What is Campi Flegrei? Supervolcano near Naples that could erupt under ancient town of Pozzuoli
SUPERVOLCANO Campi Flegrei has shown signs of "reawakening" and may be nearing a critical pressure point, experts have warned.
It could potentially lead to a “very dangerous” eruption in the surrounding area. But what makes Campi Flegrei a supervolcano and should we be worried about it erupting?
What is Campi Flegrei?
Campi Flegrei is a supervolcano beneath the Gulf of Naples.
It dwarfs Mount Vesuvius, the region’s more famous volcano, and has the power to kill hundreds of thousands of people and even change the planet’s climate.
It is a collapsed volcano which means it does not have one obvious vent or a central peak.
Instead there is a huge magma chamber deep underground.
These create the most explosive and destructive volcanic eruptions.
Italy is also home to the tallest active volcano in Europe, Mount Etna, on Sicily.
What could happen if Campi Flegrei erupts?
The slumbering Campi Flegrei volcano under the Italian city of Naples shows signs of "reawakening" and may be nearing a critical pressure point, according to a study.
Scientists have for the first time identified a threshold beyond which rising magma under the Earth's surface could trigger the release of fluids and gases at a 10-fold increased rate.
This would cause the injection of high-temperature steam into surrounding rocks, said lead author Giovanni Chiodini.
He said: "Hydrothermal rocks, if heated, can ultimately lose their mechanical resistance, causing an acceleration towards critical conditions."
It is not possible at this time to say when - or if - the volcano will erupt anew, he added.
Has Campi Flegrei erupted before?
Campi Flegrei has had two major eruptions, the BBC reports.
The first was around 39,000 years ago and the second 15,000 years ago.
Both were worldwide events, which caused temperature drops.
Campi Flegrei's last eruption, in 1538, was a relatively minor one – though it was forceful enough to form a new mountain, Monte Nuovo.
The Campi Flegrei caldera was formed 39,000 years ago in a blast that threw hundreds of cubic kilometres of lava, rock and debris into the air.
It was the largest eruption in Europe in the past 200,000 years, according to scientists.
Nearby Mount Vesuvius, whose massive eruption just over 2,000 years buried several Roman settlements in the area, including Pompeii, is also classified as an active volcano.
Should we be worried about Campi Flegrei?
If it erupted "it would be very dangerous" for the half-million people living inside and near the caldera - the scientific name for the bowl-like depression created after a volcano blows its top.
Since 2005, Campi Flegrei has been undergoing what scientists call "uplift", causing Italian authorities to raise the alert level in 2012 from green to yellow, signalling the need for active scientific monitoring.
The pace of ground deformation and low-level seismic activity has recently increased.
Worryingly, experts have estimated that the volcano is at "critical stage", as they've spotted magma swelling below the Earth's crust.
The dense urban population at risk "highlights the urgency of obtaining a better understanding of Campi Flegrei's behaviour," Chiodini said.
And Dr Christopher Kilburn from the University College London Hazard Center, published a study in the nature journal Scientific Reports in September 2017.
He said: "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, and it’s imperative that the authorities are prepared for this."
