NAPLES, ITALY — A supervolcano that last erupted nearly 500 years ago is showing signs of reawakening.
The Campi Flegrei supervolcano lies beneath the Bay of Naples in southern Italy and contains 24 craters along with numerous geysers and vents.
There has been a recent decrease in gas pressure at the supervolcano, which combined with an increase in temperature of the hydrothermal reservoir means the magma may be approaching critical degassing pressure, scientists wrote in the journal Nature on Dec. 20.
That could lead to volatility and even culminate in an eruption.
Campi Flegrei is Italian for “Burning Fields.” The supervolcano is 8 miles wide and sits directly under more than half a million people.
Campi Flegrei spewed ash across Europe for eight consecutive days when it last erupted in 1538.
The Italian government has raised the threat level of the supervolcano from green to yellow, meaning that it now requires scientific monitoring, according to National Geographic.