HR: 14:05h
AN: NG33B-02 INVITED     [Abstracts]
TI: Extended Models in Nonlinear Seismic Waveform Inversion
AU: * Symes, W W
EM: symes@caam.rice.edu
AF: William W. Symes, Computational and Applied Mathematics, Rice University, MS 134, 6100 Main St., Houston, TX 77005 United States
AB: Most progress in seismic inverse scattering has come through use of linearization (``Born approximation''), in which the reference model is also regarded as unknown - so the problem is still nonlinear, albeit less so. The data-fitting formulations familiar from other work on inverse problems have had remarkably little influence on the development of practical solution methods for the seismic problem. Instead, industrial seismologists use an apparently ad-hoc collection of techniques dubbed {\em velocity analysis}, the effectiveness of which depends on the redundancy of seismic reflection surveys. This talk will explain how to view velocity analysis as the solution of an extended Born inverse problem. The various special techniques correspond to various extensions; Analysis shows that some of these are suitable for inversion in the presence of strong refraction, while others are not. Open problems abound, not the least of which is to get rid of the Born approximation. A natural generalization of an extended inverse formulation due originally to Claerbout combines the methodology of industrial velocity analysis with full nonlinear wavefield modeling. This presentation will describe some preliminary numerical results based on acoustic modeling, as well as a more general theory of nonlinear elastic waveform inversion.
DE: 7260 Theory and modeling
DE: 3210 Modeling
DE: 3230 Numerical solutions
DE: 3260 Inverse theory
SC: Nonlinear Geophysics [NG]
MN: 2004 AGU Fall Meeting