Accession Number : ADP204417

Title :   Path Calibration and Regional Discriminants in North Africa and the Middle East,

Corporate Author : WOODWARD-CLYDE FEDERAL SERVICES PASADENA CA

Personal Author(s) : Saikia, Chandan K. ; Woods, B. B.

PDF Url : ADP204417

Report Date : 14 AUG 1995

Pagination or Media Count : 10

Abstract : Reviews on the effectiveness of regional discriminants suggest that discriminant rules developed for one region do not readily apply to another. However, it is feasible to apply these discriminants in a new region provided relative path corrections for various seismic phases are available. We are presently investigating path corrections for the North Africa and other Middle East regions around the GSETT-3 stations. Our objective is to develop regional magnitude relationships using the amplitude distance corrections that will be obtained from the crustal models. To this end, regional broadband seismograrns recorded by the operational GSETT-3 stations in these regions will be modeled by calibrating the regional waveguide to establish path corrections for individual phases. For those GSETT-3 stations which have not become operational yet, regional seismograms from the nearby WWSSN stations will be analyzed. Whenever possible, we will select large earthquakes which are recorded regionally and teleseismically, and for which their focal mechanisms have been determined previously. To date, we have collected regional waveforms recorded at KEG (Kottamiya, Egypt, operating since 1990), HLW (Halwan, Egypt) and KIV (Kislovodsk, CIS), and modeling of these waveforms has just started. This study also includes finding path corrections for regional phases around a newest GSETT-3 array, PAKO deployed near Nilore (NIL, location of a former WWSSN station) in Pakistan. This array is also located southwest of a recent PASCAL experiment which consisted of nine broadband stations. Initial success in modeling regional seismograms from this PASCAL experiment is quite promising and we have already obtained a preliminary crustal structure model near the PAKO array.

Descriptors :   *SEISMIC DETECTION, *ARMS CONTROL, *NUCLEAR EXPLOSION DETECTION, *SEISMIC DISCRIMINATION, *EARTHQUAKES, PAKISTAN, SYMPOSIA, MIDDLE EAST, UNDERGROUND EXPLOSIONS, NUCLEAR EXPLOSION TESTING, SEISMIC DATA, EARTH CRUST, SEISMIC WAVES, TREATIES, AMPLITUDE, NORTH AFRICA, SEISMOLOGICAL STATIONS, SEISMOGRAPHS.

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

Distribution Statement : APPROVED FOR PUBLIC RELEASE