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Askja

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  • Iceland
  • Iceland and Arctic Ocean
  • Stratovolcano
  • 1961 CE
  • Country
  • Volcanic Region
  • Primary Volcano Type
  • Last Known Eruption
  • 65.033°N
  • 16.783°W
  • 1080 m
    3543 ft
  • 373060
  • Latitude
  • Longitude
  • Summit
    Elevation
  • Volcano
    Number
Most Recent Weekly Report: 10 September-16 September 2014 Citation IconCite this Report

IMO had maintained the Aviation Colour Code for Askja at Yellow since 28 August due to elevated seismicity and localized deformation. On 11 September the Colour Code was reduced to Green when seismicity had diminished significantly.

Source: Icelandic Met Office (IMO)

Weekly Reports - Index


2014: September


10 September-16 September 2014 Citation IconCite this Report

IMO had maintained the Aviation Colour Code for Askja at Yellow since 28 August due to elevated seismicity and localized deformation. On 11 September the Colour Code was reduced to Green when seismicity had diminished significantly.

Source: Icelandic Met Office (IMO)


The Global Volcanism Program has no Bulletin Reports available for Askja.

This compilation of synonyms and subsidiary features may not be comprehensive. Features are organized into four major categories: Cones, Craters, Domes, and Thermal Features. Synonyms of features appear indented below the primary name. In some cases additional feature type, elevation, or location details are provided.

Eruptive History

There is data available for 14 Holocene eruptive periods.

Start Date Stop Date Eruption Certainty VEI Evidence Activity Area or Unit
1961 Oct 26 1961 Dec 5 ± 4 days Confirmed 2 Historical Observations North of Öskjuvatn lake (Vikraborgir)
1938 Dec 19 (?) Unknown Confirmed 2 Historical Observations South shore of Öskjuvatn lake
1926 Jul 15 ± 45 days Unknown Confirmed 2 Historical Observations South end of Öskjuvatn lake
1924 (?) Unknown Confirmed 0 Historical Observations South flank of Dyngjufjöll massif
1923 Jan 15 ± 45 days Unknown Confirmed 0 Historical Observations SE corner of Öskjuvatn Caldera
1922 Nov Unknown Confirmed 0 Historical Observations 1 km SW of Öskjuvatn Caldera
1921 Mar Unknown Confirmed 0 Historical Observations NE caldera wall, 0.6 km SE of Viti
1919 Unknown Confirmed 2 Historical Observations Dyngjufjöll
1875 Jan 1 1875 Oct 17 Confirmed 5 Historical Observations Öskjuvatn Caldera, Viti, Sveinagja
1797 (?) Unknown Confirmed 0 Historical Observations Holuhraun
1300 (?) Unknown Confirmed 1 Tephrochronology South of Dyngjufjöll Ytri
1250 BCE ± 300 years Unknown Confirmed 0 Tephrochronology Litladynga and Askja
2050 BCE ± 500 years Unknown Confirmed 0 Tephrochronology Flatadyngja, other areas NE of Dyngjufjöll
8910 BCE ± 200 years Unknown Confirmed 5 Radiocarbon (corrected) SE part of Askja caldera
Deformation History

There is data available for 3 deformation periods. Expand each entry for additional details.


Deformation during 2000 - 2009 [Subsidence; Observed by InSAR]

Start Date: 2000 Stop Date: 2009 Direction: Subsidence Method: InSAR
Magnitude: Unknown Spatial Extent: Unknown Latitude: Unknown Longitude: Unknown

Remarks: InSAR data from the Radarsat satellite shows that Askja continued subsiding from 2000 to 2009.
Figure (see Caption)

Average LOS velocity (mm/yr) over 9 years from the F1 (left) and F5 (right) frame. Incoherent white oval area is lake O?skjuvatn.

From: de Zeeuew-van Dalfsen et al. 2012.

Reference List: de Zeeuew-van Dalfsen et al. 2012.

Full References:

de Zeeuw-van Dalfsen, E., R. Pedersen, A. Hooper, and F. Sigmundsson,, 2012. Subsidence of Askja caldera 2000-2009: Modelling of deformation processes at an extensional plate boundary, constrained by time series InSAR analysis. J. Volcanol. Geotherm. Res., 213-214: 72-82. https://doi.org/10.1016/j.jvolgeores.2011.11.004

Deformation during 1992 - 2000 [Subsidence; Observed by InSAR]

Start Date: 1992 Stop Date: 2000 Direction: Subsidence Method: InSAR
Magnitude: Unknown Spatial Extent: Unknown Latitude: Unknown Longitude: Unknown

Remarks: InSAR data from the ERS satellite shows an average subsidence rate of 5 cm/year during 1992-2000.
Figure (see Caption)

Interferograms covering the Askja volcano. Their time span is given in the upper right corner. Overlaid are Askja volcanic settings as in Fig. 1. Panels from a to d are interferograms from track 238, panels from e to h are from track 009 and i and l are from track 281 (see Table 1). In panels a and m, we show horizontal GPS displacements.

From: Pagli et al. 2006.

Reference List: Pagli et al. 2006.

Full References:

Pagli, C., Sigmundsson, F., Árnadóttir, T., Einarsson, P., Sturkell, E.,, 2006. Deflation of the Askja volcanic system: contraints on the deformation source from combined inversion of satellite radar interferograms and GPS measurements. J. Volcanol. Geotherm. Res., 152, 97-108.

Deformation during 1983 - 1998 [Subsidence; Observed by GPS, Tilt]

Start Date: 1983 Stop Date: 1998 Direction: Subsidence Method: GPS, Tilt
Magnitude: 75.000 cm Spatial Extent: Unknown Latitude: Unknown Longitude: Unknown

Remarks: Subsidence of 75 centimeters occurred between 1983 and 1998 during a non-eruptive period.

Reference List: Sturkell and Sigmundsson 2000.

Full References:

Sturkell, E. and F. Sigmundsson,, 2000. Continuous deflation of the Askja caldera Iceland, during the 1983-1998 non-eruptive period. J. Geophys. Res., 25671-25684.

Emission History

There is no Emissions History data available for Askja.

Photo Gallery

The dark lava flow in the foreground was erupted from the NE side of Askja caldera in 1961. The flat-topped mountain in the distance to the NE is Herdubreid, the most famous of Iceland's "table mountains." These steep-sided mountains were formed by repeated eruptions during the Pleistocene through the glacial icecap. The subglacial lava flows and fragmental hyaloclastite rocks ponded against the melted walls of the glacier. Only at the last stage were minor subaerial lavas erupted above the icecap, forming the small summit peak.

Photo by Richie Williams, 1973 (U.S. Geological Survey).		 See title for photo information.
Steam rises in 1967 from a scoria cone along the Vikraborgir crater row, which was formed during an eruption of Askja volcano in 1961. The eruption began on October 26 from a fissure cutting the NE caldera floor. A chain of small scoria cones formed over the eruptive fissure, which fed lava flows that traveled 9.5 km to the east.

Photo by Richie Williams, 1967 (U.S. Geological Survey).		 See title for photo information.
An eruption from a radial fissure on the NE floor of the Askja caldera took place in 1961, during which lava fountains reached a height of 300 m. The Vikraborgir scoria-cone row, seen here, was built over the eruptive fissure. The fissure fed a 0.1 cu km basaltic lava flow that traveled 9.5 km to the east. The eruption began between 1056 and 1430 hrs on October 26, and ended in early December.

Photo by Richie Williams, 1981 (U.S. Geological Survey).		 See title for photo information.
Askja's largest historical eruption began on New Years day, 1875. Minor explosive eruptions, lava flow emission, and slow caldera collapse preceded a powerful March 28-29 eruption. Subsidence of the caldera continued for several years and resulted in the formation of Askja's inner caldera, now filled by Öskjuvatn lake, seen here from the west. The Askja eruption and collapse were intimately related to the 1875 Sveinagjá fissure eruption, which began on February 18, 1875, about 50-km north along the Askja fissure system.

Photo by Michael Ryan, 1984 (U.S. Geological Survey).		 See title for photo information.
The 1921 Batshraun lava flow descends from a vent (left center) into Öskjuvatn lake across several fault blocks related to subsidence of the Öskjuvatn caldera in 1875. This aerial view from the west shows the small 100-m-wide Viti maar (lower center), which formed during the 1875 eruption. Following slow subsidence of the caldera during the 1875 eruption and several subsequent years, the depression was filled by the waters of Öskjuvatn lake. During the 1920's, several lava flows erupted from vents surrounding the caldera and flowed into the lake.

Photo by Michael Ryan, 1984 (U.S. Geological Survey).		 See title for photo information.
An eruption from a radial fissure on the NE floor of Askja caldera took place in 1961. It produced this 0.1 cu km basaltic lava flow, seen here from the SE, which traveled 9.5 km to the east. Vigorous lava fountains feeding the eruption reached a height of 300 m. The eruption began on the afternoon of October 26, when athe ash column reachd 6 km. Lava effusion began almost immediately, and the lava flow had traveled 7.5 km from the vent at Vigraborgir by October 26. The eruption continued until early December.

Photo by Michael Ryan, 1984 (U.S. Geological Survey).		 See title for photo information.
The lava flow at the lower right was erupted during 1961 from a vent on the NE side of Askja caldera and flowed 9.5 km to the east. Snowfields cover part of the far wall of the caldera in the distance, beyond its flat lava-covered floor. The lake at the upper left is Öskjuvatn, which fills Askja's youngest caldera, formed in 1875. The irregular slopes of the Dyngjufjöll massif in the foreground are formed almost entirely by the products of subglacial eruptions.

Photo by Michael Ryan, 1984 (U.S. Geological Survey).		 See title for photo information.
Askja is a large central volcano that forms the Dyngjufjöll massif. It is truncated by three calderas, the largest of which is 8 km wide. This view from the SE looks across Öskjuvatn 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 Sveinagjá graben, is also related to the Askja volcanic system.

Photo by Michael Ryan, 1984 (U.S. Geological Survey).		 See title for photo information.
The massive Askja shield volcano, seen here from the north, forms the Dyngjufjöll massif. Almost all of the massif is composed of subglacial pillow lavas and hyaloclastites. The broad summit of the volcano is truncated by three overlapping calderas, the youngest of which formed during an eruption in 1875. An extensive 100-km-long fissure system extends north of Askja, well beyond the point of this photo. The Askja fissure system includes the Sveinagjá fissure, which was active during 1875.

Photo by Michael Ryan, 1984 (U.S. Geological Survey).		 See title for photo information.
The small 100-m-wide, steep-walled Viti maar crater, filled by a turquoise lake, was formed by phreatic explosions following a major plinian eruption at Askja on March 28-29, 1875. Note the fault cutting the left-hand crater wall. The dark lava flow in the background was erupted from a vent on the NE caldera wall of Askja. The lava flow traveled west into Öskjuvatn lake, out of view to the right.

Photo by Michael Ryan, 1984 (U.S. Geological Survey).		 See title for photo information.
The dark Batshraun lava flow descending from the left into Öskjuvatn lake was erupted during 1921. The lava flow originated from a vent below the rim of Askja's central caldera, and flowed over the low rim of the younger 1875 caldera into the lake. The lava flow was the first of several during the 1920's that flowed into the NE, SE, and west sides of Öskjuvatn lake.

Photo by Michael Ryan, 1984 (U.S. Geological Survey).		 See title for photo information.
Askja, seen here in an aerial view from the south, is a large central volcano that is truncated by three overlapping calderas. The youngest caldera, formed during Askja's largest historical eurption in 1875, is filled by Öskjuvatn lake (center). This caldera partially truncates the largest Askja caldera, whose floor forms the flat-surfaced area left of the lake. The 100-km-long Askja fissure swarm has also erupted during historical time. Twentieth-century eruptions at Askja have produced lava flows from vents located mostly near Öskjuvatn lake.

Photo by Oddur Sigurdsson, 1977 (Icelandic National Energy Authority).		 See title for photo information.
GVP Map Holdings

The Global Volcanism Program has no maps available for Askja.

Smithsonian Sample Collections Database

The following 2 samples associated with this volcano can be found in the Smithsonian's NMNH Department of Mineral Sciences collections, and may be availble for research (contact the Rock and Ore Collections Manager). Catalog number links will open a window with more information.

Catalog Number Sample Description Lava Source Collection Date
NMNH 111086 Basalt -- --
NMNH 117551-5 Obsidian -- --
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