Accession Number : ADA332350

Title :   Analysis of Digital Teleseismic Array Data Collected in South Central Siberia and Northern Mongolia, GSN SKS Waves and S Waves from Lop Nor Nuclear Explosions

Descriptive Note : Final rept. 4 Feb 94-31 Dec 96

Corporate Author : CALIFORNIA UNIV LOS ANGELES DEPT OF EARTH AND SPACE SCIENCES

Personal Author(s) : Davis, Paul M. ; Gao, Shangxing ; Borton, Laura

PDF Url : ADA332350

Report Date : 27 FEB 1997

Pagination or Media Count : 74

Abstract : The objective of this research is to provide information on seismic wave propagation in areas of large scale heterogeneity. Data collected in south central Siberia and northern Mongolia have been analyzed along with digital data from the Global Seismic Network in order to identify effects on the propagation caused by large scale heterogeneity in the mantle. These effects need to be taken into account when using seismic arrays to monitor the Comprehensive Test Ban Treaty. It has been discovered that in the vicinity of the Baikal rift zone in Siberia, P and S waves exhibit anomalous delays and attenuation. S waves show clear evidence of the effect of anisotropy. This region that extends over several hundred km along and on either side of the rift zone represents an attenuating and delaying mantle barrier to the seismic phases. These findings can be used to infer properties of analogous tectonic regions world-wide. All stations of the GSN have been analyzed for SKS splitting in the mantle which is recognized as scattering of radial energy into tangential energy. Station characteristics observations have led to development of a new method to identify deep mantle scatterers.

Descriptors :   *SEISMIC DATA, *SEISMIC WAVES, DATA BASES, NUCLEAR EXPLOSIONS, HETEROGENEITY, SEISMIC VELOCITY, SEISMIC ARRAYS, EARTH MANTLE, SIBERIA.

Subject Categories : Seismology

Distribution Statement : APPROVED FOR PUBLIC RELEASE