A crust under a European volcano is about to erupt

Campi Flegrei is often called a supervolcano, a collective term for volcanoes whose “matter” released during a single eruption exceeds 1,000 cubic kilometers.

Supervolcanoes can often be identified by their craters, their eruptions being so powerful they blow themselves to pieces, often leaving only a crater lake.

Technically speaking, the Naples volcano is not actually a supervolcano. Campi Flegrei’s largest eruption 39,000 years ago puts it just below the threshold for being classified as a “supervolcano,” which is still considered a very violent eruption, however.

Earth’s crust has compressed to the breaking point

The crater at Campi Flegrei has not erupted since 1538, but since 2005 it has caused ridges in the Earth’s surface.

Therefore, researchers at University College London and the Italian National Institute of Geophysics and Volcanology monitored the volcano’s geological activity through seismic measurements to see how likely it was that an eruption would occur.

There are indications that the crust beneath Campi Phlegrei is about to rupture.

“A supervolcano has a crust that becomes increasingly weaker and more prone to rupture, which increases the likelihood of an eruption,” explains lead author of the study Christopher Kilburn, professor of earth sciences at University College London.

However, the researchers behind the study stress that the findings do not mean that a volcanic eruption is waiting around the corner.

“Rupture can open a fissure in the Earth’s crust, but magma must also be pushed into the right place for an eruption to occur,” says Professor Christopher Kilburn.

incandescent gas pressure

The underground fermentation is likely driven by volcanic gas, which seeps into the Earth’s crust three kilometers below the surface of the Campi Flegrei, sucking it up like a sponge.

It causes the Earth’s crust to stretch and warp, causing earthquakes to rise to the surface.

If enough volcanic gas enters the crust, heat and pressure from the gas can push the crater above its “critical discharge pressure,” so that it explodes and opens a fissure where magma below can be erupted in an explosion.

According to the study, deep underground gas and magma have slowly flexed and weakened the Campi Phlegrei crust since the 1950s, reducing its tensile strength to a third of what it was in 1984.

Neighbor to half a million people

It’s possible to know when — or if — the volcano will erupt, Kilburn explains, but that eruption “would be very dangerous” for the 500,000 or so people who live near the Campi Flegrei crater.

In the worst case scenario, if Campi Flegrei repeats its previous largest eruption, the supervolcano could send molten rock and pyroclastic gases higher into the stratosphere, creating a 33.5-meter-high tsunami and spreading a cloud of toxic sulfur and ash, in addition. To kill crops and cause mass extinction of large numbers of animals could also send Earth into a multi-year global winter.