Yesterday (17-March-2016) an earthquake swarm took place in Bárðarbunga volcano. This is a weekly cycle at the moment in Bárðarbunga volcano so older readers are used to seeing and read about it already. This started in September 2015 (for the new readers) after the eruption in Holuhraun ended in February 2015. This activity suggest that magma has started to flow into the magma chamber in Bárðarbunga volcano again at faster speeds than before the eruption in Holuhraun. The exact rate is difficult to know, since the magma that started the eruption in Holhraun had been building up in Bárðarbunga volcano since 1970-ish and part of that time earthquake recording was poor or did not exist in Iceland or parts of it until 1995 when the SIL network was created by Veðurstofa Íslands.
The earthquake activity in Bárðarbunga and Grímsfjall volcanoes. Copyright of this image belongs to Iceland Met Office.
The largest earthquake this week had the magnitude of 3,4 while other earthquakes that took place had smaller magnitude. The second largest earthquake had the magnitude of 2,8. Other earthquakes where smaller in magnitude. It is also interesting that part of the earthquake swarm aligned it self along north-south fault in the eastern part of the caldera. That is a new feature, either a weakness is forming at this location or something else is up. This area has around 300 – 500 meter thick glacier on top of it and an eruption at this location would be extremely bad. The glacier flood from eruption at this location would mostly go down Jökulsá á fjöllum glacier river. Other flood locations can’t be ruled out (I’m not an expert on glacier floods and I do have limited knowledge of the landscape under the glacier).
Grímsfjall volcano
It has been five years since Grímsfjall volcano erupted in a largest eruption in 140 years for Grímsfjall volcano. Over the past few weeks there has been a slight increase in earthquake in Grímsfjall volcano. At the moment this doesn’t mean an eruption is imminent, the thing however about eruptions in Grímsfjall volcano is that they happen suddenly and without warning. Normally eruption happens in Grímsfjall volcano every 3 – 5 years on average, sometimes its shorter and sometimes its longer between eruptions.
Notice on Böðvarshólar geophone station
For the longest time now I’ve been having 3G connection issues with Böðvarshólar geophone station. The problems include poor signal, little bandwidth. The poor signal leaks into my recording of earthquakes, making them bad and extremely noisy and that makes them less usable for me. I am going to attempt to improve this situation but if that fails I will have to turn the station down. Since the cost of getting a good antenna for this location is too high and the solution takes too long to implement anyway. I will post a notice if I take down the Böðvarshólar geophone station. If it happens, it is going to happen before I move to Denmark.
Article updated on 18-March-2016 at 13:31 UTC. Minor spelling error fixes.