The Bárðarbunga volcano is now classified as “Code Yellow”, although there are no indications that magma has reached the surface.
According to a statement from the Icelandic Met Office, a cluster of earthquakes at and around the Bárðarbunga volcano – on the roughly northwest corner of Vatnajökull glacier – have been recorded and have been ongoing since about 3:00 August 16. To wit:
Long-term seismic and GPS data indicate that there is increased unrest in the northwestern region of Vatnajökull glacier, where Bárðarbunga is located.
Over the last seven years seismic activity has been gradually increasing in Bárðarbunga and the fissure swarm north of the volcano. This activity dropped down at the Grímsvötn eruption in May 2011, but soon after, the activity started to gradually increase again and has now reached similar level of activity to that just before the Grímsvötn eruption. Earlier this year, in the middle of May 2014, there was a small swarm of over 200 events and now the present swarm has already generated at least 300 earthquakes.
Since early June 2014, displacements at GPS stations around Vatnajökull (Hamarinn, Grímsfjall, Vonarskarð and Dyngjuháls) show an increased upward movement and away from Bárðarbunga.
Together, these two systems indicate magma movements in Bárðarbunga.
However, the Met Office emphasises that, as of 23:00 August 16, “there is no unequivocal indication that magma has reached the surface”.
As a precautionary measure, Bárðarbunga is now classified as Code Yellow by the International Civil Aviation Organisation (ICAO) colour system. Specifically, code yellow means “Volcano is exhibiting signs of elevated unrest above known background level.”
Bárðarbunga is a powerful volcano which last erupted in the late 19th century. While seismic activity at the site of the volcano is cause for concern, the situation has not yet reached dangerous levels nor is an eruption necessarily imminent.
UPDATE: This just in from the Civil Protection and Emergency Management in Iceland:
Regarding earthquake swarm in northern part of Vatnajökull glacier.
Situation today, 17th of august at 19:00
There was a meeting this morning with the Department of Civil Protection and emergency management, Icelandic met office and the Institute of Earth Sciences to go over the situation. The earthquake swarm is still ongoing and the intensity is concentrated to the north and east of the Bárðarbunga caldera, beneath Vatnajökull glacier. GPS measurements confirm that magma is intruding within the Bárðarbunga volcanic system. At the moment there are no indications that eruption has started.
Scientist have increased monitoring of the area and the local authorities have reviewed their response plans.
At the moment a helicopter from the Icelandic Coast Guard is in the area carrying scientist and people from the department of Civil Protection. Their objective is to install more seismic monitors and webcams in the area for increased monitoring.
The Police Commissioner of Húsavík has decided to close Gæsavatnaleið road and other highland roads east of Skjálfandafljót up to Askja. The road to Herðubreiðarlindir (F88) has also been closed due to potential flooding in the area following an eruption.
The above image is of the 2011 eruption of Grímsvötn.