GNGTS 2023 - Atti del 41° Convegno Nazionale

Session 1.1 GNGTS 2023 Investigating past earthquakes with Rare Earth Elements and high-resolution topography: a multidisciplinary approach applied along the Caggiano fault (southern Apennines, Italy) S. Bello 1,2 , M. G. Perna 1 , A. Consalvo 4 , F. Brozzetti 1,2 , P. Galli 4,5 , D. Cirillo 1,2 , C. Andrenacci 1,2 , A. C. Tangari 1 , A. Carducci 1,2 , M. Menichetti 2,6 , G. Lavecchia 1,2 , F. Stoppa 1 , and G. Rosatelli 1 1 DiSPuTer - University G. d’Annunzio Chieti-Pescara, Chieti, Italy 2 CRUST - Centro inteRUniversitario per l’analisi Sismotettonica Tridimensionale, Chieti, Italy 3 Center for Advanced Studies and Technology (CAST), University G. d’Annunzio Chieti, Italy 4 Dipartimento della Protezione Civile, Rome, Italy 5 CNR-IGAG, Consiglio Nazionale delle Ricerche, Rome, Italy 6 Department of Pure and Applied Sciences, University of Urbino, Italy The systematic study of faults that released strong earthquakes in the past is the new challenge for seismic hazard assessment. A methodology developed in recent years, informs on the slip and number of earthquakes released by a fault by sampling and analysing portions of the fault plane in order to determine the rare earth elements (REE) contents possibly correlated to various seismic cycles (Fig. 1). In our research, we apply this methodology to the Caggiano normal fault, cropping out southeast of the Irpinia 1980 earthquake fault (M w 6.9). The Caggiano fault is considered to be responsible for both the 1561 and partly the 1857 Basilicata earthquakes (M w 6.7 and 7.1) (Galli et al., 2006), and, according to Bello et al., 2022, is the northern segment of a much longer system (Caggiano-Montemurro Fault, CMF) crossing a portion of the Monti della Maddalena ridge, connecting the Auletta and Val d’Agri basins and bordering the northernmost portion of the Vallo di Diano. Previous paleoseismological investigations across the Caggiano fault (i.e., Timpa del Vento segment in Galli et al. (2006 and 2008)) account for several surface faulting events in the past 6 ka. The latest ones occurred in the last 2 kyr BP, probably during/after slope-debris deposition related to the Little Ice Age ( ∼ 1400–1800 AD). According to Castelli et al. (2008), both fault segments comprising the Caggiano fault are responsible for the two 1561 mainshocks (July 31 and August 19;