The Pacific Ring of Fire is an area where large numbers of earthquakes and volcanic eruptions occur in the basin of the Pacific Ocean. In a 25,000 mile horseshoe shape, it is associated with a nearly continuous series of oceanic trenches, volcanic arcs, and volcanic belts and/or plate movements. The Ring of Fire has 452 volcanoes and is home to over 75% of the world’s active and dormant volcanoes. Oxford University scientists have potentially discovered the explanation for why the world’s explosive volcanoes are confined to bands only a few tens of miles wide. Most of the molten rock that comes out of these volcanoes is rich in water, but the Oxford team has shown that the volcanoes are aligned above narrow regions in the mantle where water-free melting can take place.