Seismic Studies

Initial seismic refraction work during two field seasons was conducted in Devils Lane graben using a 24-channel seismograph and a sledgehammer energy source. Ten along-axis lines covering ~2 km of the graben floor revealed maximum sediment thicknesses approaching 100 m - and as importantly that the sediment thickness maximum does not correspond with the greatest fault height exposed above the surface. Maximum fault displacement is constrained by the seismic data to be at least 145 m, roughly half again what had previously been proposed on the basis of sediment thickness estimates. Subsequent study in nearby Cyclone Graben, conducted as part of an exciting Keck Geology Consortium undergraduate research project led by Dr. Kroeger, has revealed that sediments in this graben are also significantly greater than had been proposed previously.

Summary of seismic data interpretation results for Devils Lane graben. The topography data shown are derived from structural investigations by Dr. Schultz and his students.