Short-Period Earthquake Coda Shape as a Function of Geology and System Response
TELEDYNE GEOTECH ALEXANDRIA VA SEISMIC DATA ANALYSIS CENTER
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Measurements of short-period records from 33 earthquakes show that some Long Range Seismic Measurement LRSM stations have high levels of coda as compared to maximum motion, and that reverberation between successive coda maxima is less at stations overlying a low Q mantle than at those overlying a Q mantle. The differences are 0.1-0.2, and 0.1 magnitude units respectively. For times greater than 1 or 2 minutes into the coda, minimal coda levels are typically 0.3 magnitude units less than the maxima. Comparison with work by Filson shows that use of the maximum coda representation could lead to a 0.2 m sub b underestimation of the detection capability for mixed events for times greater than 2 minutes. There seems to be no difference in coda shape measurements made on data recorded at WWSSN or LRSM systems.
- Seismic Detection and Detectors