Unified continuous seismic reservoir monitoring

A method of generating a four dimensional seismic signal based on multiple sets of seismic data representing a subterranean formation. The method can include generating a tomographic velocity model based on a first set of raw seismic data and determining at least one Green's function based on the tomographic velocity model. The method can include generating a first image of a target region based on the first set of raw seismic data and the at least one Green's function. The method can include generating a second image of the target region based on a second set of raw seismic data and the at least one Green's function. The first and the second images can be compared, and a four-dimensional seismic signal can be determined based on the comparison.