Modeling the propagation of elastic waves using a modified finite-difference grid

The modeling of elastic waves with an explicit finite difference (FD) scheme on a staggered grid causes instability problems when the medium possesses high contrast discontinuities (strong heterogeneities). In this paper we have derived a new rotated staggered grid where all medium parameters are defined at appropriate positions within an elementary cell for the essential operations. Using this modified grid it is possible to simulate the propagation of elastic waves in a medium containing cracks, pores or free surfaces without applying boundary conditions. We compare the von Neumann stability criterion and the dispersion error for the new rotated staggered grid with the results of the standard staggered grid. Additionally, we show two synthetic examples and a comparison with a laboratory experiment to demonstrate advantages of the new rotated staggered grid in 2D and 3D. (C) 2000 Elsevier Science B.V. All rights reserved.