Equations are presented to determine the phase shift of the amplitude of the elastic Green tensor due to both simple (line) and point caustics in anisotropic media. The phase–shift rules for the Green tensor are expressed in terms of the paraxial–ray matrices calculated by dynamic ray tracing.
The phase–shift rules are derived both for 2×2 paraxial–ray matrices in ray–centred coordinates and for 3×3 paraxial–ray matrices in general coordinates. The reciprocity of the phase shift of the Green tensor is demonstrated.
Then a simple example is given to illustrate the positive and negative phase shifts in anisotropic media, and also to illustrate the reciprocity of the phase shift of the Green tensor.