Magma on the move in Katla volcano

While the source of the harmonic tremor yesterday in Katla volcano is not immanently clear. It is has been concluded that magma is on the move inside Katla volcano. It has been suggested that the harmonic tremor yesterday in Katla volcano is a mixture of both hydrothermal activity and water flows under the glacier. But hydrothermal activity has increased in Katla volcano since July and seems to be continuing on that path for now.

The earthquake activity in Katla volcano has been growing since July, when a sharp harmonic tremor spike did take place and was followed by a glacier flood that did destroy the Múlakvísl river bridge. But that flood did peak at ~5 meter high.

Currently the activity is quiet in Katla volcano. But that might be because the earthquakes are not being detected by the bad weather that is currently in this area (and all over Iceland for the fact).

Here is a overview of the change in activity since Week 34.

The earthquake activity in Katla volcano during Week 34. The number is the cauldron in Katla volcano. Notice the interesting earthquake activity in SE part of Katla volcano, well outside of the caldera area. Copyright of this picture belongs to Iceland Met Office.

The earthquake activity in Katla volcano during week 35. The earthquake activity in SE part of Katla volcano continues at the same place. Copyright of this picture belongs to Iceland Met Office.

The earthquake activity in KAtla volcano during week 36 (current week, last updated today 7. September 2011). Earthquake activity in SE part of Katla volcano continues as before.Copyright of this picture belongs to Iceland Met Office.

Current activity in Katla volcano is quiet (less detection due the storm is also a factor in this). But that can change without any warning at all and at any time. But there is no reason to scaremonger what is going on in Katla volcano. It is a fact of life and cannot be changed. So the best way is to prepare if people live close to Katla volcano, or if you live far from Katla volcano the best thing is to monitor and learn from what is now happening in Katla volcano. Scare tactics do not any good and serve no purposive at all and never done so.

Icelandic news about the activity in Katla volcano. Use Google translate to understand. But be aware it is not approved by Santa.

Ekki ótvíræð merki um yfirvofandi gos
(, Icelandic)
Engin augljós skýring á óróa (, Icelandic, 6. Sept, 2011)
Flogið yfir Kötlu (, Icelandic, 6. Sept, 2011)
Kvika safnast saman undir Kötlu (Rú, Icelandic)
Fylgjast með aukinni virkni í Kötlu (Ví, Icelandic, Video in Icelandic, 6. Sept, 2011)
Jarðhiti aukist mjög mikið undir Kötlu (Ví, Icelandic, 6. Sept, 2011)

Update 1: According to news the local emergency units and police have started to review the evacuation plans and emergency plans in the case of a eruption in Katla volcano.

News about that can be read here, if you risk Google Translate.

Fara yfir áætlanir um viðbrögð (, Icelandic, 7. Sept, 2011)

Blog post updated at 00:43 UTC on 8. Sept, 2011.

71 Replies to “Magma on the move in Katla volcano”

    1. Well, I was about to put it down to elves driving cars around the summit.

      And. with that happy thought, I will take myself off to bed. Hope you have a quiet night in Iceland.

  1. He, he, Katla has really got us under the nerves today.
    I think it is time for us all to relax and let Nature proceed at her pace. 🙂

  2. How does the current level of activity compare to Grimsvotn or Lady E pre-eruption? My impression, and please correct me if I am wrong, is that it is lower.

    Unfortunately, I only know where to get the 48 hr readings that IMO publish; I do not know where to get longer term tremor readings for comparison – are these available for the general public?

    1. Yesterday there was X2.1 level of flare, and today it is X1.8.

      Many people may realize that global atmosphere is under the control of the sun, and not everybody believes that global lithosphere is also influenced by the sun.

  3. Jon. Love the blog and your regular contributors. I’m a biologist to trade, but was totally overwhelmed with the geology of Iceland when I visited last year. Thanks for all the info. Learning so much.

  4. For those of you that watch webcams, it is really of no sense to ask “is this an eruption?” when you see something unusual. I know it is exciting and fun to think that you’re seeing an eruption happening. But it will be very clearly known that there is an eruption happening before anything is able to be seen in the video stream.

    1. Well said. PLEASE let’s not have any more discussion about ‘clouds’ etc.

      If you THINK it MIGHT be an eruption, for sure it is NOT.

      If and when Katla DOES go into full eruption, you’ll know it when you see it beyond the slightest doubt!


      1. As Jon’s blog grows and gets more followers more people will ask about the webcam clouds as a first contact with this community.

        First (like me) they watch the webcams and basic quake graphics, then, when they want more knowledge, they come here. These people are not stupid, everyone is duped by the clouds. Only very intelligent people come to this blog.

        Think of beginners asking about the webcam clouds as an opportunity… they want knowledge. Otherwise, as the blog gets more popular and more and more people ask about the clouds, you will get more and more irritated and go crazy… and those people looking for knowledge will never come back.

        When someone asks about the clouds, don’t get irritated think ‘yay, wev’e got another one’.

        In fact, I’m happy to answer the cloud web cam questions… having found this blog, I now thankfully can pass that knowledge.

      2. Here is an idea for Jon – How about a Q&A page for new visitors and beginners where all these sort of questions are dealt with in a good way – you could very probably go back through the archives and simply copy and paste good answers to questions that are frequently asked or simply link to an archive post that dealt with that particular question. Any one of us could direct people there with a simple, non-judgemental comment.

      3. I have thaught the same idea:
        – “No, that is not steam/ash/smoke from Katla/Hekla/Eyjafjalla, it is clouds” (and why)
        – What you can and cannot see in tremor and how wind affects
        – Solar flares/moon/horoscopes and how they affect volcanic activity
        – Collection of links for additional information

        I have posted a few stupid questions and ideas and could have used such “most frequently asked questions” or “most stupid ideas” -section not to make complete idiot of myself 😉

    2. I’m afraid that asking questions is just natural curiosity and part of the learning process. Lady E was a bit of a wake-up call for Northern Europeans (those who do not live in Iceland). She showed up our reliance on air transport and electronics. She reminded us that nature isn’t tame and there is a lot about the earth that we do not yet understand.

      1. Not fair, I meant a “live” eruption.
        Well, Caulle’s still a “live” eruption. But not fair all the same, no live cams. 🙂

  5. Jon, the tremor plots seem to be on the rise all across Iceland. Is there a possibility that what we’re seeing on the tremor measurements may be tectonic rather than magma related? If it is mostly the weather you must be having a really rough time over there.

    1. That does look like a not-weather-related spike to me….
      This is the station, I believe.

      According to IRIS. Which would put it here on the map, unless I’ve mis-translated the coordinates or IRIS is wrong. I am not sure of the name of that volcano offhand, hopefully someone else can chime in.

    2. This appears to be a new SIL station. So it might not be on the map yet. But there is just a wind noise + some technical noise on that SIL station.

      1. Thanks, both – so somewhere near Krafla, then. It looked so convincing as well… but there is no accounting for technical glitches. I can recognise *some* harmonics now, at least.

  6. This is reminding me of my years dealing with Mt. St. Helens. When the run-up to St. Helens was happening, there were all sorts saying that eruption was going to be like say,
    Etna or Stromboli. Well, it wasn’t- just hope Katla doesn’t go off in the middle of the night, or first thing in the morning…
    But, the Icelanders know what they are doing, when it comes to living with Volcanoes.

    “I wonder why the fogs aren’t croaking and the birds not singing tonight?”
    -My ex brother in law on the night of may 17th,1980.Toutle river Campground..
    Then they got up to get a “Closer look” at the Mountain…

    1. I don’t think any volcano in Iceland is at risk for a landslide / lateral blast type of eruption. And when Katla does erupt, there should I hope be sufficient warning for anyone nearby to make it to safety.

      1. St. Helens is one reason the word ‘cryptodome’ makes me nervous.

        Katla has one of those too, but I don’t believe it’s anything like as unstable as St. Helens was.


      2. Thats an interesting thought.
        No dangerous looking bulges, St Helens gave a clear warning. I feel that Katla is not likely to bulge like that.
        A cracked cryptodome would lead to water ingress, if the volcano does not like it it will spit it and hot rocks out again. How fast the spitting out dictates weather we feel the effects or not. I think what we are seeing on the graphs and charts is this, water getting through to the magma, under pressure so no steam is made, yet. Perhaps space is all that is needed, a crack gives space for steam. Super high pressure water vapour is what does the damage. The tectonics keep moving ever so slowly, the cracks form and fill, form and fill, pressure from the surrounding rocks does the filling. But one day the filling is not quick enough, bang. Either some heat and steam is released which shows as a glacial flood, or if its a big enough steam thrust, its a full eruption.
        I am thinking out loud. I am not a Volcanologist.

        One more thought, the animals can feel this, probbably because of the high pressures involved with the water magma interaction. Ultrasonic sound or something similar.

    2. Hi, wasn’t Mt St Helens eruption in 1980 a slope failure, then the blast came out the side of the mountain? If it had gone striaght up maybe there would have been less deaths? Katla wouldn’t erupt like that because of all the ice.
      Read the article in NatGeo many years ago, that was a bad eruption.

      1. Well, there is the cluster of activity at 63.55°N that is outside the caldera. That Jon keeps pointing out.

        It’s an oddity. I haven’t specifically looked at it lately, but I think some of those drop down into the body of Katla.. somewhat vertical.

        Too tired to pull and plot it right now. Maybe tomorrow.

      2. Guys, the “Cryptodome” at Godabunga seems to be a vertical sill. The best way to explain it is to think of it as a huge crack that has filled with magma. If you’ve seen sketches of it, it looks like a very large magma chamber but if you could change the point of view by 90 degrees it would only show as a thin line. It’s a bit like a cross section of a balloon, 1-1½ km in diameter but only 100 m across. The amount of magma is on the order 0f 0.05 cu km or 1/20th of the 1980 StHelens eruption.

        Also, it is part of the Eyjafjallajökull volcanic system, not Katla.

      3. It is believed that is how most volcanos start their career, and that they later on evolve into the magma-reservoired things we normally think of as volcnos.
        Godabunga is a volcano about to happen, not a bulge like Mt St Helens.

        Godabunga is believed by Sturkell to be a part of Eyjafjallajökull, but the evidence he gave seemed surprisingly light for being from him.
        Quake/time-patterning is wildly different then from either Eyja or Katla. And there are a few other things that make me doubtfull.
        Let us say that it can equally well be related to either Eyja or Katla, but it is probably even more likely that is a process of its own at work there. Or, as I have theorized before, that Godabunga and Fimmvörduhals is the same, and that the Eyjafjallajökull eruption was a case of eruption triggered by the first Fimmvörduhals eruption. This is out of the isotopic difference between Fimmvörduhals and Eyjafjallajökull.
        Point though is that nobody knows for shure untill Godabunga erupts.

      4. Cool I always look forward to your plots, this one is going to be very interesting. Thank you lots… 🙂

  7. Frogs darn it ,not the right time of year for the Cascade Mountain “croaking fogs”

  8. A very nice paroxysm indeed. Etna is really putting up a show today. Good thing the ash is drifting eastwards. I believe the population is far greater to the south.

  9. Pieter, since I’m a follower of Popper, I’d rather use the term “falsified”. Until falsified, the best theory stands irrespective of other, less explanatory, hypothesi. Now, Sturkell & al 2009, with the backing of NorVulc, the best authority on Icelandic volcanoes, claim that Godabunga is part of, not Katla, but the Eyjafjallajökull volcanic system. Furthermore, earthquake data covering a very long period of time clearly show 1) The Lady E main channel from Astenosphere to top, 2) the branching off to Fimvörduhals, and 3) The branching off to the Godabunga cryptodome.

    However, one cannot exclude the possibility that magma from the Katla volcanic system could penetrate the Godabunga cryptodome through a (radial) fissure, but this does not change or alter the origin of the Godabunga cryptodome.

    Finally, in a sound scientific environment all and every theory should be challenged! Just because current thought is that Godabunga originated with Lady E, it should not be considered ex cathedra 😉

    1. They have turned off Krisuvik. I guess something happened with it.
      First came that immense shift in intensity, then came a heavy swarm.
      Seems though like it was not cause and effect, just a pesky coincidence.
      If it is not a faulty meter though it is really bad.

      1. Ah, there were (series of) lightnings late afternoon on Tuesday at Krísuvik, perhaps that affected “the quality”

    2. No reports of anything nasty happening yesterday except very high gusting winds forecast at the time the plot. Nothing else on IMO or ESMC for Iceland there. Hope the SIL is fixed soon and the weather calms soon.

  10. And a very deep quake at Fimmvörduhals…Again…

    08.09.2011 10:35:50 63.623 -19.434 21.6 km 1.2 99.0 6.4 km SSE of Básar

    1. These have been going on for a while now (about 1 year if I remember correctly). My idea would be that if there’s a link between Eyja and Katla, this would mark it.

  11. Something is wrong at Kröfluvirkjun/Krafla, during the day there has been two instances of what looks like harmonic tremoring that is larger than normal for the area. This is not wind, that looks different (see below).

    From Melnhausar (west of Krafla):

    From Krokottuvötn (North of transverse Graben):

    From Reynihlid (South of transverse Graben):

    On the first two you are seeing the harmonic tremors. It is especially visible on the Krokottuvötn that lies north of the transform fault/transverse Graben that goes through both the visible outer Caldera of Krafla, and the inner hidden caldera (flooded with lava).
    The Reynihlid shows a pattern of daily tremoring, that is from the powerplant Kröfluvirkjun and is entirely normal, you should also use this as a reference for the wind, you can see that as the increase and decrease in the red line.

    As you see on all 3 graphs the red and the green follows the wind-pattern, but the tremoring pattern is asymptotic compared to all other SILs in the area including Reynihlid. Reynihlid should have shown the same pattern if the tremoring was wind-induced.
    A harmonic tremor occuring at Krokottuvötn (north of the transverse graben) would not be visible at Reynihlid due to inabillity for waveforms to go through the transverse graben due to wave-pattern scattering through difraction, refraction and plain mirroring.
    I therefore think that Krafla is having a harmonic tremoring or a hydrothermal event that is not related to normal operations in Kröfluvirkjun.

  12. Krysuvik plot off top of the chart from c1200hrs, no automatic data update from IMO since 05:53 local – is this just in Norfolk or general?

    1. That is general.
      That probably means one of two things.
      1. That the entire leap upwards is due to faulty equipment, or;
      2. That it is real, but the IMO do not think so and have taken it down for a recalibration.

      Time will tell.

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