Analytical study of the reflection and refraction phenomena of plane seismic waves at the interface of orthotropic material sandwiched between two highly anisotropic triclinic media under the initial stresses

Seismic wave propagation is a complex process that is influenced by various factors, including the elastic properties of the medium and the initial stress condition. In this study, we have investigated the reflection and refraction phenomena of plane waves at orthotropic layer between two triclinic half-spaces with initial stresses. It has been assumed that the lower and upper half-spaces are composed of highly anisotropic triclinic crystalline material. The calculations have been performed to determine the phase velocity of the quasi waves. The theoretical expression of reflection/refraction coefficients and energy ratios of each reflected and refracted quasi waves has been derived in closed form. It has been shown that the reflection/refraction coefficients, phase velocity and energy ratios depend on the incident angle, initial stress, propagation vector, displacement vector and elastic properties of media. Numerical results demonstrate the significant impact of initial stresses on reflection and refraction coefficients and energy ratios. The slowness surface diagrams are established for various waves and energy conservation law is verified to ensure correctness of the study. This research contributes to understanding seismic wave propagation in complex anisotropic media, with applications in forward and inverse geophysical reflection/refraction problems. The findings can be used to improve our understanding of the Earth's internal structure and seismic exploration and monitoring.