Accession Number : ADA332251

Title :   Investigation of Characteristics of Seismic Waves from the May 21, 1992 Lop Nor Nuclear Explosion Using IRIS Broadband Data

Descriptive Note : Final technical rept. 25 May 94-24 May 97

Corporate Author : CALIFORNIA UNIV SANTA CRUZ

Personal Author(s) : Zhang, Jiajun

PDF Url : ADA332251

Report Date : 06 OCT 1997

Pagination or Media Count : 28

Abstract : This is the final report for this grant to develop new seismological techniques for source characterization of nuclear explosions and earthquakes using broadband waveforms. Two studies are presented. The first study demonstrated that source parameters determined using routine methods are often biased due to unmodeled effects of the earth's structure. For the January 17, 1994 Northridge, California earthquake, we examined the results obtained using various techniques and concluded that a special technique must be developed for characterization of seismic events when the earth's velocity and attenuation structure is only moderately constrained. The primary effects of the study were directed at developing a new approach to optimizing the performance of source inversion methods. The efforts resulted in the development of an algorithm called the Earth Simplifying Transformation (EST), which can be incorporated in various methods of waveform analysis for improved source characterization. The second study extended and applied the EST algorithm to the broadband seismic recordings from earthquakes and nuclear explosions in Xinjiang, China. These studies demonstrated that the EST method holds promise for reliable source characterization for small events in a calibrated region and that the primary use of the method is in improving empirical calibrations in seismic-event monitoring.

Descriptors :   *NUCLEAR EXPLOSIONS, *EARTHQUAKES, ALGORITHMS, WAVEFORMS, GROUND SHOCK, UNDERGROUND EXPLOSIONS, GROUND MOTION, SEISMIC DATA, SEISMIC VELOCITY.

Subject Categories : Seismology
      Explosions

Distribution Statement : APPROVED FOR PUBLIC RELEASE