HR: 1340h
AN: S23B-0331    [Abstracts]
TI: Discrete Frame-Based Gaussian Beam Methods for Seismic Modeling and Imaging
AU: Li, C
EM: lcpdq@purdue.edu
AF: Purdue University, Earth and Atmos. Sci., West Lafayette, IN 47907 United States
AU: * Nowack, R L
EM: nowack@purdue.edu
AF: Purdue University, Earth and Atmos. Sci., West Lafayette, IN 47907 United States
AB: In this presentation we describe the use of discrete frame-based Gaussian beam summation methods with application to modeling and imaging. In this approach a windowed expansion is used where the individual functions are matched to paraxial Gaussian beams which are then propagated into the medium. The Gaussian windowed expansion is performed on an over-sampled position-wavenumber lattice where over-sampling is required for stability. The only window-based transform allowing critical sampling is a Wilson basis or local cosine transform which requires Gaussian beams to be launched in pairs losing some of localization properties of the method. For over-sampled Gaussian windowed expansions, dual functions must be computed to reconstruct the field, but for sufficiently high over-sampling the dual function becomes closer to a Gaussian function. An early application of windowed expansions using Gaussian beams was given by Hill (1990) for seismic migration. He also derived early sampling criteria for the expansion. Here we will give applications of the method to forward modeling including waves in a layer over half-space for a range of beam parameters. We also provide several applications of seismic imaging using surface sources and teleseismic waves incident from below.
DE: 7260 Theory and modeling
DE: 7203 Body wave propagation
DE: 7205 Continental crust (1242)
SC: Seismology [S]
MN: 2004 AGU Fall Meeting