Tectonic stability and expected ground motion at Yucca Mountain. Final report. Revision 1. August 7-8, 1984-January 25-26, 1985
The historic seismic record at Yucca Mountain is too brief and incomplete to provide an accurate assessment of the frequency/magnitude relationship of the quality required to extrapolate future seismicity. The present northwest-southwest extension rate in the general area of Yucca Mountain appears to be of the same order as that across that entire southern Great Basin averaged over the last 15 million years. Thus, Quaternary tectonic activity can be used as a rough indicator of future activity. In situ stress measurements indicate that failure is possible along favorably oriented faults in the Yucca Mountain region. However, no quantitative statements about earthquake probability and magnitude (M) associated with the failure can be determined from in situ data alone. Both weapons tests at the Nevada Test Site (NTS) and impoundment of water at Lake Mead near Las Vegas have induced or triggered earthquakes of magnitudes as high as 4 or 5 within 14 kilometers of those locations. It is quite likely that all faults with significant scarps indicative of large earthquakes (M/sub s/ {ge}7) during the Quaternary-Holocene have been located and mapped. However, fault segmentation and the possibility of strike-slip motion complicate the precise identification of active faults and potential fault rupture length. Present estimates of peak ground acceleration at Yucca Mountain are based on empirical relationships that were not specifically derived for normal, oblique-slip, or strike-slip faults within an intraplate extensional regime. Thus, they should be evaluated for application to the Yucca Mountain region, assessed for standard error and uncertainties, and updated with more recent empirical data as appropriate. The Death Valley region is about 50 kilometers from Yucca Mountain. This region may have a potential for producing large earthquakes, but more study is required to assess its earthquake capability.
- Research Organization:
- Science Applications International Corp., La Jolla, CA (United States)
- DOE Contract Number:
- AC08-83NV10270
- OSTI ID:
- 59878
- Report Number(s):
- DOE/NV/10270-2-Rev.1; SAIC-84/1847-Rev.1; ON: DE86010364
- Resource Relation:
- Other Information: PBD: Dec 1985
- Country of Publication:
- United States
- Language:
- English
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