Crustal Waveguide Effects on Regional Phases in China and Southeast Asia
Final technical rept. 11 Aug 95-11 Nov 97
CALIFORNIA UNIV SANTA CRUZ INST OF TECTONICS
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This research program addressed the issue of reducing scatter in regional phase discriminant measures associated with waveguide irregularity. We empirically reduce discriminant measure variance, using along path measures obtained from data bases for surface topography, crustal thickness, and sedimentary layer thickness. Several path specific measures are found to have significant correlations with regional discriminant measurements, both before and after correction for propagation distance, for events in China and the Middle East. For station WMQ, in western China, variance reductions two to three times as large as those for distance corrections alone can be achieved by simple empirical models obtained by multiple regression analysis. Multiple regression analysis is applied for several path properties to all CDSN stations and broadband station ABKT in the Middle East under this contract. This final report presents four preprints the first addresses variance reduction of discriminant measures at station WMQ, the second applies the same methodology to all stations in two sub-regions in China. The third applies an azimuthal sector analysis to data for station ABKT, and the fourth applies the multiple regression procedure to ABKT. Two earlier papers sponsored by this contract are now in press.
- Seismic Detection and Detectors