Volcanologists had never measured this before in the world: the high speed at which magma flowed through the fifteen kilometer long, underground magma fissure under Iceland’s Reykjanes Peninsula. The magma flow has caused earthquakes, volcanic eruptions, evacuations and a lot of damage in recent months. Just last week, the volcano erupted with fountains of bright orange lava tens of meters high. Volcanologists do not yet know exactly how such a large magma fissure forms and leads to eruptions. To learn more, Icelandic volcanologists calculated the flow rate of magma in the fissure beneath Reykjanes using satellite data, seismic data and a computer model. It moves at a speed of 7,400 cubic meters per second, they concluded in Science. For comparison: last Tuesday the flow at Lobith in the Rhine was about 5,200 cubic meters per second.