Campi Flegrei
© Flickr / Michele CostigliolaCampi Flegrei
An ancient Italian supervolcano that hasn't erupted in 500 years may be starting a stage of activity that could lead to a colossal eruption, spelling potential disaster for communities lying in its path.

Campi Flegrei may have entered a new magma cycle, according to newly released findings that suggest the feature's "subvolcanic plumbing system" is commencing "a new build-up phase." The researchers warn this could give rise "at some undetermined point in the future," to "a large volume eruption."

A large volcanic area west of Naples which has 24 volcanic craters, Campi Fieri, has "produced two cataclysmic caldera-forming eruptions and numerous smaller eruptive events over the past 60,000 years," according to the new paper. Calderas are vacant spaces left after rock explosions during eruptions.

A team of scientists examined 23 of Campi Flegeri's past eruptions and created a computer model to simulate these eruptions. The last eruption, which took place in 1538, lasted for eight days and was so powerful it created Monte Nuovo. Worryingly, this was a fairly tame eruption by Camp Flegeri's standards.

The two biggest events were the Campanian Ignimbrite eruption, which occured 39,000 years ago and spewed ash for an awesome 3.7 million square kilometers, and the Neapolitan Yellow Tuff (NYT) eruption which happened around 15,000 years ago.

After conducting chemical analysis on the rocks, minerals and glass samples from these eruptions, the scientists determined Campi Flegrei's magma conditions could be entering a phase of pressure build up, which tends to happen before eruptions.

They discovered the same kind of magma that was found leading up to the Monte Nuovo, Campanian Ignimbrite and Neapolitan Yellow Tuff eruptions - a water-saturated magma high in CO2.

With Campi Flegrei surrounded by some 1.5 million people, even a small eruption could have devastating consequences.

However, there's no reason for anyone in the vicinity to panic just yet - the study's findings do not mean a massive eruption is impending. These conditions can actually hold for a long time without escalating, and while it is possible that a massive eruption could occur, it shouldn't happen in the near future.