Paleoseismology related to deformed archaeological remains in the Fucino Plain. Implications for subrecent seismicity in Central Italy

Abstract

During paleoseismological investigations on the seismogenic structure responsible for the 1915 earthquake in the Fucino Plain (Central Italy), some trenches were excavated at the intersection between Roman-age channels and a fault characterized by Holocene activity. Channel displacement observed within the trenches has been related to an event which occurred approximately between the 6th and 9th century A.D. Written records describing damage caused in Rome indicate that two strong events occurred during this period in Central Italy, although their epicentral areas are Undefined. The first event occurred immediately before 508 A.D. while the second happened in 801 A.D. Two other earthquakes during this period (618 A.D. and 847 A.D.) are reported in catalogues, but without( corresponding information regarding damage in Rome. Available information is not conclusive about the age of the earthquake responsible for the displacement of the channels although geological, historical and archaeological data indicate it is most likely related to the 508 A.D. event. Should the hypothesis regarding the age of the earthquake be correct, a subrecent , incompletely-documented earthquake may be related to a specific seismogenetic area. Taking into account that the paleoseismological analysis has highlighted a close similarity between the surface faulting pattern of this event and the one that occurred in 1915, the former may be a "twin" of the latter.