Iceland%20volcano%20lava%20flow%2010Iceland’s Bardarbunga volcano has been erupting since Aug. 29, with lava shooting out of the ground on the Holuhraun lava field about halfway between that volcano and a neighboring volcano called Askja. The lava has flown out of the collapsed crater of Bardarbunga, known as a caldera, in a nearly 30 mile long dyke, before reaching the Earth’s surface. The flow of molten rock, or magma, out from underneath the volcano, through the dyke, and out of the ground has been so significant that the caldera itself — which sits underneath the Dyngjujokull glacier — has sunk by more than 61 feet, which is the largest amount of subsidence observed in any volcano in Iceland since such observations began in about 1950. More