In an a priori known transversely isotropic medium, we can separate the slowness surface into the P-wave slowness sheet, the SH-wave slowness sheet and the SV-wave slowness sheet. We may then trace the SH rays and SV rays, and use them as the reference rays for the prevailing-frequency approximation of the coupling ray theory. In this way, we obtain two S-wave arrivals along each SH ray and have to select the correct one of them. Analogously, we obtain two S-wave arrivals along each SV ray and have to select the correct one of them. We propose how to select the correct arrivals in this paper. We then demonstrate the accuracy of the resulting prevailing-frequency approximation of the coupling ray theory for S waves along the SH and SV reference rays in two different transversely isotropic velocity models.
Wave propagation, elastic anisotropy, transverse isotropy, heterogeneous media, S-wave coupling, prevailing frequency.
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