Seismic microzonation of the Cassino plain

Thanks to its favourable hydrogeological conditions, Cassino is one of the most studied sites of Central Italy. More than two hundred soil borings, some of them reaching depths as high as 100 m, have revealed a subsoil characterized by a calcareous platform and post-orogenetic series forming a tectonic basin filled by lacustrine and volcanic deposits. Together with the already available data, a number of geological, geotechnical and geophysical data have collected to study at a very detailed scale the seismic response of the site. Among them, a series of HVSR (horizontal to vertical spectral ratio) measurements have been performed to estimate the natural frequency of oscillation of the more deformable deposits. The combination of these data with the information given by the deep boreholes, permitted to rebuild the geological complexities of the tectonically driven seismic bedrock, outcropping continuously at east and west of the basin. This study forms the basis for mono, bi and three-dimensional numerical analyses aimed at predicting local amplification effects.