Posted on by Jón Frímann

Increased risk of eruption in Tungafellsjökull volcano

There is now an increased risk of eruption in Tungafellsjökull volcano (this is my opinion only). This volcano is different than Bárðarbunga volcano and is not connected to it on crustal levels (46 km top layer of the Earth crust in this area).

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Tungnafellsjökull volcano is to left of Bárðarbunga volcano on this image. Copyright of this image belongs to Icelandic Met Office.

There has never been any historical eruption in Tungnafellsjökull volcano far as I know. So I have no data to work with in terms of analysing historical behaviour of this volcano. There is a stress factor at work here from Bárðarbunga volcano, this means that all the activity and drop of the Bárðarbunga volcano is changing the stress in nearby crust, this is the idea for the moment about how activity in Tungnafellsjökull volcano started. There is an increased risk of magma rising from depth into Tungnafellsjökull volcano from all of this. I don’t know why that appears to be the case (based on the data that I got), since magma coming into Tungnafellsjökull volcano is from its own deep root system that is connected to Tungnafellsjökull volcano. Even if magma is entering Tungnafellsjökull volcano it does not mean an eruption is imminent. The risk of an eruption in Tungnafellsjökull volcano is increasing at the moment, it might get lowered again soon, but this is the current status. Tungnafellsjökull volcano continues to have Green status on Icelandic Met Office website.

If anything more happens in Tungnafellsjökull volcano I am going update this article or post a new one.

38 Replies to “Increased risk of eruption in Tungafellsjökull volcano”

  2. A very interesting development, have there been any similar swarms in Tungnafellsjökull for other rifting events or previous eruptions in the area such as Grímsvötn etc?

  3. Can you really rule out that there is a dike connection between Bardarbunga and Tungnafellsjökull? Seems more than a coincidence that as soon as the earthquake activity in Holoraun dies out it picks up at Tungnafellsjökull

    1. Geologist Freysteinn Sigmundsson said in an interview with RÚV today, that there were no direct connection between Tungnafellsjökull volcano and Bárðarbunga. He doesn’t think that there will be an eruption in Tungnafellsjökull. There are no movments in the crust over Tungnafellsjökull which would indicate something like that.
      http://ruv.is/frett/mikil-skjalftavirkni-i-tungnafellsjokli
      He thinks it is just an influence of Bárðarbunga like Jón said.

  4. The pathway for an eruption at Bardarbunga has become a lot more open and this would more than likely happen before a long dormant system such as Tunga could even get going.The increase gas emission from the fissure ,even with the decline in lava output is one of those counter intutitive signs that would cause concern,the same with the increasing unrest at BB even though the fissure was supposedly reducing the pressure in the system.

  5. If MAR and subplate rifting takes place (right between BB and Tunga), there might develop also space for deep magma to find a way (dykewise) up in both volcanos.
    If I look at the data from GPS it seems a giant slab of land is turning like a big ‘screw’ in a hole with width >100 km, which might also explain the ‘strange’ behaviour of 3 GPS stations around BB. This puts stress on both BB and Tunga as well and also might explain the current eruption at Holuhraun and the unrest (dykeforming? rifting?) in the N of Askja.

      1. I like your suggestions!

        See my comment below, it has a lot to do with what ou wrote.

        I think due to these GPS movements, rifting pulling tensions occurs at Tungnafellsjokull, and also Thordarhyma-Laki-Edlgjá and Oraefajokull. Rifting eruption becomes more likely at these spots.

        Conservely, it squeezes Grimsvotn, Hamarinn and Kverfjoll, to some degree.

  6. Though it does not show now on the quake maps, earlier in the eruption, shortly after the dike going northeast from Bárðarbunga toward the current eruption began to form, there was the appearance of a similar event going to the northwest toward Tungnafellsjökull. That quieted down and we didn’t hear more of it until very recently. As I recall, it began with quakes extending toward Tungnafellsjökull at about 4.5 to 5.5 km depth from under the Bárðarbunga caldera area. Then the quakes in the area between Bárðarbunga and Tungnafellsjökull seemed to stop and the activity under Tungnafellsjökull became different. It seemed to evolve into a column of seismic activity extending to great depth. It would give the appearance that somehow magma from Bárðarbunga infiltrated the magma system of Tungnafellsjökull and somehow has reactivated that system but that is speculation on my part as there is no way to know for sure what is actually happening down there. That is simply the way it seems to be behaving.

  7. And by “Though it does not show now on the quake maps” I mean it does not show on the RECENT quake maps. It would indeed show on maps going back to the formation of the dike.

  8. There seems to be no dyke connection. As we can observe here probably a hot spot activity, the rising magma seems to have reached the neighbour of Bardarbunga. Would be interesting to see 3D visualisation of the Tungnafellsjoekull earthquakes. A new magma chamber might show up.

      1. The author/s btw. registered magma movements in the volcano as far back as in 2009, movements, which lead to the formation of new fractures, fissures and sinkholes in the region.

        But if this does make an eruption in this rather sleepy volcano more probable – I don’t know.

  9. Stefan, there is a 3D representation here but it goes back only 48 hours. The representation shown a but over a month ago showed a clear link from the column of quakes under the Bárðarbunga caldera to the column that now appears under Tungnafellsjökull volcano. The quakes started from Bárðarbunga at around 5km depth and were migrating in a fairly straight line toward Tungnafellsjökull volcano. Then activity started in a column under Tungnafellsjökull and the activity between the two systems seemed to stop.

  10. As has been mentioned earlier, is there a dike connection between Bardarbunga and Tungnafellsjökull or was there one at some stage?.
    Does anyone know which is the oldest volcano either Bardarbunga or Tungnafellsjökull if
    Tungnafellsjökull is older than Bardabunga. then Barda could be the child of Tungnafellsjökull and there could be a relationship how the magma is feeding them.

  11. What is happening now is that magma is breaking the crust and pushing its way upward trough the crust. If an eruption happens it might not be a big one if this is just small amount of magma. The earthquake activity also appears to be increasing at the moment, at least that is how it looks like at the moment.

      1. Bardarbunga Tyler .I somehow do not think this involves a small amount of magma,the influences are too large.The question becomes how much is eruptible?

  12. I am skeptical of a no-connection between Bardarnbunga and Tungnafellsjokull.

    First there is a connection, at least tectonic wise. Rifting is occuring, induced probably by a magmatic pulse of the hotspot. As rifting develops, many volcanoes in the region respond to the movements, and at Tungnafellsjokull rifting IS occuring. I have been saying this. GPS of many stations there move west, but Vonarskard moves east. So the Tungnafellsjokull caldera gets a pulling/opening/ rifting tension.

    Second there might be a radial dike extending into Tungnafellsjokull. We already saw this at the start of the Bardarbunga events. Yes, tectonics drives the process, but between the void and the BB caldera, magma flows radially. We know of radial dikes in many calderas. Why not Bardarbunga?

    Yes, Bardarbunga is rewritting geology books. Magma leaves the system, goes into two rifting/dikes, flows into Grimsvotn system, nearly flows into Kverfjoll system, and then gets inside Askja fissure swarm. And as this occurs, tectonic stress reactivates swarms at Herdubreid. Its influence is massive, and we know from the past of the Bardarbunga-Torfajokull connection, and that is 100km apart. Why not between Bardarbunga and Tungnafellskokull? Refusing vehemently thi, in face of fresh evidence, is simply being attached to old school geology.

    Gjálp was already a heads up. Bardarbunga-Grimsvotn connection. Even if indirect.

    And yes, at depth there is a continuum between Hofsjokull and Bardarbunga, since this is the past track of the plume (yes, Hofsjokull and Tungnafellsjokull are the older plume center brothers of Bardarbunga, while Grimsvotn and Oraefajokull are the teen and child brothers for the new plume center), and also it has been shown in a study that the plume, as it reaches surface, has a trifurcation southwest, north and westnorthwest.

    I am going to be more bold and getting into a fringe speculation and suggest that perhaps one day we might see the Bardarbunga line of earthquakes (radial dike) reaching towards Oraefajokull. And I think one day a dike from Grimsvotn might reach Edlgjá. These are just my bold speculations but I have had others in the past and I was correct. One example was the connection Bardarbunga-Tungnagellsjokull as is between this event and many nearby Vatnajokull volcanoes.

    Third, there are indirect connections in Iceland that reach far and widely. They are tectonics, not magmatic, but behave in same principle, except that magma does not travel from X to Y, at least as far as I think. One example, 6 months after Laki, large quakes happened in SISZ, and just a few years later, Hengill had a rifting non-eruptive episode.

    Let’s be open people. I am not saying to embrance new theories without a deep examination and data, but I think this event is a great opportunity to rethink our knowledge of volcanism in Iceland. Also a good idea to just for a moment forget about all the established concepts of this central volcano and that central volcano, this is volcano region X and that is Y. No, this is all a mess, magma and tectonics transcend the volcanoes boundaries. Let’s start to see the events and see the big picture. And for that, let’sforget of old definitions for a while. They just make it difficult for our brain to see the 21st century new geology concepts unfolding in front of us.

    I never thought I could see a rifting event like this (only read it in history books), of Bardarbunga northwards. Then we have the possibility of rifting going southwest, but I never considered the possibility of the connection going northwest. And we had the Gjálp connection towards southeast.

    Let’s be aware that Tungnafellsjokull has CONFIRMED eruption in Holocene. There is a lava flow from a vent northeast of its caldera. It is Holocene. Then, the fissure swarm includes also Pleistocene eruptions towards southwest (Skrokkalda, Hagongur). I remember some months ago, a deep swarm (intrusion) NE of Tungnafellsjokull. I still call to the suggestion that rifting might progressed there and erupt there. It would be a similar situation to the deep swarm at Dyngjujokull earlier this summer (before 16th August)

    So far we had 3 rifting events. One has erupted, (Holuhraun), one has not (Kistufell) and one has just started (Tungnafellsjokull). Let’s keep an eye also in Herdubreid further north, Kverfjoll, Hamarinn and Veidivotn fissure and other volcanoes in the south part of Vatnajokull (Thordarhyma, Oraefajokull, Esjufjoll).

    1. The problem is a lot of commentators cannot get the Barda activity in context,over hyping the fissure at the expense of the caldera,transferring the focus to Tunga is dropping the ball!

      2. Well, I agree with you that the caldera is the keypoint, where events started in 16th August.

        But before that, we had deep unusual swarms at Kistufell and Dyngjujokull and even Tunganefllsjokull and Kverfjoll. Surely widescale tectonics was involved in triggering this, and before that magmatic plume pulse.

        But what’s your take on things?

      3. Yes larger forces are behind this as with any volcanic activity in a place like Iceland,but this event had its genesis probably decades ago.It maybe that a recent rifting episode allowed the intrusion of magma from depth to trigger an already semi primed system into unrest.This unrest is causing a ripple effect as Bardarbunga is a very large system,this may trigger eruptions in the future from nearby systems.The problem is are these other systems in an eruptible state at this point in time,it is hard enough to predict if the caldera will have major eruption.

      4. “dropping the ball”because a large multi faceted event at Bardarbunga “possibly” could be reaching culmination and the focus should be on this event.A large scale eruption at the caldera could have overlapping and cascading consequences and already has with the air pollution.

      1. And yeah, like someone here said, when events started in 16th August there were 3 dikes (or lines of earthquakes) we forgot, and we even ignored!

        One towards Tungnafellsjokull (radial dike?)
        Another towards Grimsvotn, caldera SE edge cauldron (radial dike)
        And yet another towards Hamarinn (SW rifting)

      2. Maybe toughts are like sheep and water, head to the least resistance hmm 🙂 but i like your toughts guys, keep up the good work, and thank you Jón for this great website, honest and open for everybody without egoist rules or ambitions!

  13. I totally agree with Irpsit. Bardarbunga is rewritting geology books, and we’ve to forget the established concepts for one moment (or two). Geology is Evolution.

  15. More about the Red Cross in Iceland:

    “…there are strong signs that a neighboring stratovolcanic site, Bárðarbunga, will become active in the near future.”

    Conclusion? yes…something will happen.

  16. If I was a betting man I would put my money on that something is going to happen at Tungnafellsjökull , and in the very near future. That would then resolve a lot of different views that have been talked about on here.
    The Eq activity has changed it is clear to see,. I would agree that there is a lot of magma trying to get out and now I think it has found another fire exit.
    This whole event reminds me of when I worked on HTHW pipework, it is just like what is unfolding here, the only thing that the volcano has not got is a bursting disk.

  18. IngeB,
    Thank you for those informative links.
    Apparently those prior earthquakes were around the mountain area. The current swarm is different. They’re concentrated under the NE sloping flank of Tungafellsjökull, at a depth of 1.1 km and deeper (than geodesic level). This is the location of a second caldera much more recent than the historic (extinct?) southern peak.

  19. Jon, I don’t think that the possibility of a rhyolitic rocks erupting from Bardarbunga in the near future can be considered unlikely. While not the norm, bimodal vulcanism is a feature of iceland. The sources for bimodal extrusive rocks are generally from separate magma chambers or from segregated magmas in a single chamber system. The earthquake activity going on for the last couple of months have generally occured in completely spacially separated clusters. The main clusters being the linear below the dike eruption and the second circular cluster (with much stronger quakes) below the Bardarbunga caldera. The subsidence of the caldera could be related to the current episode of rifting and not magma movement. But there could be a magma chamber with differentiated felsic magma which has been stewing below Bardarbunga long before the current basaltic dike eruption got going. However the input of the new basaltic magma could be adding energy to the stewing felsic magma. Rhyolitic Torfajokull is 70 km SSW directly on rift trend with Bardarbunga

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