It has been over 3 years since the last eruption in Iceland. However, there are signs that an eruption might be in the works near remote Bárðarbunga - a powerful Icelandic volcano located on Vatnajökull glacier. Two major earthquake swarms have been measured since August 16th. Seismic activity is often the precursor of an eruption.
Intense seismic activity
Over 1100 Earthquakes in the last 3 days in Iceland!
Over 200 earthquakes were recorded on August 16th - the largest of magnitude 3 and over. This is the most intense earthquake swarm in this area for years. Measurements indicate magma movement. The IMO is following the situation closely and has alerted the Civil Protection Agency and aviation authorities.
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.
Eruption in Iceland's Vatnajökull glacier?
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. Due to increased seismicity IMO has decided to turn volcano Bárðarbunga status to yellow on the aviation colour code map. In case of a sub-aerial eruption, an ash plume of potential concerns for aviation will be generated.
Oddur Sigurðsson, specialist at the Icelandic Met Office took this photo of Bárðarbunga - the ice-cap in NW Vatnajökull glacier, in 1996.
Alert levels raised to orange
Seismic activity at Bárðarbunga persists
The intense seismic activity that started on 16 of August at Bárðarbunga persists. Very strong indications of ongoing magma movement, in connection with dyke intrusion, is corroborated by GPS measurements. There are currently two swarms: one to the E of Bárðarbunga caldera and one at the edge of Dyngjujökull just East of Kistufell. At 2.37 am on the 18th a strong earthquake (M4) was located in the Kistufell swarm.
This is the strongest earthquake measured in the region since 1996. As evidence of magma movement shallower than 10 km implies increased potential of a volcanic eruption, the Bárðarbunga aviation color code has been changed to orange
. Presently there are no signs of eruption, but it cannot be excluded that the current activity will result in an explosive subglacial eruption, leading to an outburst flood (jökulhlaup) and ash emission. The situation is monitored closely.
The next alert level after orange is red, which would mean that the volcano was just about to erupt or had already erupted.
Source: The Icelandic Met Office