Separation of diffracted waves in transversely isotropic media

Abstract

Imaging diffracted waves can provide useful information about complex subsurface geology and fracture networks. Separation of diffractions from typically more intensive reflected waves can be based on specularity, which measures deviation from Snell's law. Here, we analyze two formulations of specularity and their applicability to diffraction processing for anisotropic media. We show that the most common definition of specularity, originally introduced for pure modes in isotropic media, remains valid for both pure and converted waves in arbitrarily anisotropic models. The other formulation operates directly with the difference between the slowness projections onto the reflector for the incident and reflected waves. Testing on a VTI (transversely isotropic with a vertical symmetry axis) diffraction ramp model demonstrate that both formulations produce satisfactory results for anisotropic media with appropriate tapering of the specularity gathers.