GNGTS 2024 - Atti del 42° Convegno Nazionale

Session 2.2 GNGTS 2024 Temporal and SpaHal Variability of AnelasHc AjenuaHon and Its Effects on Ground MoHon CharacterisHcs in Central Italy Simona Gabrielli (1), Aybige Akinci (1), Carolina GuHerrez (2), Javier Ojeda Vargas (2), SebasHan Arriola (3) and Sergio Ruiz (2) 1 Is9tuto Nazionale di Geofisica e Vulcanologia (INGV), Via di Vigna Murata 605, 00142, Rome, Italy 2 Departamento de Geo{sica, Universidad de Chile, Blanco Encalada, 2002, San9ago, Chile 3 Centro Sismológico Nacional Universidad de Chile, San9ago, Chile In recent decades, Central Italy has experienced seismic sequences resulCng in casualCes and significant building damage, as the one of 2016-2017, started with the Amatrice mainshock (Mw6.2) in August 2016, followed by the Visso (Mw5.9) and Norcia (Mw6.5) events in October 2016 (hereaper, AVN). Considering the frequent seismic acCvity and elevated seismic risk in the region, employing ground-moCon simulaCons is essenCal for assessing seismic risk and earthquake engineering applicaCons. Previous studies focused on ground moCon characterisCcs of the Mw6.2 Amatrice and Mw6.5 Norcia earthquakes using stochasCc and numerical approaches (Pischiuba et al., 2020; Ojeda et al., 2021; Pitarka et al., 2021). The definiCon of abenuaCon characterisCcs and their relaConship with ground moCon models have already been used for predicCng ground moCons from hypothesized events, which are fundamental to defining the accuracy of seismic assessments. Recent studies applied non-ergodic approaches to reduce the uncertainCes in ground moCon models, taking into account a range of physical parameters linked to both the seismic source and wave propagaCon, along with heterogeneiCes specific to the path. Here, we explore the seismic wave abenuaCon variability on strong-ground moCon simulaCon in the Central Apennines, using stochasCc simulaCons (Ojeda et al., 2021). First, we calculate the quality factor Q values for the area, obtaining the total abenuaCon Q as a funcCon of frequency for the 2016-2017 seismic sequence. In order to map this variaCon, we applied a 2D kernel-based imaging of coda-Q space variaCon, which confirmed the differences in abenuaCon between the pre-sequence and the AVN, with an increment in abenuaCon during the 2016 Cme period in the fault plane zones. Then, we integrate the obtained frequency-dependent Q value as input parameters for strong-ground moCon simulaCons, considering earthquake-induced ground moCons. This stochasCc methodology simulates the strong-ground moCon at high frequencies, mimicking