Methodology

In a microseismic data stream recorded by surface sensor networks, both excitation time and location of the source are unknown. An additional unknown factor, velocity, is involved and determined by estimation or prior information. Based on a specified velocity model, conventional imaging processes can be performed. In seismic diffraction imaging, path-integral time-domain migration (Burnett et al., 2011) bypasses velocity model construction and directly focuses hyperbolic events at source locations, if the onsets of the events are correctly compensated.