Perturbation-based Interferometry - Applications and Connection to Seismic Imaging

With the objective of extracting only the scattered wavefield that propagates between two receivers as if one of them acts as a source, I present a seismic interferometry method that relies on perturbation theory. This approach follows from an exact correlation-type repre-sentation theorem in perturbed media. When the receivers lie between the physical sources and the imaging target, this perturbation-based theorem can be adapted for inter-ferometry of both dual- (i.e., pressure and particle velocity) and single-field measure-ments. In the case of ocean-bottom cable (OBC) data, dual-field perturbation-based inter-ferometry retrieves the response between the receivers without the free-surface multiples. Here the reference field is taken as the direct arrival along with water bottom multiples. In the context of seismic imaging, I show that the representation theorem in perturbed media can lead to the commonly used cross-correlation imaging condition in migration by wavefield extrapolation. Thus the exact form of the perturbed representation theorem can in principle be used for the migration of multiply-scattered waves, as well as for cor-rections for migration amplitudes and artifacts.