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Country: | Iceland | |
| Subregion Name: | Northeastern Iceland | ||
| Volcano Number: | 1703-06= | ||
| Volcano Type: | Stratovolcano | ||
| Volcano Status: | Historical | ||
| Last Known Eruption: | 1961 | ||
| Summit Elevation: | 1516 m | 4,974 feet | |
| Latitude: | 65.03°N | 65°2'0"N | |
| Longitude: | 16.75°W | 16°45'0"W | |
| 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. 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. | |||
