Accession Number : ADA326979

Title :   Crustal Waveguide Effects on Regional Phases in China and Southeast Asia.

Descriptive Note : Scientific rept. no. 1,

Corporate Author : CALIFORNIA UNIV SANTA CRUZ EARTH SCIENCE BOARD

Personal Author(s) : Lay, Thorne ; Fan, Guangwei ; Rodgers, Arthur

PDF Url : ADA326979

Report Date : 10 MAR 1997

Pagination or Media Count : 159

Abstract : This research program is addressing the issue of reducing scatter in regional phase discriminant measures associated with waveguide irregularity. We seek to 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. We are applying multiple regression analysis for several path properties to all CDSN stations and all broadband stations in the Middle East under this contract. This report presents two preprints: the first addresses variance reduction of discriminant measures at station WMQ, demonstrating the new methodology, and the second is a technical study comparing discriminant measurement procedures applied to data for the Middle East. An appendix documents the full set of empirical relations found for our data for WMQ.

Descriptors :   *SEISMIC WAVES, *SEISMIC DISCRIMINATION, STATIONS, MIDDLE EAST, WAVEGUIDES, TOPOGRAPHY, REGRESSION ANALYSIS, EARTH CRUST, SEDIMENTATION, CHINA, DISCRIMINATE ANALYSIS.

Subject Categories : Seismology
      Geography
      Statistics and Probability

Distribution Statement : APPROVED FOR PUBLIC RELEASE