Short Note Semblance picking

Tomography in the post-migrated domain is quickly becoming the standard approach for obtaining velocities in complex areas. The standard flow to update the velocity through tomography in the post-migrated domain begins by migrating the data using some initial velocity model. This migration method can be Kirchhoff (Etgen, 1990), downward continuation methods (Clapp, 2001b; Mosher et al., 2001), or any other method that can produce an image as a function of offset or reflection angle. Some type of moveout analysis is then performed on the migrated volume. This moveout analysis can take the form of one (Etgen, 1990; Clapp, 2001b) or two (Biondi, 1990) parameter curvature analysis or something more complex like a residual migration scaling parameter (Etgen, 1990; Clapp, 2002). These moveouts are then converted to time errors. We approximate the non-linear relationship between slowness and travel times by linearizing around an initial slowness model. We can then solve the resulting linear system and update our slowness field.