Amplitude variation with offset

As an alternative to an investigation of the shear‐wave propagation components, we may elect instead to take a more direct approach. Once the shear‐wave components become a significant element in satisfying the Zoeppritz equations at a boundary, the pressure or P-wave amplitudes as a function of incidence angle (or offset if one prefers) begin to show more pronounced variations. This occurs because of the constraints which are imposed by the governing equations.