Near-surface velocity modeling at Yucca Mountain using borehole and surface records from underground nuclear explosions

The Department of Energy is investigating Yucca Mountain, Nevada as a potential site for commercial radioactive waste disposal in a mined geologic repository One critical aspect of site suitability is the tectonic stability of the repository site The levels of risk from both actual fault displacements in the repository block and ground shaking from nearby earthquakes are being examined In particular, it is necessary to determine the expected level of ground shaking at the repository depth for large seismic sources such as nearby large earthquakes or underground nuclear explosions (UNEs) Earthquakes are expected to cause the largest ground motions at the site, however, only underground nuclear explosion data have been obtained at the repository depth level (about 350m below the ground level) to date In this study we investigate ground motion from Nevada Test Site underground nuclear explosions recorded at Yucca Mountain to establish a compressional velocity model for the uppermost 350m of the mountain This model is useful for prediction of repository-level ground motions for potential large nearby earthquakes