'The system is likely to reach a breaking point': Major Italian volcano is speeding toward a transition, and a major eruption could be on the way

An aerial view of a caldera surrounded by lush countryside with the ocean in the background.

Campi Flegrei, a volcanic caldera west of Naples, is speeding toward a transition within the next decade, a new study suggests, but researchers can't yet say whether that transition will be an eruption or some other change in the volcano's internal plumbing.

The caldera, also known as the Phlegraean Fields, is home to about 500,000 people who would be at risk in the event of an eruption. The caldera stretches about 9 miles (15 kilometers) in diameter and formed in a massive eruption 40,000 years ago. Other, smaller eruptions have happened since, including an explosive one in 1528 that built Monte Nuovo, a 433-foot (132 meters) cinder cone.