Bárdarbunga volcano (Iceland): continuing earthquakes, no signs of magma rising to surface volcanodiscovery/bardarbunga/news.html The intense earthquake swarm continues with no significant changes. There are no signs of magma migrating towards or reaching the surface are present, although the risk of a subglacial eruption in the near future remains high. This could lead to significant glacial floods and ash emissions, which in turn could cause again disruptions of flight operations in the region, depending on the wind trajectories and the amount of ash released. A slow migration of the quakes towards the NE is visible during the past days, indicating that the intruding magma at shallow depth is currently moving horizontally. Icelands Met Office (IMO) who monitors the situation closely, published the following status report yesterday: No sign of harmonic (volcanic) tremor detected. Earthquakes The earthquake swarm that began on 16 August at 03:00 is still ongoing. Intense earthquake activity is concentrated in the region between Bárðarbunga and Kverkfjöll calderas. The swarm continues to migrate towards the NE, however at a slower rate than in the last days. The swarm north of Bárðarbunga caldera (at the edge of Dyngjujökull just E of Kistufell) has diminished. There have been some earthquakes within the Bárðarbunga caldera. Throughout the whole sequence until now, the majority of seismic events have been calculated to be at 5-10 km depth. There is no sign of upward migration. The event rate is still high. ~4000 events have been automatically detected since the beginning of the swarm on Saturday morning, ~700 since midnight today. Activity ebbs and flows in pulses of several hours lengths. The last pulse of high activity rate started at 9:30 this morning and is still continuing. All events since Monday morning have been magnitude 3.0 and less. GPS deformation The results of continuous GPS measurements continue to indicate magma intruding within the Bárðarbunga volcanic system. During the period between 8 am on the 15th of August and 4 pm on the 18th of August a GPS station on Dyngjuháls moved 5,4 cm towards the northwest and a GPS station on Grímsfjall moved 1,8 cm towards the south. Models suggest that the most likely explanation for the movements of the GPS stations is that there is an ongoing dyke intrusion east of Bárðarbunga. Overall assessment There have been no observations of migration towards the surface or any other signs of imminent or ongoing volcanic activity. We cannot exclude that the current activity will result in an explosive subglacial eruption, leading to an outburst flood (jökulhlaup) and ash emission.
Posted on: Thu, 21 Aug 2014 10:06:25 +0000
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