Accession Number : ADP204465

Title :   Wave Propagation Modeling Capabilities at LLNL: Applications to Regional Discrimination,

Corporate Author : LAWRENCE LIVERMORE NATIONAL LAB CA

Personal Author(s) : Schultz, C. A. ; Larsen, S. C. ; Goldstein, P. ; Ruppert, S. D.

PDF Url : ADP204465

Report Date : 14 AUG 1995

Pagination or Media Count : 10

Abstract : The numerical synthesis of regional seismograms has become an integral part of Lawrence Livermore National Laboratory's (LLNL) seismic discrimination program. In this paper, we summarize our fundamental approaches to numerical modeling. Our capabilities currently include reflectivity, normal mode, boundary integral, and finite-difference modeling, along with hybrid approaches which utilize two or more of these techniques together. We apply these capabilities to the discriminant variability along three different arrays deployed during the Non- Proliferation Experiment (NPE). Phase amplitudes have been calculated for the approximately three hundred regional stations which recorded the NPE. The majority of these recordings were to the west of the NPE, along one profile of the Southern Sierra Continental Dynamics (SSCD) refraction profile. Based on the three profiles which made up the SSCD refraction experiment, traveltime tomography was utilized to develop a well constrained 3D velocity model across a profile which extends from the Basin and Range, through the southern Sierra Nevada range, the Great Valley, to the San Andreas fault zone in the coastal ranges. The western array of the NPE regional deployment consisted of 285 stations coincident with this SSCD profile. This resulted in phase and discriminant coverage along one of the most well constrained velocity profiles in the western United states. Our analysis shows that although there is amplification of Pg and Lg, Pn has some of the most dramatic variations in amplitude. In California, these amplifications coincide with the western flank of the Sierra Nevada, the eastern quarter of the Great Valley, and the coastal ranges. In Nevada, a dramatic amplification occurred in the Broken Hills volcanic region.

Descriptors :   *SEISMIC DETECTION, *SEISMIC WAVES, *ARMS CONTROL, *NUCLEAR EXPLOSION DETECTION, *SEISMIC DISCRIMINATION, SYMPOSIA, SURFACE WAVES, MONITORING, UNDERGROUND EXPLOSIONS, FINITE DIFFERENCE THEORY, SEISMIC DATA, SEISMIC REFLECTION, WAVE PROPAGATION, EARTH CRUST, CALIFORNIA, ARIZONA, TREATIES, SEISMIC VELOCITY, SPECTRUM ANALYSIS, COLORADO, PRIMARY WAVES(SEISMIC WAVES), EARTH MANTLE, SURFACE TRUTH, NEVADA.

Subject Categories : Government and Political Science
      Seismology
      Seismic Detection and Detectors
      Nuclear Weapons
      Geology, Geochemistry and Mineralogy

Distribution Statement : APPROVED FOR PUBLIC RELEASE