On-line version ISSN 2411-9717
J. S. Afr. Inst. Min. Metall. vol.110 n.1 Johannesburg Jan. 2010
Mine seismicity: Prediction or forecasting?
Florida Park, Johannesburg, South Africa
Much as one hopes to predict whether damaging seismicity might occur somewhere in the next shift, this is not possible at present. Recently, an analysis of seismicity at two mines has shown that a small increase in seismicity occasionally occurs before both large and small events. This analysis is extended here to five mines, with the same results.
Earthquake seismologists forecast hazard in terms of the average incidence of earthquakes over the last 50 years, adjusted on an hourly basis according to the possibility of aftershocks of events that have happened.
The rate of seismicity in any area remains approximately constant when expressed as seismicity per area mined, or better still, per unit of elastic strain energy released. It is suggested that seismic hazard in mines be estimated using historical seismicity and forward modelling, adjusted according to the possibility of aftershocks.
In summary, medium-term forecasting of seismicity is viable; short-term prediction of large events is not.
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