Lava fountain from Eyjafjallaj繹kull, Iceland. In March of 2010, the volcano erupted for the first time in 200 years. The resulting ash cloud caused the largest air-traffic shutdown in Europe since World War II. Iceland is the largest volcanic island on Earth and is sliced down the middle by the hot, geologically active Mid-Atlantic Ridge. This unique placement marks the boundary of the American Tectonic Plate and the Eurasian Tectonic Plate. As these plates spread, lava reaches Earth's surface, and Iceland's volcanoes are born.