3D geological model of Central Archaeological Area of Rome for seismic hazard assessment

Correlation among borehole, outcrop, electrical resistivity tomography and ground penetrating radar data from a campaign of drilling and geophysical survey has allowed to reconstruct with detail the subsoil structure of the Palatine hill and Foro Romano (Rome, Italy), concerning both the natural geological substratum and the overlying anthropogenic cover (Mancini et al. 2014; Moscatelli et al. 2014). In the investigated area, several incised valleys and interfluves made of fluvial sediments and pyroclastites, overlaying the geological bedrock of Rome (i.e., Monte Vaticano Fm.), are detected below the anthropogenic deposits (masonry and infilled ground). A 3D model of the subsoil of the study area is presented here, obtained through the following three steps. 1) Production of 11 cross sections and a geological map (scale 1:2.000) with GIS software. 2) Selection of six relevant key horizons (i.e., basal unconformities of fluvial origin, bases of pyroclastic flow units, base of anthropogenic unit), that bound groups of stratigraphic units having similar lithotechnical features and parameters for numerical simulation oriented to seismic responses analyses. 3 The resulting 3D model shows geometries and spatial distribution of the geological bodies highlighting buried valleys where 2D amplification effects were calculated (Pagliaroli et al. 2014). The aim of 3D reconstruction is to provide a base for an advanced 3D numerical modelling of amplifications to be compared with the 2D simulation results.