Eyjafjallajökull, a volcano on the Eastern Volcanic Zone in southern Iceland, began to erupt on 14 April 2010.
A plume of volcanic ash was at times ejected several kilometres into the atmosphere by this eruption, potentially causing a hazard for aeroplanes. UK airspace was closed from 15–20 April, causing significant disruption, and was reopened following new guidelines about ash densities that could be tolerated by aircraft.
Occasional disruption continued when increased explosive activity at the volcano coincided with northerly to north-westerly winds that brought the ash towards Europe.
The first eruption, on 20 March 2010, came from an ice-free area on the north-east side of the volcano, which is 1660 m high (5300 feet), with an ice cap on the upper slopes. This first phase of eruption produced lava, with little explosive activity. A subsequent phase of eruption then began in a 2.5 km-wide caldera beneath the ice cap near the summit of the volcano on 14 April. This eruption caused melting of large amounts of ice, leading to flooding in southern Iceland. Researchers at the University of Iceland estimated that there was around 1 km3 of ice in the summit crater and that about 25 per cent of this was melted in the first two days of the eruption. The interaction of magma with water created a plume of volcanic ash and gas over 10 km (33 000 feet) high, which spread out and was carried by winds south-eastwards towards the Faroe Islands, Norway, and northern Scotland.
On Sunday 18 April researchers from the University of Iceland estimated that about 750 tonnes of magma were ejected from the volcano every second. By 20 April, most of the ice in the crater appeared to have melted, the plume was only reaching heights of up to 4 km (13 100 feet), and the amount of material being ejected into the plume had increased significantly. As the amount of ice available to interact with the magma decreased, the volcano changed from producing ash to mainly producing fire fountains. By the end of April explosive activity had virtually ended, with a weak plume largely made up of steam, but flowing lava had advanced a few kilometres northwards from the crater.
In early May, explosive activity began to increase again, with more ash being ejected into the plume. Plume height was generally around 4–6 km, but reaching at times up to 8–9 km. During the first two weeks of May, the activity became cyclical, and earthquake activity recorded the rise of magma and gas from depth beneath the volcano. The explosive activity was now driven by gas dissolved in the rising magma, rather than by the interaction of magma and water. Explosive activity gradually decreased and by 23 May little or no ash was being ejected from the volcano.
For the latest images from NASA see NASA Observes Ash Plume of Icelandic Volcano
The ash plume contains large amounts of microscopic particles of volcanic rock, which can clog up aeroplane engines, as described in Geoscientist Online and USGS volcanic ash: effects and mitigation strategies.
'Volcanic ash clouds are made up of small abrasive particles that can clog up jet engines and stop them working. Planes are either re-routed or grounded when there's a danger of flying into ash clouds to ensure the safety of passengers and avoid very costly damage.'
Dust particles believed to be volcanic ash were collected by a BGS scientist, from a previously-clean car windscreen, in Loughborough on 20 April 2010.
Friday 16 April — A Natural Environment Research Council research team using its highly-equipped Dornier 228 aircraft flew over the north-east of London where it located and tracked the edge of the plume over East Anglia and the North Sea, and towards the Dutch coastline.
Flying at just below 10 000 feet (3 km), the research instruments identified three distinct layers of volcanic residue. Heavy, gritty particles were sitting at around 8000 feet (2.4 km), whilst lower down in the atmosphere there were sulphurous chemicals and finer dust particles. For further information see the NERC press release 13 May and check for updates on the NERC website.
Dr Sue Loughlin, is part of a NERC scientific delegation travelling to Iceland in mid-May to discuss collaborative work on the impacts of the volcanic eruption.
Eyjafjallajökull last erupted in 1821, and the eruption continued intermittently for around two years. A major eruption then began at a nearby volcano, Katla, in 1823. Although it is possible that the new eruption of Eyjafjallajökull could be followed by an eruption at Katla, the linkages between the two volcanoes are not well understood. Monitoring of Katla is being carried out by authorities in Iceland.
Previous known eruptions at Eyjafjallajökull occurred in the 17th and 10th centuries AD, and the volcano has been periodically active for the last 800,000 years. Previous eruptive cycles at Eyjafjallajökull have begun with basaltic eruptions on the flanks of the volcano, followed by the eruption of more silica-rich magmas from the volcano's summit. Preliminary ash analyses suggest that this pattern is being followed in the 2010 eruption.
Iceland lies on the Mid-Atlantic Ridge, the boundary between the Eurasian and North American tectonic plates. As these two plates move apart, magma continually wells up along the ridge, creating new sea floor.
In Iceland, this ongoing ridge volcanism interacts with a mantle plume, which brings magma to the surface from deep within the Earth. This interaction of two different types of volcanism has created the island of Iceland, which is made up of many active volcanoes.
Contact Dr Sue Loughlin for further information.