Vulnerability of Industrial Facilities to Potential Volcanic Ash Fallouts

Following recent natural disasters, which have had a significant impact on chemical plants, the study of Natural-Technological risks (Na-Tech) has increased worldwide. This work is focused on the study of volcanic Na-Tech events and aims at defining a procedure for the representation of the vulnerability of industrial facilities in areas with the potential volcanic ash fallout using a Geographic Information System (GIS). The methodology has been applied to the area surrounding Mount Etna (Sicily, Italy). Indeed, this volcano has had recently explosive eruptions with consistent ash fallout and is surrounded by a number of industrial installations and also petrochemical plant. This paper is focused on the choice of the most suitable interpolation procedure for the vulnerability mapping in areas where input data is available only for few points, finally comments on the procedure validation are also provided. In this paper, a procedure for the estimation of the vulnerability and the construction of relative maps for volcanic Na-Tech risks has been showed. The objective is to provide local authorities and planners with useful tools for planning emergencies connected to volcanic Na-Tech risks. The procedure requires the knowledge of the exceedance probability for ash fallout at each location of the territory around the volcano and threshold limits of the parameter causing the damage with the associated eruption phenomenon. The method is also useful when the exceedance probability is known for a limited number of points. In this case, an interpolation procedure is necessary and the choice of the interpolation model is the critical step of the whole procedure.