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2010 eruptions of Eyjafjallajökull

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A series of major volcanic events occurred at Eyjafjallajökull in Iceland in 2010. Seismic activity starting around Christmas 2009, and lead to a 2010 March 20 eruption. A later eruption on 2010 April 14 lead to widespread air travel disruptions in Europe on 15 April 2010.

Background

Main article: Eyjafjallajökull

Eyjafjallajökull ([pronunciation?]) (listenⓘ) 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 m in height) which has erupted relatively frequently since the Ice Age.

Eruptions

Around Christmas 2009, seismic activity began around the Eyjafjallajökull volcano area, with thousands of small earthquakes (mostly magnitude 1–2 on the Richter magnitude scale) 7–10 kilometres beneath the volcano.[1] On 26 February 2010, the GPS navigation tools used by the Meteorological Institute of Iceland at Þorvaldseyri farm in the Eyjafjöll area (around 15 kilometres southeast of the location of the recent eruption[2]) had shown 3 centimetres displacement of the local earth crust in a southward direction, of which a 1 centimetre displacement took place within four days. This unusual seismic activity along with that rapid expansion of the Earth's crust gave geophysicists evidence that magma were 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.[3] The seismic activity continued to increase and from March 3 to 5, close to 3,000 earthquakes were measured at the epicentre in the volcano. Most were too small (magnitude 2 on Richter scale) to be read as presaging an eruption, but some could be detected in nearby towns.[4] The eruption is thought to have begun on 20 March 2010, sometime between 10:30 pm and 11:30 pm local time (UTC), a few kilometres east of the glacier in the northern slopes of Fimmvörðuháls mountain pass.[5][6]

Evacuations

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About 500 farmers and their families from the areas of Fljótshlíð, Eyjafjöll, and Landeyjar were evacuated overnight, and flights to and from Reykjavík and Keflavík International Airport were postponed, but in the evening of 21 March, domestic and international air traffic was allowed again.[7][8][9] Inhabitants of the risk zone of Fljótshlíð, Eyjafjöll, and Landeyjar area were allowed to return to their farms and homes after an evening meeting with the Civil Protection Department on 22 March and the evacuation plan was temporarily dismissed. Instead, the police closed the road to Þórsmörk, and the jeep trail from Skógar village to Fimmvörðuháls mountain pass, but these roads and trails were reopened on 29 March, only though for suitable jeeps, however when the second fissure appeared the road was closed again because of the danger of flash floods, which could have been the case if the fissure had opened near big ice caps or other snow reservoirs, but the road was again opened at around noon of the 1 April [10][11][12]

The eruption on the 25th of March, 2010

The fissure

The fissure is 500 metres long pointing northeast–southwest, with 10–12 erupting lava craters which spew around 1,000 °C (1,832 °F) hot lava up to 150 metres into the air. The lava is alkaline and is relatively viscous therefore the motion of the lava stream to the west and east of the fissure is slow, so this makes it a typical effusive eruption.[13] The molten lava has flowed more than 4000 metres to the northeast of the fissures, and into Hrunagil canyon, forming a more than 200 meter (620 ft) long "lava"-fall and is slowly approaching Þórsmörk on a slow rate, but has not yet reached the flood plains of Krossá[14][15][16]. On 25 March 2010, scientists witnessed on location, for the first time in history, the formation of a pseudocrater during a steam explosion, while studying the eruption.[17] Crustal expansion continued at Þorvaldseyri for two days after the eruption began, but has been slowly decreasing, along with increasing volcanic activity, indicating that the input of magma into the magma chamber of the volcano is roughly equal to the magma output out of the eruption, giving evidence that this volcanic activity has reached equilibrium.[18] A new fissure opened around 19:00 UTC local time (7 pm) on 31 March, around 200 meters northwest of the original fissure. Many witnesses were present while the new fissure opened. It is a bit smaller, around 300 meter long according to witnesses, and lava coming from it has now started to flow into Hvannárgil canyon. These two erupting fissures share the same magma chamber according to geophysicists. No unusual seismic activity was detected at the time the new fissure appeared, nor any crustal expansion according to many seismometers and GPS recorders situated in nearby areas.[19][20]

Geophysicist Magnús Tumi Einarsson said (at a press meeting in Hvolsvöllur on 21 March 2010) that this eruption is small compared to, for example, the eruption of Hekla in 2000. The eruption, rather than taking place under the ice cap of the glacier, occurred in the mountain pass between the Eyjafjallajökull and Mýrdalsjökull glaciers. As long as the fissure is not near the glacier, the risk of flooding is minimal; however, the fissure could extend into the ice cap thereby greatly increasing the risk of flooding.[21] The radar stations of the Meteorological Institute of Iceland did not detect any appreciable amount of volcanic ashfall during the first 24 hours of the eruption.[22] However, during the night of 22 March 2010, they reported some volcanic ash fall reaching the Fljótshlíð area (20–25 kilometres northwest of the eruption's location)[2] and Hvolsvöllur town (40 kilometres northwest of the eruption location)[2] leaving vehicles with a fine grey layer of volcanic ash. At around 7 am on 22 March, an explosion launched eruption columns as far as 4 kilometres straight up into the air. This was the highest plume since the eruption started.[23] At 08:30 UTC local time on 23 March 2010, a small vapour explosion took place, when hot magma came into contact with nearby snowdrifts, emitting a huge vapour plume which reached an altitude of 7 kilometres, and were detected on radars from the Meteorological Institute of Iceland. Since then many vapour explosions have taken place[24]

Effect on water

On 22 March 2010, around 10:00 local time (UTC), a flow meter device situated in the Krossá glacial river (which provides drainage for Eyjafjallajökull and Mýrdalsjökull glaciers) in the Þórsmörk area (a few kilometres northwest of the erupting location) started to record a sudden rise in water level and in water temperature, the total water temperature rise reaching 6 °C (43 °F) over a two hour period, which has never previously occurred this quickly in the Krossá river since measurements began. Shortly afterwards the water level returned to normal and water temperature decreased as well.[25] It is thought that this rise in water temperature is related to the eruption nearby and is affecting part of Krossá drainage basin. Hruná river which flows through the narrow Hrunárgil canyon, where the part of the lava stream has been flowing into, was recently recorded by geologists to be between 50 °C (122 °F)- 60 °C (140 °F) hot, indicating that the river has been cooling down the lava in that canyon.[26]

On Wednesday 31 March a new fissure opened up on the volcano.[27] Another eruption occurred on Tuesday 13 April.[28] The ensuing ash cloud reached 11 km, and halted air travel in northern Norway by evening the next day,[29] and all of Scotland and parts of northern England the day after that.[30]

Analysis

Samples of volcanic ash collected near the eruption showed the concentration of water-soluble fluoride is 1/3 of the concentration typical in Hekla eruptions, with a mean value of 104 milligrams of fluoride per kilogram of ash. Farmers in nearby locations have been warned not to let their livestock drink from local ponds and streams[31] as high concentrations of fluoride can have deadly renal and hepatic effects in livestock (particularly sheep).[32], but agriculture remains important in this region of Iceland.[33]

'Volcano tourism' quickly sprang up in the wake of the eruption, with tour companies offering trips to see the volcano.[27]

Second eruption

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On 14 April 2010, Eyjafjallajökull resumed erupting after a brief pause, this time in the centre of the glacier, causing meltwater floods to rush down the nearby rivers, and causing 800 people to be evacuated.[34] This eruption is estimated to be ten to twenty times more significant than the previous one on Fimmvörðuháls.

Ash plume

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By the evening, the large cloud of ash from this eruption caused the airspace over Northern Norway to be closed, and by the morning of 15 April the airspace in the rest of Norway, as well as over most of the UK, and parts of Ireland, was being closed.[35]

On 15 April 2010, flights across the United Kingdom and the Republic of Ireland were cancelled as the British National Air Traffic Services and the Irish Aviation Authority closed airspace due to the presence of volcanic ash in the upper atmosphere. The ash cloud had reached a reported height of 55,000 feet (17,000 m). The closure of airspace was a precautionary measure. In the past, aircraft had been involved in incidents caused by flying into the plumes of erupting volcanos. One incident occurred in 1982 (British Airways Flight 9) and another in 1989 (KLM Flight 867).[35] As a result of the eruption, significant flight delays occurred in Denmark, Finland, Norway, Sweden, Ireland and the United Kingdom with the closures of a number of major European airports.[36][37][34]

References

  1. ^ Veðurstofa Íslands (5 Mars 2010) "Jarðskjálftahrina undir Eyjafjallajökli". Veðurstofa Ísland (The Meteorological Institute of Iceland).
  2. ^ a b c Measurements made by using maps and measurement tools from Fasteignaskrá Íslandskort "Fasteignaskrá measurement tools".
  3. ^ Morgublaðið (26.02.2010) "Innskot undir Eyjafjallajökli". Morgunblaðið.
  4. ^ "Fyrsta háskastigi lýst yfir". Morgunblaðið.
  5. ^ "Eldgosið á Fimmvörðuhálsi".
  6. ^ Volcano Erupts Under Eyjafjallajökull Reykjavík Grapevine, March 21, 2010
  7. ^ Gos hafið í Eyjafjallajökli, Visir, March 21, 2010
  8. ^ Volcanic eruption in Eyjafjallaglacier - flights to Iceland are on hold. Icelandair. Retrieved March 21, 2010.
  9. ^ "Fyrsta vél frá Boston í loftið klukkan hálf fimm". Vísir.
  10. ^ Morgunblaðið 1. Apríl "Gosslóðirnar opnaðar aftur". Morgunblaðið.
  11. ^ Eyjan 1.Apríl "Litlar líkur taldar á öðru gosi við Eyjafjallajökul". Eyjan.
  12. ^ Morgunblaðið 22. Mars 2010 "Rýmingu aflétt". Morgunblaðið.
  13. ^ "Gossprungan um 1 km að lengd". Morgunblaðið.
  14. ^ "Gosið enn í gangi - Farið að bera á öskufalli". Vísir fréttvefur.
  15. ^ Morgunblaðið 22. March 2010 (13:11 GMT) "Hraunflæði niður í Hrunagil". Morgunblaðið.
  16. ^ Ríkisútvarpið fréttavefur "Eldgosið í jafnvægi". Rúv.
  17. ^ Kvöldfréttir Stöðvar Tvö "Viðtal við Ármann Höskuldsson eldfjallafræðing" |work= Fréttastofa Stöðvar Tvö
  18. ^ Veðurstofa Íslands (24 Mars 2010) "GPS mælingar". Veðurstofa Íslands.
  19. ^ Veðurstofa Íslands "Ný gossprunga - skráð 01.04.2010 kl. 10:00". Veðurstofa Íslands (Icelandic Meteological Office).
  20. ^ Morgunblaðið 1. Apríl "Vel gekk að rýma gossvæðið". Morgunblaðið.
  21. ^ "Eldgosið er lítið". Morgunblaðið.
  22. ^ "Eldgos í Eyjafjallajökli".
  23. ^ "Tímabundinn kraftur í gosinu". Morgunblaðið.
  24. ^ Ríkisútvarpið fréttavefur "Krafturinn ekki aukist". RÚV.
  25. ^ Meteorological Institute of Iceland: Eruption in Fimmvörðuháls mountain pass "Elsdgosið í Fimmvörðuhálsi". Veðurstofa Ísland.
  26. ^ Morgunblaðið 29. Mars "Mikill hiti í Hruná". Morgunblaðið.
  27. ^ a b Tom Robbins. "Iceland's erupting volcano | Travel". The Guardian. Retrieved 2010-04-15.
  28. ^ "Iceland's Eyjafjallajokull volcano rears back into life with new eruption". Times Online. Retrieved 2010-04-15.
  29. ^ "Feilmelding". Aftenposten.no. Retrieved 2010-04-15.
  30. ^ http://news.bbc.co.uk/1/hi/uk/8621407.stm
  31. ^ Morgunblaðið 23.Mars 2010 "Ekki mikið af flúor í öskunni". Morgunblaðið.
  32. ^ "Experimental Acute Sodium Fluoride Poisoning in Sheep: Renal, Hepatic, and Metabolic Effects". M. KESSABI, A. HAMLIRI,J. P. BRAUN and A. G. RICO: Département de Toxicologie, Pharmacie et Biochimie, Institut Agronomique et Vétérinaire Hassan II B.P. 6202, Rabat-Agdal, Maroc {dagger}Département de Biochimie et Biophysique, Ecole Nationale Vétérinaire 23, chemin des Capelles, 31076 Toulouse, France. 1985.
  33. ^ A report in Icelandic: Landbúnaður skiptir máli (transl. "Agriculture matters") says that 28% of the total workforce in agriculture are scattered throughout Southern Iceland."Landbúnaður skiptir máli". Bændasamtök Íslands.
  34. ^ a b "Iceland's volcanic ash halts flights in northern Europe". BBC News. 15 April 2010. Retrieved 15 April 2010.
  35. ^ a b "Icelandic volcanic ash alert grounds UK flights". BBC News. 15 April 2010. Retrieved 15 April 2010.
  36. ^ "Cancellations due to volcanic ash in the air". Norwegian Air Shuttle. 15 April 2010. Retrieved 15 April 2010.
  37. ^ "Iceland Volcano Spewing Ash Chokes Europe Air Travel". San Francisco Chronicle. 15 April 2010. Retrieved 15 April 2010.

Eruption of March/April 2010

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