Bárðarbunga – Nature of the beast

Dyngjujökull. Photograph by Eggert Norddahl. Used by explicit permission. If you wish to use the image contact Volcanocafé via our email.

Dyngjujökull. Photograph by Eggert Norddahl. Used by explicit permission. If you wish to use the image contact Volcanocafé via our email.

First let me write one thing, and that is that we are not in Kansas anymore. And with that I mean that we are in totally uncharted country. Icelandic Met Office has the best volcanologists on the planet, and they pretty much never make a mistake. They are quite simply the best and their reputation at this site is set in solidified lava.

So, when people like that in an hour first states that a small eruption has started and an hour later recant on the statement it does not hamper our confidence in their abilities, it is instead a sign of how “out there” what we are seeing right now really is.

What is happening now is really like if you walked down a familiar street and turn a corner and find yourself in the fabled Land of Oz

So it is time to sit down and calmly go through what is happening, and what has happened previously. Of course this will just skim the surface, but hopefully it will be enlightening.

In the beginning

Bardarbunga. Dyngjujökull. Photograph by Eggert Norddahl. Used by explicit permission. If you wish to use the image contact Volcanocafé via our email.

Bardarbunga. Dyngjujökull. Photograph by Eggert Norddahl. Used by explicit permission. If you wish to use the image contact Volcanocafé via our email.

There is of course not any beginning to our story, instead this story has been ongoing for 14 million years, and what we are seeing now is just a single word in the entire story of Iceland’s birth and growth.

So, let us just say that Bárðarbunga is the largest volcano of its type on the planet, and that it has had the largest lava flood eruptions in the last 10 000 years, and that it is prone to have what is called rifting fissure eruptions.

A rifting fissure eruption is when a large part of the fissure swarm “rifts”. Rifting is when a large part of a fissure on Iceland opens up all the way down to the mantle and as that happens a large scale decompression melt starts in the mantle and obscene amounts of magma is formed and pushed upwards filling the void that is created as the tectonic plates move apart.

Bárðarbunga has had more than half of the Icelandic rifting fissure eruptions, and of course the largest. Last time that happened to Bárðarbunga was in 1477 when a fissure opened up at Veidðivötn that extended all the way down to Torfajökull (causing an eruption there) and it also caused a VEI-6 caldera event at Bárðarbunga central volcano. The next time it happened was at the 1783 Skaftár Fires (Lakí) that happened on the Grimsvötn fissure swarm.

Back in 2010 Icelandic Met Office issued a statement that a phase of increased volcanic unrest was to be expected. These phases are due to Icelandic volcanism being cyclical, and there are two cycles. One is the Icelandic Mantleplume activity cycle; the other is the Icelandic MAR rift cycle. This time around both cycles would coincide.

Back then I also hypothesized that the rapid melt of Vatnajökull glacier would increase it further due to isostatic rebound (land lifting due to weight on top disappearing) would cause increased decompression melt.

Bárdarbunga. Dyngjujökull. Photograph by Eggert Norddahl. Used by explicit permission. If you wish to use the image contact Volcanocafé via our email.

Bárdarbunga. Dyngjujökull. Photograph by Eggert Norddahl. Used by explicit permission. If you wish to use the image contact Volcanocafé via our email.

All of this made me start to look for signs of unrest in the southern parts of the fissure swarms, and about two years ago I saw an uptick in earthquake activity at both Skaftár fissures and at Veidðivötn fissure swarm. Problem is just that there is extremely little scientific work done about these, the largest eruptions of their type on Earth. Basically there is only one good paper out there. This led me to do my own research and write a series of articles in here about the Skaftár Fires. I seriously suggest everyone to read those to get a better picture of what is happening now. My own research gave results at odds with what was previously believed about large rifting fissure eruptions, but it was based on enough data to make me believe in the validity of the result.

Around this time I and GeoLurking started to look sternly at what was going on in Iceland, and especially to track earthquakes in odd spots related to the fissure swarms.

Slightly more than a year ago odd small swarms started to appear in the area we are now looking at, and I concentrated on those that happened on the Bárðarbunga fissure swarm. Chiefly among those I noticed small swarms of deep earthquakes (20km+) under Kistufell and Trölladyngja. At the same time I noticed two odd swarms at equal or even greater depth at two points out in nowhere land. I thought those two swarms was just some odd volcanic activity related to unknown small volcanoes. Interesting, but not what I was on the prowl for.

As the months turned into a year of constant and slowly increasing activity I felt pretty sure that something was going on, and that it was time to write about what I thought would be an upcoming eruption on the Bárðarbunga fissure swarm. I though delayed writing the article for two weeks while debating it with a couple of the editors in here. In the end I decided that it was time to write about the upcoming event.

As things go I must have looked like a blatant psychic, the swarm started just a few hours later. Obviously most tree stumps are more psychic than me; instead I used science at every corner. I am though happy to have been the first to spot what would come.

What I find interesting is that those two deep swarms out in nowhere land are exactly at the spots where the meandering intrusion changed directions. That is just a bit too much of a coincidence, so I now think that those where signals of what would be coming, just that we missed them.

Now, let us look at the present.

Seismicity

Image from Icelandic Met Office. Corrected earthquake seismicity plot from onset of the swarm showing the collapsing caldera and the propagating intrusion.

Image from Icelandic Met Office. Corrected earthquake seismicity plot from onset of the swarm showing the collapsing caldera and the propagating intrusion.

Let me first start with the seismicity, in my Skaftár Fires series I wrote that we would be seeing almost constant M4 and M5+ earthquakes in an upcoming larger event in one of the fissure swarms, right now we are seeing exactly that. I do suspect we will see more of that later on if the fissure actually starts to rift. There are no signs of the seismic activity abating now, I would expect it to continue or even increase.

What is interesting is that at the current direction and speed of propagation the swarm will reach Askja in 4 days.

GPS orbits

Image by Icelandic Met Office. Kverkfjöll GPS Genggisig (GSIG).

Image by Icelandic Met Office. Kverkfjöll GPS Genggisig (GSIG).

 

Image by Icelandic Met Office. Dyngjuháls GPS-station (DYNC).

Image by Icelandic Met Office. Dyngjuháls GPS-station (DYNC).

Dyngjuháls (DYNC) has changed its orbit slightly and the rapid north motion has shifted to a slow south motion as the intrusion has passed the GPS-station. The westwards motion goes on unabated and the station has now moved 185mm in that direction.

If we look at the Kverkfjöll station named Gengissig (GSIG) we see 90mm of southwards motion combined with 180mm of eastwards motion.

If we now combine the west motion of DYNC with the east motion of GSIG we get a total rifting of 365mm in 8 days. That is an average of 45mm per day, or the equivalent motion of 14 years of normal Icelandic rifting done in only 8 days.

These two stations are though a bit distant from the rifting fissure, so the rifting is obviously larger than that. Most likely the rifting right on top of the dyke is in the order of a meter or more. This means that more than 0.8 cubic kilometers of magma has intruded.

Now, even that number is on the low side since the “lips” of the rifting fissure are still closed. As the lips open the total rifting will most likely be closer to ten or twenty meters if it occurred now. And the longer the intrusion continues before onset of eruption the larger the fissure opening will be.

Other signs

Except for this there are so far no other signs of volcanic activity. There is no gas measurements (if they are taken) indicating an eruption being close, neither are there gas or particles in the glacial run off indicating melting ice from an eruption.

Now, let us move on and talk about what type of an eruption will be most likely at this juncture in time. Remember that this might change as things evolve further.

  1. The seismic activity decreases and the intrusion lose momentum and no eruption happens at this time. For every day this scenario becomes less likely. In the beginning most scientists stated that it was fifty/fifty that an eruption would happen. The chance of it not happening is now probably below ten percent chance.
  2. A small sized eruption at Bárðarbunga central volcano. This is now a very unlikely scenario since the pressure is decreasing inside the caldera.
  3. A large phreatic event in the caldera due to magma chamber collapse. This is an increasing risk as the roof of the magma chamber is currently lowering causing those large earthquakes noted in the caldera.
  4. A small scale fissure eruption like the 1996 Gjálp. The risk for this has significantly decreased as things have moved on.
  5. A medium sized prolonged rift episode like the Krafla Fires. This is currently the most likely scenario.
  6. A large rifting fissure eruption. As time goes by the risk for this increases, currently I think the risk is around 10 percent. So, I guess it is time we start talking about this in the open and what it might entail. I once again recommend reading my series about the Skaftár Fires.

Rifting fissure eruption

Dyngjujökull. Photograph by Eggert Norddahl. Used by explicit permission. If you wish to use the image contact Volcanocafé via our email.

Dyngjujökull. Photograph by Eggert Norddahl. Used by explicit permission. If you wish to use the image contact Volcanocafé via our email.

Let me be clear about what this is, it is about as large as an eruption is likely to be in this geological era. Only full scale trap formations and supereruptions are larger.

But let me start with why I think this is an option. Foremost the length of the fissure, at 40km it is definitely long enough to be able to sustain a large eruption. The fissure is also showing signs of having opened up down to the mantle at places, and that would mean that it is possible for rapid decompression melt to occur, and that is a necessity for a large rifting fissure eruption to access large enough quantities of magma.

The most surprising sign though is that this rifting fissure is not following a single fissure swarm. This is totally unsuspected behavior that nobody has even guessed at in their most feverish fantasies. The initial intrusion charged straight out of the Bárðarbunga fissure swam, passed barren land in between fissure swarms and connected with the Grimsvötn northern fissure swarm, followed that downstream and then once again changed trajectory and entered the fissure swarm of Askja.

This means that potentially the intrusion might be feeding on the 3 largest Icelandic volcanoes if the fissure evolves a bit more. If this actually happens all bets are off and we would be most likely talking about a rifting fissure eruption with explosive components.

If the intrusion continues to move forward in this direction it will enter the caldera of Askja in 4 days. Problem here is that Askja is known to have pockets of rhyolitic explosive magma, and if those pockets suddenly reheat from the new hot magma things could get interesting fast.

Commenter Irpsit has pointed out that the area seems to be more prone to form single stage eruption volcanic shields instead of rifting fissure eruptions. I think this has great merit on what we are seeing, and that it is the single most likely thing. It is though not necessarily a better option since it would entail years and many cubic kilometers of highly gas rich magma coming forth at rapid pace.

Above I have touched on the worst case scenario. If that happens we will face temperature changes, ash and voluminous gas clouds. But one thing is certain, it would not in any way threaten life on earth, it would not even put a big hindrance on your daily life. Get real, the world will not end like this. But, expect a bit of nuisance.

CARL

Prequel to the Skaftár Fires series – https://volcanocafe.wordpress.com/2013/05/29/central-volcanoes-of-vatnajokull/

Part one of the Skaftár Fires series – https://volcanocafe.wordpress.com/2013/06/05/laki-deconstructed-anatomy-of-an-eruption/

Part two of the Skaftár Fires series – https://volcanocafe.wordpress.com/2013/06/10/laki-deconstructed-grimsvotn-and-beyond/

Part three of the Skaftár Fires series – https://volcanocafe.wordpress.com/2013/07/31/laki-deconstructed-a-timeline-for-destruction/

Volcanocafé business

I post this here so that this will not disappear in the general hubbub of comments. There will be emails coming soon to Bruce Stout, Diana Barnes, Evan Chugg, Graniya & Renato Rio. So please check the mail-boxes you have registered here.

 

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836 thoughts on “Bárðarbunga – Nature of the beast

  1. Fron RUV
    According to Gunnar B. Gudmundsson, earth scientist with jarðvárdeild IMO, the magma intrusion has already entered Askja’s fissure swarm so there’s little reason to think it will go anyway other than along this dyke all the way to Askja.

    Not sure accurate but might indicate whats happening

    • That may be because there were four smaller ‘quakes in less than two minutes at around that time – the drumplot may be ‘reading’ them as one?

  2. Thank´s Carl for your hardwork – and it shut my mouth. – This time I agree your thought.. so I got not much to say – but Irpsit may also be right..esp.with Hekla.
    We wait what´s coming.Norway need dust..
    Cafê.

    • We are finally starting to get sensible quantities of rain again in South England. So any rain will hopefully soon wash out here.

  3. True!
    Tremor rising up at fastest ratio!!

    Dyn station of course, but Askja is even at higher vibration!!!!

    Watch out for next hours!!!!!!!

    I believe this one will make it’s way out…

    Stay tuned and refresh every minute :)))))))

  4. Answering a few common questions that have popped up.

    1. Earthquake activity is cyclical. It will grow stronger and it will weaken. That’s just how these things work. Don’t expect an eruption as a result of seeing stronger earthquakes, and don’t expect a stall from seeing lower earthquakes. Before an eruption (in the fissure area) we’ll need to first see much more shallow earthquakes at a 99% quality. The shallowest I’ve seen was 1-2 quakes at a depth of around 5-6 kilometers. Right now, most of the quakes are still very deep ranging from 8-14 kilometers in the crust.

    2. Nobody knows what type of eruption will occur, but this area *has* seen mid sized fissure eruptions in the area between Askja and Bardarbunga. This isn’t predictive of what will happen here, but it does give us at least one option for what *might* happen. Currently, I would say this is the most likely scenario, but that doesn’t mean it’s incredibly likely (there are too many scenarios to choose from). So asking Carl or other people where the intrusions are likely to go is a guessing game at best. I would follow the IMO met office for information of this nature.

    3. If the mantle is involved in an eruption here, the amount of magma intruded into the swarm means zilch in terms of how large the eruption will be. Want an example of why the dike size isn’t indicative of eruption size? Just look towards Laki – Laki’s fissure was about 27 kilometers long according to most sources. Our current fissure swarm is around 35 kilometers long – already longer than Laki. if we were modeling the Laki swarm pre-eruption in the same manner as we are modeling this intrusion, we would conclude that it would be a pretty small eruption. Clearly, given the 14 cubic kilometers of magma that were erupted from Laki, that’s not the case – all because the mantle became the driving force of magma generation once the eruption started.

    So in other words, the mantle is a wildcard here, and we have no clue whether or not it will play large role in this potential eruption. If it does, expect this eruption to be big, if it doesn’t I would expect something much more benign. We just don’t know whether it will play a factor at all. We do however know that this area has had rift eruptions before that didn’t include the mantle wedge, so there is a good chance we just get a standard fissure eruption as we’ve seen in the 1800’s in this area. On the other hand, there are some extremely large lava fields and shield volcanoes that seem to indicate that you can get huge eruptions from this area, so all bets are off.

    4. This swarm is heading directly for Askja. Right now, there are no signs or reasons as to why it would change course, but magmatic pressure from the Askja system pushing back may slow the pace (as it likely already has done). When this swarm reaches Askja, nobody knows what will happen there. There is a chance it could go straight through the system and keep continuing north. It may hit the volcanic system and trigger an eruption. It may hit the system and do nothing but heat up old magma pockets for a while.

    As Henrik has mentioned, it’s unlikely we’ll see an enormous eruption from Askja by itself. Askja is explosive, and we definitely could see some big eruptions coming once the new magma reheats older pockets in the Askja area. But Askja had a VEI-5 caldera eruption just over 100 years ago, so it’s not likely that we would see an eruption larger than that with only just over 100 years in between as repose time.

    • thanks for writing things down. Food for though. So the 0.27 km3 of magma that got in the fissure (from IMO) does not really mean anything – if we compare to the Laki events of course….

      • It does and it doesnt. If the mantle doesn’t get involved, then that is likely all the magma available for an eruption. If the mantle DOES get involved, then yes, it’s useless. Once again, please read through Carl’s article series on the Skaftar fires – everything is explained there in depth :).

        https://volcanocafe.wordpress.com/2013/05/29/central-volcanoes-of-vatnajokull/
        https://volcanocafe.wordpress.com/2013/06/05/laki-deconstructed-anatomy-of-an-eruption/
        https://volcanocafe.wordpress.com/2013/06/10/laki-deconstructed-grimsvotn-and-beyond/
        https://volcanocafe.wordpress.com/2013/07/31/laki-deconstructed-a-timeline-for-destruction/

        Right now, I would say it’s less likely we’ll see the mantle get involved here, but that’s still a big unknown.

        • I am wondering how long it takes magma to freeze in the dykes that opened the south east of the caldera a week ago. These are silent now. I do wonder if it is possible for the caldera to be still feeding magma to generate seismicity 40km away?? My view is that the source has now switched towards the mantle.

          • Good question. It must depend on the thickness of the dyke. Lava tubes near the surfaces can take a couple of days to seize up after the inflow has stopped. It should take rather longer this far down. Large injections of magma, if they stay deep below and don’t erupt. can take centuries to cool. I doubt it has seized up already.

          • Magma traveled over 80 kilometers from Krafla’s central volcano down dikes during the 70’s and 80’s. I don’t think we’re getting much if any decompression melt from the mantle right now. Magma can travel very far from central volcanoes in situations like these.

            As for why the dike opening south east of the caldera – it’s silent because it’s already open. Once the rock in the area was wedged open, the magma can flow through it smoothly without making much noise. Either that, or there is just too much pressure for the magma to break through, so nothing happens and it found another way to migrate outward from a central location.

            • i was thinking: 1 m wide, velocity 1m per min ( ca 3km per day) , distance to go 30-40km. rate og ehat loos to country rock, narrowing of that 1 m width with solififed magma.
              What sort of pressure drop is needed? – hydraulic flow between plates, anyone?

    • Food for thought indeed. As I understand it is also a real possibility of no eruption at all but the swarm staying at depth going north along the fissures it encounters and then cooling off/stalling.

    • Nice post! Even if I find this very exiting to follow I belive very few of us want to see a large eruption. The dragons write info that in my eyes seems balanced. That’s what we need. Tx vm.

    • Regarding Laki:
      The erupting fissure was about 25 kilometers long but as the lava that came up in Laki was the same type as in Grimsvötn. It indicates that the intrusion / dyke was about 70 km long from the magma chamber under Grimsvotn to the eruption at Laki.
      (http://vulkan.blog.is/blog/vulkan/)

      • There are some similarities between the magma, but the thought that most of the magma came right from Grimsvotn has been mostly proven false. The dyke was likely 70km that initially came from Grimsvotn (similar to the current situation with Bardarbunga) but the majority of the magma came purely from the mantle. Carl did some of his own sampling I believe on this, he would be a much better person to ask about this, I’m just repeating what he has mentioned in the past about this.

        • I am definately no specialist what so ever 🙂
          I was quoting Haraldur Sigurðsson volcanologist regarding the length of the dyke.
          The length of the dyke would have been similar (about 70km) when magma from Bárðarbunga travelled underground to erupt in Veiðivötn 1480 and when magma from Bárðarbunga travelled to Vatnaöldur to erupt 870.

      • We did not find a single sample that contained evolved magmas.
        If there was any it was blasted away as ash and landed somewhere else.

        • Thank you Carl.
          Do you mean you did not discover any magma related to Bárðarbunga in Laki?
          Would that mean somone just assumed Laki was originated from Grimsvotn without any hard evidence?

          • Laki is definitely a Grimsvötn feature. All volcanoes on the Grimsvötn southern fissure swarms erupted during the Skaftár Fires.
            What I meant is that we did not find any evolved lavas indicating that it would be coming out of Grimsvötns magma reservoir. But, that does not prove that it did not start with a propagating intrusion down the fissure swarm. It just means that the large majority of the lavas came from the mantle.
            We calculated the bulk volume of magma deposited in the crust and the erupted lava to be in the region of 150 cubic kilometers, and that is way more than could be sustained by a central volcano magma reservoir on Iceland.

  5. The Dike: At 11am Uk time was 35km long, might be 40 by now.

    Also had 300milion cubic meter of magma….might be 350 right now….
    As it gets longer the episode, more momentum.
    Let s keep updating screens….

  6. Disclaimer – I know nothing, I’m a noob

    But I want to play the theory game and enjoy the process of throwing ideas around and see what I learn from the answers.

    I am going to make a hypothesis that this all began with some larger than usual movements of the MAR which results in stretching of the crust and opening up some cracks which the magma from Bard or mantle has taken the opportunity to pop into and fill up. I don’t imagine this is magma from Bard alone as I just have a gut feeling that this event has now become to “voluminous” and consistent in it’s progression to be purely from that Bard source alone. The progression of the swarm is fueled by these two sources of magma, and further facilitated by the additional stretching of the MAR.

    Therefore I would view this as opportunistic in nature, and not necessarily one that would result in short term eruption.

    However I understand that the game changer could be a mixing of the new magma and old evolved magma in the Askja system which could result in more explosive activity. It is the effect of shock waves from this that I feel could be the catalyst for a greater eruption, jarring open the dyke and allowing it to fissure giving the kind of release of pressure that would stimulate decompression melt in the mantle.

    Lets see what I learn from you all pulling that apart 🙂

    • I’m an old headbanger and into far, far heavier music, but laziness and beer made me stay at the Zippo Encore stage at the 2013 Download Festival to watch Europe.

      They were absolutely brilliant.

      However, in light of what the Gods may have in store for us in the not-too-distant future, I should like to offer the following (very apt) song by the band who preceded Europe that day:

  7. I put this up over at Jon’s and wanted to put it here for people to consider or comment on as well. Re-post situation in Bardarbunga:

    ==================
    Keep in mind that extension can cause it [magma and structure] to drop too, I’m not entirely satisfied with the explanation of the quakes there, as it doesn’t have to be less magma. Look at DYNC’s WSW and GSIG’s ESE. That could make the crater open [in the] E-W a bit.

    And where did the 5.3 and 5.0 quakes occur? Only on the W and ESE sides. In which case, not slumping but a bit of undermining [via distortion of shape].
    ==================

    As far as I can see this interpretation of events is not at all inconsistent with what VONC or HAFS are doing either, in fact it looks like the better explanation.

  8. I had a thought…. What (if any) is the relative buoyancy of the intruded magma compared to the solid rock it’s traveling through, and how much difference would it make if it were evolved magma from bardarbunga’s chamber vs a brand new injection of basalt from below?

    The reason I’m speculating is because I think it might have an influence on whether it opens a crack down to the mantle (as it would stay lower in the crust), or if it would stay higher in the crust, as I gather happened during Krafla…

    • I am not an expert, but I think evolved magma would not travel so relatively fast, should be more sticky. What do the others think about that?

      • This is a complicated one, because evolved magma is more silica-rich, with the denser minerals having fractionated out. A non-porous rhyolite therefore is more buoyant than a solid basalt. However, exsolved gases make a huge difference as well, but in basalts they bubbles can often escape out of the magma (when there’s somewhere for them to go to) because of the relatively low viscosity. In derived magmas, the gas bubbles are trapped within the magma, which is what leads to the rapid acceleration of buoyant magmas in andesitic and rhyolitic eruptions. If they get too highly silicic, though, the extreme viscosity makes the magma effectively solid.

        Basically, the evolved magmas are more buoyant, but the basalts are more mobile. Both are of course more buoyant than solid basaltic crust. I think that’s right, but it’s been a while since I studied igneous petrogenesis in any detail…

    • Question is how evolved this magma really is.
      Remember that it all started as Bárdarbunga got a hot new fresh batch of magma injected into the magma reservoir. I would say it is a mixture of magmas.
      Anyway, hot magma is always more buoyant compared to the surrounding rock due to the heat. The heat inflates the magma giving it lower specific weight.

  9. Hi Everyone, Thank You all so much for contributing to such an amazing Blog, especially Carl and the Dragons.

    My wife and I are lucky enough to be heading to Iceland the middle of next month, so I’ve been lurking here since the seismic activity began, it sounds like we could be in for a real Geological treat when we arrive, I can’t wait.

    I’ve been slowly working through the wealth of information you have created here over the last few years, while at the same time trying to keep up with all the new posts, needless to say I haven’t had a great deal of sleep but I’ve thoroughly enjoyed absorbing all of your theories while at the same time attempting to understand some of the basics of the science behind this whole event.

    I had a couple of queries I hoped some of you could help me with.

    1: Am I correct in thinking that the existing fissures from Askja are currently solidified, and if so what is the process when the fresh magma from Bárdarbunga reaches the existing fissures. Does the Magma contain enough energy to melt the solidified magma, or will the fresh magma from Bárdarbunga exploit weaknesses in the rock created by the Askja fussure formation and travel along those instead or is it somehow a mixture of the two.

    2: I haven’t seen any mention so far of the water table above the fissures at present, after reading “Lakí deconstructed – Anatomy of an Eruption” written by Carl last year (written very well I might add) it seems that ground water can have a role in some of these events, but I’ve yet to see any mention of the water table between Bárdarbunga and Askja.

    Does anyone know what sort of depth the water table reaches in this area, and if the Magma reaches that water table is that interaction something that could be singled out from the tremor graphs and/or seismic charts, or would the signals be too similar to Magma breaking rock to be able to differentiate between the two.

    Apologies for the rather long winded first post, and many thanks again to all who have contributed to The Volcano Café.

    • Don’t know about the deeper water table, but there is the river Jökulsá á Fjöllum to consider. It has its main sources in the Dyngjujökull (glacier) area.

    • You have a river, but otherwise the area is a desert. It is actually the place where NASA did a lot of its testing before the moon landing since it was so dry and the environment so inhospitable.

      • In Iceland, this does not mean that there is not an elevated groundwater table below, the lavas and tephras on the surface being highly porous.

        There is groundwater filling Öskjuvatn and Víti, and Thor Thordarson mentions phreatic and phreatomagmatic explosions during the 1875 volcano-tectonic episode.

        • Absolutely correct. I should have said that I do not know the depth of the water table and just shut up after that 🙂

          • Thanks for the responses Carl and IngeB, I was just curious if anything was known about the groundwater table in the region. The bottom of the water table can often be quite deep within the earth, you can even find the odd river kilometers below the earths surface.

            I was just curious if the water table often plays a role in these events, I would expect that the presence of water at depth would make it a lot easier for any magma to breach the surface.

  10. Hey! I just wanted to say thanks to Francis with on the tips with the drum plots. Is it really dark in Iceland already (still light as day, though rainy,here in Norway…but webcam suggest darkness or not working over there). Excited to see some answers to theories here!

    • Hi Philo (rest too long) 😉 I am glad something I suggested is of some use to someone as I don’t know a lot from not often having enough time to read up on things.
      Not sure which cam you are looking at but the one one this site

      http://baering.github.io/

      looks fine. There is one with three views that appears to be not working again today and just stuck on last night. The above site is also good for fast updates on quakes but of course they aren’t fully checked until later on the IMO site.

  11. Here’s a layman question. What does the quality of the earthquakes mean?

    Very glad I found this site. I follow you guys every day since the activity started at Bárðarbunga.

    Keep up the good work!

    • Basically, how certain the magnitude and location are. As they’re checked manually, they go to 99%, and anything below that is not all that trustworthy. That’s why the automated map plotting shows a huge scatter compared with the maps of the confirmed quakes, which show a nice linear fault. :o)

    • The 99% quality is best, because only these have been manually checked very thoroughly (esp. re. the depth), others are depending on percentage of checking rather prone to be errors and or even to be “ghosts” (= forget them).

      On the other hand, with all these thousands of quakes at the moment, errors are always possible.

    • lakeshadow – I believe IMO (Icelandic Met Office) gives a good visual explanation of the importance of earthquake quality on the following site where you can watch the seismic activity around Bardarbunga.

      The first image shows corrected (manually processed) earthquakes since midnight (only 99% quality and above)

      The second image shows all automatically recorded earthquqkes since midnight (all earthquakes – which of many might not even be earthquakes) As you can see this gives not nearly as clear view of what is going on as the first image.

      The third image shows corrected (manually processed) earthquqkes since 16th of August.

      DragonEdit: Link removed. Please follow our new blog rule not to link to vedur.is to avoid problems there. Better save and post images. #Granyia

  12. Just off the press:

    Right call to issue eruption alert

    kl 15:54, 25. ágúst 2014

    “… Right now we’re analyzing what was going on. As of now we don’t know, but we’ll keep analyzing and add it to the data pool,” says Sigrún Karlsdóttir, director of the Nature Watch at the Icelandic Meteorological Office … “It was the right decision at the time. In prior eruptions these signs have indicated that an eruption had started. We thought it right to react immediately,” … “That means that now is the greatest chance of an eruption, as the cavern makes its way through the crust underneath the sands north of the Dyngjujökull glacier and south of Askja,” Haraldur writes. …”

    http://www.visir.is/right-call-to-issue-eruption-alert/article/2014140829335

    • Would I be correct in thinking that the gravity loading of ASkja’s erupted mass will deter the activity form entering fissures there? So the tip of the activity will tend to steer around Askja, or erupt?

  13. M 4.6
    Region ICELAND
    Date time 2014-08-25 16:19:07.6 UTC
    Location 64.54 N ; 17.09 W
    Depth 10 km
    Distances 237 km E of Reykjavík, Iceland / pop: 113,906 / local time: 16:19:07.6 2014-08-25
    136 km S of Akureyri / pop: 16,563 / local time: 16:19:00.0 2014-08-25
    96 km W of Höfn, Iceland / pop: 1,695 / local time: 16:19:07.6 2014-08-25

  14. Question please. There seems to be a cloud of small EQ to some distance either side and forward of the main fissure. What would be the mechanism behind them that has an effect over such a large area?

  15. Anyone see Frodo and Sam in the web cam’s yet? Hope they make it before it blows or they’re spotted by a Nazgul.

  16. USGS is calling it a 5.0 at 8 km. do you know if they are typically more or less off from final manually verified intensity and depth?
    5.0
    128km NNE of Vik, Iceland
    2014-08-25 09:19:04 UTC-07:00
    8.0 km

    • If it is a normal fault it should be…. Beachballs required but interesting nonetheless.

      Given the size of the quake and its location, surprised it did not show up stronger at ASK. Thoughts on this? I know seismic waves do not flow through liquid so, if the dyke is between the ASK station and the quake, and the solidity of its contents are liquid or some kind of mush, might this account for the attenuation in the quake signature?

      Can anyone plot the exact location of the quake, the location of ASK and the current dyke intrusion? This might be interesting….

  17. Revised to M5.1 now…
    Blody big one actually. I was better off at my first attempt at calculating. I should not second guess myself.

  18. In regards of the caldera opening up a bit and letting water down.
    Remember that water expands 900 times. So, 1 million cubic meters of water would instantly change into 900 million cubic meters of steam. Now, the amount of water below the ice is a bit more than that. Well, you get the picture.

      • Well I’m just waking up here so I’m slow to take things in – needed this second look so thank you for that. 🙂 By the way, the dragons are going to spank you for posting an en.vedur.is link! No, absolutely none, nada, nil en.vedur.is links allowed! Info yes but NOT the link. And trust me, it’s best not to annoy dragons!

  19. Well. Let’s just hope the caldera doesn’t collapse completely, although I’m sure the chances of that is low. I think.

  20. Even with the corrected quake list there’s a lot more scatter all around the fissure in the last 2 hours.

  21. ust noticed the earlier 4.5 has been updated to 5.3

    Sunday
    24.08.2014 20:39:11 64.627 -17.360 2.9 km 5.3 99.0 8.1 km E of Bárðarbunga

  22. One other thing, Will any other volcanoes behaviour change because of what is happening at the moment in terms of where the fissure is growing?

  23. Also wonder if we can expect a phreatic explosion in the vicinity of Askja in the near future… maybe it already was commented, but to be honest – I haven’t read all the comments! 🙂

  24. Does the Bardarbunga caldera show on any webcam? If it would like the water heater did I would like to see it. I don’t do much else, lying here in my sickbed. (Nothing really serious, just a little cold.)

      • Thanks Carl. It´s a bit disorientating with the cams, I would like to have a pic with arrows pointing out the scenery, you know , the way they have at scenic view. When the eruption gets going I don´t think I need anymore though. 🙂

  25. Dragons:

    I think you should look into some kind of “mass E-mail notification”-system for whenever things really gets going….

    Basically potential subscribers could get an e-mail whenever its “20 minutes to go” (I know it isn’t “that simple, but still…) 😉

    I’d happily contribute a small sum of money to keep the site happy and prospering if such a “subscription option” was available….

    • I would happily add something like that. But it is not that simple really.
      We are going to move to our own server, but not untill all of this has calmed down.

      And if you seriously wish to contribute… hold on to your bucks for a little longer, there is a project in the making that I think people will wish to contribute too. Just wait a day or so. 😉

        • Of course…

          Nah, it is a bit more ambitious than that, and it will be about a very real and very interesting volcano. It is an ambitious project to say the least. It will raise the bar for volcano-sites quite a few notches.

    • I need to ask another dim question. If the caldera roof partially collapses and there is a smaller boom will this be enough to blow the lid completely and then ba ba boom?

  26. The ring atouts the caldeira is a “weakness” and the pressure/tension there is high. I’m not surprised to see some good quakes there, but doubt this already indicates we’re heading towards an imminent collapse or something.

  27. That is in 35 hours. I give it 2 days at this rate max

    Monday
    25.08.2014 16:19:03 64.612 -17.472 2.0 km 5.1 99.0 4.1 km SE of Bárðarbunga
    Sunday
    24.08.2014 20:39:11 64.627 -17.360 2.9 km 5.3 99.0 8.1 km E of Bárðarbunga
    Sunday
    24.08.2014 15:00:11 64.615 -17.442 4.6 km 4.8 99.0 5.0 km SE of Bárðarbunga
    Sunday
    24.08.2014 05:33:41 64.616 -17.450 6.0 km 5.1 99.0 4.6 km SE of Bárðarbunga

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