Finite-difference modeling of viscoelastic and anisotropic wave propagation using the rotated staggered grid

We describe the application of the rotated staggered-grid (RSG) finite-difference technique to the wave equations for anisotropic and viscoelastic media. The RSG uses rotated finite-difference operators, leading to a distribution of modeling parameters in an elementary cell where all components of one physical property are located only at one single position. This can be advantageous for modeling wave propagation in anisotropic media or complex media, including high-contrast discontinuities, because no averaging of elastic moduli is needed. The RSG can be applied both to displacement-stress and to velocity-stress finite-difference (FD) schemes, whereby the latter are commonly used to model viscoelastic wave propagation. With a von Neumann-style analysis, we estimate the dispersion error of the RSG scheme in general anisotropic media. In three different simulation examples, all based on previously published problems, we demonstrate the application and the accuracy of the proposed numerical approach.