Seismic Event Location at Regional and Teleseismic Distances
Abstract
3-component data from Kazakhstan events were analyzed to model the structure and examine the use of secondary phases in event location. Including PmP decreases focal depth uncertainty. All but one of the events are concluded to be explosions; the remaining event is uncertain. Using this structure for the source region, we model nuclear explosions at KTS recorded at 4 stations in the distance range 600-1000 km using a modification of the generalized ray method with separate source and receiver structures. We match first arrivals within about 0.3 seconds, secondary phases within about a second, and obtain good fits to the waveform envelopes. Locations of nuclear explosions from 1987 to 1989 at Balapan, KTS, were derived with a precision of about 100 m from time-sequence satellite images and teleseismic epicenter estimates. Ground control points for rectification were obtained from information on explosions in Bocharov et al. (1989). Fresh disturbances in satellite images are associated with individual explosions. The seismic locations have error estimates that are too small: in 80% of cases, events lie outside the error ellipses. Our effort was extended to the analysis of LANDSAT images. We have identified nearly all explosion sites from 1973 through 1985.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 31, 1992
- Accession Number
- ADA266873
Entities
People
- C. H. Thurber
- H. R. Quin
Organizations
- University of Wisconsin–Madison