Pearce Focal Sphere Analysis of Explosion and Earthquake Mechanisms.
Abstract
Pearce's (1977) processor for analyzing seismic focal mechanisms has been implemented on two seismic analysis systems, and it has been given limited testing for use as a discrimination aid. This algorithm uses relative amplitudes of the pP and sP depth phases with respect to the P-wave amplitude at each station in a network. If pP and/or sP cannot be identified, then the amplitude of the P-wave coda at the anticipated arrival time of the undetected depth phase may be used as an upper limit on the amplitude of that phase. The solution space of double-couple seismic sources is searched for possible solutions consistent with the relative amplitude bounds which were measured at each station. If no solution can be found, then either the 'depth phases' were misidentified or the event was not a double-couple (i.e., it may have been an explosion). The algorithm and support software have been installed at the Seismic Research Center on the Seismic Research Information System and at the Center for Seismic Studies. A description of both systems is given. Examples of the use of the algorithm as a seismic analysis tool are presented. Theoretical analysis was performed to evaluate the utility of the constraint on the amplitude of the depth phases which is provided by the amplitude of the seismic coda as a discrimination tool for testing the hypothesis that the event is an earthquake at depth.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 10, 1983
- Accession Number
- ADA145215
Entities
People
- D. W. Rivers
- K. L. Mclaughlin
- M. A. Brennan