HVSR and MASW seismic survey for characterizing the local seismic response: A case study in Catania area (Italy)

Many recent researches show that the site seismic response is strongly influenced by stratigraphic and topographic features. Site response can reduce or amplify the earthquake induced ground motion. An integrated approach based on passive (HVSR) and active (MASW) seismic surveys, was carried out at the Garibaldi Hospital, located in Catania downtown, in order to evaluate the seismic site response. Fourteen environmental noise records, located near some previously mechanical drillings, were carried out and processed by using the Horizontal to Vertical Spectral Ratio (HVSR) technique. Successively, two MASW prospections were performed at the northern and the southern sides of the Hospital building, following the information deduced from the stratigraphic characteristics of soil drillings. The data obtained from this coupled analysis, method and the information derived by mechanical drillings previously performed, allowed us to obtain the site transfer function which can be related to the H/V average spectrum. Such integrated approach, based on passive and active seismic prospections, showed to be a reliable and quick method to obtain information for a site seismic characterization. According to Italian code a Vs30 profile was achieved and the soil type category was determined.