Equations are presented to determine the phase shift of the amplitude of an elastic wavefield due to both simple (line) and point caustics in heterogeneous anisotropic media. The phase-shift rules for a general ray-theory wavefield are expressed in terms of the paraxial matrices calculated by the Hamiltonian equations of geodesic deviation (paraxial ray equations, dynamic ray tracing equations). The phase-shift rules are derived both for 2×2 paraxial matrices in ray-centred coordinates and for 3×3 paraxial matrices in general coordinates.
Anisotropy, heterogeneity, elastic wavefield, ray theory, caustics, KMAH index, paraxial rays.
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