A simplified analysis of the total seismic hazard in Italy

Total seismic hazard assessment (i.e. the base hazard modified by local site conditions) plays a key role in seismic risk prevention and mitigation. This is an important topic due to the impact of a reliable hazard assessment on the resilience of local communities in the case of an earthquake. This paper presents a study that evaluates the total seismic hazard for the entire Italy (excluding the Island of Sardinia). The results are expressed in terms of amplification factors and total hazard parameters. To this end, soil characterisation was performed, firstly using Italian Seismic Network data for 259 sites uniformly distributed across Italy, and secondly using the mean value of the shear wave velocity, available from a global dataset produced by the United States Geological Survey. The amplification effects were quantified according to i) an approach consistent with the Italian Building Code; and ii) one-dimensional site response analyses. These two procedures are referred to as "parsimonious" and "rigorous" here, respectively. The results indicate a generally satisfactory match between the estimates obtained by means of these two procedures for periods lower than 0.5 s, while parsimonious procedures at periods longer than 0.5 s provide an upper limit on the total seismic hazard. Finally, a seismic classification in terms of the classes of total hazard parameters is proposed for the Italian peninsula area.