Askja

Deutsch: Die Askja ist ein großer Zentralvulkan mit eigenem Vulkansystem im Hochland von Island. Eine bedeutende Eruption formte 1875 die letzte Caldera und den See Öskjuvatn.

English: Askja is a big central volcano with nested calderas and is located in the highland of Iceland, north of Vatnajökull.

Français : L'Askja est un emboîtement de caldeiras en Islande, éponyme d'un système volcanique appartenant au graben médian et composé de ces caldeiras, la plus interne étant occupée par un lac, l'Öskjuvatn, du massif volcanique qui les entoure, les Dyngjufjöll, reste d'un ancien volcan précédant la caldeira, ainsi que de volcans boucliers, de cratères et de fissures volcaniques s'étirant dans une direction nord-sud sur une centaine de kilomètres de longueur. La dernière éruption de l'Askja remonte à la fin 1961 mais sa plus puissante des temps historiques, responsable de la formation de la caldeira remplie par l'Öskjuvatn, s'est déroulée en 1875.

Maps

Location of the Askja central volcano, Iceland

Approaching Askja

Highland roads leading to Askja

F88: "Öskjuvegurinn"

Road F910

Aerial views

Aerial view of the nested Askja calderas as well as lake Öskjuvatn
Askja with the maar Víti in the foreground

The maar Víti

With Öskjuvatn and Dyngjufjöll in the background
With a good view of the tuff rock formations within the crater
The difference in water colour between Víti and Öskjuvatn is due to mineralisation, esp. higher sulfur content in the waters of Víti
Víti: easily eroded crater walls
Origin of Víti: maar forming phreatomag-matic eruptions, here of the Ukinrek craters in Alaska

Öskjuvatn

The origin of Öskjuvatn: 1) Eruptions - Magma chamber 2) Partially empty magma chamber, 3) The roof of the magma chamber gives in and thereby the caldera is formed in a big explosive eruption.

Lake Öskjuvatn: result of a caldera forming event
Probable distribution of volcanic ash during the 1875 eruption of Askja

Surroundings

Askja lies in a very remote part of Iceland, on high terrain with snow even in the summer time and deserts in the vicinity.

Drekagil

The canyon Drekagil
The huts at Drekagil:Accommodation and information for travellers
The huts at Drekagil

Deserts of Ódáðahraun

Aeolian sediment transport near Askja
Ódáðahraun with huts
Sandstorm south of Askja

Volcanic system of Askja

The fissure system of Askja is probably the longest in Iceland (about 200 km, mostly to the north of the volcanic center).
Magma chamber and fissure system of a similar, but different kind: at a coastal shield volcano