Seismo-acoustic propagation near thin and low-shear speed ocean bottom sediments

Abstract

Accurate and efficient parabolic equation solutions exist for complex propagation environments with elastic sediments. Certain ocean acoustic environments (such as harbors or estuaries) can feature a seafloor interface consisting of partially consolidated sediments, which can be described as a transitional solid. These complex sediments are generally thin, with low-shear wave speeds, and can cause numerical instabilities to arise in parabolic equation solutions. These instabilities make it difficult to obtain accurate solutions. In the low-shear limit, this problem can be treated as a multiple-scale problem. In this talk, such an ocean environment is modeled as a water layer overlying a thin transitional solid sediment layer over an elastic basement. An elastic parabolic equation approach is developed using asymptotic solutions for the displacements in the transitional solid, which are then incorporated into existing seismo-acoustic parabolic equation solutions by explicitly enforcing fluid-solid and soli...