Abstract
The purpose of this paper is to characterise the source mechanisms of two large seismic events (magnitude Nuttli ≥ 3.0) using routine seismic data analysis tools. When there is no clear evidence of source mechanism type, there is a prevailing tendency to attribute fault slip mechanisms to large magnitude seismic events.This study uses seismic source parameter analysis to highlight characteristics of two large events that are more consistent with a stress-driven mechanism than a fault-related failure process.
While fault-related seismicity tends to be confined to the plane of a geologic feature, stress-driven seismicity tends to be controlled by regions of mining-induced stress around mine voids and can migrate as mining progresses. Using seismic data from an ultra-deep open stoping mine in northern Quebec, this study characterises a migrating rock mass failure region in the mine abutments. The locations of seismic events, including mine-scale occurrences, are linked to the advancing stoping front of the mine abutment. Introducing a novel tool, plane-based time–distance charts, enables the exploration of migrating regions of rock mass yield and facilitates event clustering for source parameter analysis. The self-similarity of the large events with the broader migrating failure region is assessed using the Gutenburg–Richter frequency–magnitude relation.
This analysis sheds light on the distinctive nature of stress-induced rock mass yield zones, providing insights for seismic hazard assessment in deep mining environments.
