Dip moveout (DMO) is often applied to prestack data to better preserve dipping events when performing partial stacks over ranges of offset. The tests presented in this paper, conducted on the SEG-EAGE salt data set, indicate that the application of azimuth moveout (AMO) in place of constant-velocity DMO yields better partial stacks in two important cases: first, when the velocity increases with depth. Second, when a salt body causes NMO-velocity conflicts between deeper flat reflectors and shallower dipping reflectors.
AMO is less sensitive to velocity variations than DMO because it is a residual operator, and thus it has less tendency to overcorrect reflections that have been moved out with too high NMO velocity. AMO has also the potential advantage over V(z) DMOs to be less sensitive to the given velocity function.