Italian Supervolcano Could Be Closer To Erupting Than Previously Thought


Robin Andrews

Science & Policy Writer

The Bay of Naples. Campi Flegrei can be found beneath the northern-central section of this image, and Vesuvius can be spotted to the east. NASA/JPL

Heads up, ladies and gentlemen – the Phlegraean Fields supervolcano, known in its native Italy as Campi Flegrei, is potentially on the edge of an eruption. A brand new modeling study has concluded that the prolonged period of unrest it's going through has pushed the volcano closer to an eruption than previous research has suggested.

As the team from University College London (UCL) and the Vesuvius Observatory have highlighted, the 13-kilometer-wide (8 miles) caldera has been rumbling for nearly 70 years. It seems to go through periods of inflation and deflation, which puts a lot of stress on the overlying crust, which keeps the magma trapped underground.


It was initially thought that the energy used to stretch the crust in this way was lost during each deflation period, but, according to the team’s computer models, this isn’t true – it just accumulates over time, without really dissipating.

“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,” lead author Christopher Kilburn, Director of the UCL Hazard Centre, said in a statement via email.

“It’s imperative that the authorities are prepared for this.”

Although a specific eruption timeline is not yet possible to ascertain, the team, writing in Nature Communications, note that Campi Flegrei is certainly trending towards conditions that favor an eruption, rather than remaining merely dormant.


Two recent papers have also pointed out that Campi Flegrei is exhibiting unrest. One notes that the earth has risen 0.38 meters (1.25 feet) since 2005, while the other suspects a critical threshold has been reached in which the caldera is slowly, but surely, priming itself for an eruption.

It’s difficult to tell why the ground is rising, and there are various explanations that can be attributed to it. Gas expansion, the movement of fluids, and the production of magma are all possible, and they’re all equally likely. The third option is by far the most concerning, but there’s no way we can tell for sure just yet.

An eruption at Sicily's Mount Etna. Any event at Campi Flegrei would be magnitudes worse. Wead/Shutterstock

The level of ground deformation at present, which is indubitably worrying, has been eclipsed in the past, however, to no consequence. Between 1982 and 1984, the ground rose by 1.8 meters (5.9 feet), a rate roughly 24 times that which is currently being observed – and yet, nothing disastrous happened. The current level of unrest, then, may be another red herring.

Nevertheless, the scientific concern over Campi Flegrei is far from hyperbolic. Kilburn told IFLScience that the unrest at the volcano from 1950 onwards is the “first sign of uplift at the caldera for four centuries,” noting that the last time this pattern was observed, Campi Flegrei erupted, in 1538.


“Please note, though, that an eruption is not guaranteed – it’s just more likely than during previous episodes of uplift,” he said.

The 1538 eruption, by the way, was peanuts compared to its formation 40,000 years ago, which was easily one of the most powerful in the last few million years. This blast produced between 100 and 500 cubic kilometers (20 to 120 cubic miles) of volcanic debris, some of which made it all the way up to Greenland.

“At present, there are residents who have been through two emergencies without eruption, so it is natural for them to be skeptical,” Kilburn said. “However, the lack of eruption until now is no reason to believe this will always be the case.”

IFLScience and WIRED, through different means, both came to the conclusion that this particular caldera is the most dangerous volcano in the world, by far – something that few volcanologists would disagree with.


At least 1 million live within its crater, and up to 6 million live within the “blast zone.” There is definitely an active magma chamber beneath the surface, and unlike Yellowstone – a far more famous “supervolcano” – it is showing signs of unrest. This latest study adds another worrying facet to its potential future ferocity.

Buona fortuna, everyone.

The Bay of Naples, featuring Vesuvius. Campi Flegrei encompasses this entire area, and more. S-F/Shutterstock


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