Naples – A restive "super volcano" west of Naples is raising nervousness in the local Italian population. The ground of the Campi Flegrei "burning fields", also known as the Phlegraean Fields, has risen more in recent weeks than it has in a long time. The Phlegraean Fields are a large caldera, or volcanic crater, lying mostly underwater off the Italian coast. The caldera is thought to have been formed by a massive eruption some 35 000 to 40 000 years ago. The team has drilled a pilot hole to a depth of 500 metres but no data has been gathered yet, Wiersberg said in an interview with dpa.No forecasts have been made thus far. Since super volcanoes seldom undergo massive eruptions, empirical data is lacking. "It's easy to assert there'll be an eruption sometime. That doesn't help us, though. We need more specific information," Wiersberg said.