The collapse of Torrione Sucai (Mt. Viso, Italy): rockfall analysis and data calibration

In December 2019 a large collapse affected the Torrione Sucai, a rocky structure located on the North-Eastern slope of Mt. Viso (Italy) at about 3100 m a.s.l. Mt Viso has been included in the UNESCO World Heritage Sites since 2013 as a biosphere reserve. Therefore, hazard and risk assessment is a priority for the protection of people and the environment. The rockfall was triggered by a combination of high fracturing of the rock mass and permafrost degradation, with associated phenomena that weakened the rock mass and created conditions for slope instability. This study entails a multi-scale analysis of fracture distribution and intersections, in order to identify the zones most prone to collapse. Moreover, a multi-scale back analysis of the run-out behavior of the 2019 rockfall was performed. The results were used to calibrate preliminary susceptibility analyses for the entire area, presented and discussed in the paper.