GNGTS 2024 - Atti del 42° Convegno Nazionale

Session 1.1 GNGTS 2024 Fig. 1 – (a) Digital Terrain Model of the 2016 epicentral area with the main actve fault segments. (b) Digital Terrain Model of the 2009 epicentral area with the main actve fault segments. (c) Hypocentral distributon of the 2016 seismic sequence. (d) Hypocentral distributon of the 2009 seismic sequence. Coseismic ruptures in the Norcia basin. The coseismic ruptures observed in the Norcia basin refect the emergence of the master fault and the synthetc and antthetcal splays already known and recognized as actve in Galli et al. (2005; 2018; 2023). Following the earthquake of 30 October 2016, in total, over 2 km of coseismic ruptures with a maximum vertcal ofset of ~12 cm were measured. In December 2017, Galli et al. (2018) excavated a trench for paleoseismological studies along the coseismic rupture, where it was found that this rupture occurred in correspondence with the surface expression of the main splay observed on the walls of the trench. Coulomb stress transfer . According to Coulomb stress change theory, following a seismic event part of the statc stress can be transferred to nearby fault systems (King et al, 1994). Some authors have already analysed the variaton in the statc Coulomb stress produced by the 30 October event (Improta et al, 2019), with partcular reference to the lateral interactons that occur between neighbouring seismogenic systems (Mildon et al, 2019). In our case, however, it is observed that part of the Coulomb stress is transferred frontally from the MVFS to the NFS. We then calculated the Coulomb stress changes generated on 30 October by the MVFS using the Coulomb 3.3 sofware (Toda et al, 2011). To defne the Coulomb stress variaton the sofware uses this equaton: