A 3D pseudospectral method for SH-wave simulation in heterogeneous media

Abstract

The second order velocity-displacement SH-wave equation in VTI media is reduced to first order equations. During SH-wave simulation, the spatial derivatives of the new developed first order SH-wave equations are transformed into wavenumber domain and a staggeredgrid Fourier pseudospectral time-domain method is used to obtain discretized forms of these wavenumber operators, which in turn, effectively eliminates the Gibbs phenomenon. The first order velocitydisplacement SH-wave equations also make it possible to set hybrid perfectly matched layers around computational boundaries to mitigate artificial reflections. This new scheme is applied for wavefield modeling in two-layer heterogeneous media. Comparisons of simulation results with pseudo-spectral method using second-order SH-wave equation further verify its accuracy. Finally, SH wavefield simulation in a three-dimensional over-thrust model is illustrated.