CORRELATION DETECTION OF SEISMIC DISTURBANCES

Abstract : In a medium in which noise and signal propagate with different velocities, a detection scheme making use of the cross-correlation between the received waveforms at two different locations offers a number of distinct advantages over one making use of ordinary autocorrelation of the received waveform. These advantages arise from the resultant relative shift between the noise and signal autocorrelation functions allowing for separation of noise and signal when the noise characteristics or statistics are unknown, and even where the processes are non-stationary. Ramifications of the correlation shift are an improvement in signal-to-noise ratio (even when noise characteristics are known) , and capability for measurement of velocity, signal source direction, and signal and noise and channel characteristics. (Author)