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Askja volcan

stratovolcan 1516 m (4,974 ft)
Central Iceland, 65.03°N / -16.75°W
Condition actuelle: en sommeil (1 sur 5)
Dernière mise à jour: 4 avril 2012 (Augmentation des températures du lac, le lac de la caldeira sans glace en hiver pour la première fois sur de nombreuses années)
Style éruptif tipique: explosive + effusive
Eruptions du volcan Askja : 1797(?), 1875, 1919, 1921, 1922, 1923, 1924(?), 1926, 1938, 1961
Askja is a large basaltic central volcano that forms the Dyngjufjöll massif. It is truncated by three overlapping calderas, the largest of which is 8 km wide and may have been produced primarily from subglacial ring-fracture eruptions rather than by subsidence.

Introduction:

A major rhyolitic explosive eruption from Dyngjufjöll about 10,000 years ago was in part associated with the formation of Askja caldera. Many postglacial eruptions also occurred along the ring-fracture. A major explosive eruption on the SE caldera margin in 1875 was one of Iceland's largest during historical time. It resulted in the formation of a smaller 4.5-km-wide caldera, now filled by Öskjuvatn lake, that truncates the rim of the larger central caldera. The 100-km-long Askja fissure swarm, which includes the Sveinagja graben, is also related to the Askja volcanic system, as are several small shield volcanoes such as Kollatadyngja. Twentieth-century eruptions at Askja have produced lava flows from vents located mostly near Öskjuvatn lake.

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Source: GVP, Smithsonian Institution