GNGTS 2024 - Atti del 42° Convegno Nazionale

Session 1.1 GNGTS 2024 Conversely, in the Database of Individual Seismogenic Sources (DISS – DISS Working Group, 2021; Basili et al., 2008) the 1706 earthquake, being the only meaningful seismic event in that area may relate with the largest and proximal individual seismogenic source labelled ITIS027 (see Fig. 1), associated with the Mt. Morrone fault. This consist of a dip-slip structure with surface expression consistent with a maximum magnitude of 6.7±0.1 (Galli et al., 2015), being composed by two major sub-parallel WSW-dipping splays, extending approximately 24 km across the western slope of Mt. Morrone. Lastly, Bordoni et al., (2023) presented a seismic scenario where the synchronous actvaton of both the Mt. Morrone fault and the Mt. Porrara fault, with a 43 km total fault length at surface and an 806 km2 maximum rupture area, would generate an earthquake consistent with the 1706 (labelled BORDONI23 in Fig. 1). In this study we provide a comprehensive review of various hypotheses concerning the 1706 seismic source, along with another possible causatve structure implying the dip-slip re-actvaton of the Mt. Morrone fault plus the Palena fault (labelled TONDI24 in Fig.1). As far as the Palena fault, Pizzi et al. (2010) hypothesized its Quaternary actvity that, with an almost pure dip-slip kinematcs, represents an inherited Pliocene syn-orogenic oblique structure. The results of this study, combined with the development of a shaking scenario, are expected to ofer valuable insights to the earthquake geology community involved in studies on seismic risk assessment in this area. Source Modelling In our pursuit to identfy the most likely source of 1706 Maiella earthquake, based on intensity data, we applied the procedure outlined by Gironelli et al. (2023) and schematsed in the workfow in Figure 2. This methodology ofers the advantage of testng various potental sources and conductng a quanttatve interpretaton of the earthquake-fault associaton. Figure 2. Summary workfow showing the main stages following Gironelli et al., 2023.