Event tree analysis for rockfall risk assessment along a strategic mountainous transportation route

A quantitative risk analysis has been performed in a tourist area of Sicily (Italy) with the aim of assessing the rockfall risk along an important transportation corridor, crossing a geologically complex area and poor rock masses. The procedure followed herein is based on an event tree analysis, which was properly customized to take into account the peculiarity of the area and of the road path. Rock mass surveys, trajectory simulations and probabilistic models are proposed with the aim of calculating the probability related to possible scenarios in case of rockfalls. Achieved outcomes demonstrate that such procedure, resulting from a multifaceted study, is a reliable tool, which can be taken as reference to calibrate further risk models in comparable contexts of the world, where rockfall threaten communication routes. This would represent a helpful instrument to the scientific community and to local authorities dealing with one of the most troublesome natural phenomena affecting the public safety.