Geologic and hydrologic investigations of a potential nuclear waste disposal site at Yucca Mountain, southern Nevada

Crustal velocity sections based on two seismic-refraction profiles are presented for the area west of Yucca Mountain, Nye County, Nevada. The Crater Flat profile is interpreted in terms of six velocity layers ranging from 1.5 to 6.1 km/s. Interpretation of the Beatty profile reveals an escarpment near the northeast edge of Bare Mountain, where Paleozoic rocks are probably down-faulted 2600 m into a volcano-tectonic depression in Crater Flat. The seismic profiles and inferred density-velocity relations have been incorporated into an east-west gravity model from Death Valley to Crater Flat, corresponding to the Beatty seismic profile. An important feature of this model is the inferred continuity of a layer interpreted as the lower plate of a regional decollement or detachment fault.