Discrimination of P-wave interval in time-quefrency analysis for proximity microseismic doublets

We describe a new method to determine an interval between P-waves in similar, overlapping microseismic events. Analysis of such similar, overlapping microseismic events can provide precise relative source location because change of velocity structure is negligible. It is necessary to detect the interval between the P-waves for the relative source location. Cepstrum analysis can provide the interval even though the second event overlaps the first event. However, the cepstrum has two peaks, one representing the interval between the arrivals of the two P-waves, and the other the interval between the arrivals of the two S-waves. We used window functions in cepstrum analysis to suppress the second S-wave. We extend the window function and calculate cepstrum in each window function. These cepstra are arranged in a contour plot. We describe four points of view to discriminate the P-wave peak from the S-wave peak in the contour plot.