Earthquake grouping criteria for spatially heterogeneous seismicity

An advanced method for estimating the earthquake grouping parameters R cr and T cr is proposed in order to identify interrelated seismic events. The method pursues continuity with the previous algorithm suggested in (Mirzoev, 1980; 1988a; 1988b; 1992; Mirzoev and Azizova, 1983; 1984) but uses a more realistic spatial model of the background seismicity. All the calculations in the method can be fully formalized and a preliminary expert estimation of the parameters is not required. The method provides stable estimates of the critical radius R cr and time T cr of grouping. Group earthquakes make up 50 to 75% of their total number.