'Rosetta Stone' of supervolcanoes discovered in Italian Alps Rare uplift reveals for the first time the deep plumbing of a supervolcano Scientists have found the "Rosetta Stone" of supervolcanoes, those giant pockmarks in the Earth's surface produced by rare and massive explosive eruptions that rank among nature's most violent events. The eruptions produce devastation on a regional scale - and possibly trigger climatic and environmental effects at a global scale.