Over the past few hours a sequence of deep earthquakes has been taking place in Bárðarbunga volcano. The depth of those earthquakes is from 19 km and up to 11 km, how they spread out suggesting a dyke intrusion in Bárðarbunga volcano fissure swarm or on the edge of the volcano.
The deep earthquakes taking place almost south of the main caldera in Bárðarbunga volcano (few blue/yellow dots). Copyright of this image belongs to Icelandic Met Office.
Deep earthquake activity suggests that fresh magma is pushing into the volcano at more pressure than in past few days. The clues about this happening have been the stronger earthquake activity in Bárðarbunga volcano over the past few weeks. New dykes can also form without warning and start an eruption if the pressure is enough in them, such eruption might not last long, not even a whole day in some cases.
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Mike again 🙂 The depth clearly points to ascending Magam. But this has been happening since the end of the eruption in February 2015. Until the empty magma chamber is full again many more years will pass. No one of us will be able to experience a burst of Bardarbunga. The last outbreak was too great (1.3 km / 3). It will take many years (20 years +?) Until the magma chamber is full again. On average the volcano in the Holocene has broken out at intervals of about 250 to 600 years. It’s better you take a look at Katla. Hydrothermal activity continues unchanged. 🙂
This is not a magma chamber, this is a dyke. It might be connected to a magma chamber, but I’m not sure if that is actually the case. This dyke in question has been active since at least 2005 – 2008, it’s unclear when it formed exactly (it might be way older).
I consider the earthquakes and the GPS data to be unobtrusive. This type of earthquake we have had since the end of the February 2015 eruption (almost 2 years) Once a month, the IMO flies over the caldera. They, too, did not detect any changes (New Funnels). Is there any information about the composition of the gases? Is there any new information about the Rift activity? What makes hydrothermal activity? Are there any conspicuous features in the Bardabunga rivers? So I find nothing. And please do not be mad. I find them doing a great job. But over Bardarbunga I have a different meaning than you. 🙂
The magma chamber of Bárðarbunga was only partially emptied . A rifting phenomenon is a sequence of eruptions in a few years. That means it will be the next area between Hamariin and Grimsvotn. I do not think we will take a long time to uns new eruption. This is confirmed by scientists.
I seem to remember that during the last eruption, an annalist of the magma was done and found to of come from deep magma and not from a magma chamber. If this was correct them as Kovich and Jon have commented, the magma chambers in Bard will not take long to refill. Form what I understand, an eruption from a magma chamber and a rift event are totally different in the way they behave.
Although I couldn’t find the exact analysis results on the internet, the chemistry and volume indeed suggest that the 2014/15 eruption was tapping from deep in the crust as mentioned in (a.o.): http://www.nature.com/news/gas-spewing-icelandic-volcano-stuns-scientists-1.16234 .
There seem to be some deformation signals and the seimicity is on the up again. The IMO statement of May shows also some key facts regarding uplift as discussed here in several posts.
If you look at the Krafla rifing episode of 1974-1989: https://www.researchgate.net/profile/Pall_Einarsson/publication/228423567_Tectonic_stress_and_magma_chamber_size_as_controls_on_dike_propagation_Constraints_from_the_1975-1984_Krafla_rifting_episode/links/00b7d51e519dbaa595000000.pdf
The first dike breakout event needed the most pressure. The second dike went also northwards, then two went in the opposite direction. And so on till it became more and more of eruptive nature nearby the central chamber and dike forming stopped due to (most of the) tectonic stress relief. The larger the magma chamber, the longer the dike propagation and subsequently pressure reduction. You should say if the BB episode behaved the same way, ideally (if there is such a thing as an ideal situation) the next propagation would be towards Veidivötn, probably using the weak lock at the start of the first breakout.
http://gji.oxfordjournals.org/content/177/2/691.full.pdf+html
The clues I’m seeing at the moment suggest Trölladyngja since deep earthquakes [that started after the 1st eruption in Bárðarbunga] have been happening under that shield volcano (it might be a volcano within Bárðarbunga fissure swarm, I’m not sure). During the eruption cycle in the 19th century the eruption did go south and erupted in Tröllagígar, they are in the Veiðavatna area fissure swarm.
This whole thing is complicated and a lot is not known on how it works and what might happen next.
Information (Icelandic): https://is.wikipedia.org/wiki/Tr%C3%B6llahraun
Information (English): https://en.wikipedia.org/wiki/Tr%C3%B6lladyngja
The eruption in Tröllagígar (Tröllahraun) lasted for two years (1862 – 1864) with breaks in them. That means the eruption did go completely silent for some period of time. I suspect that might happen again with Holuhraun, if an new eruption does not start at a new location.