Analyzing the Role of Triangular Surface Irregularity and Initial Stress on SH-Wave Behavior in Multilayer Anisotropic Media

This study examines the behavior of shear waves in a fluid-saturated porous layer (FSPL) that exhibits transverse isotropy. The FSPL is positioned between a homogeneous layer and an elastic half-space, where a triangular-shaped surface irregularity is present at the interface between the FSPL and the half-space. Using the Fourier transform method and perturbation analysis, the dispersion relation is derived for the shear waves. Computational simulations of this relation, conducted with MATLAB, reveal several key insights. Specifically, as the material's inhomogeneity, anisotropy, and porosity increase, the phase velocity of the shear waves decreases significantly. Moreover, phase velocity drops notably with an increase in wave number. The study also finds that the wave number, the depth of the surface irregularity, and initial stress all significantly affect the phase velocity. These results have important implications for geophysical exploration, as well as for understanding earthquake dynamics and damage.