Fast Finite-Difference Modeling of 3-D Elastic Wave Propagation

We present an efficient method for wavefield modeling in arhi-trarily inhomogeneous 3-D elastic media, based on optimized difference operators for spatial differentiation (Holberg, 1987). This technique offers accurate results on coarse spatial grids, ie. of the order of 3 gridpoints per shortest wavelength. In 3-D applications, this fast finite difference technique is at least two orders of magnitude more efficient than conventional finite dif-ference schemes and typically 2.5 to 6 times more efficient than the pseudospectral method, depending on the sampling of the model. This makes it practicable to run realistic 3-D simulations on existing vector computers. In t,he present paper we discuss the practical implementation of this method and give timings for various model sizes and computer configurations. We also give several numerical examples, ranging from simulat~ions in simple geometries with well known solutions to geometries of realistic complexity