Spectral Discrimination between Explosions and Earthquakes in Central Eurasia
Rept. for 1 May 1989-May 1990
TELEDYNE GEOTECH ALEXANDRIA VA
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An analysis is performed of the seismic discrimination capabilities of regional phases recorded at the station WMQ in the Chinese Digital Seismic Network CDSN. This station is located at regional distances from both the Soviet test site in E. Kazakhstan and the seismically active Tien Shan area. The study is based on 3 spectral ratio discriminants PgLg spectral ratios, Pg and Lg frequency band ratios, and verticalhorizontal spectral ratios. Both short- period and broad-band data are used. The PgLg ratio is an effective discriminant between 3 and 12 Hz, and the verticalhorizontal ratios perform similarly to it, although in the case of Lg more study is needed to explain the value of this ratio. The Pg and Lg frequency band ratios were ineffective discriminants. The study attempts to identify the effects of propagation path and event depth on the discriminants. It appears that the spectral ratio discriminant remains effective for 2 earthquakes observed along paths close to the path from the test site to WMQ. In the scale of kilometers, event depth does control the Pg and Lg spectral ratios, but it is unlikely that this effect is observable in the scale of meters. Keywords Seismic data discrimination.
- Seismic Detection and Detectors