This research will deal with determination of the 3-D seismic velocity structure in the area of the Southern Great Basin Seismic Network, effectively covering southern Nevada. The technique involves inversion of P and S seismic wave travel times from local events and teleseisms. Geologic mapping reveals that the upper crustal extension has been quite heterogeneous, with highly extended terranes adjoining virtually unextended terranes. How this extension is manifested in the middle and lower crust and upper mantle remains in dispute. This analysis is expected to resolve structural elements of about 10 km size down to approximately 300 km depth. This analysis bears on the nature of active normal faulting at depth in the Basin and Range province. This research is a component of the National Earthquake Hazard Reduction Program.
