EVALUATION OF THE MULTIPLE ARRAY PROCESSOR IN DETECTING P-WAVE MOTION AT THE T.F.S.O.
Special rept. no. 14,
UNITED ELECTRODYNAMICS INC PASADENA CALIF
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The MIP detected a lower number of arrivals than Sum B sub 2, probably because it enhances high frequency noise at any single seismometer and because of its lower re sponse to signals with periods greater than 1.0 seconds. The wave form of a seismic signal is changed to some extent by MIP, but direction of first motion appears to be the same as for Z-1 and Sum B sub 2. This may be caused by background noise on one or more seismometers. Examination of the records indicates that MIP, used with individual seismometers andor a high gain filtered summation trace, is quite useful as an analysis aid, but possibly due to phase shift, or period of the first P arrival, the time delay appears to vary from 0.8 to 1.2 seconds, so timing of events is not being done from this trace. Visual evaluation of signal-to-noise ratios on MIP, Z-1, Sum B sub 1 and Sum B sub 2 shows there is generally an enhancement of signal-to-noise ratio by MIP relative to Z-1, Sum B sub 1 and Sum B sub 2, but high frequency noise on a single seismometer causes much more noise on MIP than on Sums B sub 1 and B sub 2.