Volcanic unrest scenarios and impact assessment at Campi Flegrei caldera, Southern Italy

At Campi Flegrei caldera, volcanic unrest hazards during 1982–1984 caused significant building damage and led to the evacuation of over 40,000 residents in the central town of Pozzuoli. Past hazard assessments in this region have focused on eruption hazards rather than on hazards from volcanic unrest. In this study, we developed a hypothetical unrest hazard scenario applied to three locations within Campi Flegrei caldera: Pozzuoli, Agnano and Baia. We also collated GIS exposure datasets and used vulnerability models of building and road damage to carry out an impact assessment for future volcanic unrest at these three test locations. The resulting impact maps provide useful insight into the effects future unrest could have on businesses, buildings and livelihoods within Campi Flegrei.The impact maps show that, depending on the location of unrest, evacuations associated with future unrest may involve displacement of large numbers of residents, and significant damage to buildings and infrastructure. The Agnano scenario is associated with the greatest impact and involves the potential evacuation of 136,000 people and damage to about 2400 buildings, with up to 200 km of roads and 17 km of high-voltage electricity network also exposed. Agnano also lies between Naples and the rest of Campi Flegrei, so that damage to infrastructure may trigger a cascade of obstacles to managing evacuations and repairs during an emergency. The results highlight how a simple impact assessment can be used to explore the possible effects of future unrest hazard, and the importance of considering scenarios in which renewed ground uplift is not necessarily focused beneath Pozzuoli.