Recent seismic activity and earthquake occurrence along the Apennines

ABSTRACT

In this paper we analyze the seismicity along the Apennines in order to relate the seismicity pattern to the seismogenic environment and to the active tectonic processes. The analysis of crustal and subcrustal seismicity show that the northern and southern Apennines are characterized by two distinct patterns of seismicity. These two domains are separated by two important lithological discontinuities (the Ancona - Anzio and the Ortona - Roccamonfina lines). The seismicity along the Apennines is mainly concentrated in a narrow belt running along the chain, with an evident geometrical offset which corresponds to the Ancona-Anzio line. We discuss these observations considering both the seismological evidence and the present tectonic regime in which the earthquakes occur. We focus on the southern Apennines, where the largest earthquakes (6 ó M ó 7.0) have occurred. We analyze the main features of some recent seismic sequences in order to discuss the seismicity patterns in terms of the hypothesis of segmentation of the southern Apennine seismogenic belt. This work aims to be a preliminary contributions to the important goals of understanding the spatial and temporal patterns of seismicity and of identifying active faults