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

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  Location of the Askja central volcano, Iceland

Approaching Askja

Highland roads leading to Askja

F88: "Öskjuvegurinn"

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Road F910

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Aerial views

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

The maar Víti

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  With Öskjuvatn and Dyngjufjöll in the background
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  With a good view of the tuff rock formations within the crater
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  The difference in water colour between Víti and Öskjuvatn is due to mineralisation, esp. higher sulfur content in the waters of Víti
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  Víti: easily eroded crater walls
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  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.

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  Lake Öskjuvatn: result of a caldera forming event
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  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

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

Deserts of Ódáðahraun

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

Volcanic system of Askja

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

Eruption fissures of Askja

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  Crater rows on Möðrudalsheiði
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  Eruption fissure of the Askja system
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  Jökulsárgljúfur: A fissure of the Askja system crosses just north of Dettifoss
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  Another caused eruptions in Vesturdalur, about 2500 years ago

Lava of Askja volcanic system

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  Pahoehoe lava of Askja
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  Ropy pahoehoe at Askja
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  The formation of pahoehoe lava (here: active lava flows of Kilauea)
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  Pillow lavas of Askja: subglacial or subaqueous origin

Herðubreið: A tuya in the region of the Askja system

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  Herðubreið with snow on her top
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  Lava fields in the foreground
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  Herðubreið