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2010 eruptions of Eyjafjallajökull

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The second eruption on 17 April 2010.

The 2010 eruptions of Eyjafjallajökull are a series of major volcanic events occurring at Eyjafjallajökull in Iceland. Seismic activity started at the end of 2009, and led to a volcanic eruption on 20 March 2010, placing its Volcanic Explosivity Index (VEI) at 1.[1] A later eruption from 14 April 2010 led to widespread disruption of air travel in Europe from 15 April, grounding planes and affecting the travel plans of millions of passengers worldwide. This caused a knock-on effect to many events around the world.

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 metres (5,466 ft) in height that has erupted relatively frequently since the Ice Age. There have been three previous major eruptions in historic times: in 920, 1612 and from 1821 to 1823. Previous eruptions of Eyjafjallajökull have been followed by eruptions at its larger neighbour, Katla.[2]

First eruption

People observing the volcano

At the end of December 2009, seismic activity began around the Eyjafjallajökull volcano area, with thousands of small earthquakes (mostly of magnitude 1–2 Mw), 7–10 kilometres beneath the volcano.[3] By 26 February 2010 the Global Positioning System (GPS) equipment 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[4]) had shown 3 centimetres displacement of the local crust in a southward direction, of which a 1 centimetre displacement had taken place within four days. This unusual seismic activity along with the rapid movement of the Earth's crust in the area gave geophysicists evidence that magma was flowing from underneath the crust into the magma chamber of the Eyjafjallajökull volcano and that pressure stemming from the process caused the (in geophysical terms) huge crustal displacement at Þorvaldseyri farm.[5] The seismic activity continued to increase and, from 3 to 5 March, close to 3,000 earthquakes were measured at the epicentre in the volcano. Most were too small (magnitude 2) to be read as presaging an eruption, but some could be detected in nearby towns.[6] The eruption is thought to have begun on 20 March 2010, some time 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.[7][8]

"Volcano tourism" quickly sprang up in the wake of the eruption, with tour companies offering trips to see the volcano.[9] The Icelandic Telecommunications company Mila[10] has installed 3 webcams giving views of the eruption from Valahnúkur, Hvolsvöllur and Þórólfsfell.[11]

Evacuations

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.[12][13][14] 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 four wheel drive trail from Skógar village to Fimmvörðuháls mountain pass, but these roads and trails were reopened on 29 March, though only for suitable four wheel drives. However, when the second fissure appeared, the road was closed again because of the danger of flash floods, which could have developed if the fissure had opened near big ice caps or other snow reservoirs, but the road was again opened at around noon on 1 April.[15][16][17]

The fissure

The fissure is 500 metres 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 into the air. The lava is alkali olivine basalt.[18] 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.[19] The molten lava has flowed more than 4000 metres to the north-east of the fissures, and into Hrunagil canyon, forming a more than 200 metre (620 ft) long fall of lava, and is slowly approaching Þórsmörk, but has not yet reached the flood plains of Krossá.[20][21][22] On 25 March 2010, while studying the eruption, scientists witnessed, for the first time in history, the formation of a pseudocrater during a steam explosion.[23] 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.[24] A new fissure opened on 31 March, around 200 metres north-west of the original fissure. Many witnesses were present while the new fissure opened. It is a bit smaller, around 300 metres 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.[25][26]

Second fissure, viewed from the north, on 2 April 2010

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.[27] 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.[28] However, during the night of 22 March 2010, they reported some volcanic ash fall reaching the Fljótshlíð area (20–25 kilometres north-west of the eruption's location)[4] and Hvolsvöllur town (40 kilometres north-west of the eruption location)[4] leaving vehicles with a fine grey layer of volcanic ash. At around 07:00 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.[29] 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 was detected on radars from the Meteorological Institute of Iceland. Since then many vapour explosions have taken place.[30]

On Wednesday 31 March, a new fissure opened up on the volcano.[9]

Effect on water

On 22 March 2010, a flow meter device situated in the Krossá glacial river (which drains Eyjafjallajökull and Mýrdalsjökull glaciers) in the Þórsmörk area (a few kilometres 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 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.[31] It is thought that this rise in water temperature is related to the eruption nearby and is affecting part of the Krossá drainage basin. The temperature of 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) and 60 °C (140 °F), indicating that the river has been cooling the lava in that canyon.[32]

Analysis

Samples of volcanic ash collected near the eruption showed a silica concentration of 58%—much higher than in the lava flows.[33] The concentration of water-soluble fluoride is one third of the concentration typical in Hekla eruptions, with a mean value of 104 milligrams of fluoride per kilogram of ash. Agriculture is important in this region of Iceland,[34] and farmers near the volcano have been warned not to let their livestock drink from contaminated streams and water sources,[35] as high concentrations of fluoride can have deadly renal and hepatic effects, particularly in sheep.[36]

Second eruption

Approximate depiction of the estimated ash cloud at 18:00 UTC on 17 April 2010. The current forecasts are updated at London Volcanic Ash Advisory Centre site (Met Office, UK).

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 in two flows on either side of the volcano, and requiring 800 people to be evacuated. The road along the Markarfljót river had been washed away in several places.[37]

Unlike the earlier eruption, the second eruption occurred beneath glacial ice. Cold water from melted ice chills the lava quickly and fragments it into glass, creating small glass particles that get carried into the eruption plume. This, together with the magnitude of the eruption, estimated to be ten to twenty times larger than that on Fimmvörðuháls on 20 March, created a glass-rich plume in the upper atmosphere, which is very hazardous to aircraft.[38]

As of 17 April 2010 the eruption was continuing, but less explosively; the plume was rising to 5 kilometres (3 mi) rather than 13 kilometres (8 mi) as before, not high enough to travel across Europe.[39] The forecast for 18 April at 06:00 showed a significant plume continuing over northern Europe.[40]

Effects of the ash plume on air travel

Main article: Air travel disruption after the 2010 Eyjafjallajökull eruption

Volcanic ash is a major hazard to aircraft.[41] The presence and location of the plume depend upon the state of the eruption and the winds.

There was extensive air travel disruption following the second eruption. While some ash fell on uninhabited areas in Iceland, most was carried by westerly winds resulting in the shut down of a large air space over Europe. Smoke and ash from the eruption reduced visibility for visual navigation, and microscopic debris in the ash could sandblast windscreens or melt in the heat of aircraft turbine engines and then solidify again, causing engines to shut down.[41][38]

Long-term weather and environmental effects

Photograph from satellite Aqua showing the ash plume over North Atlantic at 13:30 GMT on April 15.

High-fluoride Hekla eruptions pose a threat to foraging livestock, especially sheep. Fluoride poisoning can start in sheep at a diet with fluorine content of 25 ppm. At 250 ppm, death can occur within a few days.[42] In 1783, 79 per cent of the Icelandic sheep stock were killed, probably as a result of fluorosis caused by the eruption of Lakagígar.[43] The effect can spread beyond Iceland, as happened during the 1783 Laki eruption.[44] Ash from the current Eyjafjallajökull eruption contains one third the concentration typical in Hekla eruptions, with a mean value of 104 milligrams of fluoride per kilogram of ash. Large-scale release of sulphur dioxide into the atmosphere also poses a potential health risk, especially to people with pre-existing breathing disorders.

As of 15 April, the eruption was not large enough to have an effect on global temperatures like that of Mount Pinatubo and other major past volcanic eruptions.[45][46] However, previous eruptions of the volcano have lasted as long as a year, and the potential remains for a temporary global cooling effect. By analogy, the Laki eruption has been linked with extreme weather events from severe hailstorms in Great Britain to the Mississippi River freezing at New Orleans.[47][48] Sulfate aerosols that reach the stratosphere catalyze the production of chlorine monoxide (ClO), which destroys ozone (O3). In the upper troposphere, the same aerosols become nuclei for cirrus clouds, which increase the Earth's albedo and thus alter its radiation balance.[49] Several eruptions during the past century have caused a decline in the average temperature at the Earth's surface of up to half a degree Celsius for periods of one to three years.[49][50]

At a local level, some effects on the weather may occur. Red sunsets across most of northern Europe are likely.[51] If reinforced by a complementary weather system, volcanic haze can contribute to a general increase in severe weather.


See also

References

  1. ^ Institute of Earth Sciences. ""Eruption in Eyjafjallajökull"". University of Iceland. Retrieved 17 April 2010.
  2. ^ Roger Boyes. ""Iceland prepares for second, more devastating volcanic eruption"". TimesOnline. Retrieved 17 April 2010.
  3. ^ Veðurstofa Íslands (5 March 2010) "Jarðskjálftahrina undir Eyjafjallajökli". Veðurstofa Ísland (The Meteorological Institute of Iceland).
  4. ^ a b c Measurements made by using maps and measurement tools from Fasteignaskrá Íslandskort "Fasteignaskrá measurement tools".
  5. ^ Morgublaðið (26.02.2010) "Innskot undir Eyjafjallajökli". Morgunblaðið.
  6. ^ "Fyrsta háskastigi lýst yfir". Morgunblaðið.
  7. ^ "Eldgosið á Fimmvörðuhálsi".
  8. ^ Volcano Erupts Under Eyjafjallajökull Reykjavík Grapevine, March 21, 2010
  9. ^ a b Tom Robbins. "Iceland's erupting volcano | Travel". The Guardian. Retrieved 2010-04-15.
  10. ^ [1] Forsiða
  11. ^ [2] Vefmyndavélar
  12. ^ Gos hafið í Eyjafjallajökli, Visir, March 21, 2010
  13. ^ Volcanic eruption in Eyjafjallaglacier – flights to Iceland are on hold. Icelandair. Retrieved March 21, 2010.
  14. ^ "Fyrsta vél frá Boston í loftið klukkan hálf fimm". Vísir.
  15. ^ Morgunblaðið 1. Apríl "Gosslóðirnar opnaðar aftur". Morgunblaðið.
  16. ^ Eyjan 1. Apríl "Litlar líkur taldar á öðru gosi við Eyjafjallajökul". Eyjan.
  17. ^ Morgunblaðið 22. Mars 2010 "Rýmingu aflétt". Morgunblaðið.
  18. ^ "Eruption in Eyjafjallajökull". Earthice.hi.is. Retrieved 2010-04-18.
  19. ^ "Gossprungan um 1 km að lengd". Morgunblaðið.
  20. ^ "Gosið enn í gangi – Farið að bera á öskufalli". Vísir fréttvefur.
  21. ^ Morgunblaðið 22. March 2010 (13:11 GMT) "Hraunflæði niður í Hrunagil". Morgunblaðið.
  22. ^ Ríkisútvarpið fréttavefur "Eldgosið í jafnvægi". Rúv.
  23. ^ Kvöldfréttir Stöðvar Tvö "Viðtal við Ármann Höskuldsson eldfjallafræðing" Fréttastofa Stöðvar Tvö
  24. ^ Veðurstofa Íslands (24 March 2010) "GPS mælingar". Veðurstofa Íslands.
  25. ^ Veðurstofa Íslands "Ný gossprunga – skráð 01.04.2010 kl. 10:00". Veðurstofa Íslands (Icelandic Meteorological Office).
  26. ^ Morgunblaðið 1. Apríl "Vel gekk að rýma gossvæðið". Morgunblaðið.
  27. ^ "Eldgosið er lítið". Morgunblaðið.
  28. ^ "Eldgos í Eyjafjallajökli".
  29. ^ "Tímabundinn kraftur í gosinu". Morgunblaðið.
  30. ^ Ríkisútvarpið fréttavefur "Krafturinn ekki aukist". RÚV.
  31. ^ Meteorological Institute of Iceland: Eruption in Fimmvörðuháls mountain pass "Elsdgosið í Fimmvörðuhálsi". Veðurstofa Ísland.
  32. ^ Morgunblaðið 29. Mars "Mikill hiti í Hruná". Morgunblaðið.
  33. ^ "Eruption in Eyjafjallajökull". Earthice.hi.is. Retrieved 2010-04-18.
  34. ^ A report in Icelandic: Landbúnaður skiptir máli (transl. "Agriculture matters") says that 28 per cent of the total workforce in agriculture are scattered throughout southern Iceland."Landbúnaður skiptir máli". Bændasamtök Íslands.
  35. ^ Morgunblaðið 23. Mars 2010 "Ekki mikið af flúor í öskunni". Morgunblaðið.
  36. ^ "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.
  37. ^ Robert Barr (15 April 2010). "Iceland's volcanic ash halts flights in northern Europe". BBC News. Retrieved 15 April 2010.
  38. ^ a b "Iceland's volcanic ash halts flights across Europe" The Guardian newspaper (from AP)
  39. ^ Robert Booth, Dan Milmo, et. al. "Volcanic ash keeps flights across Europe grounded ", The Guardian, 16 April 2010
  40. ^ "Volcanic Ash Advisory ", Met Office(UK), from London, 17 April 2010 at 12:00
  41. ^ a b C. M. Riley, "Tephra " Michigan Technological University Geological & Mining, Engineering & Sciences, Retrieved on 2008-01-23.
  42. ^ "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.
  43. ^ Thorarinsson, Hekla, A Notorious Volcano, p. 39-58
  44. ^ Tom de Castella (April 16,2010) "The eruption that changed Iceland forever ", BBC News, Retrieved April 18, 2010.
  45. ^ "Volcano could mean cooling, acid rain: 'Not like Pinatubo' so far, but potential is there". MSNBC.com. 2010-04-15.
  46. ^ Sara Phillips "Icelandic volcano won't affect the world's climate" ABC, April 16, 2010.
  47. ^ Wood, C.A., 1992. "The climatic effects of the 1783 Laki eruption" in C. R. Harrington (Ed.), The Year Without a Summer? Canadian Museum of Nature, Ottawa, pp. 58– 77.
  48. ^ "Volcanoes from Iceland: Laki". lave club-internet fr. Retrieved 2010-03-30.
  49. ^ a b "Volcanic Gases and Their Effects" (HTML). U.S. Geological Survey. Retrieved 2007-06-16.
  50. ^ "Icelandic volcano: are you enjoying the clear skies?" The Guardian, April 16, 2010.
  51. ^ "Spectacular sunset possible this evening due to volcanic ash - send us your photos!". Bournemouth Echo. Retrieved 2010-04-16.
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