GNGTS 2017 - 36° Convegno Nazionale

370 GNGTS 2017 S essione 2.2 Fig. 1 - Map showing the location of the University of Catania building groups (”comparti”) where the investigations have been performed (green) or are planned (red). Methodology. Usually the most vulnerable area of a city is its downtown where several historic buildings are erected. The cultural heritage safeguarding is becoming in recent time particularly important due to its economic and social significance. These valuable constructions often undergo to a reduced structural capacity due to deterioration phenomena and damages suffered in the past. Geophysical surveys are normally adopted as tool for cultural heritages restoration and protection plans (e.g. Imposa et al. , 2014; Imposa and Grassi, 2015). Moreover, cultural heritage buildings were typically built without considering seismic action and therefore they are potentially susceptible to earthquake damage. It is, indeed, well known that the level of building damage and its distribution during an earthquake is due to the combined effect of the local site response, based on subsurface ground conditions, and the dynamic features of the structure itself. The dynamic properties of a building is usually described through its natural frequency and