Sediment Thickness of the Contiguous United States from Teleseismic Receiver Functions

Abstract

Sediment thickness is a crucial measure for many seismic studies. The slow seismic velocities associated with thick sedimentary sequences can be problematic when inverting for regional tomographic images of the crust and upper-mantle structure, and is an essential piece of information for better constraining ground-motion models as sediments can amplify shaking. Yet there is currently no map of sediment thickness across the conterminous United States that is not a combination of smaller regional studies with potentially inconsistent methodologies. In this work, we measure the delay time of P to S conversions at the sediment–basement interface from a set of teleseismic receiver functions and demonstrate the geographical correlation with known sedimentary provinces. From this, we produce two maps of sediment thickness, using (1) a borehole-derived empirical relation and (2) the mean velocity in the upper 5 km of a tomographic model. Although the former is likely an underestimate, the latter is an excellent first-order representation of sediment thickness across the United States. Show more