Three-dimensional wave propagation simulation in elastic-anisotropic media

This work presents a new scheme for wave propagation simulation in three-dimensional elastic-anisotropic media. The modeling is based on the rapid expansion method (REM) as time integration algorithm, and the Fourier pseudospectral method for computation of the spatial derivatives. The modeling allows arbitrary elasticities and density in lateral and vertical directions. Numerical methods which are based on finite-difference techniques (in time and space) are not efficient when applied to realistic 3-D models, since they require considerable computer memory and time to obtain accurate results. On the other hand, the Fourier method permits a significant reduction of the working space, and the REM algorithm gives machine accuracy with the same computational effort as the usual second-order temporal differencing scheme. The modeling scheme was implemented on a CONVEX vector computer. Due to memory limitations the example presented in this work is restricted to the problem of wave propagation in a homogeneous transversely-isotropic medium, although the computer code is available for the computation of snapshots and synthetic seismograms in heterogeneous models, and for the use in parallel computers like for instance the CRAY X-MP system.