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

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...

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Bibliographic Details
Main Authors: Lay, Thorne, Wu, Ru-Shan
Other Authors: CALIFORNIA UNIV SANTA CRUZ INST OF TECTONICS
Format: Text
Language:English
Published: 1994
Subjects:
Seismology
Nuclear Weapons
*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
RALEIGH WAVES
Raleigh
Novaya Zemlya
Online Access:http://www.dtic.mil/docs/citations/ADA291214
http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA291214
Description
Summary: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)

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