Seismicity of Northwestern Italy during the last 30 years

The aim of this work is to describe the seismicity of Northwestern Italy from the very detailed picture provided by 30 years of accurate instrumental recordings coming from the Regional Seismic Network of Northwestern Italy (RSNI—University of Genoa). In an attempt to provide, for the first time, a comprehensive view of the seismicity in the area, this study describes the main characteristics of the database collected by the RSNI network. The seismicity is spread almost over the entire area, but it is mainly concentrated in the Northern Apennines and in the western sector of the Alps. The seismicity of the area is superficial: It is almost confined to the first 20 km of depth. Only a few deeper events are located in a small area southwest of the city of Turin, down to a depth of 80 km, and below the Northern Apennines down to 60–70-km depth. The majority of the earthquakes in this sector of the Italian peninsula are of low magnitude; nevertheless, the areas where the highest magnitude earthquakes took place during the last three decades are the Northern Apennines and the lower Piedmont, on land, and the Ligurian Sea, offshore. They are indeed the areas where the most damaging historical earthquakes have occurred, giving emphasis, if necessary, to the importance of continuous seismic monitoring.