Eyjafjallajökull

Eyjafjallajökull (; "glacier of (the mountain) Eyjafjöll"), sometimes referred to by the numeronym E15, is one of the smaller ice caps of Iceland, north of Skógar and west of Mýrdalsjökull. The ice cap covers the caldera of a volcano with a summit elevation of . The volcano has erupted relatively frequently since the Last Glacial Period, most recently in 2010, when, although relatively small for a volcanic eruption, it caused enormous disruption to air travel across northern and western Europe for a week.

Geography

Eyjafjallajökull consists of a volcano completely covered by an ice cap. The retreating ice cap covered an area of in 2019, with many outlet glaciers. The main outlet glaciers are to the north: Gígjökull, flowing into Lónið, and Steinsholtsjökull, flowing into Steinsholtslón. In 1967, there was a massive landslide on the Steinsholtsjökull glacial tongue. On 16 January 1967 at 13:47:55 there was an explosion on the glacier. It can be timed because the seismometers at Kirkjubæjarklaustur monitored the movement. When about of material hit the glacier a massive amount of air, ice, and water began to move out from under the glacier into the lagoon at the foot of the glacier. stands at its highest point, and has a crater in diameter, open to the north.

Etymology

The name means "glacier of Eyjafjöll" (or more properly here "ice cap"). is the name of the southern side of the volcanic massif together with the small mountains which form the foot of the volcano. The word , meaning glacier or ice cap, is a cognate with the Middle English word surviving in the -icle of English icicle.

The name is made up of the words (genitive plural of , meaning eyot or island), and the plural word , meaning fells or mountains, and together literally means: "the mountains of the islands". The name probably refers to the close by archipelago of Vestmannaeyjar.

The word is the genitive plural of , and so is the genitive form of and means: "of the Eyjafjöll".

A literal part-by-part translation of would thus be "Islands' Mountains' glacier".

Hence the southern slopes of the mountain Eyjafjöll result in the sea side strip of land beyond being called Undir Eyjafjöllum. However, fissure vents occur on both (mainly the west) sides of the volcano.

The volcano is fed by a magma chamber under the mountain, which in turn derives from the tectonic divergence of the Mid-Atlantic Ridge. It is part of a chain of volcanoes stretching across Iceland. Its nearest active neighbours are Katla, to the northeast, and Eldfell, on Heimaey, to the southwest.

The volcano is thought to be related to Katla geologically, in that eruptions of Eyjafjallajökull have generally been followed by eruptions of Katla.

Eyjafjallajökull erupted in the years 920, 1612, 1821, and 2010. The Skerin Ridge eruption in 920 was a VEI 3 radial fissure eruption while the subsequent 1612 and 1821 eruptions were VEI 2 small summit eruptions. Notably, the ash released from the eruption contained a large fraction of fluoride, which in high doses may damage the bone structure of cattle, horses, sheep and humans. The eruption also caused some small and medium glacier runs (jökulhlaups) and flooding in nearby rivers Markarfljót and .

In 1823, some men went hiking up on Eyjafjallajökull to inspect the craters. They discovered a fissure vent near the summit caldera a bit to the west of Guðnasteinn.

2010 eruptions

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On 26 February 2010, unusual seismic activity along with rapid expansion of the Earth's crust was registered by the Icelandic Meteorological Office. This gave geophysicists evidence that magma was pouring from underneath the crust into the magma chamber of the Eyjafjallajökull volcano and that pressure stemming from the process caused the huge crustal displacement at Þorvaldseyri farm. In March 2010, almost three thousand small earthquakes were detected near the volcano, all having a depth of . The seismic activity continued to increase and from 3–5 March, over a thousand earthquakes were measured at the epicenter of the volcano.

thumb|right|The eruption on 27 March 2010

The eruption begun on 20 March 2010, about east of the top crater of the volcano, on Fimmvörðuháls, the high neck between Eyjafjallajökull and the neighbouring icecap, Mýrdalsjökull.

On 14 April 2010 Eyjafjallajökull resumed erupting after a brief pause, this time from the top crater in the centre of the glacier, causing jökulhlaup (meltwater floods) to rush down the nearby rivers, and requiring 800 people to be evacuated. This disruption affected over 20 countries and as many as 10 million air travelers. The volcano erupted again in May 2010, causing the closure of airspace over many parts of Europe. The eruptions also created electrical storms. The London Volcanic Ash Advisory Centre declared the eruption to have stopped on the 23rd of May 2010, but stated that they were continuing to monitor the volcano. As a direct result of this disruption being viewed by some as excessive, new standards for the closure of airspace as a result of air contamination by dust/ash were agreed internationally. As of August 2010, Eyjafjallajökull was considered dormant. Infrasound sensors have been installed around Eyjafjallajökull to monitor for future eruptions.

In total, the 2010 eruptions generated about 0.27 cubic km (270,000,000 cubic metres) of tephra, causing ash fallout over central southern Iceland and parts of continental Europe. Nearby areas saw an ash layer of up to several centimeters, and surrounding glaciers saw a significant albedo reduction due to the ash. Each of the eruptions of Eyjafjallajökull in 920, 1612, and 1821–1823 has preceded an eruption of Katla. Katla did not display any unusual activity (such as expansion of the crust or seismic activity) during the 2010 eruptions of Eyjafjallajökull, though geologists have been concerned about the general instability of Katla since 1999. Some geophysicists in Iceland believe that the Eyjafjallajökull eruption may trigger an eruption of Katla, which would cause major flooding due to melting of glacial ice and send up massive plumes of ash. On 20 April 2010, Icelandic President Ólafur Grímsson said "the time for Katla to erupt is coming close...we [Iceland] have prepared...it is high time for European governments and airline authorities all over the world to start planning for the eventual Katla eruption".

Volcanologists continue to monitor Katla, aware that any eruption from Katla following an eruption from Eyjafjallajökull has historically occurred within months of an Eyjafjallajökull eruption. The Icelandic Meteorological Office updates its website with reports of quakes at both Eyjafjallajökull and Katla.

Postage stamp

Icelandic Post issued three special stamps in 2010 for the eruption of the Eyjafjallajökull volcano. All stamps contain real volcanic ash which fell on 17 April 2010.

Gallery

References

External links

Eyjafjallajökull in the Catalogue of Icelandic Volcanoes

Photos

Satellite image of 2010 eruption by NASA
A collection of satellite images from the CIMSS Satellite Blog
Best of Photo Collection

Videos and webcams

Webcams of the eruption
A short time-lapse from April 17, 2010. About 30 minutes played in 18 second.
Video of the first 2010 eruption
Video of the first 2010 eruption by Raw Iceland
Video of the aftermath of Eyjafjallajokull eruption. Shot on July 28, 2010
A film crew lands on Eyjafjallajokull during the 2010 eruption

Geological articles

Magma pathways and earthquakes at Eyjafjallajökull, Icelandic Meteorological Institute (PDF)
SI / USGS Weekly Volcanic Activity Report for Eyjafjallajökull

Aviation ash forecasts

Volcanic Ash Advisory Graphical Forecast for the North Atlantic region

Maps

Contour map