The January 15, 1466 and November 23, 1980 Irpinia (Italy) earthquakes

On the night between 14 and 15 January of 1466, an earthquake damaged towns close to those more recently destroyed by the 1980 Irpinia earthquake. It was felt in Naples, about 80 km from the epicentre, resulting in panic and slight damage. To obtain source parameters related to January 15, 1466, the observed macroseismic field of the November 23, 1980 earthquake was reproduced by synthetic peak strong acceleration. The results suggest that the whole of the 1466 faulting was again activated by the 1980 event and that the northern part remained non-activated. Quite possibly, the near southernmost source of the large earthquake of 1456 affected the occurrence of the nearby event ten years later. Furthermore, the value of Mo=7.5 1018 Nm obtained makes the medieval event of 1466 one of the most severe recorded in southern Italy.