Eyjafjallajökull ([ˈɛɪjaˌfjatl̥aˌjœːkʏtl] (listen)) is one of Iceland's smaller ice caps located in the far south of the island.
Situated to the north of Skógar and to the west of the larger ice cap Mýrdalsjökull, Eyjafjallajökull covers the caldera of a volcano 1,666 m (5,466 ft) high, which has erupted relatively frequently since the last ice age.
The most recent major eruptions occurred in 920, 1612, 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, "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 were 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 was small, rising to no more than 4 km (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 km (5.0 mi) into the atmosphere.
The second phase was estimated to be a VEI 4 eruption, which was 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.
This second phase erupted trachyandesite.

This volcanic activity so disruptive to air travel because of a combination of factors:
The volcano was directly under the jet stream.

The direction of the jet stream was unusually stable at the time of the eruption's second phase, continuously southeast.

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:
The rapidly vaporising water significantly increased the eruption's explosive power.

The erupting lava cooled very fast, which created a cloud of highly abrasive, glass-rich ash.

The volcano's explosive power was enough to inject ash directly into the jet stream.
Eyjafjallajökull ([ˈɛɪjaˌfjatl̥aˌjœːkʏtl] (listen)) is one of Iceland's smaller ice caps located in the far south of the island. Situated to the north of Skógar and to the west of the larger ice cap Mýrdalsjökull, Eyjafjallajökull covers the caldera of a volcano 1,666 m (5,466 ft) high, which has erupted relatively frequently since the last ice age. The most recent major eruptions occurred in 920, 1612, 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, "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 were 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 was small, rising to no more than 4 km (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 km (5.0 mi) into the atmosphere. The second phase was estimated to be a VEI 4 eruption, which was 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. This second phase erupted trachyandesite.
This volcanic activity so disruptive to air travel because of a combination of factors:
The volcano was directly under the jet stream.
The direction of the jet stream was unusually stable at the time of the eruption's second phase, continuously southeast.
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:
The rapidly vaporising water significantly increased the eruption's explosive power.
The erupting lava cooled very fast, which created a cloud of highly abrasive, glass-rich ash.
The volcano's explosive power was enough to inject ash directly into the jet stream.
2010 eruptions of Eyjafjallajökull