Modeling of the hydroacoustic signal and tsunami wave generated by seafloor motion including a porous seabed

Abstract

Within the framework of a 2‐D compressible tsunami generation model with a flat porous seabed, acoustic waves are generated and travel outward from the source area. The effects of the porous seabed during tsunami generation and propagation processes include wave amplitude attenuation and low‐pass filtering of both the hydroacoustic signal and tsunami wave. The period of the acoustic wave generated by the seafloor motion depends on water depth over the source area and is given by four times the period of time required for sound to travel from the seabed to the surface. These waves carry information about seafloor motion. The semianalytical solution of the 2‐D compressible water layer model overlying a porous seabed is presented and discussed. Furthermore, to include the effects generated by the coupling between compressible porous sedimentary and water layers, a simplified two‐layer model with the sediment modeled as a compressible viscous fluid is presented.