Eyjafjallajökull

Location in Iceland
Location	Iceland
Area	100 km2 (40 sq mi)

Eyjafjallajökull , translated "island mountain glacier") () is one of the smaller glaciers of Iceland. It is situated to the north of Skógar and to the west of the larger glacier Mýrdalsjökull.

The icecap of the glacier covers a volcano (1,666 metres or 5,466 feet in height) which has erupted relatively frequently since the Ice Age, at times bringing rhyolite to the surface.[2] The volcano erupted twice in 2010, on 20 March and 15 April. The April eruption caused massive disruption to air traffic across Northern Europe and scientists claimed it was ten to twenty times more powerful than the March event. The most recent eruption before 2010 was from 1821 to 1823, causing a fatal glacial lake outburst flood. A previous eruption was in 1612. The crater of the volcano has a diameter of 3–4 kilometres (1.9–2.5 mi) and the glacier covers an area of about 100 square kilometres (39 sq mi).

The south end of the mountain was once part of the island's Atlantic coastline. As the sea has since retreated some 5 kilometres (3.1 mi), the former coastline has left behind sheer cliffs with a multitude of beautiful waterfalls, the best known of them being Skógafoss. In strong winds, the water of the smaller falls can even be blown up the mountain.

The eruption of Eyjafjallajökull 1821–1823

This event was a rather small eruption, despite which, some damage was caused. This was especially because the ash contained a high quota of fluoride, which in high doses may have a negative influence on the bone structure of cattle, horses, sheep and humans. The eruption also caused some small and medium glacier runs and flooding at nearby rivers Markarfljót and Holtsá. The eruptive phase started on 19 and 20 December by a series of explosive eruptions continuing during the next days. The sources talk about heavy ash fall in the area around the volcano especially to the south and west.

After that event the eruption continued on a more subdued level until June 1822.

From the end of June till the beginning of August 1822, another series of explosive eruptions followed. The eruption columns were shot to considerable heights, with ashfall both in the far north of the country, in Eyjafjörður, and in the southwest, on the peninsula of Seltjarnarnes near Reykjavík.

The period from August to December 1822 seemed quieter, but farmers attributed the death of cattle and sheep in the Eyjafjörður area to poisoning from this eruption, which modern analysis identifies as fluoride poisoning. Some small glacier runs occurred in the river Holtsá. A bigger one flooded the plains near the river Markarfljót. The sources don’t indicate the exact date.

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.

In the spring of 1823, the nearby volcano Katla under the glacier Mýrdalsjökull erupted and at the same time steam columns were seen on the summit of Eyjafjallajökull.

The ash of Eyjafjallajökull’s 1821 eruptions is to be found all over the south of Iceland. It is dark grey in colour, small-grained and intermediate rock containing about 68-70% SiO₂.

2010 eruption

Main article: 2010 eruption of Eyjafjallajökull

A photo of Eyjafjallajökull taken from Route 1 (Iceland) in August 2009. The fields and buildings have since been flooded by the glacial melt water from the eruption.

Around Christmas 2009, seismic activity was detected in the volcano area, with thousands of small earthquakes (mostly magnitude 1–2 on the Richter magnitude scale, with only a couple greater than 3 magnitude) 7–10 kilometres (4.3–6.2 mi) beneath the volcano. On 26 February 2010, unusual seismic activity along with rapid expansion of the Earth's crust was registered by the Meteorological Institute of Iceland. 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. The seismic activity continued to increase and from 3 March to 5, close to 3,000 earthquakes were measured at the epicentre in the volcano.

The eruption on 25 March 2010

The eruption is thought to have begun on 20 March 2010, about 8 kilometres (5.0 mi) east of the top crater of the volcano in a popular hiking region called Fimmvörðuháls. This first eruption, in the form of a fissure vent, did not occur under the glacier and was smaller in scale than had been feared by some geologists. On 14 April 2010 Eyjafjallajökull resumed erupting after a brief pause, this time from the top crater in the centre of the glacier, causing meltwater floods (also known as jökulhlaup) to rush down the nearby rivers, and requiring 800 people to be evacuated. This eruption was explosive in nature and is estimated to be ten to twenty times larger than the previous one in Fimmvörðuháls. This second eruption threw volcanic ash several kilometres up in the atmosphere which led to travel disruptions in northwest Europe on 15 April 2010 including the closure of airspace over most of Northern Europe.

Eyjafjallajökull and Katla

Over the past 1,100 years, Eyjafjallajökull has erupted four times: in 920, 1612, between 1821–1823, and in 2010. Each of the first three of these incidents directly preceded a major eruption in the nearby subglacial volcano, Katla. There is so far no evidence that Katla will erupt because of its vicinity to the current eruption in Eyjafjallajökull. Katla, which is a much more active volcano, known for its powerful subglacial eruptions and its large magma chamber, much larger than that of the Eyjafjallajökull volcano system, has still not shown any unusual activity, like expansion of the crust or seismic activity. However, one cannot rule out that possibility, since history has shown that Eyjafjallajökull can be a precursor to additional Katla activity. Some geophysicists in Iceland support the notion that the recent volcanic eruption at Eyjafjallajökull may trigger a second eruption at Katla, which would cause a major flooding event due to melting of glacial ice.

Etymology

The name usually describes the small mountains which form the foot of the volcano. The village and museum of Skógar are also part of the region "undir Eyjafjöllum" (under the mountains Eyjafjöll).

See also

• Glaciers of Iceland
• Volcanism in Iceland
• Waterfalls of Iceland

References

63.61958°N 19.61042°W / 63.61958; -19.61042

External links

Photos

• Satellite image of 2010 eruption by NASA
• Photos of the 2010 eruption by Fred Kamphues

Geological articles

• Univ. of Iceland: History of Eyjafjallajökull Template:Is icon
• Geology of Katla and Eyjafjallajökull volcanoes, University of Iceland
• Magma pathways and earthquakes at Eyjafjallajökull, Icelandic Meteorological Institute (PDF)

Related art

• The Eyjafjallajoekull Art Project