Active tectonics and seismicity in the area of the 1997 earthquake sequence in central Italy: A short review

摘要

A first tentative comparison between the structural framework related to the active tectonics and the long-term seismicity of the Umbria-Marche Apennines (affected by the 1997 seismic sequence) has provided some insight for discussing the seismotectonic characteristics of the area. This Apennine sector is affected by 15 to 20-km-long active fault systems,consisting of minor fault-segments. Each of these fault-segments may be responsible for earthquakes characterised by magnitudes ranging between 5.5 and 6.0 (such as those occurred in 1599, 1730, 1838, 1859, 1979). However, the occurrence of one large-magnitude event (1703, M_s = 6.7) and of seismic sequences (1747-1751; 1997-1998) indicate that an entire fault system may be activated suddenly (at least in the southern part of the investigated area) or during seismic crises which may last many months. The comparison between the active faulting framework and the long-term seismicity also indicates that no significant earthquakes may be related to the Mt. vettore Fault System since 1000 AD.