Propagation of SH elastic waves in deep sedimentary basins with an oblique velocity gradient

The propagation of elastic waves in heterogeneous sedimentary basins under incident SH plane waves is computed using the indirect boundary element method (IBEM). We work with sedimentary basins in which the S wave velocity varies with both the horizontal and the vertical directions. We use approximate analytical expressions for the two-dimensional Green's functions of the medium with an oblique constant-gradient Wave velocity. Whereas for the homogeneous half-space, underlying the sedimentary basin, Green's functions for a homogeneous full space were used. We analyze the response of these basins by means of frequency-space diagrams, frequency-wave-number plots, synthetic seismograms, and snapshots of the displacements. Moreover, a parametric study computing a set of various cases, which have different distributions of physical properties along two dimensions of the space, was carried out. The main differences between the media, using different obliquity angles, are pointed out. (C) 2003 Elsevier Science B.V. All rights reserved.