Mapping the vulnerability for evacuation of the Campi Flegrei territorial system in case of a volcanic unrest

Over the past few decades the Campi Flegrei territorial system was interested by intense urban expansion overlooking the volcanic risk. In this active volcanic area, where a short period evacuation could be necessary, the emergency management cannot be based solely on the hazard related information, but the territorial and social features must be as well taken into account. In this framework, the main purpose of this research is to point out the seriousness of the present setting of Campi Flegrei territorial system in case an evacuation would become necessary. Following the concept of regional evacuation, the zone to be involved in emergency planning was identified as the whole of the area threatened by the volcanic events occurred in the last 10 ka. Inside this area the spatial relation between the residents distribution and the outflows of routes, railway stations and harbours, necessary to leave the dangerous area, was investigated. A spatial relational GIS-based procedure was used to draw the territorial system vulnerability map for evacuation, depicting the zones with different capability to support the evacuation of residents in case of renewal of volcanic activity. Basing on the concept that people could leave the dangerous area by the means of transport supplied by Civil Protection, and using the threshold value of over-crowding of 0,70 people/ m2, we identified the collection points for residents to be immediately evacuated in case of volcanic unrest, and five microzones displaying different capability to cope with an emergency phase

Hazard and risk assessment in a complex multi-source volcanic area: the example of the Campania region, Italy

In order to zone the territory of Campania Region (southern Italy) with regard to the hazard related to future explosive activity of Somma-Vesuvio, Campi Flegrei and Ischia island, we drew a multi-source hazard map for tephra and pyroclastic flows. This map, which merges the areas possibly endangered by the three volcanic sources takes into account a large set of tephra fall and pyroclastic flow events occurred in the last 10 ka. In detail, for fall products at Campi Flegrei and Somma-Vesuvio we used the dispersal of past eruption products as deduced by fields surveys and their recurrence over the whole area. For pyroclastic flows the field data were integrated with VEI=4 simulated events; about 100 simulations sourcing from different points of the area were performed, considering the different probability of vent opening. The spatial recurrence of products of both past eruptions and simulated events was used to assign a weight to the area endangered by the single volcanic sources. The sum of these weights in the areas exposed to the activity of two sources and/or to different kinds of products was used to draw a hazard map, which highlights the spatial trend and the extent of the single equivalent classes at a regional scale. A multi-source risk map was developed for the same areas as the graphic result of the product of volcanic hazard and exposure, assessed in detail from a dasymetric map. The resulting multi-source hazard and risk maps are essential tools for communication between scientists, local authorities and the public and may prove highly practical for long-term regional-scale mitigation planning