SCALING RELATIONS FOR SEISMIC EVENTS INDUCED BY MINING

The values of seismic moment and S-wave corner frequency from 1575 seismic events induced in South African, Canadian, Polish, and German underground mines were collected to study their scaling relations. The values of P-wave corner frequency from 649 events were also available. Seismic moments of these events range from 5 * 10(3) to 2 * 10(15) N . m (moment magnitude is from -3.6 to 4.1), the S-wave corner frequency ranges from 0.7 to 4438 Hz, and the P-wave corner frequency is between 5 and 4010 Hz. The slope of a regression line between the logarithm of S- and P-wave corner frequencies is equal to one, and the corner frequencies of P waves are higher than those of S waves on the average by about 25 percent. In studies of large and moderate earthquakes it has been found that stress drop is approximately independent of the seismic moment, which means that seismic moment is inversely proportional to the third power of corner frequency. Such a behavior was confirmed for most of the data considered here. A breakdown in the similarity between large and small events seems to occur for the events with moment magnitude below -2.5. The average values of seismic moment referred to the same range of corner frequency, however, are vastly different in various mining areas.