Shear wave diffraction loss for circular plane-polarized source and receiver

Abstract

An integral expression is derived which gives the shear wave magnitude received by a circular plane-polarized receiver that is identical to and coaxial with a source on the surface of an isotropic solid half-space. Numerical evaluation of the expression shows that the shear wave diffraction profile (i.e., the received magnitude as a function of source/receiver separation) is very similar to that for compressional waves in a solid and acoustic waves in a fluid in the Kirchoff limit of large ka, where k is the wave number and a is the source and receiver radius. Under such conditions, simplified acoustic diffraction formulas may be applied to shear wave data with little loss of rigor. In the opposite limit of small ka, the shear diffraction profile differs significantly from that of compressional or acoustic waves and the shear wave diffraction formula presented herein should be employed.