Active faults and related hazards: new insights on the Central Appennine seismotectonics and surface faulting zonation

Abstract

The term active and capable fault (ACF) defines an active tectonic structure able to rupture permanently the ground surface. When an ACF represents the expression at surface of a seismogenic source, the study of an ACF involves a twofold aspect: one concerns surface faulting hazard, with engineering implications regarding infrastructures crossing the trace of a ACF, the other concerns the definition of geometric and kinematic characteristics of seismogenic sources, with implications regarding the definition of the seismogenic potential of a given active tectonic structure. Here, we show the results of geological investigations regarding two case studies in the central Apennines. The first site is located near the village of Venere dei Marsi (AQ), where the detailed characterization of geometry and kinematics of a fault splay connected to “San Benedetto dei Marsi – Gioia dei Marsi” active fault segment, allowed us to verify the effectiveness of the ACF territory zonation proposed in “Guidelines for the management of territories affected by Active and Capable Faults” promulgated by the Dipartimento della Protezione Civile Nazionale of Italy in 2015. The second case study is located close to Preci (PG), where field geological investigations were aimed to verify the presence of an ACF in the area of the Sant’Eutizio Abbey severely damaged by the 30 October 2016 Mw 6.5 seismic event, for retrofitting activities, and to characterize the Campi fault segment in terms of recent activity. This allowed to better define the geometric and kinematic characteristics of seismogenic source, responsible for the 2 February 1703 (Mw = 6.8), nucleated by the Norcia active faults system.