Microearthquake clustering near Fairview Peak, Nevada, and in the Nevada Seismic Zone

The spatial-temporal clustering of microearthquakes near Fairview Peak, Nevada, is parameterized by means of a generalized Poisson model. A ‘cluster’ is defined empirically with the criteria that (1) occurrence times of shocks are within 10 min of each other and (2) focal separation is less than several hundred meters. The cluster size parameter for this sequence E = 3.5 is similar to that found for other world regions. For larger events (2 < M < 4.2) occurring in the Nevada seismic zone, significant variations in clustering tendency were observed for six areas examined. However, the occurrences of clusters and single events were found to be approximately randomly distributed in time during a 2-year period.