- Copyright © 1989, by the Seismological Society of America
The clustering properties of Italian seismicity are analyzed statistically on the basis of the Istituto Nazionale di Geofisica seismic catalog. The traditional generalized Poisson model is found to be inefficient for a quantitative analysis. Based on the influence region, a new model is developed that allows to assess some spatial features of clustering as well. The results are the following: (1) there is no evidence of migration; (2) clustering is mostly originated by main shock-aftershock sequences; (3) cluster parameters are function of the region studied; (4) several different parameterizations are possible; and (5) the best fit is provided by an influence region of respectively 14 days to 60 days and 80 to 140 km.