Ground movement around Campi Flegrei, an ancient supervolcano, is nearing a critical stage where further unrest could lead to a massive eruption that would affect at least 360,000 inhabitants of the area. "By studying how the ground is cracking and moving at Campi Flegrei, we think it may be approaching a critical stage where further unrest will increase the possibility of an eruption," said Christopher Kilburn, Director of The Hazard Centre at University College London, in a paper written in the journal Nature Communications. The paper makes clear that an eruption is not imminent, but a critical phase is on the horizon. The last time Campi Flegrei erupted was in 1538. It then went quiet until 1950, when periodic "unrest" began. During the geological unrest in 1970 and 1983 the port of Pozzuoli, near the centre of the caldera, was pushed more than three metres out of the sea. Scientists previously thought that the stress built up during periods of unrest dissipated during quieter intervals between — but according to the team's new analysis, this is not the case. "We consider that the crust in the caldera has a kind of memory and stress accumulates over the decades," said Stefano Carlino of the Vesuvius Observatory. Any substantial new uplift could split the ground beyond its breaking point and trigger an eruption, he said.
