Rockfall Hazard and Risk Assessment: The Promontory of the Pre-Hellenic Village Castelmola Case, North-Eastern Sicily (Italy)

Abstract

Castelmola (northeastern Sicily) is a densely inhabited pre-Hellenic village, which probably used to be Taormina acropolis thanks to its location. It is counted among the “Most Beautiful Italian Villages”, and so it represents an important tourist attraction. The village lies on a carbonate cliff, which is the summit of a SW-dipping monocline on Peloritani Mountain Belt. The geostructural layout of the site is characterized by regional fault systems, which are the main cause of the high seismic activity of the study area. In this paper a rockfall analysis performed along the eastern side of the cliff, where several rockfalls occurred in the latest years, involving the downstream houses and road, is described. The last, nearly tragic event was in 2006. Moreover, on the top of the cliff several buildings stand on the edge, and the detachment of volumes of material, which causes a slow but inexorable rockwall retreat, may affect the stability of the above structures. Since the noticeable instability afflicting the whole eastern cliff, this research aims to assess the rockfall hazard and risk, in order to build a risk map on the basis of the performed geostructural surveys, geomechanical, kinematic and stability analysis, rockfall simulations and risk assessment. Remedial measures are also suggested on the basis of field observations and rockfall risk evaluation.