Archaeological evidence for Roman-age faulting in central-northern Sicily; possible effects of coseismic deformation

We analyzed displacement on man-made structures and destructive effects on the ancient Roman community in two archaeological sites located on the southern Madonie Mountains, central-northern Sicily. At the archaeological site of Mount Alburchia, a votive niche of the Late Roman period is offset approximately 15 cm by a NNW-SSE-striking normal fault belonging to a NNW-SSE-trending en-echelon system related to an E-W-oriented regional shear zone. Structural analysis of deformed conglomerates suggests a coseismic origin of displacement. At the Gangi Vecchio archaeological site, 3 km northeast of Mount Alburchia, the prevalence of pottery pieces and coins dated from the fourth century B.C. to the fourth century A.D. and a sudden decrease of evidence of human activity at the end of the fourth century A.D. have been emphasized by archaeologists. Furthermore, recent archaeological excavations have revealed a Roman-age grave where remains of some women and children are mixed. Because ancient Romans usually did not use common burial, this could be related to an unexpected natural disaster. This event was conceivably a strong earthquake that probably occurred in the Late Roman period. An analysis of historical catalogs suggests that this event could be referred to the A.D. 361 earthquake, the epicenter of which, in central Sicily, is poorly defined. Our data represent a first step for the relocation of this seismic event northward in the Madonie Mountains area.