f Determination of elastic constants pertaining to a symmetry plane of an orthorhombic medium under arbitrary overburden from three-component offset VSP measurements

The propagation of elastic waves in the 1-3 plane of an orthorhombic medium (3-axis vertically downwards) is controlled by six elastic stiffnesses: c11, c13, c33, c44, c55, and c66. For propagation in the 2-3 plane c1 and c13 are replaced by c22 and c23. The remaining elastic stiffness c12 influences propagation in the horizontal (symmetry) plane. Propagation in oblique directions involves all nine elastic stiffnesses.