Efficient synthetic‐seismogram generation in transversely isotropic, inhomogeneous media

Abstract

I develop an efficient modeling technique for transversely isotropic, inhomogeneous media using a mix of analytical equations and numerical calculations. The analytic equation for the raypath in a factorized transversely isotropic (FTI) media with linear velocity variation, derived by Shearer and Chapman, is used to trace rays between two points. In addition, I derive an analytical equation for geometrical spreading in FTI media that aids in preserving program efficiency; however, the traveltimes are calculated numerically. I then generalize the method to treat general transversely isotropic (TI) media that are not factorized anisotropic inhomogeneous by perturbing the FTI traveltimes, following the perturbation ideas of Červený and Filho. A Kirchhoff‐summation‐based program relying on Trorey’s diffraction method is used to generate synthetic seismograms for such a medium. For the type of velocity models treated, the program is much more efficient than finite‐difference or general ray‐trace modeling techniques.