n the relation between seismic interferometry and the migration esolution function

Seismic interferometry refers to the process of retrieving new seismic responses by crosscorrelating seismic observations at different receiver locations. Seismic migration is the process of forming an image of the subsurface by wavefield extrapolation. Comparing the expressions for backward propagation known from migration literature with the Green’s function representations for seismic interferometry reveals that these seemingly distinct concepts are mathematically equivalent. The frequency-domain representation for the resolution function of migration is identical to that for the Green’s function retrieved by seismic interferometry or its square, in the case of double focusing . In practice, they differ because the involved Green’s functions in seismic interferometry are all defined in the actual medium, whereas in migration one of the Green’s functions is defined in a background medium.