V,

PRELIMINARY PROPOSAL, -

REMOTE SENSING AND RELATED SEISMOTECTONIC ANALYSES

FOR

FAULTS AND FOLDS OF THE

YAKIMA FOLD BELT,

WASHINGTON

by

David B. Slemmons, Consulting Geologist

Lawrence Livermore National Laboratory

P.O. Box 808 -

Livermore, CA 94550

November 26, 1986

gO?> OAP97 - * -

REMOTE SENSING ANALYSIS OF FAULTS AND FOLDS OF THE YAKIMA FOLD BELT, WASHINGTON

NEED FOR ANALYSIS:

Several factors make this type of study important to understanding the seismotectonic setting of the Hanford area: First, a maximum earthquake of magnitude 6.5 has been proposed for the RAW (Rattlesnake-Wallula Alignment), CLEW (Cle. Elum-Wallula Lineament, or OWL (Olympic-Wallula Lineament). This magnitude is based on a length of about 120 km along a zone that may be longer if the orginal definition for OWL is assumed, or if westward extensions concealed by the Yakima Fold Belt, or if there is a change in orientation of the zone toward La Grande graben. The fault zone, marked at the surface by discontinuous faults, brachydomes and anticlines, is inferred to be a right- @- lateral or right-reverse oblique type (Slemmons, 1982a and 1982b). The right-lateral or right-reverse oblique character is inferred from the non-definitive literature for this zone. The maximum earthquake for the Yakima Fold Belt, which adjoins the BWIP site, was estimated by Slemmons (1982a; 1982b) to be of 7.2 to 7.6 magnitude at Toppenish Ridge.

Second, studies of recent earthquakes by Berberian (1982) for Tobas-E-Golshan in Iran (Ms = 7.5), by Philip and Meghraoui (1983) and Meghraoui and others (1986) for El Asnam area in Algeria -(Ms = 7.25), and by King and Stein (1983 and 1984) for Coalinga area in California (Ms = 6.5), all showed co-seismic folding. Although the faulting parameters are appropriate for the associated earthquake magnitudes, the folding partly to completely obscures the seismogenic faults. To adequately assess the earthquake potential for each of these areas prior to these kJ earthquakes, the co-seismic character of folding should have been assessed. This suggests the need to provide data for similar evaluations of the anticlinal folds of the Yakima Fold Belt. Third, recent neotectonic studies of the Yakima Fold Belt, show that northwest trending strike-slip faults are believed by Anderson and Tolan (1986) to be contemporaneous with the anticlinal folds. This indicates the need for a broad-scale regional evaluation and a further investigation of the intertie between the northwesterly trending right-slip faults and the east-west trending anticlines.

APPROACH:

To quickly and at relatively low cost obtain preliminary evaluations of the neotectonic character of the Yakima Fold Belt, a remote sensing study is recommended. Earlier studies in this area include regional evaluations of this region for lineaments and major structures by Slemmons and Glass. They also acquired and evaluated by low-sun angle aerial photography parts of the Columbia Plateau and Cascd'e Range. Fault mapping been completed by the U. S. Corps of Engineers for this region. This study will build on this data base, but will expand the analysis using current knowledge, use and "multi" methods of study (Slemmons, 1981; Slemmons and others, 1981). This investigation will focus on specific faults and folds that will provide key information.

DISCUSSION: The possibility of active (capable) tectonic features in the Yakima Fold Belt was first recognized by Campbell and Bentley in 1981 (Appendix A) when they recognized late Quaternary fault scarps along a crestal graben, a hinge fault, and a fan along the Mill Creek thrust fault at the northern edge of the Toppenish V, Ridge anticline. They measured fault scarps with heights of up to 4 m, presumably from one faulting event, and a zone of faulting of 32 km length. Slemmons (1982a and 1982b) in NUREG- 0892, Supplement No. 1 and NUREG-0309, Supplement No. 3, showed that if the scarps were seismogenic and were formed during one earthquake, the Ms magnitude was about 7.4 with a deviation of about 0.3. This suggests a possible maximum earthquake for the Yakima Fold Belt Province, since this is along one of the longest and most prominent folds in the province. The El Asnam earthquake in Algeria was associated with similar fault scarps, grabens, and anticlinal co-seismic folding along the main anticline (Philip and Meghraoui, 1983; Meghraoui and others, 1986). In Algeria, the surface faulting was also over a length of 32 km and the maximum offset was between 2 and 5 m, depending on the observations used. I have examined both the El Asnam faulting of 1984 and the Toppenish Ridge scarps and believe that Toppenish Ridge scarps may also be capable, seismogenic faults. Other observers who have examined both zones believe that this geologic structure may be seismogenic and should receive further study and evaluation. Another possibility is noted by Yeats (1986), who discusses this zone as a zone of flexural slip. He notes that other areas of flexural-slip faulting in southern California may be "low-shake" earthquake effects. The proposed study will provide initial data to assist in resolving this issue. During the past two or three years co-seismic folding has been recognized to be an important tectonic effect of some large earthquakes (King and Stein, 1983). These relations appear to be especially well expressed in compressional tectonic regions like those of El Asnam, Tobas-E-Golshan and Coalinga. The lack of previous recognition of folds as seismogenic geologic structures, and the subdued surface expression of their active faults makes active fault recognition and evaluation a difficult task, especially for places like the Yakima Fold Belt, that needs more thorough remote sensing, field mapping and tectonic study.

3 ; - * The recent abstract .Anderson and Tolan (1986..) strongly suggests that the active folds at the Toppenish Ridge latitude - are interconnected with contemporaneous wrench (right-slip) faults of the Maupin, Laurel, Luna Butte, and Arlington faults. Their oral presentation at the Cordilleran Section of the Geological Society of America shows late Quaternary faulting and such major geomorphic expressions as excarpments, brachydomes, and interconnection with "conjugate" folds. These northwest- trending strike-slip faults are mentioned by Plescia and Golombek (1986) as possible "tear" faults. Their prevalence and apparent conjugate pattern to folds is summarized in a tectonic map of the region (Fig. 1) from the U. S. Army Engineer District (1981).

Some of the mapped faults of Toppenish Ridge (e.g. the Mill Creek fault) is about 1/2 mile north of the Satus Peak anticline, and in Qal and Topchet beds that appear on the map to be unaffected by the anticlinal growth or landslide processes. This may favor a tectonic origin.

The main goal of this unified remote sensing, including low- sun angle analysis, is needed to determine the continuity, length and interrelation of active appearing structures, including the apparent conjugate relation of faulting to folding.

A second goal of this study will be to determine:

(1) the locations of areas that are especially suitable to assessing the capability and style of deformation of faults and folds of the-province.

(2) determine locations of possible sites that are suitable for exploratory trenching and detailed mapping of faults and folds.

STUDY METHOD:

The imagery will be analyzed by "multi" methods that are described in Slemmons, (1981) as shown in Appendix B. These methods should include methods for synoptic examination and low- sun angle evaluation, the most effective method for evaluation and detection of active (capable) faults. The imagery analysis will include:

(1) Radar imagery (already acquired by the Corps of Engineers), and new imagery to be obtained by the U. S. Geological Survey during the next year,

(2) Landsat imagery (older imagery is already acquired). New thematic mapper imagery will be added for this project for the Yakima Fold Belt at 1:250,000 scale in color and for selected selected MS wavelengths at 1:1,000,000 scale,

(3) Low-sun angle aerial photography will be acquired only

4 for those areas that were not included in the original photography collected by Washington Public Power Supply System, (4) High altitude color IR and B&W aerial photography will be obtained for the region, and selected strips along faults and folds will be added for detailed study of selected structures. The imagery analysis of major lineaments will be compiled at 1:250,000 scale on a map base. Emphasis will be on those faults and related folds that show geomorphic evidence for activity and have lengths or structural relations that are significant to the siting area. The imagery analysis will receive a field and aerial reconnaissance evaluation to provide visual confirmations of the general findings. The final report will include recommendations for selection of specific field areas, or fault-fold geologic structures that need further evaluation. The compilation can be initiated immediately and is not weather dependant. The field and aerial reconnaissance should be during the summer months, when clear weather is more frequent.

REFERENCES: Anderson, J. L., and Tolan, T. L., 1986, Ages of wrench faulting in interridge basins, southwest Columbia Plateau: Geological Society of America, Abstracts with Programs, v. 18, p. 82. Campbell, N.P., and Bentley, R.D., 1981, Late Quaternary deformation of the Toppenish Ridge uplift in south-central Washington: Geology, v. 9, p. 519-524. King, G., and Stein, R., 1983, -Surface folding, river terrace deformation rate and earthquake repeat time in a.reverse faulting environment: The 1983 Coalinga, California, Earthquake of May 1983, in The 1983 Coalinga, California, Earthquake, Bennett, J.H. and Sherburne, R.W., editors, California Division of Mines and Geology Special Publication 66, p. 261-274. Meghraoui, M., Cisternas, A., and Philip, H., 1986, -Seismotectonics of the lower Cheliff Basin: Tectonics, v. 5, n.6, p. 809-836 Philip, H., and Meghraoui, M., 1983, Structural analysis and interpretation of the surface deformation of the El Asnam earthquake of October 10, 1980: Tectonics, v. 2, p. 17-49. Plescia, J.B., and Golombek, M. P., 1996, Origin of planetary wrinkle ridges based on the study of terrestrial analogs: Geological Society of America Bulletin, v. 97, p. 1289-1299.

S Slemmons, D. B., 1981c, A iocedure for analyzing faLS- controlled lineaments and the activity of faults: in O'Leary, D.W., and Earle, J.L, editors, Proceedings of the Third International Conference on Basement Tectonics, n. 3, p. 33-49.

Slemmons, D.B., 1982a, Independent assessment of geologic and seismologic data to determine fault capability and earthquake parameters for the Washington, Public Power Supply System Project No. 2, in Safety Evaluation Report related to the operation of WPPSS Nuclear Project No. 2, U. S. Nuclear Regulatory Commission, NUREG-0892, p.Hi-H48.

Slemmons, D.B., 1982b, Fault capability and earthquake parameters at the Skagit/Hanford Site of Puget Sound Power and Light and other utilities: in Safety Evaluation Report related to the construction of SEigit/Hanford Nuclear Project, Units 1 and 2, U. S. Nuclear Regulatory Commission, HUREG-0309, Supplement No. 3, p. Gl-G56.

U. S. Army Engineer District, 1981, Composite Structure Map of the Columbia Plateau: U. S. Army Enginner District, Seattle, Corps of Engineers, Scale: 1: 500,000, Yeats, R. S., 1986, Active faults related to folding: in Active Tectonics, Wallace, R.E., Editor, National Academy Press, Washington, D.C., p. 63-79.

Yeats, R. S., 1986, Active faults rlated to folding: in Wallace, R.E. (editor), National Academy of Sciences, National Academy Press, Washington, D.C., p. 63-79.

Yeats, R. S., 1982, Low-shake faults of the Ventura Basin: California in Neotectonics in southern California, Cooper, J. D. (compiler), Cordilleran Section, Geological Society of America Field Trip Guidebook, p. 3-15.

6 414.2/HEL/02FEB1987 - I -

ENCLOSURE B

ATTENnANCE LIST

DR. D. P. SLEMMONS'S PROPOSAL PRESENTATION U. S. N11CLEAR REGULATORY COMMISSION SILVFR SPRING, MARYLAND January 13, 1987

NMSS: NRR RESEARCH M. Rlackford L. Reiter T. Alterman 0. Brooks P. McMullen A. Ibrahim P. Justus H. Lefevre LLNL K. McConnell J. Trapp D. Slemmons K. Stablein R. Wright J. Warner n. Chung 414.2/HEL/02FEB1987

ENCLOSURE C

PRESENTATION SUMMARY NOTES

DR. D. B. SLEMMONS' PRESENTATION OF HIS PRnPOSAL "REMOTE SENSING AND RELATED SEISMOTECTONIC ANALYSES FOR FAULTS AND FOLDS OF THE YAKIMA FOLD BELT, WASHINGTON" AT NRC OFFICES, SILVER SPRING, MARYLAND

January 13, 1987 BACKGROUND

Based upon his dual role as an NRC consultant both to the Office of Nuclear Reactor Regulation (NRR) and to the Office of Nuclear Material Safety and Safeguards (NMSS), Dr. Slemmons has prepared a preliminary proposal for a remote sensing study of tectonic structures near the Hanford Site, Washington. Dr. Slemmons has suggested, because of post-1982* developments, that the proposed investigations be conducted for several reasons including (1) recently-reported (1986) Quaternary faulting south of the Toppenish Ridge area possibly linking northwest-trending strike-slip faults with east-west anticlinal folds and (2) recognition of the possibility (based upon recent papers (1982 through 1986) describing earthquakes in Algeria, Iran, and California) of the possibility that the anticlinal folds of the Yakima Fold Belt may obscure seismogenic faults. This proposed remote sensing study was designed to supplement work conducted previously in the area by the nuclear industry (Washington Public Power Supply System), bv the U. S. Army Corps of Engineers and by the Department of Energy. The geographic area being Proposed by Dr. Slemmons for supplemental investigation (principally through evaluation of low-sun angle aerial photography yet to be acouired} includes Toppenish Ridge and the area south to the Columbia River. Toppenish Ridoe is approximately twenty-eight miles southwest of the R8WIP site and about forty-two miles southwest of the WNP-? nuclear power facility. *NOTE: 1982 is considered a milestone date since NRR's present positions on the seismic potential of the Yakima Fold Pelt structures including Rattlesnake Mountain and Toppenish Ridge, are contained in the NRC's 198P Safety Fvaluation Report of the WNP-? nuclear power plant which is located on the Manford site. 414.2/HEL/02FEB1987

PURPOSE As stated in Dr. Slemmons' proposal the main goal of the remote sensing study, including low-sun angle analysis, is needed to determine the continuity, length and interrelation of active-appearing structures, including the apparent conjugate relation of faulting to folding. The secondary goals of the study are to determine the (1) locations of areas that are especially suitable to assessing the capability and style of deformation of faults and folds of the province and to determine (2) locations of possible sites that are suitable for exploratory trenching and detailed mapping of faults and folds.

SUMMARY Questions were directed to Dr. Slemmons both during and folowing his presentation. The main thrust of the questions, originating principally by Dr. Leon Reiter of the Office of Nuclear Reactor Regulation (NRRI was, based upon the post-1982 developments described by Dr. Slemmons, directed toward Dr. Slemmons' opinion of the potential impact of the results of the proposed investigation on the seismic desian of the Washington Public Power Supply System (WPPSS) WNP-2 nuclear reactor. Additional comments, observations, and experiences were conveyed by several meeting participants including Keith McConnell of NMSS and Richard McMullen of Research. Their comments were directed toward the reported Quaternary faulting adjacent to the Columbia River south of Toppenish Ridge. Based upon K. McConnell's personal communication with J. Anderson of Anderson and Tolan (GSA Abstract, 1986), the senior author expressed some reservation about supporting a Quaternary age for the surface faulting in his study area, suggesting a more definitive statement regarding the faulting ace be determined by a geologist more expert than himself in identifying Ouaternarv deposits. R.McMullen related that extensive Ouaternary faulting investigations conducted by the nuclear power industry in conjunction with the proposed Pebble Springs nuclear power plant site in Oregon included portions of the region described by Anderson and Tolan. These detailed field investigations found no evidence suggesting faulting more recent than early Pleistocene, perhaps even Pliocene. POST-PRESENTATION ACTIVITIES NRR-RESEARCH

The NRR representative, Dr. Leon Reiter, in corroboration with Dr. Tna Alterman of Research will prepare a position statement regarding the need tfrom the perspective of the NRC as the regulator of the operating nuclear power plant at the Hanford site - WNP-2) for conducting, or not conducting, investigations as suggested in Dr. Slemmons' preliminary proposal. - e

414.2/HEL/02FEB1987 -4-

NMSS Subsequent to the proposal presentation, NMSS staff and LLNL representatives determined: (1) The proposed goals, as described by Dr. Slemmons are not without merit, but need not be sponsored or initiated by NMSS at this particular time. One reason for deferring consideration of the present proposal is the uncertainty associated with the actual presence of active faulting in the area described in the Anderson and Tolan paper (GSA Abstract, 1986). Since this (presence of active faulting) is a major criterion in Dr. Slemmons' proposal for suggesting that an additional evaluation of the seismic potential of the Yakima Fold Belt be initiated, confirmation of active faulting in this area should be made prior to initiating such a study. NOTE: In the long term, such supplemental remote sensing investigations should be considered in order to completely and adequately assess the tectonic environment of the BWIP area. (2) LLNL was asked to prepare and to submit an alternative remote-sensing proposal aimed at the possible acquisition of existing imagery and low-sun angle photos used by WPPSS in conjunction with the utility's regional tectonic studies. The geographic region to be considered in this alternative proposal would include that portion of the anticlinal folds of the Yakima Fold Belt that may project into the BW1P site vicinity. These folds include Yakima Ridge, Umtanum Ridge, Rattlesnake Hills and Manastash Ridge. (3) NMSS will contact WPPSS in an attempt to acquire pertinent copies of the low-sun angle photos (and possibly other imagery) used by WPPSS in its analyses of the Yakima Fold Relt. 414.2/HEL/03FEB1987 - 2 -

OFFICIAL CONCURRENCE AND DISTRIBUTION RECORD

MEMORANDUM FOR: Philip S. Justus FROM: Harold E. Lefevre

SUBJECT: PROPOSAL PRESENTATTON BY DR. O. B. SLEMMONS DATE: February 4, 1987 FEB 0 4 1987

n!STR!BUTION WM/SF NMSS RF RBrowning, WM Mgell, WM JBunting, WMPC PJustus, WMGT JLinehan, WMRP .!Greeves, WMEG JTrapp, WMGT RJohnson, WMRP PHildenbrand, WMRP NColeman, WMGT HLefevre, WMGT h RF MRlackford, WMGT JWarner, WMGT KMcConnell, WMGT DRrooks, WMGT JBuckley, WMEG AHale, WMPC FCook, WM JBradfute, NRR LReiter, NRR lAlterman, RES RMcMullen, RES *lKeating, nnE, RL ODahlem, DOE, RL 'WKiel, WPPSS WBrewer, WASH PDR

CONCURPENCES

ORnANTZATION/CONCUREE INTTIALS nATE CONCURREn WM/GT HLefevre ;41FE-73 i/S'7 WM/GT KMcConnell . a dt WM/GT MBlackford 917!0Lowto WM/GT JTrapp F 7/0 -aI EL