SPACE-TIME VARIATIONS OF THE FREQUENCY-ENERGY RELATION FOR MINING-INDUCED SEISMICITY IN THE OSTRAVA-KARVINA MINING DISTRICT

The values of parameters of the relation log N = a - b log E character ize in general the level of seismicity of individual regions. In the p resent paper, a detailed analysis of b values of the frequency-energy distributions was carried out with the aid of a database of seismic ev ents recorded by the seismological networks in the Ostrava-Karvina Coa l Mine District (Czech Republic), using the least squares regression a nd maximum likelihood method, as well. The determination of b value wa s performed for a relatively large number of regions investigated and for different time series of observations. Special attention has been paid to induced seismic events statistics for the vicinity of one of t he coalfaces in the Lazy Mine. It could be generally stated that lower b values correspond to a higher level of induced seismic activity, wh ile the higher ones correspond to a low and a moderate seismic activit y.