Rockfall Analysis for Preliminary Hazard Assessment of the Cliff of Taormina Saracen Castle (Sicily)

A rockfall analysis at one of the most relevant cultural heritage sites of northeastern Sicily (Italy) is presented herein with the aim of assessing the hazard arising from the unstable conditions of the rock cliff of Taormina city, upon which the Saracen Castle is perched on its top. Several rockfalls affected this area in the latest years, representing a serious threat for the safety of inhabitants and tourists. Therefore, the qualitative Evolving Rockfall Hazard Assessment (ERHA) was applied for the hazard zonation, supported by rock mass surveys and Terrestrial Laser Scanner prospecting. Kinematic analysis revealed that the unstable rock failure patterns are represented by planar/wedge sliding and toppling, while simulation of potential rockfalls allowed studying the impact of future events in terms of trajectory and energy. This is higher at the foot of scarps and in steeper sectors, where the application of ERHA identified a critical zone close to the inhabited center, which is one of the main elements at risk, along with a pedestrian tourist path. Achieved results represent a starting point for the definition of risk management strategies and provide a scientific contribution to the study of hazard and risk arising from rockfall occurrence.