UCL Earth Sciences


News from the UCL Hazard Centre

20 December 2017

Believing forecasts of volcanic eruption

Pozzuoli harbour

Forecasts of eruptions are rendered useless if they are not believed. A crucial example in Europe is the active volcanic district of Campi Flegrei, outside the western suburbs of Naples in southern Italy. After 400 years without an eruption, the volcano has returned to intermittent unrest since 1950. Warnings of eruption have twice triggered mass evacuations, of about 40,000 people, from the commercial hub of Campi Flegrei at Pozzuoli. In neither case did an eruption occur. The warnings have been seen as false alarms by the population, raising concern that future warnings may not be heeded. 

Studies led by the UCL Hazard Centre show that the episodes of unrest belong to a gradual build-up of stress in the crust beneath Campi Flegrei. Such a build-up means that the crust is more likely to break in the future, so that molten rock below the surface has a better chance of erupting. Public experience of past emergencies is thus a poor guide to what might happen in the future.