Öræfajökull (; ' Öræfi glacier' or 'wasteland glacier') is an ice-covered

volcano A volcano is commonly defined as a vent or fissure in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most oft ...

in south-east

Iceland Iceland is a Nordic countries, Nordic island country between the Atlantic Ocean, North Atlantic and Arctic Oceans, on the Mid-Atlantic Ridge between North America and Europe. It is culturally and politically linked with Europe and is the regi ...

. The largest active volcano and the highest peak in Iceland at , it lies within the

Vatnajökull National Park Vatnajökull National Park ( ) is one of three national parks in Iceland, and is the largest one. It encompasses all of Vatnajökull glacier and extensive surrounding areas. These include the national parks previously existing at Skaftafell in th ...

and is covered by part of the glacier. The original Norse settlers named the volcano Knappafellsjǫkull (

Old Norse Old Norse, also referred to as Old Nordic or Old Scandinavian, was a stage of development of North Germanic languages, North Germanic dialects before their final divergence into separate Nordic languages. Old Norse was spoken by inhabitants ...

: ;

Modern Icelandic Icelandic ( ; , ) is a North Germanic language from the Indo-European language family spoken by about 314,000 people, the vast majority of whom live in Iceland, where it is the national language. Since it is a West Scandinavian language, it ...

: Hnappafellsjökull ; 'knobs mountain glacier'). The current name, ''Öræfajökull'', was eventually adopted after the 1362 eruption.

Description

Öræfajökull is located at the southern extremity of the

Vatnajökull Vatnajökull ( Icelandic pronunciation: , literally "Glacier of Lakes"; sometimes translated as Vatna Glacier in English) is the largest and most voluminous ice cap in Iceland, and the second largest in area in Europe after the Severny Island i ...

glacier and overlooking the

Ring Road A ring road (also known as circular road, beltline, beltway, circumferential (high)way, loop or orbital) is a road or a series of connected roads encircling a town, city or country. The most common purpose of a ring road is to assist in reducin ...

between

Höfn Höfn () or Höfn í Hornafirði (, ) is an Icelandic fishing town in the southeastern part of the country. It lies near Hornafjörður fjord. The town, the second largest in the southeastern part of Iceland, offers scenic views of Vatnajökull ...

and Vík. It is the largest active volcano in the country, and on the summit crater's north-western rim is Hvannadalshnúkur, the highest peak in Iceland at . Geographically, Öræfajökull as the glacier, is considered part of

, and the area covered by glacier is within the boundary of

. There are a number of outlet glaciers in the ice cap within the area of the central volcano which clockwise from north are:

Breiðamerkurjökull Breiðamerkurjökull (, ) is an outlet glacier of the larger glacier of Vatnajökull and a piedmont glacier in the southern part of Vatnajökull National Park, Iceland. Emerging as a tongue of the Vatnajökull, it ends in two lagoons, famous J ...

, Fjallsjökull, Hrútárjökull, Bræðrajökull, Kviarjökull, Hólárjökull, Stórhöfðajökull, Gljúfursárjökull, Rótarfjallsjökull (which has a western branch called Kotárjökull), Grænafjallsjökull, Falljökull, Virkisjökull, Svinafellsjökull and Skaftafellsjökull. While most of the outlet glaciers have reasonably clear catchments, not all do. Some of the icecap feeds directly into river catchments without a named glacier and this happens between the Hrútárjökull and Bræðrajökull, and the Virkisá river drains a number of glaciers between Rótarfjallsjökull and Svinafellsjökull (see map on this page). The summit caldera of this

stratovolcano A stratovolcano, also known as a composite volcano, is a typically conical volcano built up by many alternating layers (strata) of hardened lava and tephra. Unlike shield volcanoes, stratovolcanoes are characterized by a steep profile with ...

is and the volcano is in diameter. It is the most southern of the volcanoes in the Öræfi volcanic belt (Öræfajökull volcanic belt), which is possibly an embryonic rift parallel and to the east of the Eastern volcanic zone. The presently active summit caldera may have a subcaldera within it. Eruptions in this area are most likely to result in

jökulhlaup A jökulhlaup ( ) (literally "glacial run") is a type of glacial outburst flood. It is an Icelandic term that has been adopted in glaciological terminology in many languages. It originally referred to the well-known subglacial outburst floo ...

s that will produce floods at the outlets of the Kviarjökull and Virkisá catchments as these overlap the present caldera. There is possibly an old caldera to the north of the current caldera and flank eruptions could produce jökulhlaup from other outlet glaciers. The topographical map on this page can be enlarged to show this detail.

Activity

Öræfajökull has erupted twice in historical times, in 1362 and 1728. These were explosive silicic eruptions with bulk tephra volumes of and jökulhlaups occurred. The deposits closer to the central volcano are rhyolytic but the more distal lava flows which can extend for from the caldera are alkali

olivine basalt Basalt (; ) is an aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron ( mafic lava) exposed at or very near the surface of a rocky planet or moon. More than 90% ...

and both have been erupted in the

Holocene The Holocene () is the current geologic time scale, geological epoch, beginning approximately 11,700 years ago. It follows the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene to ...

1362 eruption

In 1362, Knappafellsjökull erupted explosively, ejecting 10 cubic kilometres of

tephra Tephra is fragmental material produced by a Volcano, volcanic eruption regardless of composition, fragment size, or emplacement mechanism. Volcanologists also refer to airborne fragments as pyroclasts. Once clasts have fallen to the ground, ...

, similar in scale to the

1991 eruption of Mount Pinatubo The 1991 eruption of Mount Pinatubo in the Philippines' Luzon Volcanic Arc was the second-largest volcanic eruption of the 20th century, behind only the 1912 eruption of Novarupta in Alaska. Eruptive activity began on April 2 as a series of p ...

. The eruption sequence lasted for several months, being from a medium-potassium alkali rhyolite and has been assigned a VEI of 6 although

dense-rock equivalent Dense-rock equivalent (DRE) is a volcanologic calculation used to estimate volcanic eruption volume. One of the widely accepted measures of the size of a historic or prehistoric eruption is the volume of magma ejected as pumice and volcanic ash, k ...

volume may be less than previous estimates at . The wealthy district of Litlahérað was destroyed by

flood A flood is an overflow of water (list of non-water floods, or rarely other fluids) that submerges land that is usually dry. In the sense of "flowing water", the word may also be applied to the inflow of the tide. Floods are of significant con ...

pyroclastic flow A pyroclastic flow (also known as a pyroclastic density current or a pyroclastic cloud) is a fast-moving current of hot gas and volcanic matter (collectively known as tephra) that flows along the ground away from a volcano at average speeds of b ...

s and ashfall. Sailors reported pumice “in such masses that ships could hardly make their way through it.” Thick volcanic deposits obliterated farmland, and ash travelled as far as

western Europe Western Europe is the western region of Europe. The region's extent varies depending on context. The concept of "the West" appeared in Europe in juxtaposition to "the East" and originally applied to the Western half of the ancient Mediterranean ...

. Forty farms were destroyed. More than 40 years passed before people again settled the area, which became known as Öræfi. The name literally means 'an area without harbour,' but it took on a meaning of 'wasteland' in Icelandic, as the 1362 eruption had drastically altered the environment around the mountain. The volcano likewise took on the new name Öræfajökull.

1728 eruption

An eruption in August 1727–1728 was smaller than 1362, though floods are known to have caused three fatalities when the meltwater swept their farm away.

2017 activity

Increased earthquake activity in the form of small tremors ranging from a depth of 1.5–10 km beneath the summit crater, began in August 2017 according to the

Icelandic Meteorological Office Icelandic Meteorological Office (IMO; ) is Iceland's national weather service and as such a government agency under the Ministry of Environment and Natural Resources. It is also active in volcano monitoring, esp. volcano seismology, and, toget ...

. The Aviation Colour Code of the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

was raised to yellow on 17 November 2017, after the appearance of an

ice cauldron Ice cauldrons are ice formations within glaciers that cover some subglacial volcanoes. They can have circular to oblong forms. Their surface areas reach from some meters (as indentations or holes in the ice) to up to 1 or more kilometers (as b ...

inside the main crater and increased

geothermal activity Geothermal activity is a group of natural heat transfer processes, occurring on Earth's surface, caused by the presence of excess heat in the subsurface of the affected area, usually caused by the presence of an igneous intrusion underground. Geot ...

under the glacier.

2018 activity

The seismic and geothermal activity which began in August 2017 continued into 2018, but at reduced levels. On 4 May 2018, the Icelandic Meteorological Office lowered the Aviation Colour Code to green.

Landslide

In 2013 due to paraglacial slope failure, a large

landslide Landslides, also known as landslips, rockslips or rockslides, are several forms of mass wasting that may include a wide range of ground movements, such as rockfalls, mudflows, shallow or deep-seated slope failures and debris flows. Landslides ...

affecting an area of occurred, that deposited debris on the volcano's Svínafellsjökull outlet glacier.

References

External links

Öræfajökull
in the Catalogue of Icelandic Volcanoes
Volcano Images of Europe

Photos of Öræfajökull
www.Icelandportfolio.com *
Google Earth view

Official Website of Vatnajökull National Park
{{DEFAULTSORT:Oraefajokull Southern Region (Iceland) Stratovolcanoes of Iceland Mountains of Iceland Glaciers of Iceland VEI-6 volcanoes Active volcanoes Öræfajökull Belt Two-thousanders of Iceland 1362 1727 disasters 1720s natural disasters Subglacial calderas Subglacial volcanoes of Iceland Calderas of Iceland Central volcanoes of Iceland