An analysis of the three-dimensional sound field in a penetrable wedge with a stratified fluid or elastic basement

A new analytical solution for the three-dimensional sound field due to an harmonic, point source in a broad class of penetrable wedges is presented. The only restriction on the wedge basement is that it be horizontally stratified. Thus realistic models of the ocean floor, such as a fluid or elastic sediment layer overlying a hard elastic substrate, can be handled. The wave-theoretic solution is based on the method of source images in conjunction with an extension of Brekhovskikh and Lysanov’s analysis of the reflection of a spherical wave field from a planar interface. The new solution is accurate throughout the wedge, including the normally difficult modal cutoff regions, where energy propagates through the wedge at grazing angles close to the critical grazing angle; and it is also valid through the hyperbolic caustics that border the region ensonified by each mode.