Eyjafjallajoekull and the subglacial eruption in 2010
The volcano Eyjafjalla is a sub-glacial stratovolcano. Its summit is covered by the mighty, 200 m high glacier Eyjafjallajökull. Under the ice, a caldera formed with a diameter of 3x4 km. It contains several craters.
The creation of the volcano started approx. 800,000 years ago. 12 eruption cycles of Eyjafjallajökull are known from the times before the colonisation of Iceland. The most recent eruption took place in the spring of 2010.
Eyjafjallajökull lies on a fissure system running NE-SW, which forms the eastern volcano zone of Iceland.
The volcanic rock of Eyjafjallajökull consists primarily of an intermediate basalt between tholeiite and alkali basalt. Andesite, dacite and trachyte have also been produced.
The eruption history of the volcano is as varied as the rocks: there are known to have been purely effusive eruptions, but also explosive eruptions and volcanic eruptions that combine both eruption types.
Glacier runs are a great danger of subglacial volcanic eruptions. This took place in several eruptions, the last time in 2010.
The last eruption in spring 2010 occurred in 2 phases. At first, an effusive crevice opened on the western flank of the volcano. The crevice occurred on a saddle between Eyjafjallajökull and Myrdalsjökull and produced lava fountains and lava flows. Shortly after the end of the first eruption phase, which produced lava fountains and lava flows, there came the 2nd eruption phase: an explosive eruption of a volcanic type, which started from the summit caldera of Eyjafjallajökull. Melt water increased the explosiveness of the eruption and a mighty cloud of ash rose up to 9 km high. It was guided in a southerly direction by strong air currents. On the second day of the volcanic eruption, airspace over large parts of Europe was already declared unsafe for flights and there was severe disruption of air transport.