Observations of shear-wave splitting from mining induced stress-failures

Local networks operated in the gold mines of South Africa record mining-induced events with local magnitude as low as -4 (Legge and Spottiswoode 1987) and occasionally exceeding 5 on the Richter scale. Nearly all events of magnitude 2 and above are also recorded and located by the National Seismological Network of the South African Geological Survey (Femandez and Du PIessis 1988).