A ‘supervolcano’ in a densely populated part of Italy could be on the verge of its first eruption since 1538, researchers have warned.
The Campi Flegrei volcano near Naples in southern Italy has become weaker and more likely to rupture, making an eruption more likely, experts say.
Located about 14.5 km west of Naples, it is one of the few active supervolcanoes in the world.
About 360,000 people live in Campi Flegrei and may need to evacuate if experts believe there is an immediate danger of an eruption, although scientists say there is no guarantee an eruption will occur. produce soon.
When the volcano eventually erupts, it will likely be comparable in size to the eruption of Vesuvius that destroyed the cities of Pompeii and Herculaneum in AD 79.
The Campi Flegrei volcano in southern Italy has become weaker and more likely to rupture, making an eruption more likely, experts say. Pictured is Solfatara, a shallow volcanic crater that is part of the Campi Flegrei. Note the yellow rocks made by sulphurous gases
Campi Flegrei lies about 14.5 km west of Naples and is one of the few active supervolcanoes in the world.
The study was conducted by experts from the Italian National Research Institute for Geophysics and Volcanology (INGV) and University College London (UCL).
Lead author Professor Christopher Kilburn of UCL’s Department of Earth Sciences said Campi Flegrei is more prone to ‘rupture’ – a break or fracture through the rock that makes up the body of the volcano .
“It’s a natural result when the volcano stretches as pressure builds up underground,” Prof Kilburn told MailOnline.
“Once a rupture has occurred, it will be easier for volcanic fluids to escape.
“That doesn’t mean they will escape, only that it will be easier than before.”
A rupture could open a crack in the earth’s crust, although magma still needs to push into the right place for an eruption to occur.
The large, 13 km wide Caldera of Campi Flegrei – its basin-like depression resulting from an earlier explosion – is located below the western outskirts of the city of Naples.
About a third of the caldera is partially submerged below Pozzuoli Bay, but the remaining two-thirds is land that is home to over 360,000 people.
Campi Flegrei (or “burning fields”) is defined as a supervolcano because it has the potential to produce a magnitude eight eruption, capable of discharging over 200 cubic miles of material.
Approximately 7 to 9 miles (12 to 15 km) in diameter, Campi Flegrei is the largest active caldera in Europe and extends west from the outskirts of Naples to the Tyrrhenian Sea. About a third is partially submerged below Pozzuoli Bay; the remaining two-thirds are home to over 360,000 people. The caldera is marked by the yellow dotted line; a landslide has occurred in the central region marked in blue
The image from the research paper shows a section of the large Caldera of Campi Flegrei, eight miles wide. Small, persistent earthquakes have been recorded there since the mid-1980s. Red dots mark seismicity between 1982 and 1984, while green dots mark seismicity since 2005
People live in the area and would be in danger if the volcano erupts again and shoots out “pyroclastic currents” – hot, fast gas streams and solidified lava particles.
The Campi Flegrei last erupted when Henry VIII was last on the throne of England, and this event occurred after an interval of about 3,000 years.
But researchers warn that large calderas of this type frequently go through several decades of turmoil before erupting.
Campi Flegrei has been restless since the middle of the 20th century, which is of particular concern to scientists.
It experienced several two-year periods of unrest in the 1950s, 1970s, and 1980s, causing small local earthquakes and ground uplift due to movement of magma below the surface.
However, Campi Flegrei’s current tensile strength – the maximum stress a material can withstand before breaking when stretched – is likely to be around a third of what it was in 1984, the researchers said.
Additionally, over the past decade, the ground beneath Pozzuoli has been rising about four inches per year as gas increases pressure in the magma, causing the ground surface to swell and warp.
The new study used a volcanic fracturing model, developed at UCL, to interpret earthquake and ground uplift patterns, and concluded that parts of the volcano had been stretched almost to breaking point.
Around 360,000 people live in Campi Flegrei (pictured), according to London researchers
‘This is the first time that we have applied our model, based on the physics of rock fracture, in real time to any volcano,’ Prof Kilburn said.
“Our first use of the model was in 2017 and since then Campi Flegrei has behaved as we expected, with an increasing number of small earthquakes indicating pressure from below.
“We will now need to adjust our procedures to estimate the chances of new routes opening up for magma or gas to reach the surface.”
Worryingly, a possible eruption could be preceded by relatively weak signals such as a lower rate of ground uplift and fewer earthquakes.
Such was the case with the Rabaul caldera eruption in Papua New Guinea in 1994, which killed only five people, largely due to good disaster planning.
The eruption was preceded by small earthquakes occurring at a tenth of the rate of that which had occurred in a crisis a decade earlier.
Prof Kilburn said authorities were well prepared should an emergency develop, although “there is no reason to believe they are needed now”.
Immediate signs that a volcano is about to erupt include cracks in the ground and dark streams of volcanic gas being emitted, although Campi Flegrei is not at this stage.
“The volcano is showing signs that the crust is weakening as it continues to stretch,” Prof Kilburn told MailOnline.
“It’s a natural process, but we’re finally able to recognize it as it’s happening.
“This will help provide clearer assessments of the volcano’s future behavior.”
The team will now apply the volcanic fracturing model to other volcanoes that have woken up after a long period of time, to help “establish more reliable criteria for deciding whether an eruption is likely”.
The study was published in the journal Earth & Environment Communications.
