Italy's supervolcano on the course to unleash a fiery eruption, scientists warn

A long-quiet, yet massive supervolcano in southern Italy may be on course to erupt a lot sooner than once expected, scientists warn.

Campi Flegrei, a lava-filled mountain that sits several miles outside of a city of nearly 4 million people "may be approaching a critical stage," according to researchers from the Vesuvius Observatory and University College London.

Check out photos of the rumbling Campi Flegrei:

"Further unrest will increase the possibility of an eruption... It's imperative that the authorities are prepared for this," Christopher Kilburn, Director of the UCL Hazard Centre, wrote in Nature Communications.

Although Kilburn notes that an eruption is not imminent, he warns that there is a critical phase on the horizon. The alert level has rested at amber for the restless supervolcano since 2012, which was once green.

Campi Flegrei, which means "burning fields" in Italian, hasn't erupted since 1538, but experts have been studying the patterns of unrest in the supervolcano's activity for the last 500 years. Today, scientists warn the eight-mile-wide supervolcano's recent activity could be showing signs of reawakening.

With small earthquakes occurring throughout the past century, the caldera's crust has been placed under stress during periods of inflation and deflation, which were previously thought to diffuse energy. The team's most recent analysis, however, shows this does not appear to be the case.

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Based on computer modeling and physical measurements, "magma could be approaching the CDP [critical degassing pressure] at Campi Flegrei, a volcano in the metropolitan area of Naples, one of the most densely inhabited areas in the world, and where accelerating deformation and heating are currently being observed," Giovanni Chiodini, a scientist working at the Italian National Institute of Geophysics in Rome, also wrote in Nature Communications.

Though the timing of an eruption remains unknown, scientists warn that a release of hot magmatic gasses is becoming more possible, which could trigger another devastating eruption.

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