Proposta metodologica per la valutazione di indicatori di pericolo e rischio da frana a scala intermedia:l'area della Stretta di Catanzaro

Landslide hazard and risk are amongst items of major concern in the field of slope stability studies. These topics can be suitable for disciplinary treatment, but they can be most effectively faced with an interdisciplinary approach. Based on this concept, in this paper a method for the assessment of landslide hazard and risk is proposed. The procedure has been developed by means of elements extracted from the geological and mass movements map of the Stretta di Catanzaro (Central Calabria, Southern Italy), drawn at 1:50,000 scale for this purpose. The paper shows how the Map efficiently provides evaluation elements given the adopted intermediate scale. The procedure, simple and robust, permits to get conventional rank elements for hazard and risk assessment (Hazard Index and Risk Index) that allow to delineate action priorities and to properly address detail studies. The evaluation procedure can easily include elements of specific and general knowledge as they are available. In the study area it is evident that slope instability phenomena are characterised by a medium value of Hazard Index (iP2) in the 58% of cases, and by a moderate value (iP1), in the 32% of cases. The risk estimation, carried out as an example on a group of instability phenomena, underlined the extremely important role played by the elements considered to define Hazard Index classes.