Rapid evaluation of rockfall risk scenarios for purpose of civil protection

For a rapid and complete definition of rockfall risk scenarios useful in terms of civil protection, a wellstructured semi-automatic procedure, integrated with traditional methods, is presented. In order to cover a wide range of features, and investigating the main advantages and drawbacks of the proposed approach, the data collection was carried out in three different slopes along the Nera valley (Central Italy), which is characterized by a high rockfall risk, especially in the villages and along the main roads, because of its morphology, high local seismic activity and diversified rockmass features. The above-mentioned measurement phase mainly consisted of laser scanning and geomechanical surveys; the latter were executed by using both traditional methodology and by analy zing remote data obtained with the laser scanning survey itself. All collected data were used to create a detailed digital elevation model, to obtain the shape and volume of the most unstable blocks, to define the position of the main rockfall source areas, and to precisely distinguish the outcropping materials and the position of the elements at risk for reliable runout analyses. Such analyses were performed for each investigated site applying both 2D and 3D simulations. Different risk scenarios with medium -high criticality have thus been highlighted, which can be useful in supporting proper maintenance and land management policies both in ordinary circumstances and in emergency contexts. Moreover the presented approach proved to be objective, reliable and easily exportable, even if , each time, some integration to the local situations could be necessary.