“…The other main group of factors affecting stability on rock slopes is represented by the geologic and geotechnical conditions of each site, namely, fractured rock, adverse dip of the joints and soil decomposition and earthquakes can trigger collapse (Peckover and Kerr, 1977;Giani, 1992;Duncan and Norman, 1996;Guzzetti et al, 2003;Wieczorek et al, 2008;Casale et al, 2008). If the detached rock block moves downwards towards the infrastructures and interferes with them, it is necessary to design protection works that are able to intercept the blocks and stop them (Peckover and Kerr, 1977;Duncan and Norman, 1996;Peila et al, 1998Peila et al, , 2006Peila et al, , 2007Pelizza et al, 2004), such as ground embankments and net fences, which must be placed on the slopes after an evaluation of the possible trajectories of the falling blocks.…”