Accession Number : ADP204427

Title :   Investigation of Attenuation and Blockage of Lg in the Vicinity of the Kyrgyz Array,

Corporate Author : CONNECTICUT UNIV STORRS

Personal Author(s) : Cormier, Vernon F. ; Anderson, Tom

PDF Url : ADP204427

Report Date : 14 AUG 1995

Pagination or Media Count : 8

Abstract : Synthetic seismograms and ray paths obtained by 3-D dynamic ray tracing are compared with regional seismograms from the KNET array in the Republic of Kyrgyzstan, in the former Soviet Union. Variations in regional waveforms recorded by the KNET array in the Republic of Kyrgyzstan are compared with predicted variations in the paths of multiple SmS waves comprising the Lg phase using the database of Moho topography by Fielding et al. (1993). Ray diagrams predict strong regional variations Lg efficiency in Kyrgyz area. The strongest variations in observed Lg amplitudes and predicted Lg paths are associated with strong gradients in Moho topography along the Hindu Kush and Pamir mountain ranges. Lg is nearly extinguished for paths from shallow events to the southwest of the Kyrgyz array, which traverse regions of strong Moho gradient Detailed variations of waveforms across the Kyrgyz array are consistent with Lg efficiency being proportional to the length and number of times SmS ray paths traverse regions of strong Moho gradient Synthetic seismograms predict that crustal thickness variations will either compress or stretch the Lg coda compared to that predicted in a crust of uniform thickness.

Descriptors :   *SEISMIC DETECTION, *SEISMIC WAVES, *ARMS CONTROL, *NUCLEAR EXPLOSION DETECTION, *SEISMIC DISCRIMINATION, *MOHOROVICIC DISCONTINUITY, USSR, SYMPOSIA, SURFACE WAVES, VERIFICATION, UNDERGROUND EXPLOSIONS, TOPOGRAPHY, NUCLEAR EXPLOSION TESTING, THREE DIMENSIONAL, SEISMIC DATA, EARTH CRUST, TREATIES, RAY TRACING, EARTH MANTLE, SEISMOGRAPHS.

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

Distribution Statement : APPROVED FOR PUBLIC RELEASE