P-wave diffraction and reflection traveltimes for a homogeneous 3D TTI medium
Hao, Q. and Stovas, A., 2014. P-wave diffraction and reflection traveltimes for a homogeneous 3D TTI medium. Journal of Seismic Exploration, 23: 405-429. Diffractions are produced by material discontinuities. Diffraction traveltime contains information about the velocity along the entire ray path, which is useful for improving the image quality. We derive an analytical midpoint-offset diffraction traveltime approximation for P-waves in a 3D homogeneous transversely isotropic medium with a tilted symmetry axis (TTI) under the assumption of weak anellipticity of the medium. From the proposed diffraction traveltime approximation, we also derive the P-wave reflection traveltime for a dip-constrained transversely isotropic (DTI) model. Two numerical examples illustrate the accuracy of both approximations for diffraction and reflection traveltime. One example is provided to analyze the shape of midpoint-offset diffraction traveltime. A short discussion on possible applications in heterogeneous TTI and multi-layered DTI models concludes the paper.
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