Campi Flegrei, which translates to “burning fields,” is a massive caldera that rests on top of an ancient volcano near the city of Naples in Italy. Scientists warn that hydrothermal activity in the caldera is reaching a critical point, which could trigger an eruption.
The 7.5-mile-wide cauldron formed when magma inside the volcano blew, and continues to spout geysers, boiling mud and sulfuric acid. Half of the caldera is underneath the Mediterranean, while the other half contains cinder cones and smaller craters from eruptions, the Washington Post reports.
Now, decreased pressure on rising magma might cause gas and fluid to release in what would be a catastrophic geological event. While forecasting volcanic eruptions is not an exact science, lead author Giovanni Chiodoni says that an eruption would devastate around 500,000 people living in and around the caldera. Chiodoni is a volcanologist at the National Institute of Geophysics in Rome.
The last time the volcano erupted was in 1538, where it spewed for a week, expelling enough material to create Monte Nuovo, a cinder cone mountain.
The caldera itself is 39,000 years old, formed by the larges eruption in 200,000 years of European history. Anthropology studies suggest that it was so massive that it caused a “volcanic winter” and led to the death of the Neanderthals.
For 50 years, scientists have been monitoring Campi Flegrei and its relentless activities. Significant uplifts in magma filling the mountains inner chamber prompted Italian authorities to raise alert levels from green (quiet) to yellow (scientific attention) in 2012.
Chiodoni says that scientists have been seeing increasing signs of an imminent reaction, following a pattern of activity seen around similar volcanoes before their eruptions.
But residents of Naples shouldn’t panic just yet. “In general, unfortunately, volcanology is not a precise science,” Chiodoni explans. “We have many uncertainties and long-term previsions are at the moment not possible! For example, the process that we describe could evolve in both directions: toward pre-eruptive conditions or to the finish of the volcanic unrest.”
The report was published in the journal Nature.