GNGTS 2023 - Atti del 41° Convegno Nazionale

Session 2.1 - POSTER GNGTS 2023 The PBS computation (Moratto et al., 2015) assumes as the Maximum Credible Earthquake case an Mw=6.7 earthquake and it is consistent with some field geology studies (e.g. Boncio et al., 2014). It provides the ground motion parameters for three receivers (PCB=Poggio Cancelli; RFC=Rio Fucino; SPD=Sella Pedicate) placed in near-source close the three dams that confine the Campotosto Lake. The ground motion variability is captured by a pseudo-dynamic source model (Mena et al., 2012), which encompass spatial and temporal variations in the slip, rise time, and rupture propagation, heavily affecting the near-source ground motion. Indeed, the ground motion above the rupture volume is mainly influenced by the epistemic uncertainties of rupture nucleation and slip distribution (e.g. Moratto et al., 2017). We reproduce the variability due to the source rupture parameters that affect the simulated ground motion in the near-source (Fig. 3). This variability is related to the rupture propagation model heterogeneities and reliable finite fault parameters input in the modelling. The most significant ground motion values are obtained above the rupture area (PCB and SPD receivers), particularly at long periods. At the same time, high-frequency shaking characterizes the RFC receiver placed at the edge of the main fault. On average, the associated variability can reproduce the strong motion characteristics recorded in near-source for similar earthquakes. The Campotosto scenario shows that the vertical component might experience shaking values comparable with the horizontal. Therefore, their quantification can better constrain seismic hazard in the near-source area and support seismic design. The considered GMM (Schiappapietra et al., 2022) probably underestimates the vertical component's ground motion, especially at longer periods and above the rupture area (Fig. 3). In contrast, our PBS simulations generate vertical peak parameters and spectra comparable with the values recorded in near-source for the 2016 M W 6.6 Norcia mainshock, also in the low frequency band (PGD and SO).