Recent work on retrieving the Green's function with the Marchenko equation shows how
these functions for a virtual source in the subsurface can be obtained from reflection data.
The response to the virtual source is the Green's function from the location of the virtual
source to the surface. The Green's function is retrieved using only the reflection response of
the medium and an estimate of the first arrival at the surface from the virtual source. Current
techniques, however, only include primaries and internal multiples. Therefore, all surface …