Further Development of the Matched Filter Method for Solving Seismological Problems

The progress of seismology and geophysics as a whole depends on the detection thresholds and the accuracy of measuring physical signals. The repeatability of geophysical phenomena, such as earthquakes, allows for the efficient use of the matched filter (MF) as a detector of repeating signals. The MF detection threshold depends on the noise characteristics. For example, microseismic noise (MsN) is created by many physical sources and includes signals that may be partly coherent with the templates. Stochastic noise (StN), which is not present in a mathematically defined form in nature, is optimal for MF. In this paper, stochastization of MsN is achieved by adding StN generated by a random number generator to waveforms on seismic arrays (SA). The signal-to-noise ratio on SA increases by a factor of 5 in the presence of noise coherent to the signal in MsN. For MsN without dominant components, adding StN provides a gain of 2–3 times. A decrease in the rate of false alarms is observed, which also lowers the detection threshold.

matched filter, seismic array, physical noise, microseismic noise, stochastic noise