GNGTS 2023 - Atti del 41° Convegno Nazionale

Session 3.2 ___ GNGTS 2023 Reconstruction of a 3D geological model of the quaternary deposits filling the Cassino intermontane basin (central Italy) M. Rompato 1 , M. Saroli 1,2 , M. Albano 2 , M. Moro 2 , F. Bozzano 3 , G. Scarascia Mugnozza 3 1 Department of Civil and Mechanical Engineering (DiCeM), University of Cassino and Southern Lazio. 2 National Institute of Geophysics and Volcanology (INGV), Rome. 3 Department of Earth Sciences and CERI Research Center on Geological Risks, Sapienza University of Rome. This work aims to investigate the shape and engineering geological features of the subsoil of the city of Cassino (Central Italy) through the interpretation of an extensive database of geophysical, geognostic and bibliographic data. Geological models of urban areas provide critical information for geological and hydrogeological analysis and studies. In this case study, we develop a 3D subsoil model to describe the relationship between the different geological bodies and the lithologies composing the recent filling deposits. To this aim, Cassino's urban area (Central Italy) has been chosen as a test case. The area is located at the end of the Latina Valley. The carbonate structures of Mt. Cairo border it to the NW, Mt. Venafro to the NE and SE, and several main tectonic elements mainly in Apennine development. The available dataset comprises about 180 geognostic boreholes from previous fieldwork performed in the past years that reach different depths up to 300m. This dataset provides information about the lithotypes' nature, thickness, and distribution. We also used about 100 HVSR measurements to estimate the resonant site period (RP) to identify the depth of the impedance contrast (Saroli et al., 2020). The collected data were processed through the 3D geological modelling software Leapfrog (Seequent Limited). The 3D model is made by stacking on top of each interpolated surface representing stratigraphic boundaries. Such a model highlights the subsoil's main structural and lithological elements, such as the surface of the bedrock buried below the city. A second detailed model was performed to define better the relationship between the different lithologies that compose the quaternary fluvial-lacustrine filling. We processed the same geological dataset with the Lithology Modeling tool by software Rockworks (RockWare) (Fig1).