Seismic sources in seismo-acoustic propagation models

Abstract

An important generating mechanism for received underwater acoustic and seismic signals are buried or earth-bound sources. Most underwater acoustic studies involve purely compressional sources in the water column. The more complicated case of a coupled shear and compressional seismic source in the sediment has recently been implemented in an elastic parabolic equation solution [Frank et al., J. Acoust. Soc. Am. 133]. In this talk, generic seismic sources including those giving shear field contributions, are contrasted in normal mode and parabolic equation solutions. Scenarios considered are for an elastic-bottom Pekeris waveguide and a canonical Arctic propagation scenario with an elastic ice cover over the ocean and an elastic basement. For the Arctic case, the source is allowed in either the ice cover or in the elastic bottom. Solutions are benchmarked for purely compressional and shear seismic sources, and their relation to the seismic moment tensor is discussed. The ultimate goal of these solutions is to allow for seismic sources capable of representing generic geophysical events.