Generation and propagation of oceanic T-waves using elastic parabolic equation solutions

Abstract

Oceanic T-waves are essential for location and identification of seismic sources since they travel long distances in the ocean and are typically the largest signals received at hydrophone arrays or coastal monitoring stations. T-waves either link directly into the SOFAR channel by conversion of elastic wave energy at a downward sloping interface between the elastic and fluid media, or are generated when elastic energy couples into low order acoustic modes due to bathymetric inhomogeneities. Elastic parabolic equation solutions will demonstrate generation and long range propagation of oceanic T-waves in the water column when the source is located in an elastic ocean bottom. Elastic parabolic equation solutions will be used to describe effects of ocean bottom parameters on transmission characteristics of a sloping boundary. The impact of small-scale bathymetric changes, for example due to a rough ocean bottom, will be characterized by averaging acoustic wavenumber spectra resulting from multiple bottom realizations. Favorable characteristics for T-wave generation will be determined. The impact of large scale bathymetry changes, such as a seamount or underwater ridge, will also be discussed. [Work supported by ONR.]