Engineering geological mapping in Tuscany (Italy)

Lithological and geomechanical characters of outcropping rocks are relevant input for applications where geological issues are involved. These information are implemented in spatial planning actions/rules influencing land use and transport infrastructure plans. The same data are used when mapping landslide susceptibility/hazard and preparing for landslide risk management. Many geomechanical classification systems for rock masses have been developed for geological applications. Nevertheless, these are site-specific systems, hence, due to effects of structural setting and spatial variability of lithology, jointing and physical-mechanical properties of rocks, they are not fully adequate for continuous representation of engineering geological properties of geological formations over wide (map scale) areas. In this framework, we describe the implementation of a GIS integrating results of lithological-geomechanical data measurements with existing geological map to obtain an engineering geological map at the scale of 1:10,000 for the provinces of Arezzo and Lucca (Tuscany, Italy - FIG. 1). The study area is representative of different structural and lithologic features of the Northern Apennines chain. In both areas different types of landslides are widespread hence an engineering geological GIS may be a valuable input tool for map scale landslide hazard evaluation