Graduate Seminar

Scheduled Talk - September 2, 2009 - [ 12:00PM in DH 1064 ]

Chao Wang

"Differential Semblance Velocity Analysis via Normal Moveout Correction"

Abstract:
To estimate seismic velocity from the recorded seismogram can be considered as an inverse problem. This problem is highly nonlinear and thus is very difficult to solve. The Differential Semblance (DS) underlies a class of algorithms for seismic velocity estimation. The simplest variant of DS is based on a drastic approximation to the scattering of waves, called "Normal Moveout" (NMO). This simple NMO-driven DS algorithm is very fast relative to other variants based on more faithful approximations to wave physics, but nonetheless accurate enough to be used to process field data. A recent implementation of NMO-based DS demonstrated these capabilities, but it also exhibited numerical irregularity which may have affected the stability of its velocity estimates. My alternative approach avoids some interpolation noise that existed in previous work and so results in more stable numerical optimization.