COMPUTATION OF SYNTHETIC SEISMOGRAMS FOR STRATIFIED AZIMUTHALLY ANISOTROPIC MEDIA

We outline a method of computing synthetic seismograms for stratified, azimuthally anisotropic, viscoelastic earth models. This method is an extended form of the Kennett algorithm that is efficient for multioffset vertical seismic profiling. The model consists of a stack of homogeneous plane layers, and the response is computed iteratively by successive inclusion of deeper layers. Example computations are given for azimuthally isotropic and azimuthally anisotropic (AA) earth models. Comparison of computations using single and double wavenumber integrations for a realistic AA model shows that single wave-number integration often gives incorrect answers especially at near offsets. Errors due to use of a single wavenumber integration are explained heuristically by use of wave front diagrams for point and line sources. -from Authors