GNGTS 2024 - Atti del 42° Convegno Nazionale

Session 2.2 GNGTS 2024 StochasHc modelling as a method for providing seismic hazard esHmates of site effects over wide areas I. Gaudiosi 1 , G. Acunzo 2 , D. Albarello 3 , M. Moscatelli 1 1 Is9tuto di Geologia Ambientale e Geoingegneria (CNR, Italy) 2 Theta Group (Italy) 3 Dipar9mento di Scienze Fisiche, della Terra e dell’Ambiente (Università degli Studi di Siena, Italy) Numerical simulaCons of seismic site response require the characterizaCon of the nonlinear behaviour of shallow subsoil and their mechanical characterizaCon. When extensive evaluaCons are of concern, as in the case of seismic microzonaCon studies, funding problems prevent a systemaCc use of laboratory tests or S-waves velocity profiles to provide detailed evaluaCons. For this purpose, we invesCgate the use of staCsCcal laws for both the main mechanical and dynamic parameters. A staCsCcal analysis of the data were carried out in previous studies (Romagnoli et al., 2021; Gaudiosi et al., 2023) with the aim of shedding light on the significant difference between the laboratory and in situ classificaCon of samples and soils and the macroscopic/engineering geological one, provided during seismic microzonaCon studies. Since the engineering geological classificaCon plays a prominent role in extensive site response evaluaCons, the outcomes of the present work may be of help at least when preliminary seismic response esCmates are of concern. The preliminary tests carried out in the framework of the PRIN SERENA Projects provide reference informaCon that can serve as key data for large-scale hazard assessments in the Italian territory. The variability of the syntheCc hazard parameters may be modelled throughout the NC92 code (Acunzo et al., 2024) by considering the probability distribuCons obtained for each seismo-straCgraphy. These probability distribuCons may be combined in the frame of a Bayesian approach to determine a probabilisCc esCmate of the hazard parameters at output nodes, as well as its variability range. References Acunzo G., Falcone G., di Lernia A., Mori F., Mendicelli A., Naso G., Albarello D., Moscatelli M.; 2024. NC92Soil: A computer code for determinis9c and stochas9c 1D equivalent linear seismic site response analyses . Computers and Geotechnics, 165 , 105857. Gaudiosi I., Romagnoli G., Albarello D., Fortunato C., Imprescia P., SCgliano F., Moscatelli M.; 2023. Shear modulus reducCon and damping raCos curves joined with engineering geological units in Italy. ScienCfic Data 10 , 625. hbps://doi.org/10.1038/ s41597-023-02412-8