Bardarbunga volcano erupts - lava flows observed at surface, Iceland

Bardarbunga volcano erupts - lava flows observed at surface, Iceland

After nearly two weeks of seismic unrest lava flows from Bárðarbunga volcano were finally observed on the surface. The eruption started at around 00:02 UTC today on an old volcanic fissure on the Holuhraun lava field, between Bárðarbunga and Askja volcano, and peaked between 00:40 and 01:00 UTC. The active fissure was about 600 m in length.

Intense earthquake swarm below Bárðarbunga began on August 16. Since then, vast amounts of magma have formed a sheet of freshly cooled rock, called a dyke, that stretches for about 45 kilometers north of Bárðarbunga.

Evgenia Ilyinskaya, a volcanologist with the British Geological Survey in Edinburgh, said that the sheer volume of magma involved — perhaps some 0.4 cubic kilometres in the dyke — suggests that it is coming directly from Earth’s mantle. That places the source perhaps hundreds of kilometers below the surface of the crust, rather than in a shallow magma chamber of the sort found beneath many volcanoes. (Nature)

By 07:00 UTC seismic activity has temporarily decreased as a result of this pressure release, however a significant amount of earthquakes was still detected in the magma dyke.

Seismicity has since returned to levels observed in recent days.

Strongest events were M3.8 in the caldera of Bárðarbunga at 04:37, as well as M2.9 at 05:39 and M3.5 at 06:38 UTC in the dyke but no significant change was observed in volcanic activity. M4.1 occurred at 16:27 UTC on the northern rim of Bárðarbunga caldera.

The following image shows the new lava in Holuhraun, approximately 5 km north of Dyngjujökull. The photo was taken from TF-Sif, the airplane of the Icelandic Coast Guard at 10:44 UTC today.

Image credit The Icelandic Coast Guard

At 10:00 UTC, Icelandic Meteorological Office (IMO) lowered the Aviation Color Code for Bárðarbunga to ‘orange', signifying that significant emission of ash into the atmosphere is unlikely. The aviation color for the Askja volcano remains at ‘yellow'.

According to IMO, it is unclear at this moment how the situation will develop. However, three scenarios are considered most likely:

  • The migration of magma could stop, resulting in a gradual reduction in seismic activity and no further eruptions.
  • The dyke could reach the Earth's surface north of Dyngjujökull causing another eruption, possibly on a new fissure. Such an eruption could include lava flow and (or) explosive activity.
  • The intrusion reaches the surface and an eruption occurs again where either the fissure is partly or entirely beneath Dyngjujökull. This would most likely produce a flood in Jökulsá á Fjöllum and perhaps explosive, ash-producing activity. 

Other scenarios cannot be excluded. For example, an eruption inside the Bárdarbunga caldera.

Bárdarbunga volcano eruption on August 29, 2014. Image credit Icelandic Civil Protection

Bárdarbunga volcano eruption on August 29, 2014. Image credit Icelandic Civil Protection

Bárdarbunga volcano eruption on August 29, 2014. Image credit Icelandic Civil Protection

Bárdarbunga volcano eruption on August 29, 2014. Image credit Icelandic Civil Protection

Bárðarbunga volcano webcams:

Live stream

Video courtesy YAYnews

Geologic summary

The large central volcano of Bárdarbunga lies beneath the NW part of the Vatnajökull icecap, NW of Grímsvötn volcano, and contains a subglacial 700-m-deep caldera. Related fissure systems include the Veidivötn and Trollagigar fissures, which extend about 100 km SW to near Torfajökull volcano and 50 km NE to near Askja volcano, respectively. Voluminous fissure eruptions, including one at Thjorsarhraun, which produced the largest known Holocene lava flow on Earth with a volume of more than 21 cu km, have occurred throughout the Holocene into historical time from the Veidivötn fissure system.

The last major eruption of Veidivötn, in 1477, also produced a large tephra deposit. The subglacial Loki-Fögrufjöll volcanic system located SW of Bárdarbunga volcano is also part of the Bárdarbunga volcanic system and contains two subglacial ridges extending from the largely subglacial Hamarinn central volcano; the Loki ridge trends to the NE and the Fögrufjöll ridge to the SW. Jökulhlaups (glacier-outburst floods) from eruptions at Bárdarbunga potentially affect drainages in all directions. (GVP)

Featured image: Bárdarbunga volcano eruption on August 29, 2014. Image credit Icelandic Civil Protection

Tags: bardarbunga

Comments

stephen andrew persaud 5 years ago

it has begun....

Post a comment

Your name: *

Your email address: *

Comment text: *

The image that appears on your comment is your Gravatar