Reflection of P and SV waves at the free surface of a prestressed elastic half-space

The propagation of plane waves in a prestressed elastic solid with incremental elastic coefficients possessing orthotropic symmetry is discussed. Two types of plane waves, called quasi-P and quasi-S waves, are shown to exist. An expression for the group velocity of these waves is obtained. The velocities of quasi-P and quasi-S waves are found to depend on the angle of propagation. The reflection coefficients of these waves incident at the free surface of a prestressed elastic half-space are derived. Critical reflection of quasi-P and quasi-S waves has been discussed. It is found that while quasi-S waves always have critical reflection, quasi-P waves can have critical reflection only if incremental elastic coefficients satisfy a certain condition