Comparison and generalization of correlation-based seismic source imaging methods

Migration-based seismic location methods can reliably and automatically image weak seismic sources with low signal-to-noise ratios, such as microseisms and microtremors. Compared with traditional diffraction stacking, cross-correlation stacking can extract more redundancy in the data and suppress noise better, since it delays and stacks cross-correlograms of pairwise receivers. In this work, we propose to double the correlation process of relative-correlation stacking, which is based on the differential traveltime from a master event and a target event to receivers. By doubling the correlation process, the origin time decouples itself to the relative location problem, and the stacking process becomes less sensitive to traveltime perturbations. We also generalize different correlation-based imaging methods by approximating the beamforming algorithm with cross-correlation process. Numerical examples demonstrate the feasibility of the proposed method and the generalization.