3D reconstruction of shallow subsurface geological bodies: methods and applications

An original approach for the 3D visualisation and modeling of buried deep and shallow subsurface geological bodies by means of GOCAD is presented in this paper. Cartographic data and structural surface observations have been used, establishing a link between the Geographic Information Systems, where the data are stored, and the GOCAD environment. Four main sources of information are needed for the development of a 3D structural model: 1 - topographic data represented by contour lines and quoted points; 2 - geological, geomorphological and tectonic boundaries consisting of 2D linear elements; 3 - mesoscopic structural measurements including attitude of planar and linear elements (bedding, thrusts, strike-slip, normal faults, lineations, etc.); 4 - geological cross-section reconstructed through the analysis of surface geological data; Other sources of geological information as wells data, seismic sections, etc, can be also introduced into the model. The analysed geological bodies consist of a deep landslide developed in the sedimentary cover of the Southern Alps (Lombardia, Northern Italy), and of the sedimentary successions of the Sant'Arcangelo basin, a recent piggy-back basin located in the Southern Apennines (Basilicata, Southern Italy). The geometric features of the reconstructed geological bodies can be used to design preliminary monitoring plans or subsurface investigations through seismic surveys and drilling. The characterisation of the shallow subsurface is important for civil engineering and environmental applications that depend upon precise definitions of the geometrical, geomechanical and hydrological properties of rock bodies.