Updates to the SPECFEM3D wave propagation code will be developed so that it can handle fully elastic, 3-D behavior at and near the seafloor-ocean interface. The current version does not fully account for attenuation, which 2-D modeling has shown is a key factor in partitioning of compressional and shear energy at the solid-fluid interface and within porous shallow sediments that characterize most of the seafloor. Predictions from the updated code are to be benchmarked against a commonly used Parabolic Equation algorithm that is well suited for long-distance (far field) calculations, thus enabling study study of water-borne seismic phases all the way from source, through the near field, to far-range receivers. A dataset from the North Pacific will provide constraints for model parameter testing.
