HR: 1340h
AN: S33A-1077    [Abstracts]
TI: Using geologic information for constraining near surface velocity estimation
AU: * Clapp, R G
EM: bob@sep.stanford.edu
AF: Stanford University, Geophysics Department, Stanford, Ca 94305 United States
AU: Wilson, C K
EM: wilsonck@stanford.edu
AF: Stanford University, Geophysics Department, Stanford, Ca 94305 United States
AB: Tomography problems often have a large null space. A standard approach is to apply Tikonov regularization. The ideal roughening operator is the inverse model covariance, but isn't known {\it a priori}. Some initial guess of the geologic structure often is known. From this initial model we construct a non-stationary filter, a {\it steering filter} that tends to create velocity trends similar to our structural model. We apply this technique to the problem of estimating near surface velocity from earthquake arrivals. On two examples we show that the updated velocity model shows more consistency with our geologic model than more standard techniques. We also show how the steering filters can be used to assess model validity.
DE: 1734 Seismology
DE: 0902 Computational methods, seismic
DE: 0935 Seismic methods (3025)
SC: Seismology [S]
MN: 2004 AGU Fall Meeting