Mine seismicity: prediction or
forecasting?
SM Spottiswoode
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.