GNGTS 2024 - Atti del 42° Convegno Nazionale

Session 2.2 GNGTS 2024 One-dimensional numerical approach VERSUS experimental quanHficaHons of site effect parameters: the Ferrara test area C. Barnaba (1), L. Minarelli (2), G. Di Giulio (2), G. Laurenzano (1), A. Affatato (1), P. Taverna (1), M. Vassallo (2), R. Caputo (3), G. Cultrera (2) 1 Na9onal Ins9tute of Oceanography and Applied Geophysics –OGS, Italy 2 Na9onal Ins9tute of Geophysics and Volcanology –INGV, Italy 3 University of Ferrara - Italy Within the work package WP06 - Empirical TesCng and CalibraCon of the ongoing project PRIN-SERENA (Mapping Seismic Site Effects at REGional and NAConal Scale), we test the predicted esCmates of ground moCon parameters with the experimental values in an area with high-density geophysical invesCgaCons. The study area belongs to the lower alluvial Po plain, near Ferrara, and corresponds to an external buried porCon of the Apennines foredeep basin, involved into acCve thrust-fold compressive structures (Martelli et al. 2017), of late Neogene-Quaternary age (Ghielmi et al., 2013). The acCve faults induce an important earthquake acCvity, documented by many historic events (Guidoboni et al., 2018, 2019), including the most recent ones in May 2012. The subsurface thick unlithified terrigenous Quaternary successions record an evoluCon from deep marine to alluvial plain environments. The successions are characterized by low seismic velociCes (Minarelli et al. 2016; Petronio et al. 2023), and reduced seismic impedance contrasts (Mascandola et al., 2021). Shortly aper the event of May 20, 2012, the IsCtuto Nazionale di Geofisica e Vulcanologia (INGV) and the IsCtuto Nazionale di Oceanografia e di Geofisica Sperimentale (OGS) set up a dense temporary network of 18 staCons (see Morem et al., 2012; Priolo et al.,2012; Bordoni et al., 2012; Milana et al., 2014), equipped with short period and strong moCon sensors. In addiCon, geophysical data were collected from microzonaCons studies and research projects performed by the city of Ferrara as well as by INGV and OGS. Around 200 single-staCon ambient noise measurements, 300 Vs profiles derived by seismic cone (SCPT) and 6 deep seismic boreholes (DH) were carried out. The large amount of geophysical data (Vp, Vs, DH, noise measurements) and the availability of earthquake records, combined with the flat topography, make the Ferrara area the perfect site to test the resolving power of the one-dimensional numerical approaches (e.g. Falcone et al., 2021) to determine the amplificaCon factors.