Abstract: Migration velocity analysis (MVA) can be viewed as a solution
method for the linearized (Born) inverse scattering problem, in its
reflection seismic incarnation. MVA is limited by the single scattering
assumption - for example, it misinterprets multiply scattered waves - but
it is capable of making large changes in the model, and moving estimated
locations of scatterers by many wavelengths. The salient features of MVA
is its use of an extended (nonphysical) scattering model. Nonlinear least
squares inversion (NLS), on the other hand, incorporates whatever
details of wave physics are built into its underlying modeling engine.
However success appears to require that the initial estimate of wave
velocity (in an iterative solution method) be ``accurate to within a
wavelength'', i.e. have kinematic properties very close to that of the
optimal model.
This talk will describe a nonlinear extended scattering model and a related optimization formulation of inverse scattering. I will present the results of some preliminary numerical explorations which suggest that this approach may combine the global nature of MVA with the capacity of NLS to accomodate nonlinear wave phenomena.
This seminar is easily accessible to persons with disabilities. For more information or for assistance, please contact the Mathematics Department at 743-3500.