Data-driven wavefield reconstruction and focusing for laterally-varying velocity models, spatially-extended virtual sources, and inaccurate direct arrivals

Seismic interferometry allows one to create a virtual source inside a medium, assuming a receiver is present at the position of the virtual source. We discuss a method that creates a virtual source inside a medium from reflection data measured at the surface, without needing a receiver inside the medium and, hence, presenting and advantage over seismic interferometry. In addition to the reflection data, an estimate of the direct arrivals is required. However, no information about the medium is needed. We analyze the proposed method for a simple configuration using physical arguments based on the stationary-phase method and show that the retrieved virtual-source response correctly contains the multiples due to the inhomogeneous medium. We illustrate the method with numerical examples in lossless acoustic media with laterally-varying velocity and density and take into consideration finite acquisition aperture and spatiallyextended virtual sources. We examine the reconstructed wavefield when a macro model is used to estimate the direct arrivals.