Accession Number : ADP204501

Title :   New Techniques for Estimating Source Depth and Other Diagnostic Source Characteristics of Shallow Events from Regional Observations of P, Lg, and Rg Signals,

Corporate Author : PENNSYLVANIA STATE UNIV UNIVERSITY PARK

Personal Author(s) : Alexander, Shelton S. ; Hsu, Roy C. ; Karl, Sheri L. ; Gupta, Indra N. ; Salzbert, David H.

PDF Url : ADP204501

Report Date : 14 AUG 1995

Pagination or Media Count : 10

Abstract : As part of a broader study to develop effective regional discriminants for Iran (and other areas of interest) a new cepstral stacking method for estimating source depth from a single, short-period regional station has been developed and tested, and new insights have been gained on why high frequency Lg/P is a very good discriminant for different source regions while low-frequency (less than about 5 Hz) Lg/P is not. It is shown that stacking (product or sum) of the cepstra of multiple sub-windows spanning the total P and P-coda time window enhances the depth phase delays, (pP - P) and (sP - P), with respect to other delay times from crnstal phases, such that accurate depth determination can be made from a single, short-period regional signal. Further enhancement can be achieved by also stacking individual stacked cepstra over multiple regional stations. The stacked product of individual cepstra gives a better result than the stacked sum, because contributions from other delay times that are prominent in some sub-windows are more-effectively suppressed in the product. The method has been tested on regional events in fran for which multiple teleseismic pP observations are available; on Soviet Test Site (STS) nuclear explosions and one STS earthquake recorded in Iran; and on synthetic regional signals. It appears that with reasonable signal bandwidth and signal-to-noise levels accuracies in depth of about 1 km or better can be achieved for crustal events using this method.

Descriptors :   *SEISMIC DETECTION, *SEISMIC WAVES, *ARMS CONTROL, *NUCLEAR EXPLOSION DETECTION, USSR, SYMPOSIA, SURFACE WAVES, VERIFICATION, MONITORING, SIGNAL TO NOISE RATIO, UNDERGROUND EXPLOSIONS, MINING ENGINEERING, EARTH CRUST, SEISMIC DISCRIMINATION, TREATIES, EARTHQUAKES, STACKING, IRAN, RAYLEIGH WAVES, SEISMOLOGICAL STATIONS, DEPTH FINDING.

Subject Categories : Government and Political Science
      Seismology
      Seismic Detection and Detectors
      Nuclear Weapons

Distribution Statement : APPROVED FOR PUBLIC RELEASE