Askja is a large central volcano that forms the Dyngjufjšll massif. It is truncated by three calderas, the largest of which is 8 km wide. This view from the SE looks across …skjuvatn lake, which fills the youngest caldera. It formed in 1875 during Askja's largest historical eruption and truncates a larger caldera, whose wall is seen in the distance above the lava-covered caldera floor. The 100-km-long Askja fissure swarm, which includes the Sveinagj‡ graben, is also related to the Askja volcanic system.