Short review of retarded Snell midpoint coordinates
, by Jon F. Claerbout
A convenient coordinate system in which to formulate many problems of
reflection seismic data processing is the retarded, Snell, common midpoint
system. It is particularly well-adapted to problems of accurate velocity
estimation, migration, and migration before stack when the velocity v(z)
is stratified. It also seems to have some utility in the presence of lateral
velocity variation, but for this problem and the problem of diffracted multiple
reflections, it may be preferable to avoid common midpoint coordinates.
STANFORD