LARGE APERTURE SEISMIC ARRAY CAPABILITIES
MASSACHUSETTS INST OF TECH LEXINGTON LINCOLN LAB
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The report presents the results of a study of the effectiveness of the experimental Large Aperture Seismic Array in Montana. An attempt has been made, where possible, to draw conclusions from the study of this one station about the performance that might be expected from a worldwide net of several of them. The report discusses the reliability and continuity of observations obtainable from a LASA system, the threshold level for automatic detection and location of weak events, the various signal-to-noise enhancement processes available for on-line and off-line use, and the effect of such enhancements on the ability to discriminate source type. The engineering approaches and system organization that were chosen appear to have resulted in a system of high reliability in the presence of normal component failures, noise, and seismic interference. The 50 percent detection threshold being currently achieved by relatively crude on-site processing is estimated at magnitude 3.5. Off-line processing gains in signal-to-noise ratio equivalent to a magnitude differential of 1-14 over a single seismometer output are available. The improvement in ability to see waveform features for identification depends on the type of feature being examined. For first motion, it varies with the signal-to-noise gain for pP, it is significantly larger.
- Seismic Detection and Detectors