not quite line up. On the basis of aerial photo inspection the newly discovered fault appears to cut alluvial deposits of the sane age as the much more prcnounced Blythe graben. The two separate scarps could have been produced by two or more earthquakes, however. Me believe the discovery of the small additional fault strengthens the argument that the entire northeast side of McCoy Wash structural trough should be considered a capable fault zonc. It is our opinion that the Blythe-McCoy Wash gravity anomaly suggests that a major structural through extends from east of the Colorado River northwestward about 25 miles (40 km). The nearest approach of the southwest side of this structural trough to the Sundesert site is about 15 miles (24 km). The northeast, possibly active side, which coincides with the scarps in alluvium, lies from 20 to 23 miles (32-37 km) from the site. The applicant has used a design earthquake of magnitude 8.5 located 35 miles (56 km) southwest of the Sand Hills fault, the nearest possibly active aajor strand of the San Andreas system On the basis of our inspection of the applicant's geologic work in the Chocolate Mountains arec, we believe this to be a conservative assumption. Helicopter surveillance and enminat ion of high-quality areal photo-graphs revealed no large capable faults in thn are] bet. men the site and the Sand Hills fault. 5tvoral sr4 1 w a r p s, s r. t ca % )y as "\\ p i ' ~ '

young as 10,000 years, were seen on the southwest side of the Chocolate Mountains 30=40 miles (48-64 km) from the site. These active faults appear to be part of the en echelon frontal fault system between the Chocolate Mountains and Salton trough, and though individually short ( l mile 01/2 km) or less) they probably form a zone that extends for many miles alcng the southwest side of the mountains. There is no evidence to suggest that these small faults are part of the San Andreas system, nor are any faults seen within the Chocolate Mountains active strands of the San Andreas. The Sand Hills fault is completely buried southeast of the Sal ton Sea. In summary, the Geological Survey reviewers believe that the applicant has done a good job of investigating the geology of the region with the possible exceotion of the Trigo Mountains area in Arizona. Concerns about northeastward extent of active faults of the San Andreas system in the Chocolate Mountains area, and the eastvard extent of east-trending faults of the Pinto Mountain, Blue Cut, Salton Creek system seem to be adequately resolved. Ages of the alluvial Pleistocene units, though not precise, are probably well enough known under the present state-of-the-art. ?r i

i t, J

B-ll a s-

Seismology Introduction The investigations contained in the seismology section and amendments 1-12 of the Sundesert ESRR have been reviewed by the U.S. Gtological Survey and have been found satisfactory. Earlier problems concerning the Blythe Graben and the 1852 Fort Yuma earthquake have been resolved. There are no known large historic earthquakes within the immediate area of the site. The applicant's Safe Shutdown Earthquake (SSE) acceleration value of 0.35 g at the site was obtained by assuming a ma.gnitude 8.5 earthquake on the nearest approach of the San Andreas fault system (that is, on the Sand Hills /Algodones fault) about 56 km (35 mi) southwest of the site. Mest of the historic seismic activity in the southern California area has occurred on the San Jacinto and Imperial faults, west of the San Andreas fault system. The only historic magnitude 8 earthquakes on the San Andreas fault system in southern California is the 1857 Fort Tejon earthquake, which occurred north of the Sand Hills /Algodones fault and propagated southward to within about 240 km (150 mi) of the site (Saint-Amand and others, 1963, Fig. 5). In the absence of Strong motion data from seismograms recorded within 100 km (62 mi) of a magnitude 81/2 event, attenuation relations developed by Schnabel and Sced (1973), Housner (1965), and Donovan (1973) were used to scale real earthquake response spectra from smaller earthquakes recorded at sites with soil characteristics similar to the Sundesert site and of comparable epicentral distances. E fuf B-12 7 3 !U /l.<

g - x .r e. ~ -,. k5 g g. . ~. 1 p .a.-,.... ..F, '? ~- y y .~ ', e. . r. s... ... *. ~ ~ I' f e ; p, L.' .L.. ' ' . s.- l 7

s. L nr. -

v..

v., s..

• : '.. A.

s. _ y' ' -... ., g [ _.. ; c L -. g t, ..,: {. . g . _ ~,.. e ' ,p _.J,p - \\ _g .a. 4.- ~ s .-..,c .. e.. .r. .a.;g,4,*4'.sas.,,, ',,,,,,, v - - l. >.sa . ; J. s.~. '-.1.- 143 w ..7 ..e - t .~ - n.- s

r.. e.., n -.

s.e ns. .. _.gs . 4.. s T'{. .1.' L. s., ~ ~ s ..(...

..'.. _. s

).) ..,f 1, -.....,.;.',s.- (- ~. s. s%..;.- g d ):, p'"N* Q Q'5l'4 %. t.pN *y::;W, ; @' 4**V Tt* 4)y* Q>.' L,'CA' W *>!'*f+ W B W Af - A, A :<.l.%. * .n L '.

• 13 ~ ~

a .) -ys. <. ;.,ii. ,-.s

• \\

7,- -- sw, gl ~.,n,-9.,~. + - na h r & N M. p i -w y . o,.. !; &,!?'i % $ q$~9^4 f.yRu ' +. k'&~ ',,. *,,. " c. ? 1 >:,'v, /~. v, / 8 ~.'e!w .'s.. O U d ':.. : ~t,. Ao , $ s? b.(kt,.f W '"&<;?'1.WWh'. &wug?"; ~ /,% r%Wi/? f..;..Q,[h,,9 k;~' L.2 2:ie .. '* v, s T s re f g wW of +4, ^ L :l ~i!' 73 g. s s ^M r ? y7

• * . p 3

&p jt/Q'g Q,&s.y % C ,1 <y~., >rt' c + n ~ .Q,k' n - h

• QN*.ly% <.hr. 0%'It'oh. N

%w$ l ' ', ',n Q: < * * !a,3,,k. :lp.h - Q.' ' L ',' ' l p CTN Mq..., d M M @m &,p h~ n y kh h,3 h.4 ISM.v.,MNMMB NM~,[v f'W. h5 ./, v,~, n s m s. m wees$h h w%me,c. e.. Q( m.~[E$ $e $ m. u. w g h4 N' M N h ?' 5N M. u.n.n:x/U g c P x 'i D.N[mqw%ff[.&WMhl W M w % g $ S N %w. W & p 4 ; W W W wd T ' R* !.%We%QW 9, W5 %?

• w& &w.:2. w m'y*.iiTQ W,% T G S W %:

N9hb.,2d,idN>yh.$N-4f,Q?.'~ chm.:jy$N.N. n u n. a s. W. O m. w ~ u OW ' V,in * ' % i 7:4 j.. . p. !Q:? M,,(MM,}.,Q .~ 4'wn 9+1 I8f f M$ @I'U %~' M~ N.,'.'l[. N?n, s.m>la$c*'.%mlJ' : *d'n~ %'$D? *'

• V'W N O N'

^T 1 ' L ' ~' N O. $ U W Y'~ y % :.5. lW'N,h. 4s&'NWN N 'W1,1 f*N.f.WMs a,> '<g %,.n Q.,$.;l.h* )'&. ','%n YE < d' + ::Jw, < %.*...u'%'.W. ~:?<,,': W. u ' % n a E,c%(**vp;s -W. 2.M -3r

v. ~ w,., ? ?. ',;' ' n 'vvg' M,

Mrm \\ X;'y,ria: M'$'pyj(f6Wf?Tl&.g&,m.s,k,U,'Y~pQ 5&. h td c '~ GM %q'vo *pMl~ % >.,'. : ~ **D, ' :. 2 ~..W ' ' / ' i ^-: s ' M<"&..- ' j. % ',.$ @ L'e. '.D s.

~..

aW

• Ln>q s

s, & Qr,f.h' - $'l1,4'dQR'.<*h:',lg, ., *.Q,,- Q~;< i,' 'ifil% *'y,'? %.T -::- Y I l J vf. s . ~;- L,J q '. ' y'l['Q ~a Wpjb! 4..w:!-<.f:? W W{ s%,.W'W: d 4$W15 w ~ W.m' : "f

• i':?i s:n w

.w m y. ~: n ?bf],

• 8,'* DjU >f3':~:W
• W d'}RyiQ%i 5 *i;'-: * ; i ^* ~.% ' '~ 1 ^~-

C',*S*: ?l.}"' J - ). ';N. ff. ', ' f.y.h.Y -{ h-lu m s wmnA.way!'h%w . i h hh h f Y kh mm:nw ymgya m@QP W@e&n:g.:.w Ef s t a m :w v; p w :. m na a w. nm, 8Nj.MyNibiM M dDUS{.f #MNW:'iW%"M"?m)M' MM(9$m%ks%e.pg%xsW' Aw - wwMpw w%gM $MWh$@f%%p}p%w@&mW'.o w.u e;sw w.o. w.: A.rw.p e m sh% n 1 WGM W 5.P W.X: MC'M r4;+

.A Q 6;;q>e'$p %y e,;q, % & g7%p e a 0 s p+y,,,,,W' k",,,, S 4,? / 5 ~ xy -E eMUAN TEST TARGET (MT-3) 1.0 lf52 m as p t= =- [3}, n lll l,l h_ !b!N lll pa 1.25 IA bi 1.6 4 6" d,!,!rI,,4 't[8h . _m y s g 4 N t+ 4p 'y s

4) f ".9 > %%')t$9 // ' g? >, NNf// Y*(pz, /g [4[* N %h& /4,Y \\ IMAGE EVALUATION TEST TARGET (MT-3) 1.0 lt ES 5 i= :n p2 s a a 7 33 t m lljll2.0 j.l L l 1.8 1.25 IA 1.6 4 6" M*e 4$<$ 44 %.f$::ls ffh gh nQ~' a / "g'

e v

y O Qs', gg

Blythe Graben (Zone D) The applicant has divided the area within 320 km (220 mi) of the site into six seismic zones identified as Zones A, Al, B, C. D, and E. They determined that a San Andreas (Zone A) earthquake, as discussed above, would generate an acceleration of 0.35 g at the site (Zone D), which would be significantly greater than those acclerations produced by earthquakes occurring in the other five zones. However, one possible exception to this might have been an event on the structure described in the ESRR as the "Blythe Graben," which is in the same zone as the site. The applicant has mapped the Graben for 5.6 km (3.5 mi) along the southwest flank of the Big Maria Maur.tains, 35 km (22 mi) north of the site. Because a pronounced gravity anomaly coincides with the Graben, the applicant has assumed a maximum fault length of 31 km (19 mi) (the applicant's interpreted length of the anomaly) at a distance of 35 km (22 mi) from the site. From this the applicant derived a fault-rupture length of 14 to 24 km (9-15 mi) and a magnitude 6.5 earthquake, re;ulting in 0.23 9 at the site (sections 2.5.2.8.8, P. 2.5-124 and 2.5.2.9.5, P. 2.5-128). The USGS reviewer of the site geology reports found an additional short fault scarp 6 km (4 mi) to the southeast and states that "The Bll:the-McCoy wash gravity anomaly suggests that a major structural trough extends from east of the Colorado River north-westwardabout40km(25mi)." This trough comes withh, 24 km (15 mi) of the Sundesert site. Based on the foregoing, we have assumed that an earthquake associated with the Graben is likely to generate accelerations at the site less than those from the applicant's postulated San Andreas event. [] 5 l)[ B-13 n 7,. /1O Uvi

The applicant notes that "no historic or recorded epicenters can be associated with the Blythe Graben" (P. 2.5-124). However, two very small earthquakes of about magnitude 1 recorded by the eastern Mojave seismic net in May 1976 (G. Fuis, U.S. Geol. Survey, Oral Commun.) are located at approximately lat. 34* north and long. 115* west as a point about 40 km (25 mi) north 50* west of the "Blythe Graben." These microearthquakes represent the only seismic activity detected in the region in two years of recording. Although these two epicenters have been located generally on strike with +.he northwest extension of this structure, it is not possible to conclude that they are associated with it because the structure is not known to exist in that vicinity. The recorded first motions of the two events are inconclusive (G. Fuis, Oral Commun.); thus, it is not possible to discuss their focal mechanisms relative to the strike or sense of motion of the Graben. November 29, 1852, Fort Yuma Earthquake Amentment 12 to the ESRR contains the applicant's justification for the removal of the 1852 Fort Yuma eartnquake from seismic 7one D (the site zone) and its relocation in seismic Zone A (the San Andreas fault system). Their rese6rch seems to support such a move. Confusion about the date of the shock has been resolved satisfactorily and questions about the location, felt area, and magnitude of the event have been adequately discussed. 73~ / v' L! U L. B-14 7]E llO

Date The date of the earthquake has now been established as November 29, 1852. This is based on two sources, first on the diaries of Major Heintzelman and Lieutenant Sweeny of Fort Yuma which record an earthquake on November 29, but do not mcncion an earlier shock, and second on accounts in the San Diego Herald Newspaper. The applicant has traced the various other dates back to their original sources and has provided convincing evidence t' tat the earthquake that was felt at Fort Yuma occurred on November 29, 1852.

Locatior, The location of the earthquake is not precisely established, but enoun't evidence has been submitted to justify the applicant's removal of f.he earthquake from seismic Zone D, where it has traditionally been placed, and relocated in seismic Zone A.

Although it would be difficult to assign intensities to many of the reports available, and althouoh there are too few reports available to make an isoseismal map, never-theless it seems evident that the highest known intensities did occur in the vicinity of the Co'orado River along some 100 km (62 mi) of the river from the Fort southwestward (that is, within the San Andreas fault system, seismic Zone A). The earthquake and several of its aftershocks were felt west of the Fort at San Diego and Vallecito. Evidence is presented that the earthquake probably was not felt at San Bernardino, northwest of the Fort. North of the Fort .re was a rockslide at Chimney Peak. East of the Fort there were no felt reports because the area was largely uninhabited; however, the diaries of r T ',7 j t iJ Uu s ?1C jja / B-15

- i. - en.. .g. 6 4 ?" Heintzelman and Sweeny contain no accounts of the earthquake reported by travelers passing through Fort Yuma from the east. Southwest of ll. ' the Fort several reports were obtained describing lurching, liquefaction, changes in the course of the Colorado River and unusual activity at a mud volcano in northern Baja California. The applicant has compared these effects with the effects of modern earthquakes in this area and concluded that the epicenter was most likely in the Salton Trough southwest of Fort Yuma. Although the reviewers do not concede that the epicenter was necessarily within the boundaries sugges rd by the applicant (an area of approxim-3500 sq. km (1400 sq. mi) centered about 4 50 km (31 mi) southwest of Yuma and shown in Fig. 2.5P-6), we do agree that the evidence presented in Appendix 2.5P and at the meeting with the applicant on December 15, 1976, does indicate that the epicenter of the 1852 Fort Yuma earthquake was within the applicant's seismic f' Zone A rather than seismic Zone D. Ik Felt Area The earthquake is now known to have been felt from San Diego to Fort iuma and from Picacho Peak to the mouth of the Colorado River. Because the land was largely uninhabited, it is impossible to tell how far beyond these points the felt area might have extended. The establishment of the correct date for the earthquake, the applicant's search of existing records in the United States and Mexico, and the tracing of the various accounts back to their original sources have eliminated felt reports from far outside the Colorado River-San Diego area. -9 71 i ld d, v t B-16 -<.J_ 3,n 7.g .'3_

.g l O e b e 4 O s .s=~ b e s e e M ) J e 6 $e I k 's 0 ., - +. 4 p .ga ' n e,

FN r% b, lh D 1L u References cited es g-Carr, W. J., and Dickey, D. D., 1976,SouthernCalipehbis' L 3 Edison Company, Vidal Nuclear Generating Station, Units 1 and 2, San Bernardino County, California: N '.C Docket No. 486, U.S. Geol. Survey Final Review, 3 p. Coffman, J. L., and von Hake, C. A., 1973, Earthquake history of the United States: U.S. Dept. Commerce Pub. 41-1, Rev. Ed. (through 1970), 208 p. Davenport, A. G., 1972, A Statistical Relationship between Shock Amplitude Magnitude and Epicentral Distance and Its Application to Seismic Zoning: Engineering Science Research Report BLWT-4-72, Univ. of W. Ontario, London, Ontario, Ca.

Donovan, N.

C., 1973, A statistical evaluation of strong motion data including the February 9, 1971, San Fernando earthquake: World Conf. on Earthquake Eng., Rome, Italy, 5th. Holden, Edward S., 1898, A catalogue of earthquakes on the Pacific coast 1769 to 1897: Smithsonian Inst., Wash., D.C. Housner, G. W., 1965, Intensity of ground shaking near the causative fault: World Conf. on Earthquake Eng., V.I. Auckland and Wellington, New Zealand, 3rd, P-oc. Saint -Amand, Pierre. Lombardi, Oreste W., and.Shuler, Herbert, 1963, Earthquakes in the western United States: Buletin Bibliografico de Geofisica & Oceanografia Americanas, v. 3,

p. 40-105.

Schnabel, P. B., and Sced, H. B., 1913, Accelerations in rock for earthquakes in thu western United States: Seismol. Soc. America Bull., v. 63, u. 2,

p. 501-516.

Sturgul, John R., and Irwin, Thomas D., 1971, Earthquake history of Arizona and New Mexico, 1850-1966: Ariz. Geol. Soc. Digest, v. 9, p. 1-37. Tovaley, Sidney D., and Allen, Maxwell W., 1939, Descriptive catalog of earthqr. ekes of the Pacific coast of the Unitad. tates 1769 to 1928: Seismol. Soc. America Bull., v. 29, no. 1, p. 1-297. Trask, J. B., 1856, On,,rthquakes in California from 1812 to 1355: Am. Jour Sc v. 22, p. 110-116. Wood, Harry 0., 1916, Cat. >rnia earthquakes: Seismol. Soc. America Bull., v. 6, nos. 2-3, p. 55-180. r. ', 0 e 7;o dv /, B-18 j 1, c !LL

1, References not cited ~ Bonilla, M. G., and Buchanan, Jane M., 1970, Interim report on worldw2de historic surface faulting: U.S. Geol. Survey open-file rept., 32 p. Brazee, Rutlage J., 1976, Final report, an analysis of earth-quake intensities with respect to attenuation, magnitude, and rate of recurrence: NOAA Tech. Memo. EDS NCSDC-2, 53 p. Ila y s, Walter W., Algermissen, S. T., Espinosa, Alvaro F., Perkins, David M., and Rinehart, Wilbur A.,

1975, Guidelines for developing design earthquake respc..se spectra:

Construction Engineering Research Laboratory Technical Report M-ll4, 349 p. -s D1uI D) mpg-l u d7 m/ i J e e uo/ 4

~

7}r 5,f 'lJ B-19

APPENDIX C BIBLIOGRAPHY 1. Anderson, D. L., 1971, "The San Andreas Fault." Scientific American, Volume 225, pages 53-8. 2. Atwater, T.,1970, " Implications of Plate Tectonics for the Cenozoic Tectonic Evolution of Western North America," Geological Society of America Bulletin, Volume 81, pages 3513-3536. 3. Bonilla, M. G.,1967, " Historic Surface Faulting in the Continental United States and Adjacent Parts of Mexico." U. S. Geological Survey Publication, TID-24124, 4. Bonilla, M. G. and J. M. Buchanan,1970, " Interim Report on Worldwide Histc,ric Surface Faulting," open file report No.16113, U. S. Geological survey. 5. Coffman, J. L. and C. A. von Hake,1973, " Earthquake History of the United States," U. S. Department of Commerce Publication 41-1. 6. Diary of Major Heintzelman, available on microfilm at Arizona Western College, Yuma, Arizona. 7. Donovan, M. D., 1973, "A Statistical Evaluation of Strong Motion Data Including the February 9,1971, San Fernando Earthquake," Proceedings of the Fif t5 World Conference on Earthquake Engineering. 8. Eardley, A. J.,1962, " Structural Geology of North Am'rica," Harper and Row Publishers, New York. 9. Earthquake Data File 1927-1973, National Oceanic and Atmospheric Administration, U. S. Department of Commerce. 10. Earthquake Epicenter and Fault Map of California, Department of Water Resourtas, Resources Agency of Californi.

11. Esteva, L.,1969, "Seisr.ic Risk and Seis:nic Design Deci.icns," Proceedings of the Seminar on the Seismic Design of Nuclear Power Plants, Massachusetts Institute of Technology.

12. Fault Map of California, 1975. Department of Conservation. Resources Agency of California.

13. Garfunkel, Z.,1974, "Model for the Late Cenozoic Tectonic His+ory c the Mojave Desert, Califor:ia, and for Its Ralation to Adjacent Fagions," GeologicJ *)ciety of America Bulletin, Volume 85, pages 1931-1944.

/iy J.<v 7 } 'c l!4 a C-1

14. Giane.la, V.

P., and E. Callaghan, 1934. "The [arthquake of Decenber 20, 1932, at Cedar flountain, Nevada, and its Bearir 9 on the Genesis of Basin Range Structure," Journal of Geology, Volume 42, pages 1-22. 15. Gumper, F. J., and C. Scholz,1971, "Microseismicity and Tectonics of the fievada Seismic Zone," Bulletin of the Seismological Society of America, Volune 61, pages 1413 '423. 16. Hamilton, 9 and W. B. Myers, 1956, " Cenozoic Tectonics of the Western United States,' Reviews of Geophysics, volume 4, pages 509-549.

17. Hamilton, R. ft and J. H. Healy,1969, "Af tershocks of the 3enham Nuclear Explosion," Bulletin of the Seismological Society of America, Volume 59, pages 2271-2281.

18. Heck, N. H.,1947, " Earthquake History of the United States (Exclusive of California and Western Nevcda) and Alaska,' Serial No. 609, U. S. Department of Connerce, Coast and Geodetic Survey. 19. Hill, D. P., P. Mowinckel, and L. G. Peake, 1975, " Earthquakes, Active Faults, and Gerthermal Areas in the Imperial Valley, California," Science, Volure ISS, pages 1306-1308. 20. Hofrann, R. B.,1974, " State-of-the-Art for Assessing Earthqaake Hazards in the United States, Report 3, Factors in the Specification of Ground Motions for Design Farthquakes in California,' Miscellaneous Pace 5-73-1, U. S. Arry Engine Waterw.ys Experinent Station. 21. Folden, E. D.,1893, ' Catalogue of Earthwakes on the Pacific Coast 1769-1897," Smithsonian liscellaaecus Collections No. 1037. 22. Housner, G. W.,1965, " Intensity of Earthquake Grouna Shaking near the Causative Fault," Proceedings of tLe Third ','orld Conferenen.. Earthquake Engineering. 23. Ives, J. C.,1061, "Peport upon the Colorado '?iver of the West, explored in 1057 and 1858 by Lt. Joseph C. Ives," Governrvnt Printing Of fice, Washington. 24 Journal of Lt. Thoras W. Sweeney,1E49-1P,53, edited by Arthur Wooc' ward,1956, Westernlore Press 25. trini t zky, E. L.,1974, " Sate-of-the-Art for Assessing Hazards in the United States, Report 2, Faul t Assessnent in Earthquake Engineering," Miscellareous Paper 5-73-1, U. S. Army Engineer Waterways Experinent Station. 25. Long. ell, C. R.,1960, "Possible Explanation of Diverse Structural Patterns in Southern Nevada." Amrican Journal of Science, Volume 258-A, paces 192-203. 27. Fecord of Earthquakes in the Yuma Area, 1976, Special Report, Bureau of Reclamation, United S Utes Dcpartment of the Interior. -) i b2 7)U f p,,] / UG/

28. Richter, C. F.,1958. Flementary Seisnelogy. 29. Rogers, A. M. and W. H. K. Lee,1976, " Seismic Study of Earthquakes in the Lake hkad, Nevada-Arizona Region" Bulletin of the Seismological Society of America, Volume 66, pages 1657-1681. 30. Ryall, A. S., D. B. Slemmons, and L. D. Gedney, 1966, " Seismicity Tectonism, and Surface ' aulting in the Western U ted States During Historic Time," Bulletin of the Seismological r Society of Anerica, Voll, 56, pages 1105-1135. 31. San Diego Herald of December 4, 1852. 32. San Francisco Daily Alta California cf December 12, 1852. 33. Savage, J. C., J. F. Church, and W. H. Prescott,1375, " Geodetic Measurement of Deformation in Owens Valley, Califernia," Bulletin of the Seismological Society of America, Volume 65, pages L65-874. 34. Schnabel, P. 3. and H. B. Seed, 1973, " Accelerations in Rock fnr Earthquakes in the Western United States," Bulletin of the Seismological Society of America, Volune 63, pages 501-516. 35. Scholz, C. H., M. Carazangi, and M. L. Sbar,1971, " Late Cenozoic Evolution of the Great Basin, Western United States, As An Ensialic Interarc Basin," Geological Society of America Culletin, Volume 82, pages 2979-2990. 30 Shawe, D. R.,1965, " Strike-Slip Coatrol of Basin and Range Structure Indicated by Historical Faults in Western fievada," Geological Society of America Bulletin, Volume 76, pages 1361-1378. 37. Slennons, D. B., 1967, " Pliocene and Quaternary Crustal Movements of the Basin and Range Province," Journal Geosciences, Osaka City University, Volume 10, pages 91-103. 38. Smith, R. B. and M. L. Sbar, 1974, " Contemporary Tectonics and Seismicity of the Western U. S. with Emphasis on the Intercountain seismic Belt," Geological Society of America Eulletin, Volune 85, pages 1205-1218. 33. Stewar', J. H.,1967, "Possible large Right-lateral Displacerent Along Faults and Shear Zones in Death Valley - Las Vegas Area, California and f.evada," Geological Scciety of America Bulletin, Volune 78, pages 131-142. 40. Stewart, J. H., J. P. Albers, and E. G. Poole,1968, " Summary of Regional Evidence for Right-Lateral Displacement in the Western Great Basin," Geological Society of America Sulletin, Volume 79, pages 1407-1414. 41. Sum er, J. R., and G. A. Thompson,1974, " Estimates of Strike-Slip Offset in Southwestern Arizona," Geological Society of America Bulletin, Volume 85, pages 943-946. 5 g 9q, f_ U --{ i - t C-3 / l0 V. u) na r n1 /

42. Townley, S. D. and M. !l. Allen,1939 " Description Catalog of Earthquakes of the Pacific Coast of the United States 1769 to 1928," Bulletin of the Seismological 'ociety of Anerica, Volume 29, pages 1-297. 43. Trifunac,fi. D., and A. G. Brady, 1975, "On the Correlation of Seismic Intensity Scales with the Peaks of Recorded Strong Ground Motion," Bulletin of the Seis.ological Society of Anerica, Volume 65, pages 139-162. 44. Wood, H. O., it. H. Heck, and R. A. Eppley,1966, " Earthquake history of the United States, Part II, Stronger Earthquakes of California and Western fievada," U. S. Department of Comerce Publication No. 41-1. 45. Wright L. A., and B. W. Troxel,1967, " Limitations on Right-lateral, Strike-slip Displace-rent Death Valley and Furnace Creek Fault Zoi s, California," Geological Society of America Bulletin, Volume 78, pages 933-950. m s ? n-4 h %0 l p i. -- i [9 ' / 1 ' t j-C-4 .u s. covea%vc=T m =ri~o orsect-4 ii}}