This research is to develop a theoretical method based on a Green's function, membrane approach to model seismic surface-wave propagation in laterally varying crust and upper mantle. Surface waves are typically assumed to travel in great-circle paths and this is clearly not the case because of lateral variations. The method will be applied to study of the crust and upper mantle of the California region using new digital broadband seismometer data from California, and to study of global variations using the global network data. This research deals with the determination of the seismic structure of California and therefore has application to the constraint of physical models of earthquake occurrence related to the National Earthquake Hazard Reduction Program.
