Eyjafjallajökull

Iceland
Introduction
Iceland has a high concentration of active volcanoes due to unique geological conditions. The island has about 130 volcanic mountains, of which 18 have erupted since the settlement of Iceland in 874 AD. Over the past 500 years, Iceland's volcanoes have erupted a third of the total global lava output.[1] Although the Laki eruption in 1783 had the largest eruption of lava in the last 500 years, the Eldgjá eruption of 934 AD and other Holocene eruptions were even larger.
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|Location |Iceland |
|Coordinates |[pic]63°38′N 19°36′W / 63.633°N 19.6°W / 63.633; -19.6 |
|Area |100 km2 (40 sq mi) |
|Thickness |28018 |

Eyjafjallajökull
The most recent[update] volcanic eruption in Iceland was that of Eyjafjallajökull, which started on April 14, 2010. The Eyjafjallajökull eruption closely followed an eruption in Fimmvörðuháls, which had erupted on March 20, temporarily quiesced by April 12, and then erupted with a large ash plume (due to magma coming out under ice) on April 15. The ash cloud was significant enough to shut down airports across more than 20 European countries, many of which only began to reopen on April 20.
The 2010 eruptions of Eyjafjallajökull were a sequence of major volcanic events at Eyjafjallajökull in Iceland which disrupted air travel across western and northern Europe over an initial period of 6 days in April 2010. Further more localized disruption continued into May 2010.

First eruption

A study by the Icelandic Meteorological Office published on December 2009 indicated an increase in seismic activity around Eyjafjallajökull area during the years 2006–2009.
"Volcano tourism" quickly sprang up in the wake of the eruption, with tour companies offering trips to see the volcano.[13] The Icelandic Telecommunications company Mila has installed 3 webcams giving views of the eruption from Valahnúkur, Hvolsvöllur and Þórólfsfell.

Evacuations

About 500 farmers and their families from the areas of Fljótshlíð, Eyjafjöll, and Landeyjar were evacuated overnight, flights to and from Reykjavík Keflavík International were postponed, but on the evening of 21 March, domestic and international air traffic was allowed again.

, the police closed the road to Þórsmörk, and the four-wheel-drive trail from Skógar village to the Fimmvörðuháls mountain pass, but these roads and trails were reopened on 29 March, When the second fissure appeared, the road was closed again because of the danger of flash floods,

The fissure

The fissure is 150 metres (490 ft) long in a north-east to south-west direction, with 10 to 12 erupting lava craters which spew lava at a temperature of about 1,000 °C (1,800 °F) up to 150 metres (490 ft) into the air. The lava is alkali olivine basalt. [21] It is relatively viscous, causing the motion of the lava stream to the west and east of the fissure to be slow, making the eruption a typical effusive eruption.

Effect on water

On 22 March, a flow meter device situated in the Krossá glacial river (which drains Eyjafjallajökull and Mýrdalsjökull glaciers) in the Þórsmörk area (a few kilometers north-west of the erupting location) started to record a sudden rise in water level and in water temperature – the total water temperature rose by 6 °C (11 °F) over a two-hour period, which had never occurred so quickly in the Krossá river since measurements began

. Farming

The Icelandic Food and Veterinary Authority released an announcement on 18 April 2010, asking that all horse owners who keep their herds outside be on the alert for ash fall. The thick layer of ash that has fallen on some Icelandic farms and pastures at Raufarfell has become wet and compact, making it very difficult to continue farming, harvesting or grazing livestock. [41]

Analysis

Samples of volcanic ash collected near the eruption showed a silica concentration of 58%—much higher than in the lava flows. [36] The concentration of water-soluble fluoride is one third of the concentration typical in Hekla eruptions. Agriculture is important in this region of Iceland,[37] and farmers near the volcano have been warned not to let their livestock drink from contaminated streams and water sources,[38] as high concentrations of fluoride can have deadly renal and hepatic effects, particularly in sheep.[39]