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Broadband records of earthquakes in deep gold mines and a comparison with results from SAFOD, California

January 1, 2009

For one week during September 2007, we deployed a temporary network of field recorders and accelerometers at four sites within two deep, seismically active mines. The ground-motion data, recorded at 200 samples/sec, are well suited to determining source and ground-motion parameters for the mining-induced earthquakes within and adjacent to our network. Four earthquakes with magnitudes close to 2 were recorded with high signal/noise at all four sites. Analysis of seismic moments and peak velocities, in conjunction with the results of laboratory stick-slip friction experiments, were used to estimate source processes that are key to understanding source physics and to assessing underground seismic hazard. The maximum displacements on the rupture surfaces can be estimated from the parameter , where  is the peak ground velocity at a given recording site, and R is the hypocentral distance. For each earthquake, the maximum slip and seismic moment can be combined with results from laboratory friction experiments to estimate the maximum slip rate within the rupture zone. Analysis of the four M 2 earthquakes recorded during our deployment and one of special interest recorded by the in-mine seismic network in 2004 revealed maximum slips ranging from 4 to 27 mm and maximum slip rates from 1.1 to 6.3 m/sec. Applying the same analyses to an M 2.1 earthquake within a cluster of repeating earthquakes near the San Andreas Fault Observatory at Depth site, California, yielded similar results for maximum slip and slip rate, 14 mm and 4.0 m/sec.

Publication Year 2009
Title Broadband records of earthquakes in deep gold mines and a comparison with results from SAFOD, California
DOI 10.1785/0120080336
Authors Arthur F. McGarr, M. Boettcher, Jon Peter B. Fletcher, Russell Sell, Malcolm J. S. Johnston, R. Durrheim, S. Spottiswoode, A. Milev
Publication Type Article
Publication Subtype Journal Article
Series Title Bulletin of the Seismological Society of America
Index ID 70035875
Record Source USGS Publications Warehouse
USGS Organization Earthquake Science Center