Seismic magnitude scales the amount of slip, the area of the surface ruptured or slipped, and a factor for the resistance or friction encountered. These factors can be estimated for an existing fault to determine the magnitude of past earthquakes, or what might be anticipated for the future. An earthquake's seismic moment can be estimated in various ways, which are the bases of the M, M, M, M, M, M, and M scales, all subtypes of the generic M scale. See for details. Seismic moment is considered the most objective measure of an earthquake's "size" in regard of total energy. However, it is
Seismic interferometry of primaries and multiples. Additional equations can be derived to reconstruct signal geometries in a wide variety of cases. Seismic interferometry is currently utilized primarily in research and academic settings. In one example, passive listening and the crosscorrelation of long noise traces was used to approximate the impulse response for shallow subsurface velocity analysis in Southern California. Seismic interferometry provided a result comparable to that indicated using elaborate inversion techniques. Seismic interferometry is most often used for the examination of the near surface and is often utilized to reconstruct surface and direct waves only. As such, seismic interferometry is commonly