GNGTS 2023 - Atti del 41° Convegno Nazionale

Session 1.1 GNGTS 2023 Breaking news on the Norcia fault (central Italian Apennines) P. Galli 1,2 , E. Peronace 2 , S. Piscitelli 3 , J. Bellanova 3 , G. Calamita 3 , P. Messina 2 , A. Perrone 3 , F. Polpetta 2 1 Dipartimento Protezione Civile, Roma 2 CNR-IGAG, Roma 3 CNR-IMAA, Tito (PZ) Introduction Following the destructive 2016 earthquakes in central Italy, the Special Commissioner for the Reconstruction has promoted seismic microzonation activities aimed at the definition of “attention zones” around capable faults. CNR-IGAG was in charge to perform new studies along the Norcia fault, focusing within the inhabited areas traversed by the fault path. Specifically, besides geological field survey, stereoscopic air-photos and LiDAR analyses, we performed Electrical Resistivity Tomography (ERT) and paleoseismological trenches in Norcia, Pielarocca, Capo del Colle, and Campi settlements, all affected by the abovementioned fault. The Norcia fault is an active, seismogenic fault, responsible for several strong earthquakes that were likely sourced both by the entire, 30-km-long fault system (e.g., Mw 6.9, 1703 event) or by single or grouped segments (Mw 6.4, 1328 event; Mw 5.9, 1599: Mw 5.8 1859; Mw 6.0, 1979) (Galli and Galadini, 1999). Its three main segments are the Campi-Preci, Norcia-Nottoria, and Cascia-Mt Alvagnano. Here we focused on the first two segments, both bounding intermontane basins and both characterized by linear fault-slopes with triangular facets. Unlike the Campi-Preci segment, which had never been studied, the Norcia-Nottoria fault had already been investigated through 10 paleoseismic trenches opened between 1999 and 2017 (Galli et al., 2005; 2018). Now we present the results concerning 6 new excavations, 3 across the Norcia-Nottoria segment and 3 across the Campi-Preci one (Fig. 1).