Attenuation relationship of macroseismic intensity in Italy for probabilistic seismic hazard assessment

A statistical analysis of macrosesmic intensity decay with distance has been conducted by using the most recent compilation of felt intensities relative to Italian earthquakes. An innovative aspect of the present study has been the attempt to define criteria for the validation of the attenuation relationships considered in their complete probabilistic form by a quantitative comparison with observed macroseismic fields. From the results of our analyses, a new attenuation relationship is proposed for the Italian territory, based on two independent variables only: epicentral intensity and hypocentral distance. Preliminary indications on the existence of differentiated attenuation features of macroseismic intensity over the national territory were gained.