Seismic moment Seismic moment Seismic moment is a quantity used by seismologists to measure the size of an earthquake. The scalar seismic moment formula_1 is defined by the equation formula_2, where formula_1 thus has dimensions of torque, measured in newton meters. The connection between seismic moment and a torque is natural in the representation of seismic sources as a pair of force couples. Seismic moment is not a measure of energy. The relations between seismic moment, potential energy drop and radiated energy are indirect and approximative. The seismic moment of an earthquake is typically estimated using whatever information is available to constrain
Seismic interferometry particularly for exploration in subsalt settings. Seismic interferometry provides for the possibility of reconstructing the subsurface reflection response using the crosscorrelations of two seismic traces. Recent work has mathematically demonstrated applications of crosscorrelation for reconstructing Green's function using wave field reciprocity theorem in a lossless, 3D heterogeneous medium. Traces are most often extended records of passive background noise, but it is also possible to utilize active sources depending on the objective. Seismic interferometry essentially exploits the phase difference between adjacent receiver locations to image the subsurface. Seismic interferometry consists of simple crosscorrelation and stacking of actual receiver responses to approximate