Case Studies of Seismic Discrimination Problems and Regional Discriminant Transportability.
Abstract
This report describes case studies of regional seismic discriminants, using the Intelligent Seismic Event Identification System (ISEIS), and addresses issues related to the transportability of regional discriminants. Some of the key results of this study include: (1) Observations of large Lg waves from mine blasts. (2) Investigation of the P/S frequency-dependence discriminant. (3)The importance of signal decorrelation in the generation of spectral scalloping by ripple fired mine blasts. (4) Path corrections for the Lg spectral ratio discriminant using a simple anelastic attenuation model. Also described in this report is a discrimination study of the January 5, 1995 Urals mine event. Because there were no nearby earthquakes or blasts in the Urals mine region, recordings of the event at regional station ARU were compared with WMQ recordings of Chinese nuclear blasts and earthquakes at comparable distance, but in a different geographic and tectonic region. This comparison indicated that the January 3, 1995 event had Pn/Lg amplitude ratios more comparable to Chinese earthquakes than nuclear explosions. Based on the analysis of Pn/Lg ratios at NORESS and comparison those produced by PNEs in the same region recorded at NORSAR, we conclude that the January 3, 1995 event produced much stronger shear waves (Sn, Lg) relative to P than did nuclear blasts. We conclude that the event was probably a mine tremor or collapse.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 31, 1995
- Accession Number
- ADA302362
Entities
People
- Douglas R. Baumgardt