2014–2015 eruption of Bárðarbunga

2014-2015 eruption of Bárðarbunga
Eruption at Holuhraun, September 4, 2014
Volcano	Bárðarbunga
Date	August 29, 2014 – February 27, 2015
Type	Effusive
Location	Bárðarbunga, Iceland 64°51′N 16°50′W / 64.85°N 16.83°W / 64.85; -16.83Coordinates: 64°51′N 16°50′W / 64.85°N 16.83°W / 64.85; -16.83
Impact	Air pollution

The 2014–2015 eruption of Bárðarbunga was an eruption in the Bárðarbunga volcanic system in Iceland, that began on August 29, 2014 and ended on February 27, 2015. The eruption emitted large volumes of sulphur dioxide and impacted air quality in Iceland. There was no effect on flights outside of the immediate vicinity due to a lack of a significant emission of volcanic ash. The eruption took place in the lava field of Holuhraun northeast of the Bárðarbunga caldera proper.

Seismic activity surrounding the Bárðarbunga volcano gradually increased from 2007 to 2014, with a brief pause during the nearby eruption at Grímsvötn in 2011. By the summer of 2014 activity reached a level similar to that just before the Grímsvötn eruption. In May 2014 there was a small earthquake sequence of about 200 events. GPS data recorded a displacement of 14 cm in the region since the beginning of the phase of unrest, compared to a figure of 2 cm over the rest of Iceland. This displacement is attributed to the separation of two continental plates: the Eurasian Plate in the east and the North American Plate in the west. Further earthquake swarms were detected: one at Bárðarbunga caldera, attributed to subsidence due to the magma chamber emptying; and another at the head of a dyke which extends approximately 40 km outwards from the vent, at a depth of 5–8 km below the surface. Evidence of minor sub-glacial eruptions occurred as early as 23 August when tremors were detected, but it was not until 29 August when lava erupted onto the surface at the fissure, forming a crater and substantial lava field to the north of the glacier in Holuhraun.

Scientists at the Icelandic Met Office and the University of Iceland outlined three possible scenarios:

A swarm of 1600 earthquakes with an average magnitude of 1.5 up to 3 began at 03:00 on August 16, 2014. There were "very strong indications of ongoing magma movement, in connection with dyke intrusion" according to the Icelandic Meteorological Office. The activity was in fact two swarms; one located east of Bárðarbunga caldera; and one at the edge of Dyngjujökull glacier just east of Kistufell. The Aviation Color Code was raised to Yellow. By 18 August about 2600 earthquakes were detected, with some larger than magnitude 3, the largest of which being of magnitude 4.5. The Aviation Color Code was raised to Orange. The majority of events were recorded at a depth of 5–10 km.