Seismicity in Mines

Recent seismological research has focused on processes other than pure shear failure (double-couple) as an alternative mechanism for some types of seismic events. This has been stimulated by what appears to be anomalous focal mecha nisms observed for several earthquakes of possible volcanic nature in the 1980 Mammoth Lakes, California sequence (JULIAN and SIPKIN, 1985; SIPKIN, 1986). Although studies have concentrated on earthquakes associated with magmatic processes, possible non-double-couple seismic failure has been observed, but not widely known, in cases of mine seismicity in the past three decades. Such cases have occurred on a world-wide basis; however, no cases until now have been observed in the United States. The existence of non-double-couple failure in mine seismicity has been controversial as it has been for tectonic/volcanic earthquakes. Several of the benchmark studies of mine seismicity in the deep South African gold mines have resulted in the belief that no fundamental distinction in the source mechanism exists between tectonic earthquakes and rock bursts (MCGARR, 1984); both types of events are the result of pure shear failure. However, the reported cases of implo sional focal mechanisms for mine seismicity continue to increase in number and prolong the controversy. During the summer of 1984, a three-dimensional, high resolution micro earthquake network was operated by Woodward-Clyde Consultants (WCC) in the vicinity of two coal mines beneath Gentry Mountain in the eastern Wasatch Plateau of central Utah.

Inhalt
Fred Leighton Memorial Workshop on Mining Induced Seismicity, August 30, 1987. Editorial. Papers presented at the Workshop. Panel discussion.- Analysis of exceptionally large tremors in two gold mining districts of South Africa.- The mechanism of small mining tremors from amplitude inversion.- Source mechanism of a large scale gas outburst at Sunagawa coal mine in Japan.- Mining-related and tectonic seismicity in the East Mountain area, Wasatch Plateau, Utah, U.S.A..- Observations of mine seismicity in the eastern Wasatch Plateau, Utah, U.S.A.: A possible case of implosional failure.- Microearthquake activity associated with underground coal-mining in Buchanan County, Virginia, U.S.A..- The Alabama, U.S.A., seismic event and strata collapse of May 7, 1986.- Induced seismicity in mines in Canadaan overview.- Analysis of mining-induced microseismic events at Strathcona mine, Sudbury, Canada.- Microseismicity in a flooded potash mine, the Hope mine, Federal Republic of Germany.- Changes in the early part of the seismic coda due to localized scatterers: The estimation of Q in a stope environment.- Seismological models for mining-induced seismic events.- Continuous evaluation of seismic hazard induced by the deposit extraction in selected coal mines in Poland.- Induced gravity anomalies and seismic energy as a basis for prediction of mining tremors.- Application of singular value decomposition method for location of seismic events in mines.- Geotomographic imaging in the study of mining induced seismicity.- Seismic tomography in the Ostrava-Karviná mining region.- Recognition of the zones of seismic hazard in Polish coal mines by using a seismic method.- Rockburst research at Falconbridge's Strathcona mine, Sudbury, Canada.- Laboratory and field investigations ofrockburst phenomena using concurrent geotomographic imaging and acoustic emission/microseismic techniques.- The Canada-Ontario-industry rockburst project.- Perspectives on seismic and rockburst research in the South African gold mining industry: 19831987.