Rumblings of Italy's supervolcano: Will the sleeping giant awaken?

A massive supervolcano under the city of Naples, Italy, is showing signs of life again, prompting concern among some scientists.

The Campi Flegrei, Italian for "burning fields," that make up the vocano's crater, or caldera, have been full of boiling mud, steam, and even smaller volcanoes for centuries. The people of ancient Rome believed the area to be the home of the Roman god of fire and volcanoes, Vulcan. Today, the fields are a popular tourist destination. But the caldera has been showing signs of an explosive awakening since 2012, and a new study indicates that a destructive eruption of the volcano could be coming soon.

While the volcano could pose a threat to the 500,000 people living in or around the caldera of the volcano, the researchers involved in the study stress that volcanoes are extremely hard to predict, and it is possible that it could fizzle out before reaching a critical pressure. But based on their findings, it will be prudent to continue monitoring the volcano.

The last time Campi Flegrei erupted was in 1538, when, over the course of a week, enough material was expelled to create a new mountain, known as Monte Nuovo. Its most significant eruption, however, occurred 39,000 years ago, when the caldera itself was actually formed in one of the largest volcanic events ever to occur in Europe. A 2010 study suggests that this eruption might have led to a volcanic winter that helped killed off the Neanderthals and pave the way for the expansion of Homo sapiens across the continent. While an eruption today would probably not be as catastrophic as the one 39,000 years ago, it would still have a significant impact on the neighboring urban area, home to more than half a million people.

Since 2005, Campi Flegrei, also known as Phlegraean Fields, has been undergoing uplift caused by phenomena known as "bradyseisms," with the surface of the volcano literally being pushed upward by magma underneath the caldera. As the magma chambers underneath the surface filled, scientists identified a threshold beyond which this magma could increase the release of gases and fluids and eruptive rates, triggered by steam injected into the surrounding rock.

"Hydrothermal rocks, if heated, can ultimately lose their mechanical resistance, causing an acceleration towards critical conditions," Giovanni Chiodini, a researcher at Italy's National Institute of Geophysics and Volcanology in Bologna and lead author of the study, told Agence France-Presse.

Despite the dire news described in the paper, published Tuesday in the journal Nature Communications, Dr. Chiodini emphasizes that this "critical degassing pressure" is not necessarily inevitable.

"In general, unfortunately, volcanology is not a precise science," he wrote in an email to The Washington Post. "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."

Volcanoes are notoriously difficult to predict, since their active lifespans often extend back for hundreds of thousands or even millions of years and involve processes occurring far underground.

This article contains material from Reuters.