A "breathing" cap of magma has been discovered inside the Yellowstone supervolcano, and it might help determine when the volcano will next erupt, a new study has found.
Yellowstone hasn't had a major eruption for hundreds of thousands of years, but it's still very much an active system. This newly discovered cap, which is 2.6 miles (3.8 kilometers) below the surface, acts like a lid, according to a recent statement. Not only does this lid trap a significant amount of heat and pressure inside, but it also appears to be porous enough to steadily release some of that pressure, so the whole system doesn't blow.
