Photographer Unknown, Volcanic Crevasse at Grimsvotn, Iceland
Grímsvötn is a volcano in South-East Iceland. It is in the highlands of Iceland at the northwestern side of the Vatnajökull ice-cap.
Grímsvötn is a basaltic volcano which has the highest eruption frequency of all the volcanoes in Iceland and has a southwest-northeast-trending fissure system. The massive climate-impacting Lake fissure eruption of 1783–1784 was a part of the same fissure system. Grímsvötn was erupting at the same time as Laki during 1783, but continued to erupt until 1785. Because most of the volcano lies underneath Vatnajökull, most of its eruptions have been subglacial and the interaction of magma and meltwater from the ice causes phreatomagmaticexplosive activity.
Grimsvotn erupted again on 21 May 2011 with 12 kilometer high plumes accompanied by multiple earthquakes. This forced the cancelation of nine hundred flights in Iceland, the United Kingdom, Greenland, Germany, Ireland and Norway on the 22-25 May.