Volcanoes that sit within Earth's tectonic plates don't erupt how scientists thought they did. It turns out, magma within these volcanoes is propelled up and out of the ground by carbon dioxide — not by water, as was previously thought, a new study finds.
This magma also shoots up from much deeper reserves than previously estimated, originating in Earth's mantle at depths of 12 to 19 miles (20 to 30 kilometers), rather than in the outer crust, 4 to 8 miles (7 to 13 km) deep.
