2010 eruptions of Eyjafjallajökull

2010 eruptions of Eyjafjallajökull
Volcano plume on 17 April 2010
Volcano	Eyjafjallajökull
Date	14 April 2010
Type	stratovolcano
Location	Iceland 63.633°N 19.6°W / 63.633; -19.6
VEI	4
Impact	large-scale disruption to air travel, smaller effects on farming in Iceland
Composite map of the volcanic ash cloud spanning 14–25 April 2010

The 2010 eruptions of Eyjafjallajökull were volcanic events at Eyjafjallajökull in Iceland which, although relatively small for volcanic eruptions, caused enormous disruption to air travel across western and northern Europe over an initial period of six days in April 2010. Additional localised disruption continued into May 2010. The eruption was declared officially over in October 2010, when snow on the glacier did not melt. From 14–20 April, ash covered large areas of northern Europe when the volcano erupted. About 20 countries closed their airspace (a condition known as ATC Zero) and it affected over 100,000 travellers. The grounding of European flights avoided about 344×10⁶ kg of CO₂ emissions per day, while the volcano emitted about 150×10⁶ kg of CO₂ per day.

Seismic activity started at the end of 2009 and gradually increased in intensity until on 20 March 2010, a small eruption started rated as a 1 on the Volcanic Explosivity Index.

Beginning on 14 April 2010, the eruption entered a second phase and created an ash cloud that led to the closure of most of the European IFR airspace from 15 until 20 April 2010. Consequently, a very high proportion of flights within, to, and from Europe were cancelled, creating the highest level of air travel disruption since the Second World War.

The second phase of the eruption started on 14 April 2010 and resulted in an estimated 250 million cubic metres (330,000,000 cu yd) (¼ km³) of ejected tephra. The ash plume rose to a height of approximately 9 kilometres (30,000 ft), which rates the explosive power of the eruption as a 4 on the Volcanic Explosivity Index.

By 21 May 2010, the second eruption phase had subsided to the point that no further lava or ash was being produced. More seismic activity was produced.

By the morning of 24 May 2010, the view from the web camera installed on Þórólfsfell showed only a plume of water vapour surrounded by a bluish haze caused by emission of sulphurous gases.

Due to the large quantities of dry volcanic ash lying on the ground, surface winds frequently lifted up an "ash mist" that significantly reduced visibility and made web camera observation of the volcano impossible.

By the evening of 6 June 2010, a small new crater had opened up on the west side of the main crater. Explosive activity from this new crater was observed with emission of small quantities of ash. Seismic data showed that the frequency and intensity of earth tremors still exceeded the levels observed before the eruption, therefore scientists at the Icelandic Meteorological Office (IMO) and the Institute of Earth Sciences, University of Iceland (IES) continued to monitor the volcano.

In October 2010, Ármann Höskuldsson, a scientist at the University of Iceland Institute of Earth Sciences, stated that the eruption was officially over, although the area was still geothermally active and might erupt again.

In May 2011, a nearby volcano named Grímsvötn started erupting, disrupting air travel mostly in Iceland.

Background

Main article: Iceland

Dust particles that get suspended in the atmosphere scattering light from the setting sun, which generates 'volcanic lavenders' like this one over the flight path of Leeds-Bradford Airport in England during the aviation shutdown

Eyjafjallajökull (pronounced [ˈɛɪjaˌfjatl̥aˌjœkʏtl̥] ^ⓘ) is one of the Iceland's smaller ice caps located in the far south of the island. It's situated to the north of Skógar and to the west of the larger ice cap Mýrdalsjökull.

The ice cap covers the caldera of a volcano 1,666 metres (5,466 ft) high, which has erupted relatively frequently since the last ice age. The most recent major eruptions occurred in 1921, 1612 (believed to have lasted only three days) and from 1821 to 1823. Previous eruptions of Eyjafjallajökull have been followed by eruptions at its larger neighbour, Katla;. On 20 April 2010 Icelandic President Ólafur Grímsson said that, "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".

The volcanic events starting in March 2010 are considered to be a single eruption divided into phases. The first eruption phase ejected olivine basaltic andesite lava several hundred metres into the air in what is known as an effusive eruption. Ash ejection from this phase of the eruption is small, rising to no more than 4 kilometres (2.5 mi) into the atmosphere.

On 14 April 2010, however, the eruption entered an explosive phase and ejected fine glass-rich ash to over 8 kilometres (5.0 mi) into the atmosphere. The second phase is estimated to be a VEI 4 eruption, which is large, but not nearly the most powerful eruption possible by volcanic standards. By way of comparison, the Mount St. Helens eruption of 1980 was rated as 5 on the VEI, and the 1991 eruption of Mount Pinatubo was rated as a 6.

What made this volcanic activity so disruptive to air travel was the combination of these four factors:

1. The volcano was directly under the jet stream.
2. The direction of the jet stream was unusually stable at the time of the eruption's second phase, continuously south-east.
3. The second eruptive phase happened under 200 m (660 ft) of glacial ice. The resulting meltwater flowed back into the erupting volcano, which created two specific phenomena:
   1. The rapidly vaporising water significantly increased the eruption's explosive power.
   2. The erupting lava cooled very fast, which created a cloud of highly abrasive glass-rich ash. This caused a large number of flights to be cancelled in the U.K.
4. The volcano's explosive power was enough to inject ash directly into the jet stream.

Without this combination of these factors, the eruption of Eyjafjallajökull would have been a medium sized, somewhat nondescript eruption of little interest to those outside the scientific community or those living nearby. However, the above factors were precisely those needed for the jet stream to carry the ash directly over northern Europe into some of the busiest airspace in the world.

Public observations

People observing the first fissure at Fimmvörðuháls

"Volcano tourism" quickly sprang up in the wake of the eruption, with local tour companies offering day trips to see the volcano. The Civil Protection Department of the Icelandic Police produced regular reports about access to the area, including a map of the Restricted Area around Eyjafjallajokull, from which the public was excluded. Teams from the Icelandic Association for Search and Rescue were stationed at the eruption site as part of standard safety measures and to assist in enforcing access restrictions.

Vodafone and the Icelandic telecommunications company Míla installed webcams giving views of the eruption from Valahnúkur, Hvolsvöllur and Þórólfsfell. The view of the eruption from Þórólfsfell also includes a thermal imaging camera.

Scientific observations

This eruption has been assigned the volcano number 1702-02 by the Global Volcanism Program.

The London Volcanic Ash Advisory Centre (VAAC), part of the UK Met Office, is responsible for forecasting the presence of volcanic ash in the north-east Atlantic. All ash dispersion models for this geographic region are produced by the VAAC in London.

A study by the Icelandic Meteorological Office published on December 2009 indicated an increase in seismic activity around the Eyjafjallajökull area during the years 2006–2009. The study reported increased activity that occurred between June and August 2009 (200 events), compared to a total of about 250 earthquakes recorded between September 2006 and August 2009. It further indicated that the locations of most of the earthquakes in 2009 occurred between 8 to 12 kilometres (5.0 to 7.5 mi) depth east of the volcano‘s top crater. At the end of December 2009, seismic activity began around the Eyjafjallajökull volcano area, with thousands of small earthquakes (mostly of magnitude 1–2 M_w), 7 to 10 kilometres (4.3 to 6.2 mi) beneath the volcano.

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. However, during the night of 22 March, they reported some volcanic ash fall reaching the Fljótshlíð area (20 to 25 kilometres (12 to 16 mi) north-west of the eruption's location) and Hvolsvöllur town (40 kilometres (25 mi) north-west of the eruption location) 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 (13,000 ft) straight up into the air. This was the highest plume since the eruption started. On 23 March, 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 (23,000 ft), and was detected on radars from the Meteorological Institute of Iceland. Since then many vapour explosions have taken place.

By 26 February 2010 the Global Positioning System (GPS) equipment used by the Iceland Meteorological Office at Þorvaldseyri farm in the Eyjafjöll area (around 15 kilometres (9.3 mi) southeast of the location of the recent eruption) had shown 3 centimetres of displacement of the local crust in a southward direction, of which a 1 centimetre displacement had taken place within four days. (See the GPS Time Series page of the Nordic Volcanological Center's website for detailed information on the degree of movement detected in the Earth's crust in the Eyjafjallajökull locality.)

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 Eyjafjallajökull's magma chamber and that pressure stemming from the process caused (in geophysical terms) the huge crustal displacement at Þorvaldseyri farm. The seismic activity continued to increase and from 3 to 5 March, close to 3,000 earthquakes were measured having their epicentre at the volcano. Most of these were too small (magnitude 2) to be interpreted as precursors to an eruption, but some could be detected in nearby towns.

The most recent scientific observations are on the website of the Institute of Earth Sciences which details the current situation for the eruption in Eyjafjallajökull. The Nordic Volcanological Center also maintains an Eyjafjallajökull status page.

Phase 1: Effusive eruption

The first phase of the eruption lasted from 20 March to 12 April 2010 and was characterised by alkali-olivine basalt lava flowing from various eruptive vents on the flanks of the mountain.

Evacuations

About 500 farmers and their families from the areas of Fljótshlíð, Eyjafjöll, and Landeyjar were evacuated overnight (including a group of 30 schoolchildren and their 3 teachers from Caistor Grammar School in England), and flights to and from Reykjavík and Keflavík International Airport were postponed, but on the evening of 21 March, domestic and international air traffic was allowed again. 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 the Fimmvörðuháls mountain pass, but these roads and trails were reopened on 29 March, though only for suitable four-wheel drives. 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.

Effect on river water

On 22 March, a flow meter device 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 had never happened so quickly in the Krossá river since measurements began. Shortly afterward, the water level returned to normal and water temperature decreased. 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, into which part of the lava stream has been flowing, 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.

Fissure

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

The first phase of the 2010 eruption began late on the evening of 20 March at the Eyjafjallajökull.

The initial visual report of the eruption was at 23:52 GMT, when a red cloud was seen at the north slopes of Fimmvörðuháls mountain pass, lighting up the sky above the eruptive site. The eruption was preceded by intense seismicity and high rates of deformation in the weeks before the eruption, in association with magma recharging of the volcano. Immediately before the eruption the depth of the seismicity had become shallow, but was not significantly enhanced from what it had been in the previous weeks. Deformation was occurring at rates of up to a centimetre a day since 4 March at various GPS sites installed within 12 kilometres (7.5 mi) from the eruptive site.

A fissure opened up about 150 metres (490 ft) in length running in a north-east to south-west direction, with 10 to 12 erupting lava craters ejecting 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 and is relatively viscous causing the motion of the lava stream to the west and east of the fissure to be slow. The molten lava has flowed more than 4,000 metres (2.5 mi) to the north-east of the fissure and into Hrunagil canyon, forming a lava fall more than 200 metres (660 ft) long and is slowly approaching Þórsmörk, but has not yet reached the flood plains of Krossá.

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. Crustal expansion continued at Þorvaldseyri for two days after the eruption began, but has been slowly decreasing whilst the volcanic activity increased. This indicates that the rate at which magma is flowing into the magma chamber roughly equals the rate at which it is being lost due to the eruption, giving evidence that this phase of volcanic activity has reached equilibrium.

A new fissure opened on 31 March, around 200 metres (660 ft) north-west of the original fissure. Many witnesses were present while the new fissure opened. It is a bit smaller, around 300 metres (980 ft) 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.

Geophysicist Magnús Tumi Einarsson said (at a press meeting in Hvolsvöllur on 21 March) 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.

Phase 2: Explosive eruption

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

The estimated ash cloud at 18:00 GMT on 15 April.

After a short hiatus in eruptive activity a new set of craters opened early in the morning of 14 April 2010 under the volcano's ice covered central summit caldera. Prior to this event, a large increase in seismic activity was detected between 23:00 on 13 April and 1:00 on 14 April. The earthquake swarm was followed by the onset of a seismic eruption tremor. Meltwater started to emanate from the ice cap around 07:00 on 14 April and an eruption plume was observed in the early morning. Visual observations were greatly restricted due to cloud cover over the volcano, but an aeroplane of the Icelandic Coast Guard imaged eruptive craters with radar instruments. A series of vents along a 2-kilometre (1.2 mi) long north-south oriented fissure were active, with meltwater flowing mostly down the northern slopes of the volcano, but also to the south. An ash loaded eruption plume rose to more than 8 kilometres (5.0 mi), deflected to the east by westerly winds.

Ash analysis

Upper: Ash covers the Thórsmörk valley in early June 2010, immediately after the eruption. Lower: The same area, in September 2011.

Samples of volcanic ash collected near the eruption showed a silica concentration of 58%—much higher than in the lava flows. 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, and farmers near the volcano have been warned not to let their livestock drink from contaminated streams and water sources, as high concentrations of fluoride can have deadly renal and hepatic effects, particularly in sheep.

Impact on 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. Where there is significant ash fall all horses must be sheltered indoors. 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.

Timeline of the second eruption phase

Unlike the earlier eruption phase, the second phase occurred beneath glacial ice. Cold water from melted ice quickly chilled the lava causing it to fragment into highly abrasive glass particles that were then carried into the eruption plume. This, together with the magnitude of the eruption (estimated to be VEI 4) and being ten to twenty times larger than the eruption of Fimmvörðuháls on 20 March, injected a glass-rich ash plume into the Jet Stream.

In addition to volcanic ash being very hazardous to aircraft, the location of this eruption directly under the Jet Stream ensured that the ash was carried into the heavily used airspace over northern and central Europe.

Date	Status	Images
April 2010
14 April	Eyjafjallajökull resumed erupting after a brief pause. This marks the start of the explosive phase of the eruption as the main eruption site is now under the centre of the glacier. The sudden release of meltwater caused flooding in nearby rivers as it travelled in two flows down either side of the volcano, forcing the evacuation of around 800 people. A second jökulhlaup/lahar travelled down the Markarfljót valley that evening. The road along the Markarfljót river had been washed away in several places.	Depiction of the estimated ash cloud at 18:00 UTC on 14 April 2010.
15 April	Explosive eruption continues. Due to the unusually stable jet stream present at the time, the ash cloud reaches mainland Europe, forcing the closure of airspace over a large part of the UK, Scandinavia and Northern Europe. Eruption tremors continue at a similar level to those observed immediately before the start of the second eruption phase.	MODIS image of the ash cloud at 11:39 GMT on 15 April 2010.
16 April	A pulsating eruptive column reached above 8 kilometres (5 mi) altitude, and lightning was frequently seen within the plume.	Depiction of the estimated ash cloud at 18:00 UTC on 16 April 2010.
17 April	The eruption continued, but less explosively, with the plume rising to 5 kilometres (3 mi) rather than 13 kilometres (8 mi) as before, not high enough to travel across Europe. The forecast for 18 April at 06:00 showed a significant plume continuing over northern Europe.	The MODIS instrument on NASA's Aqua satellite captured an ash plume from Eyjafjallajökull Volcano over the North Atlantic at 13:20 UTC on 17 April 2010.
18 April	The Icelandic Meteorological Office (IMO) noted that radar measurement near Keflavik has not detected any plume from Eyjafjallajökull since 8 o'clock (local time), which implies that its level was below 10,000 feet (3,048 m). No reports of ash or floods were reported, although strong seismic activity was continuing.	Same image as above, uncropped version
19 April	According to IMO, the ash cloud reached a height of 5 kilometres (3 mi) and up to 5–6 km height south of the eruptive site. The IMO indicated that the ash producing phase of the eruption was giving way to a phase of lava flow. Magma splatters 1.5 to 3 kilometres (0.93 to 1.86 mi) into the air were detected.	Ash plume over the North Atlantic on 19 April 2010
20 April	Al-Jazeera English service correspondent David Chater, reporting from Hvolsvöllur in southern Iceland, said that the volcano had begun spewing lava and heavy volcanic ash again, after appearing to calm down in the previous 24 hours. He said the activity at the volcano began to increase again late on 19 April and, "We are seeing a spectacular light show right now... fresh, huge bursts of lava flowing over the rim in front of me. There is fresh volcanic activity." He also noted a much heavier cloud of ash rising throughout Monday and drifting towards the Atlantic. Latest results from GPS stations around Eyjafjallajökull by the Institute of Earth Sciences on 20 April 2010 showed deflation associated with the eruption and no movements associated with the Katla volcano presently observed.	The second eruption phase of Eyjafjallajökull. Seen from Fljótshlíð on 20 April 2010.
21 April	The ash plume rose up to 2 kilometres (1 mi) above the volcano and up to 5 kilometres (3 mi) south of the volcano. The IMO reported decrease of seismic activity. Other reports indicated decrease of ash ejection and increase in lava flow. Southern skies off the coast of Iceland became ash free for the first time since the start of the 2nd eruption phase.	Approximate depiction of the ash cloud at 18:00 UTC on 21 April 2010.
22 April	The ash plume rose up to 3 to 4 kilometres (1.9 to 2.5 mi) high, seismic activity at Katla decreased since midnight but it was still relatively high. There have been criticisms by the Icelandic press and travel industry to Iceland's President Ólafur Ragnar Grímsson who ignited tourists fears of much bigger eruption at Katla volcano. He stated that the current eruption in Eyjafjallajökull is only a "small rehearsal" for an eruption in Katla, which would have much more dangerous consequences. Katla which last erupted in 1918 and has erupted shortly after the three known historic eruptions of Eyjafjallajökull in the years 920, 1612 and 1821. Scientists disagree regarding evidence of any imminent eruption at Katla.	Approximate depiction of the ash cloud at 18:00 UTC on 22 April 2010.
23 April	The IMO and Institute of Earth Sciences reported stable seismic activity for the last 24–48 hours with some fluctuations and no movements associated with Katla volcano. Water level in Markarfljót river slightly increased in concordance with the seismic activity recorded. The plume reported at altitudes of 3 to 4.8 kilometres (1.9 to 3.0 mi) and up to 6 kilometres (4 mi) blowing in a south westerly direction. The plume steam could be visually seen for the first time from Iceland's apital Reykjavík, which had caused the closure of international flights at the city's airport, although little or no ash fall is predicted in Reykjavík. The increase in seismic activity is raising some geologists concern of a stir up of Katla volcano, which if it erupted would be huge compared to Eyjafjallajokulls' eruption and could cause major flooding and ash. It last erupted in 1918 for 24 consecutive days and lies underneath 1,000 feet (300 m) of ice.	Approximate depiction of the ash cloud at 18:00 UTC on 23 April 2010.
24 April	Eleven days since the start of the second eruption phase, the plume reached 13,000 feet (4,000 m) with mild explosive activity.	Approximate depiction of the ash cloud at 18:00 UTC on 24 April 2010.
25 April	The ash plume did not exceed the height of the cloud cover (5.3 km (17,000 ft)) and light ash fall was reported at two farms 10 mi (16 km) north-west of the vents Overall activity similar to the previous day. Geologist's field observations, taken from 2–10 kilometres (1.2–6.2 mi) from the vents, showed that explosivity was magmatic and that the tephra produced since 18 April was much coarser than during the first four days. Explosions were heard at Fljótshlíð, 10–15 kilometres (6.2–9.3 mi) north-west of the vents. Meltwater discharge suggested similar lava activity. Processing of data obtained the previous day shows that lava had advanced 400–500 metres (1,300–1,600 ft) northwards from the crater, forming an ice depression extending some 700 m (2,300 ft) from the vents. The eruption showed no signs of termination.	Approximate depiction of the ash cloud at 18:00 UTC on 25 April 2010.
28 April	Continued disruption to flights and closure of some airports in Iceland.
29 April	Plume elevations, magma discharge levels and tremors continued similar to the previous seven days, but with less intensity than at the peak. There were no measurable indications that the eruption is about to end since the rate at which magma is entering the magma chamber is roughly equal to the rate at which tephra is being ejected; thus, this eruption phase appeared to be in equilibrium. It is not known for how long such a state of equilibrium will be maintained. The lava flow determined to have commenced on 21 April 2010 had been melting the thick glacier ice north of the crater, resulting in water flow of 100–120 m3/s evident in a semi-continuous discharge of meltwater from Gígjökull. This generated large quantities of steam where the lava meets the ice. The flow of lava and magma was estimated at 20–40 t/s. Volcanic tremor activity remains the same over the past 2–3 days. The World Meteorological Organization (WMO) warned on 25 April that the volcano was liable to revert to explosive eruptions at any time.
May 2010
2 May	The Institute of Earth Sciences reported changes during the last two to three days. This included a lava producing phase being larger than the explosive phase. Plume became darker, denser and wider than in the preceding week. Tephra fall-out increased in the vicinity of the volcano. Lava advanced over 3 km north of the eruption site and may have advanced further over the glacier edge side. Lava production is estimated at 20 m3/s (50 tonnes/s). Explosive activity increased in intensity during the last few days, and can be heard up to 40 km south-east of the eruption site. Glacier meltwater discharge had increased since 30 April 2010. Tremor levels had intensified, and were attributed to lava-ice interactions or conditions at the eruption site. Reported deflation of magma reservoir beneath Eyjafjallajökull and changes of deformation pattern. The eruption plume extended to altitudes between 4–5.4 km (13,000–18,000 ft) height and is visible 200 km from eruption site. Wind direction on 3 May 2010 is pushing the ash cloud to east-south direction back towards Britain creating fears of new travel disruptions.
3 May	Height of the plume reported at 5–5.5 km (16,000–18,000 ft) altitude heading to south-east direction and visible from 200 km distance away from the eruption site. Scientists at eruption site experienced discomfort due to erupting gas. Tremor levels have intensified. Overall activity was similar to the day before. Due to wind direction resulting in renewed emergence of volcanic ash, the United Kingdom Civil Aviation Authority (CAA) closed the airspace over the Outer Hebrides which cancelled flight operations at Stornoway, Barra and Benbecula.
4 May	Plume observed at 5.8–6 km (19,000–20,000 ft) height, heading at south east direction and visible up to 300–400 km distance from the eruption site. Tremor levels decreased to a similar level as on 18 April 2010. Several earthquakes were detected beneath Eyjafjallajökull at 14–20 km depth. More explosive activity and ash production reported than was observed in the day before. Progression of the lava seems to be slower. Disruption to aviation continued in Ireland and United Kingdom: from 07:00 to 13:00, Shannon and Dublin ceased flights due to the Irish Aviation Authority (IAA) imposing a no-fly zone with a 60-mile (97 km) buffer over Ireland. Northern Ireland and parts of Scotland are also under a no-fly zone issued by the Civil Aviation Authority; however, flights over Ireland to or from the UK or Europe were allowed to continue.
5–6 May	The IMO stated that the volcano had entered a new phase with a shift back from lava to more ash production. An increase in explosive activity and considerable ash fall out reported at a distance 65–70 km (40–43 mi) from the eruption site. Plumes observed by radar at 5.5–6.5 km (18,000–21,000 ft) height (above sea level) according to IMO's weather radar and have reached above 9 km (30,000 ft) level. Increased seismic activity since 3 May 2010 indicates that "new" magma is intruding into the magma conduit causing a difference in pressure at the surface. The IMO anticipated that the eruption will continue at full force in the next days. The ash cloud moved to south westerly direction and remained lying off the west of Ireland resulting in no flight restrictions within UK.	Ash eruptions from the volcano on 6 May 2010.
7–8 May	The eruption was still in a strong explosive phase although its explosive activity has decreased compared to 6 May 2010. The ash plume was rising to a lower altitude and was lighter in colour, but there were still no signs that the eruption was going to end. In southern Iceland, extensive ash fall resulted in the closure of schools and the Environment Agency of Iceland warned that air pollution due to ash fall the previous day (6 May 2010) was higher than ever measured in Iceland before and is above the health protection limit. Consequently, people living in areas subject to ash fall were told to stay inside their homes.
9 May	An ash cloud stretching 1,200-mile (2,000-kilometre) from Iceland to northern Spain is causing disruption and delays to transatlantic flights. Flights had to be rerouted north over Greenland or south around Spain to avoid the ash cloud. European air traffic faced disruptions over the weekend of 8–9 May 2010 in several countries including Ireland, Spain, France and Portugal. Having reopened 19 airports in the north of Spain on 8 May 2010, Spanish Air Traffic Control was forced to reclose seven airports at 15:00 GMT on 9 May 2010.
10 May	The ash cloud rose to between 5 and 6 kilometres (16,000 and 20,000 ft). Most European airports affected by the weekend closures reopened, apart from a few in Portuguese controlled airspace (The Azores and the Madeira Islands) and Iceland.	The eruption seen from Þórolfsfell on 10 May 2010.
11 May	The explosive eruption phase continues with a darkening of the ejected ash towards the end of the day. Radar measurements show the ash cloud extends to a height of 5–6 km (16,000–20,000 ft) and is heading in a south by south-easterly direction.	Ash plume from Eyjafjallajökull on 11 May 2010, as imaged by the Terra satellite.
12 May	The average height of the ash cloud ranged between 4–5 km (13,000–16,000 ft) and peaked at 6 km (20,000 ft) maintaining a mainly grey colour. Over the course of the day the wind changed from a generally northerly direction to a generally westerly direction. The ash cloud was now heading in an east by south easterly direction.
13 May	The majority of the ash cloud rose to 6 km (20,000 ft) with some parts rising up to a maximum of 9 km (30,000 ft). Unstable air to the south affected the height of the ash cloud which headed in a south-easterly direction. At around 16:00 UTC, four earthquakes were measured beneath Eyjafjallajökull, all of which were located at a shallow depth.
14 May	No major changes seen in either the explosive force of the eruption or the ash cloud height.
15 May	The ash cloud rose to an average of 6 km (20,000 ft) and a maximum of 8 km (26,000 ft) and headed in south to south-westerly direction. The activity witnessed on this day shows little change from the activity seen during the previous week.
16 May	Due to calm weather conditions around the volcano, the ash cloud rose higher than it has done in previous days to a height of 7–9 km (23,000–30,000 ft). The wind direction maintained a general heading of south-east and east by south-east. To the south-east, grey ash fallout was reported from Skógar to Pétursey on Mýrdalssandur. An unusually high number (over 150) of lightning strikes were recorded in the ash cloud on ATDNet during the last 24 hours, with 54 of those strikes occurring between 08:00 and 11:00.
17 May	The continued south-easterly heading of the ash cloud caused the CAA to impose a no-fly zone from 01:00 to 07:00 BST for the following UK airports: London Heathrow, Gatwick, Farnborough, London City, Shoreham, Biggin Hill, all airfields in Northern Ireland, Outer Hebrides, Oban, Campbeltown, Caernarfon and Aberdeen. Cardiff remains open but operations may be limited due to close proximity of the no-fly zone. From 07:00 to 13:00 BST, the following UK airports were still within the no-fly zone: Ronaldsway (N. Ireland), Edinburgh, Aberdeen, Inverness and Northern Scotland; Cardiff, Swansea, Bristol and Farnborough. For the Netherlands, the airports Schiphol (Amsterdam) and Rotterdam Airport were closed till at least 2 pm. According to radar observations, the ash cloud averaged a height of 6–7 km (20,000–23,000 ft) occasionally pulsating to 9 km (30,000 ft). The wind speed around the volcano had increased slightly, which reduced the height of the plume that was now drifting due east. Ash had fallen in the Gnúpverjahreppur area, on the road to Stultartangi Power Station and in the Biskupstungur area (very fine particled and grey). ATDNet reports that lightning activity has been regular (up to 10 flashes per hour) and sustained. The volcano's activity remained explosive, but there are indications that its output has lessened somewhat since the most recent maximum of 13 May. Considerable quantities of ash have fallen on the neighbouring communities and this is expected to continue. Fluctuations in the strength of the eruption and in ashfall can still be expected.
18 May	According to radar observations, the plume had been mostly at 7 km (23,000 ft). At this altitude, the winds have been south and south-westerly at 25–35 knots (46–65 km/h; 29–40 mph) but near the surface, the wind was easterly. The grey ash cloud was now moving in a general north-easterly direction. Ash had fallen in the Gnúpverjahreppur area, Hrauneyjar and in the north-east and eastern part of Iceland (from Laugar in South Thingeyjarsýsla to Seyðisfjörður). Higher aerosol concentrations have been recorded in Reykjavík around midday due to ash drifting over the area. ATDNet reported more than 70 lightning strikes between midnight and midday (up to 10 flashes per hour until noon but deacresed activity in the afternoon). The explosive eruption phase was ongoing and the height of the ash cloud suggests a tephra ejection rate in excess of 200 tonnes per second. Fallout of tephra had been detected mainly to the north-east, with recorded fallout as far as the north-east coast. Some tephra dispersion occurred towards the west in the afternoon.
19 May	According to radar and pilot observations, the ash cloud was slightly lower than the day before, at 5–6 km (16,000–20,000 ft). Southerly winds prevailed this morning over the volcano, turning to the south-west at 54–64 km/h (34–40 mph). Consequently, the light grey ash cloud drifted north-west early this morning, but then according to radar, turned north by north-east. Ash fell in the south at Flúðir, Fljótshlíð and Rangárþing ytri, and with rainfall in the north in Húsavík and Skagafjörður right before noon. ATDNet reports over twenty lightning strikes from midnight to midday, which was considerably fewer than the previous day. Due to heavy rainfall, the rivers in the area of Eyjafjallajökull were swollen which, together with ash from an area of a few square kilometres, resulted in a mudslide in Svaðbæli River. This also resulted in the greatest discharge at the old bridge over the Markarfljót River since 15 April. The discharge at Gígjökull is still low.
20 May	The volcano has not been visible for two days due to cloudy weather. Radar images from TF-SIF show no major changes in the ice cauldrons where the cinder cone is forming. The eruption is mainly explosive and almost no lava flowed down Gígjökull. According to radar observations, the ash cloud rose to around 5 km (16,000 ft). At the volcano, the wind was blowing from the south at 10 metres per second (22 mph), but at the top of the ash cloud, the wind was south by south-westerly at 13 metres per second (29 mph). The grey ash cloud headed north but turned to the north-east over the highlands (according to radar and weather satellite). Ash fall was only reported at Fljótsdalur, the innermost farm in Fljótshlíð, beginning the previous night and continuing all day. ATDNet reported ten lightning strikes between midnight and 13:00 GMT, but none since. Water discharge in rivers around the Eyjafjallajökull glacier has decreased after the increase caused by the previous day's rainfall. On 21 May 2010, water gauges will be installed in Bakkakot River to monitor potential mudslides, such as the one that occurred on 19 May 2010 in Svaðbæli River. The height of the ash cloud has decreased in the last few days which suggests a decrease in magma flow (considerably less than 50 tonnes/sec) compared to the flow observed over the last week. Fluctuations in eruption activity and varying ashfall can still be expected.

Phase 3: Return to dormancy

Since 21 May 2010, the eruptive vent has been emitting a column of steam (water vapour) plus sulphurous gases. Therefore there has been no further report of any ash fall from the surrounding area.

Data from seismic recorders in the area indicates that the frequency and strength of earth tremors has diminished, but is continuing.

Due to the volcano's currently quiet state, scientists from the Icelandic Meteorological Office (IMO) and the IES will no longer produce status reports on a daily basis, but rather every few days; however, the volcano remains under close scientific observation.

As of 23 June 2010, the activity of Eyjafjallajökull has reduced to occasional, brief bursts of ash that travel no more than a few tens of metres.

In October 2010, Ármann Höskuldsson, a scientist at the University of Iceland Institute of Earth Sciences, stated that the eruption is officially over, although the area is still geothermally active and might erupt again. Steam still rises from the lava flows.

Date	Status	Images
May 2010
21 May	Observation from inspection flights and other pilot reports show that the plume is at a height of 3–3.5 km (9,800–11,500 ft) and was blown first towards the north-east and then later towards the north-west by light southerly winds. There were no reports of ash fall. Reports from Neðri-Þverá and Hlíðarendakot in Fljótshlíð of bluish gas clouds in Fljótsdalur along the hillsides smelling of rot (causing people headaches). No lightning strikes were detected since 13:00 GMT on 20 May 2010. The eruption declined a great deal and the flow of magma into the crater was roughly estimated at 5 tonnes/s, carried away by a plume that rises 1.5–2 km (4,900–6,600 ft) above the crater. There were no reports of lava flows.
22 May	According to a reconnaissance flight, the plume was estimated at 4 km (13,000 ft). A light easterly wind blew it to the west There were no reports of ash fall neither were any lightning strikes detected. The eruption rate was similar to the day before with some explosive activity seen from reconnaissance flights. Due to the cloud cover, it was not possible to observe any lava flow from the crater.
23 May	The Icelandic Meteorological Office reported at 11:00 GMT that there was "no ash plume" and that "hopefully the eruption is over". According to pilot observations, the plume was estimated at 3 km (9,800 ft) heading in a southerly direction. The plume was completely white in colour indicating that it was composed entirely of water vapour. There were no reports of ash fall, neither did ATDNet report any lightning strikes. Measurements made from an aircraft mounted thermal camera indicated that at the crater, the highest observable temperature was almost 100 °C (212 °F); however, the crater could not be observed directly due to the quantity of steam rising from it. No signs of magma extrusion were visible. Seismographic data indicated that the volcanic tremors decreased to almost the level that existed before the eruption. Further to this, GPS sensors indicated a continued horizontal displacement toward the centre of the Eyjafjallajökull volcano. This was interpreted as showing that the magma chamber was not being replenished. The overall assessment was that in spite of the high quantity of steam, the eruption appeared to be dormant.
24–26 May	According to a web camera and an observation flight, the white plume was estimated at no more than 2 km (6,600 ft) heading south as a consequence of a light northerly wind. A blue smog was seen in the atmosphere and a strong sulphurous smell was noticed inside the airplane when flying south of the volcano. There were no reports of either ash fall or lightning strikes. The seismic data indicated that tremors were decreasing but were still slightly higher than the levels observed before the eruption. Twenty three small earthquakes were recorded in this three day period, most of which were in the lowest frequency band of 0.5 to 1.0 Hz. GPS sensors indicated a decreasing amount of horizontal deformation and subsidence toward the centre of the volcano. There was still a large amount of steam rising from the eruption vent and a single, small ash blast was observed by a group of scientists who went to the crater. Nonetheless, the activity was low enough to describe the volcano as dormant. Visibility of the volcano was periodically obscured due to an ash mist that was raised by surface winds around the volcano. This reduced visibility in Vestmannaeyjar to 1 km (0.62 mi) and in Vatnaskarðshólar to 2 kilometres (1.2 mi). Under these conditions, the view of the volcano from the web cameras was completely obscured.
27 May	The IES conducted an expedition to the summit of Eyjafjallajökull to measure the tephra thickness in and around the eastern half of the crater. Tephra up to 40 metres (130 ft) thick was measured close to the eruption vents. Intense clouds of steam continued to rise from the vents, with occasional small ash explosions. The noise of intense boiling and or degassing was heard, but visibility into the vents was limited due to the clouds of steam. The crater rim was coated with a fine ash that extended 20 metres (66 ft) from the edge and the whole area had a strong smell of sulphur. At 20:45 GMT the steam plume was measured to be at an altitude of 2.8 km (9,200 ft).
28 May	During the morning, the top of the mountain was hidden by clouds thus obscuring the view of the eruption plume from the web cameras. Volcanic tremors were still more frequent than before the eruption and have been rather steady since 22 May. Small pulses, mostly in the lowest frequency range (0.5–1.0 Hz), were detected by earthquake stations around the volcano. Rain prevented surface winds from lifting the ash around the volcano to form an ash mist. The volcano continues to be monitored closely.
June 2010
1 June	The crater continued to emit a large quantity of steam, but for the last couple of days, the summit of the volcano was not directly observable due to cloud and mist. At 08:00 GMT, web camera observations showed the white plume to be at a height of around 2 km (6,600 ft). Winds of up to 10 metres per second (22 mph) blew from the east. The volcano has not produced any ash since around 20 May 2010, but there has been widespread drifting of existing ash in southwest Iceland. High concentrations of airborne dust were reported in Reykjavík on both 31 May and 1 June. Since 22 May, a steady stream of small, pulse tremors has been detected around the volcano in the lowest frequency range (0.5 Hz – 1 Hz). This is a greater level of seismic activity than was detected before the eruption and is currently ongoing.
4 June	On Wednesday, 2 June a white steam cloud was seen rising up to 2.5 km (8,200 ft). On Thursday 3 June, IES scientists visited the crater area and observed a considerable quantity of the steam being emitted from the crater, although it was less than the previous week. The steam rose some 200–400 m (660–1,310 ft) above the crater rim. On 4 June south of the volcano, the wind was measured at between 8–13 metres per second (18–29 mph) blowing from the east. By 19:50 GMT, the plume had been observed at a height of 4.5 km (2.8 mi). No ash was reported emitting from the volcano, but widespread drifting of existing ash occurred in south and south-west Iceland. In the crater area, solfatara was observed steaming out with a noise like that from a high temperature geothermal drill. Considerable rumbling noises were heard at Raufarfell (10 kilometres (6.2 mi) south of the crater) during the afternoon. During the afternoon, an increase in tremor activity was recorded at seismic stations around the volcano, but decreased in the evening. There are still more volcanic tremors than before the eruption and the rate has fairly steady since 22 May. An eyewitness at Ásólfsskálaheiði (9 kilometres (5.6 mi) SW of crater) observed two small flashes of lightning during the evening. Several small and shallow earthquakes have been detected on a daily basis under the volcano.
7 June	Small tremor pulses were recorded on and off during the night of 4 June and at around 09:00 GMT on 5 June, the tremors reached a maximum before decreasing again. Another increase was recorded late on 6 June for a short time and small pulses were again recorded during that night. These tremors were predominantly at high frequencies. On the evening of 6 June, a plume of steam was observed from a plane at a height of between 4.5–6 km (2.8–3.7 mi). By the morning of 7 June, a steam plume was observed for a short period at a height of 3 km (9,800 ft) heading in a southerly direction. The plume was mostly white in colour at the top and greyish and dark at the bottom due to continued explosive activity. This accounts for the intermittent tephra fallout near the crater. ATDNet recorded four lightning flashes during the morning. A considerable quantity of steam was seen emanating from the big crater and has increased since 3 June. In the western part of the crater, a new crater formed at the site of new explosive (but small) activity. Tremor pulses late on 6 June accompanied steam plumes from this new crater. Between explosions, the lava can be heard caving in within the eruptive conduit. Due to the large quantity of steam, only a part of the new active crater could seen. The glacial ice at the top is rapidly advancing to the Gígjökull outlet glacier. The various GPS monitoring stations around Eyjafjallajökull did not report any significant deformation. There is some new eruptive activity on the western side of the crater with intermittent magma explosions that produce ash which falls near the crater. This explosive activity was accompanied by an abrupt increase in tremors. White steam clouds have reached a height of 6 km (20,000 ft) following these explosions.
10 June	A slight increase in seismic activity was observed on the evening of Monday, 7 June in the frequency range 1–2 Hz. An increase was also observed in the 0.5–1 Hz range on 10 June that was probably due to the weather. No plume height information was available due to cloud cover. At around 15:00 GMT on 9 June, rumbling noises were heard at Gígjökull just before a steam cloud rose from the crater. GPS monitoring showed that over the last two days, there had been a slow and continuous deformation towards the volcano. In the same time period, a few small, shallow earthquakes were recorded beneath the top crater. IES scientists continue to monitor the volcano closely.
11 June	The eruption plume was confined mostly to within the crater, with steam clouds occasionally rising above the crater rim. No tephra fallout was reported, neither were any lightning strikes detected. Heavy rainfall during the night of 9 June and early on the morning of 10 June caused considerable swelling in the Svaðbælisá River. A considerable quantity of mud has accumulated in the river channel since the eruption began, decreasing the channel's depth. The decreased channel caused water to flow up onto a road west of the bridge. There was also sufficient mud bearing water to overflow the levee that had been erected to protect the farming land at Þorvaldseyri. A lake, about 300 m (980 ft) in diameter, has formed at the bottom of the big crater. Steam has been observed rising from the rims, especially on the north side. In the morning, the steam cloud only rose about 100 m (330 ft) over the crater but by evening, had reached a height of 500–1,000 m (1,600–3,300 ft). On the western side of the crater just above the surface of the water, a brown coloured cloud can be seen rising from two small openings. Mounds of sulphur have formed by steam eyes in the lava vein, just north of the crater. The eruption did not produce any magma on this day, with the activity being confined to steaming. Water has started to accumulate in the main crater and the threat of sudden drainage creates the possibility of a significant flood down Gígjökull in the coming weeks.
15 June	Observation flights were conducted over the eruption site on 11 and 14 June. A white plume was observed to be at a height of over 100 m (330 ft) No tephra fallout or lightning was reported. Low level seismic tremors and pulses were intermittently observed. In addition to this, a few small, shallow earthquakes were recorded beneath the Eyjafjallajökull summit in the last weeks. Thirteen microearthquakes were recorded in the Mýrdalsjökull caldera from 11 to 14 June, most of which were at a shallow depth. The seismic activity beneath Mýrdalsjökull glacier does not appear to be related to inflation of the area observed by the GPS monitoring stations. No significant vertical deformation was observed at GPS stations at or around the glacier. However, a station at the northeastern caldera rim (AUST), moved inwards (south-west) towards the caldera by about three centimetres between 9 and 13 June. A wall of ice has formed along the eastern, southern and western sides of the crater lake. On the northern side, a tephra wall rises some 20 metres (66 ft) above the water. The ice walls at the south-western corner of the crater are melting at the site of the vent that was active between 4–6 June. The rate of melting is estimated to be about 1 cubic metre (35 cu ft) per second. The level of water in the crater lake rose between 1–2 metres (3.3–6.6 ft) on the weekend of 12–13 June. The rate at which the crater lake fills depends on the how fast the surrounding ice melts. Therefore, several days or even weeks are likely to pass before the crater has filled up. This could extend to months if the melting slows down. The water level in the crater will be monitored regularly as its volume is now estimated to be approaching 500,000 cubic metres (650,000 cu yd). If the water level rises a further 20 metres (66 ft) and then escapes, an estimated 3,000,000 cubic metres (3,900,000 cu yd) of water will flood northwards down the Gígjökull valley glacier at an estimated rate of 1,500–2,000 cubic metres (2,000–2,600 cu yd) per second.
23 June	Since the last report, there has been very little activity at the Eyjafjallajökull volcano. Small ash clouds are seen occasionally, but they disappear again after some minutes. Water accumulation in the crater is slow as the surrounding ice is no longer in contact with hot material. GPS measurements show slight movements towards the mountain except at Austmannsbunga in Mýrdalsjökull, which shows movement towards the southwest. No obvious explanation has been found for this movement.

Volume of erupted material and magma discharge

The Institute of Earth Sciences made a preliminary estimate of erupted material in the first three days of the eruption on 14 April 2010 at Eyjafjallajökull. The erupted products are fragmented material, the majority fine-grained airborne tephra. Eruptive products can be split into three categories along with preliminary estimated erupted volumes:

1. Material (tephra) in the ice cauldrons around the volcanic vents: 30 million cubic metres (39,000,000 cu yd)
2. Tephra filling the glacial lagoon of Gígjökulslón, carried by floods down the outlet glacier Gígjökull: 10 million cubic metres (13,000,000 cu yd)
3. Airborne tephra that has been carried to the east and south of the volcano. Uncompacted tephra fallout from eruption plume: 100 million cubic metres (130,000,000 cu yd)

Total: 140 million cubic metres (180,000,000 cu yd) which corresponds to some 70–80 million cubic metres (92,000,000–105,000,000 cu yd) of magma. The magma discharge rate is about 300 cubic metres per second (11,000 cu ft/s) or 750 t/s. This is 10–20 times the average discharge rate in the preceding flank eruption at Fimmvörðuháls.(First Eruption on 20 March 2010).

The IES updated the eruption flow rate on 21 April 2010 to estimation of less than 30 cubic metres per second (1,100 cu ft/s) of magma, or 75 tonnes/s, with a large uncertainty. IES also noted that the eruption continue with less explosive activity.

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. Smoke and ash from eruptions reduce visibility for visual navigation, and microscopic debris in the ash can sandblast windscreens and melt in the heat of aircraft turbine engines, damaging engines and making them shut down. Many flights within, to, and from Europe were cancelled following the 14 April 2010 eruption, and although no commercial aircraft were damaged, the engines of some military aircraft were harmed. The presence and location of the plume depends upon the state of the eruption and the winds. While some ash fell on uninhabited areas in Iceland, most had been carried by westerly winds resulting in the shut down of a large air space over Europe. The shut down had a knock on impact on the economy and cultural events across Europe. The Icelandic flag carrier airline, Icelandair, seemed at first especially vulnerable, but managed to deal effectively with the eruption and subsequently published a detailed report about its actions and conclusions.

Short- and long-term weather and environmental effects

Ash fallout from Eyjafjallajökull on a car, Manchester, England, 21 April 2010

At the mouth of the crater, the gases, ejecta, and volcanic plume have created a rare weather phenomenon known as volcanic lightning (or a "dirty thunderstorm"). When rocks and other ejecta collide with one another, they create static electricity. This, with the abundant water-ice at the summit, aids in making lightning.

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. In 1783, 79 percent of the Icelandic sheep stock were killed, probably as a result of fluorosis caused by the eruption of Laki. The effect also spread beyond Iceland. 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 troposphere also poses a potential health risk, especially to people with pre-existing breathing disorders.

While it is suspected that major volcanic eruptions that coincide with cyclic solar minimum activity could produce temporary global cooling or reduction in global temperature, it is noted that coincidentally the earth-facing side of the Sun was mostly blank with no sun spots since the start of the second eruption phase on 14 until 29 April 2010. Although the current unusually long solar minimum came to a close earlier this year, the current cycle may witness unusual weak solar maximum. Other research links volcanic eruptions including recent Icelandic activity to the solar cycle. Most consider the climate anomaly of the Year Without A Summer 1816 to have been caused by a combination of a historic low in solar activity with a volcanic winter event; the latter caused by a succession of major volcanic eruptions capped off by the Mount Tambora eruption of 1815, the largest known eruption in over 1,600 years. One proposed volcanic winter happened c. 70,000 years ago following the supereruption of Lake Toba on Sumatra island in Indonesia.

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. One previous related sequence of eruptions of this volcano, beginning in 1821 is recorded as having lasted for over two years, however no single set of major eruptions is known to have lasted more than 'several days'. Should the eruption continue for a sufficient length of time at its current intensity, 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. 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. 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.

The eruption may have affected atmospheric carbon dioxide levels by fertilizing oceans with iron. According to the Nordic Volcanological Center at the University of Iceland ash samples contained 8 to 12% iron oxide. Observations at the Mauna Loa Observatory show increased carbon dioxide absorption for each of the three months following the eruption compared to the 30 year mean for the same months. Over May, June and July 2010 atmospheric carbon dioxide decreased by a total of 2.40 ppm. The thirty year mean for the same months is 1.66 ppm with a standard deviation of 0.52ppm. The probability of a chance result is less than 8%.

Comparison to other recent eruptions

The recent eruptions of Eyjafjallajökull and the largest ash plume associated with the second eruption phase were not unparalleled in either volume or abundance; however, the location was the critical factor because it affected air travel across Europe. Neither phase of the eruption was unusually powerful. Other notable volcanic eruptions in recent years include the eruption of Mount Pinatubo of 1991 of VEI 6. This eruption lasted 8 days, from 7 – 15 June of that year, with an ash cloud that would have required additional days to dissipate, and resulted in worldwide abnormal weather and decrease in global temperature over the next few years. However, the second phase of Eyjafjallajökull's eruption lasted longer than that of Mount Pinatubo.

According to the SI / USGS Weekly Volcanic Activity Report (14–20 April 2010) by the Smithsonian's Global Volcanism Program, the second eruption phase at Eyjafjallajökull coincided with eruptions at a number of other volcanoes, including new activity at:

1. Barren Island, Andaman, India: plume rose to an altitude of 2.4 kilometres (7,900 ft) and drifting 55 kilometres (34 mi) to the north on 19 April 2010.
2. Gaua, Banks Islands, SW Pacific, Vanuatu: ash plumes reported from during 13–16 and 19–21 April 2010. The plumes regularly rose to altitudes of 3 kilometres (9,800 ft). A spokesman for the Vanuatu Disaster Management Office described the activity as "huge, dark plumes" in an AAP news report.

Public media

• In television news reports in Britain, news presenters always or nearly always abdicated out of trying to pronounce "Eyjafjallajökull" Icelandic-fashion, but called it "the Iceland volcano" and similar.

See also

• 1783 eruption of Laki
• 2010 eruptions of Mount Merapi
• Air travel disruption after the 2010 Eyjafjallajökull eruption
  • British Airways Flight 9
  • KLM Flight 867
• Consequences of the April 2010 Eyjafjallajökull eruption
• List of volcanoes in Iceland
• North Atlantic oscillation
• Timetable of major worldwide volcanic eruptions
• Tuya

External links

• Update on Activity – from the Icelandic Met Office and University of Iceland (will be updated if activity resumes)
• Frequently Asked Questions on the Eruption in Iceland – from the Icelandic Met Office
• Current seismology around Eyjafjallajökull and Mýrdalsjökull – Earthquakes in last 48 hours
• Information about eruption on Eyjafjallajökull: Institute of Earth Sciences, University of Iceland (will be updated if activity resumes)
• Iceland Volcano Ash Causing Huge Economic Loss
• BBC webpage with film of the volcano, taken from 500m from the crater's edge, by Chris Weber on 13 May 2010
• Volcanic Ash and Aviation Safety – SKYbrary guidance to pilots and controllers concerning the effects of volcanic ash.
• Collection of Scientific Earth Observations and Models
• Met Office (UK) Iceland Volcano Update (not updated since May 2010)
• NASA Observes the Icelandic Volcano
• NASA Earth Observatory satellite imagery
• National Environmental Research Institute, Denmark – Dispersion of the volcanic plume
• EUMETSAT imagery products
• NOAA view of the concentrated ash plume, April 2010
• CIMSS Satellite Blog Volcano posts
• Satellite evidence of hot lava flows from an Icelandic volcano (CIMSS Satellite Blog) (March 2010)
• IsEyjafjallajokullStillErupting.com
• Description of beginning of current eruption, (March 2010), Icelandic Met Office
• Volcanoes in European history – Podcast placing the Eyjafjallajökull eruption in a historical perspective.

Photography

• Photos from Icelanders and by visitors (Flickr Group)
• In pictures (Fotopedia slideshow)
• A short time-lapse from 17 April 2010. About 30 minutes played in 18 seconds.
• Eruptions in Iceland! – slideshow by Life magazine
• Photos of the 2010 eruptions by Fred Kamphues
• Recent Photographs from Nachofoto
• Photographs by Raw Iceland, a Reykjavik-based organisation that organises amateur and professional photography tours to the volcano
• Icelandic Coast Guard, radar images of the volcano

Webcams

• Míla webcam from Hvolsvelli Location: 63°44.977′N 20°13.913′W facing SE
• Míla webcam and thermal imagery from Þórólfsfell or Thermal and normal cameras side by side Location: 63°42.699′N 19°39.277′W facing S
• Vodafone webcam from Þórólfsfell (now offline, July 2010)
• Mulakot airstrip webcam (still views – use F5 to reload) (Not updated since 02:00 14 July 2010) Location: 63°50′00″N 17°58′00″E ICAO code: BIMK
• Heklubyggð webcam

Audio

• Volcanic Eyjafjallajökull run off: Seljalandsfoss Waterfall (binaural recording optimised for headphones)