GNGTS 2013 - Atti del 32° Convegno Nazionale

site) and in the Emilia Romagna region (Mirandola, Casaglia, and Po River banks). Concerning Soncino, an accurate soil profile was determined using the Pianengo borehole data down to 200m depth, while for Mirandola and Casaglia a variety of data from microzonation studies, geophysical investigations, and investigation of potential geothermal reservoirs (Martelli and Molinari, 2008) were used. Tab. 2 shows the 1D model parameters used in the ground response analyses for the 3 sites considered. The soil profile parameterization also includes the variability (values in brackets) assumed to affect soil properties and model geometry, which was taken into account by means of a Monte Carlo simulation procedure (e.g., Bazzurro and Cornell, 2004a; Barani et al. , 2008, 2013). Besides site specific data, which were used to define the numerical models for the ground response analyses, regional soil zonation maps were defined, consistent with the NTC08 provisions, to derive ground shaking hazard (GSH) maps. An example of such zonation map is shown in Fig. 3a, in the sequel. Ground response. In this study two different numerical characterizations of the soil column were used, namely a basic model and a randomized model . The former consists of a 1D model with soil parameter values equal to their field or laboratory best estimates. The latter, instead, introduces the uncertainty in the soil parameter estimates through a Monte Carlo approach by randomly varying unit weight ( γ ), shear wave velocity ( V S ), shear modulus degradation curve, and damping curve. The uncertainty associated with model geometry was also considered by randomizing the thickness ( h ) of each soil layer. Numerical ground response analyses were performed with the Shake91 (Idriss and Sun, 1992) and EERA (Bardet et al. , 2000) codes, which implement an equivalent linear approach to model the nonlinear response of soils. Fig. 1 – Comparison of soil amplification functions for Mirandola (a), Casaglia (b), and Soncino (c). 18 GNGTS 2013 S essione 2.1