Site Response Analysis of the Monte Po Hill in the City of Catania

The Monte Po Hill is located in the North-eastern part of the city of Catania; this area is prone to high seismic risk due to the presence of several constructions, including a school, in the vicinity of a toe of a slope, characterized by precarious stability conditions. For site characterization of the soil, deep site investigations have been undertaken. Borings and dynamic in situ tests have been performed. Among them Down-Hole (D-H) and Seismic Dilatometer Marchetti Tests (SDMT) have been carried out, with the aim to evaluate the soil profile of shear waves velocity (Vs). The Seismic Dilatometer Marchetti Tests were performed up to a depth of 15 meters. The results show a very detailed and stable shear waves profile. The shear waves profiles obtained by SDMT compare well with other in situ tests. Synthetic seismograms have been drawn for the site long a set of receivers placed at different depths, starting from the surface up to almost 40 m. After evaluating the synthetic accelerograms at the bedrock, the ground response analysis at the surface, in terms of time history and response spectra, has been obtained by a 1-D non-linear model. In particular the study has regarded the evaluation of site effects in correspondence of the site, to which corresponds a different value of the Seismic Geotechnical Hazard. In the beginning of 2007 a seismic station has been also located into the school building, with the aim of recording seismic events. Seismograms obtained by the seismic station have been also used to evaluate the ground response analysis at the surface. In the beginning of 2007 a seismic station has been also located into the school building, with the aim of recording seismic events. Seismograms obtained by the seismic station have been also used to evaluate the ground response analysis at the surface. Finally the 1-D computer code EERA was also used to model the equivalent-linear earthquake site response analyses of layered soil deposits of the hill. The detail with which the hill has been studied has allowed the construction of a detailed 2-D model of its structure. It has been explored the differences between the computed ground motion for different Vs profiles using QUAD4M 2-D code. It has been also possible to compare the results from different 1-D models reflecting current approaches to the determination of site response.