Accession Number : ADA291214

Title :   Analysis of 3D Complex Structure and Heterogeneity Effects on Formation and Propagation of Regional Phases in Eurasia.

Descriptive Note : Final rept. 15 Aug 92-30 Sep 94,

Corporate Author : CALIFORNIA UNIV SANTA CRUZ INST OF TECTONICS

Personal Author(s) : Lay, Thorne ; Wu, Ru-Shan

PDF Url : ADA291214

Report Date : 13 DEC 1994

Pagination or Media Count : 66

Abstract : This is the final report for this grant to develop new three-dimensional wave propagation techniques for high frequency waves in heterogeneous media. The report is divided into four sections, each being a published paper sponsored by this grant. In the first section we formulate a one-way wide-angle elastic wave propagation method for arbitrarily heterogeneous media in both the space and wavenumber domains using elastic Rayleigh integrals and local elastic Born scattering theory. In the second section this complex phase screen method is compared with fourth-order finite differences and exact eigenfunction expansion calculations for two-dimensional inhomogeneous media to assess the accuracy of the one-way propagation algorithm. In the third section, an observational study of continental margin structure influence on Lg propagation is presented, using data from the former Soviet stations for nuclear explosions at Novaya Zemlya. We find that bathymetric features can be correlated with energy levels of Lg, suggesting that waveguide structure influences regional phase energy partitioning. This idea is pursued in the fourth section, using Eurasian earthquake and nuclear explosion data along with information about the crustal structure in Eurasia. We develop empirical relations that reduce the scatter in the P/Lg discriminant at low frequency. (MM)

Descriptors :   *SEISMIC WAVES, *NUCLEAR EXPLOSION DETECTION, *EARTHQUAKES, USSR, SCATTERING, HIGH FREQUENCY, ACOUSTIC WAVES, WAVEGUIDES, SEISMIC DETECTION, THREE DIMENSIONAL, WAVE PROPAGATION, EARTH CRUST, SEDIMENTS, EURASIA, PRIMARY WAVES(SEISMIC WAVES), ELASTIC WAVES, SECONDARY WAVES, BORN APPROXIMATIONS.

Subject Categories : Seismology
      Nuclear Weapons

Distribution Statement : APPROVED FOR PUBLIC RELEASE