Accession Number : ADP204418

Title :   Regional Wave Attenuation and the Lg/P Discriminant,

Corporate Author : SCIENCE APPLICATIONS INTERNATIONAL CORP SAN DIEGO CA

Personal Author(s) : Sereno, Thomas J., Jr. ; Wahl, Darrin D. ; Jenkins, Richard D. ; Williams, Donna J.

PDF Url : ADP204418

Report Date : 14 AUG 1995

Pagination or Media Count : 11

Abstract : Results from previous empirical studies indicate that the high-frequency Lg/P ratio is one of the most promising discriminants at regional distances. However, many of these studies are based on co-located earthquakes and explosions in limited geographic regions, and their results must be recalibrated for each new source region. We just started a two-year research project to develop frequency-dependent attenuation models for regional phases and to use them to generalize the high-frequency Lg/P discriminant for use in uncalibrated source regions. We plan to develop attenuation models for up to 10 primary (or Alpha) stations from the Group of Scientific Experts Technical Test (GSETT-3). These models will be used to normalize frequency-dependent Lg/P amplitude ratios for thousands of events recorded during GSETT-3 to a common reference distance. We will develop discriminants based on these distance-corrected ratios, and we will evaluate their effectiveness and limitations (including the sensitivity to the accuracy of the attenuation models). We will obtain ground-truth identification for as many of the events as possible, and we will use knowledge of the local natural and industrial seismicity to qualitatively evaluate effectiveness when this information is not available. We will attempt to generalize the distance-corrected Lg/P ratio by geological and tectonic environment so that this discriminant can be extrapolated with confidence to uncalibrated regions.

Descriptors :   *SEISMIC DETECTION, *ARMS CONTROL, *NUCLEAR EXPLOSION DETECTION, *SEISMIC DISCRIMINATION, *EARTHQUAKES, COMPUTER PROGRAMS, EUROPE, SYMPOSIA, UNDERGROUND EXPLOSIONS, NUCLEAR EXPLOSION TESTING, MINING ENGINEERING, SEISMIC WAVES, ATTENUATION, TREATIES, AMPLITUDE, ELASTIC WAVES, TECTONICS, SURFACE TRUTH.

Subject Categories : Government and Political Science
      Seismology
      Target Direction, Range and Position Finding
      Nuclear Weapons
      Mining Engineering
      Computer Programming and Software

Distribution Statement : APPROVED FOR PUBLIC RELEASE