Rockburst Model Validation
Abstract
Characterization of mining-related seismic events is critical to the implementation of the Comprehensive Nuclear Test-Ban Treaty monitoring system. Mine seismicity from uncontrolled sources are particularly troublesome, with magnitudes up to 4 or 5, producing signal strengths comparable to 1-10 kiloton contained nuclear explosions. The Coeur d'Alene district in northern Idaho is the most rockburst-prone mining district in the United States, producing a daily average of about 3 events with magnitudes ranging from 0 to 4. The hypocenter of many of these events are determined to an accuracy of within 30 meters by in-mine rockburst monitoring systems operated by the mining companies. Focal mechanism studies based on these systems, and a district-wide surface seismic network, indicate predominantly dilatational first motions events. We deployed a local seismograph system in the summer of 1998 to determine the source parameters and moment tensors for seismic events in the region in particular to confirm the shear implosional mechanisms suggested by the first motion studies. In this study, ground motions from four surface stations and one underground station were inverted to determine the complete moment tensor of a relatively large rockburst in the Coeur d'Alene Mining District in northern Idaho. Many rockbursts induced by the mining process show shear implosional source mechanisms a feature that should be useful to discriminate mining-related events from underground explosions.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 2004
- Accession Number
- ADA423547
Entities
People
- Allan C. Rohay
- Kenneth F. Sprenke
- Michael C. Stickney
Organizations
- University of Idaho