Posted on by Jón Frímann

Small earthquake swarm in Katla volcano caldera

At the moment there appears to be a small earthquake swarm in Katla volcano. Currently this is just a earthquake swarm. All the tremor plots are normal and show no signs of harmonic tremors and magma on the move. The largest earthquake in this earthquake swarm in inside Katla volcano caldera was a ML1.3 with the depth of 1.7 km according to reviewed data from Icelandic Met Office.


The earthquake swarm in Katla voclano. It is deep inside Katla volcano caldera as can clearly be seen. Copyright of this picture belongs in Icelandic Met Office.


The ML1.3 earthquake as I did record it on my Heklubyggð geophone. Given the shape and how low period this earthquake is. I would say that it was created by magma pushing upwards in the crust inside Katla volcano caldera. This picture is released under Creative Commons licence, see the licence web page for more details.

At the moment (when this is written) it seems that this earthquake swarm is over. For the moment anyway. But it hard to know for sure if it resumes or something else starts in Katla volcano.

Update 1: A earthquake with the magnitude ML3.8 did happen in Katla volcano caldera at 02:02 UTC. Following this earthquake there have been many aftershocks. It is not yet clear if this means that Katla volcano is starting a eruption or not. But that should be clear in few hours if that is the case or not.


The ML3.8 earthquake that happened at 02:02 UTC. This is by the automatic SIL system, so it’s size can change. This picture is released under Creative Commons licence, see the licence web page for more details.


The location of the ML3.8 earthquake in Katla volcano caldera and the following aftershocks. Copyright of this picture belongs to Icelandic Met Office.

Blog post updated at 02:26 UTC on 18. July 2011.
Blog post updated at 02:40 UTC on 18. July 2011.

393 Replies to “Small earthquake swarm in Katla volcano caldera”

  1. I am wondering if the water we saw yesterday in the crater has gone? More high temps for the area in the coming days!! Does any one know the temp at the top of katla? With that much ash and water, the ice will melt quicker than normal. Is there daily flights now checking katla? Like tourist or official? Last nights swarm was spaced apart allot more than the last one. Me think it was more water or steam based than anything else. I would love to see a infra red image of the area,

    1. I remember watching this with my old man after a ‘few’ beers.

      I wasn’t the nicest to Julia Bradbury when she started with her so-called ‘facts’!

      1. As I said in the other thread last night Scuji, whoever wrote the script needed a good kick up the pants. I did suspect that anyone from here seeing it might want to hurl boulders at the screen. Volcanoes pushing continental plates apart indeed!

  3. Significant bit of time harmonic tremors seem to rise in South
    ALF ESK HVO, is my point of view and is very early to get a good look
    Greetings.

    1. I have been watching that on ESK and ALF, I wasn’t sure if it was a harmonic tremor or something else.

      No wind at Jon’s geophone location anyway.

      1. 0.5 – 1.0 band clearly rising at ALF & ESK now, though still not very high.

  6. New large earthquake is taking place (Size estimate ML2.5 to 3.0). I am watching it on taking place on my geophone. But this earthquake does not look like it is from Katla volcano it self. Maybe nearby it ?

    This comment has been updated.

    1. Showed up nicely on your geophone! Looks like just a normal tectonic earthquake?

  11. I have been watching the Katla webcam on and off all night. I think that is steam. Sometimes it wafts into the air, as it is now. Sometimes it looks like a cloud laying on the ground.

    1. If it is steam, I think you could compare it to taking an ice cube out of the freezer on a hot day. I think it’s the suns heat causing evaporation which can sometimes look like steam.

  12. The Katla webcam is amazing. The low clouds in the Myrdalsjökull like an minor eruption, but is only low cloud !

    1. Looks like they have set it back to the original automatic data, the depth and quality and reverted back too. I guess they are reviewing it again.

      1. strange or they had another problem and had to put a backup in or something.

    2. The 3+ has been put up to 4- (very higt???!!) in last few minutes. What is the reason these high and lows??? Thanks for a short answer.

  14. Monday
    18.07.2011 02:02:27 63.660 -19.116 1.1 km 3.8 90.09 7.0 km ENE of Goðabunga this one appears at last in earthquake sistem

  16. Things are certainly getting interesting. First the graph changes and now the 3.8 is back.

    Better news is i’ve found the earthquakes on my phone’s internet and I can keep an eye when working.

  17. The M3.8 Earthquake is Magmatic or Tectonic ? I think if magmatic, the eruption is not really far ! In my opinion, whithout the Myrdalsjökull Icecap, we can see the eruption and ash cloud !

      1. I think he means if the extra pressure of the ice from the glacier wasn’t there it might have blown by now. I’m not so sure of that in this case. However the little sub-glacial eruption would have looked a bit more interesting.

      2. No, not yet.

        You need much higher pressure from beneath for that. And in the absence of strong earthquake swarms, there is currently no evidence for that overpressure.

    1. Never seen such a reaction to a 0.6 earthquake before 🙂 But yes, first since the swarm.

      1. I think that this might be some type of noise. So far it has not appeared and behaved like something from a volcano at current time.

        So I am thinking that this might be some type of environment noise rather then from Katla volcano.

    1. Blue 1-pixel spikes showing on all stations at the same time are usually local earthquakes. This one doesn’t seem to very big however.

  21. Lol the quake shurk again, think they had to backup for some reason then forgot to change the 3.8 to 2.9 till now.

  22. The Katla webcam show like an eruption, but surely an optical illusion !

    1. I was thinking the same thing, it looks that way but the clouds have decieved me before.

      1. I couldn´t resist,

        I’ve looked at clouds from both sides now,
        From up and down, and still somehow
        It’s cloud illusions i recall.
        I really don’t know clouds at all.

        Joni Mitchell

    1. Not at all odd, but very amusing! Due to vertical air movement, clouds can take very funny shapes. Add to that “suitable” land formations, and this is the result.

  24. Someone in the IMO is jerking our chains. 😀 It’s back up to a 3.8.

    Could someone please explain why earthquakes are downgraded by the met office? Is it to do with background noise or are there other reasons. Thanks.

      1. It seems to happen at coffee breaks/lunch times. They must get bored, log on here and think to themselves that they’ll have a bit of a laugh at our expense.

      2. I have been looking at the quake page off and on this morning and it seems to me that they keep fixing the big quake but it somehow jumps back up to the old automatic number every time there is a new quake in the area.
        I guess they might be having some problems with the site because I got an error page when I tried for it this morning but it worked fine a few minutes later and has been since, except for this quake that is jumping up and down all the time.

  26. @ Webcam watchers.

    Remember that the clouds and fog formations sometimes gets created out of nothing due to the altitude and the features of the landscape. I have seen on many occassions clouds or fogbanks which could easily have been mistaken for steam.

    If Katla decides to let loose I dont think we will see any steam. It will probably be an explosive event and the only precursors will be tremors and earthquakes. Not steam.

    1. Agreed steam will be the after effect while the ground is still hot like katla’s neighbor she still steams.

    2. I even don’t look at the webcam. The eruption that people are “interested” in, VEI 4/5/6 (depending on how freaky You like it), will not show as something You can’t recognise from a fog-bank. A little bit of steam here and there might be somewhat of the result of a precursing event, but it’s like any little swarm.
      Dear webcam-watchers, take Your eyes from ruv.is for 10 minutes and once again (because I’m sure You all know very well) read whatever wiki-something about what a VEI 4, 5 or 6 really means, just for recalling some basics.
      Katla-cam is nice for the sheep, the amazing 4×4, naked men Diana is waiting for (sorry, had to be… 🙂 ), and of course the dopamine-kick and thrill in general. But Katla’s eruption will start with eartquakes, and what comes out of it’s top will be more than a nearly undistinguishible steam-plume, even if it’s a “small” eruption.
      I love it to read the post of all of You guys sick as I feel myself…

  27. I think when Katla erupts there will be no doubt that this has happened. Even if it is a small eruption it will produce a flood as was seen two weeks ago. She will produce more dramatic effect than a few small puffs of steam. There will also be some definite and dramatic changes to the tremor graphs.

    1. Same thought at the same moment. Interstellar harmony raining down on this blog. LOL

      1. OMG! GeoLoco! Let’s not bring the Psychics in here . If we are not careful we will be beamed up harmonically by winged aliens playing the theme tune to “Close Encounters” 😀

      2. This is what I call a reference! Made my day… (except for the moment when I was alone in the office and sung the Ave Maria from Schubert… 🙂 ).

    2. I just see some small spikes from local earthquakes on a few of the stations, I don’t think there is any harmonic tremor right now.

    1. Actually they state, that an imminent eruption is not likely. They’d be foolish to say it will not erupt, as it does surely erupt, sooner or later!

    1. The SIL station Vatnsfell is a noisy station. So it is just noise that you are seeing at the moment.

      Skrokkalda is seeing earthquakes both from Katla and Vatnajökull area. Larger earthquakes (larger then ML2.0) can often be seen up to 100 km away from it’s epicentre.

  32. I have a few questions regarding Katla.. I wonder how thick the ice above the crater is and in case of an eruption, how long time does the volcano use to melt down this icecap?

      1. Wow. She can really stir things up if she erupts. That is a huge amount of ice/water in a short period of time. Thanks for this video, really informative!

      2. Thank You Gandalfi.
        I think this video should be essential viewing for all who come here. It explains very well the geomorphology of the Mydalsjokull
        area and shows what we should be looking out for on the Katla cam. I think we shall not mistake the eruption for clouds! Of course I shall be watching still for who knows what things of interest can be seen in this wild and beautiful countryside! 😀

      3. Next time I can organise a trip to Iceland I shall run naked in front of Katla-Cam… 🙂 (with a sheep mask – I’m kind of shy…)

      4. ……. Stands by with thermal blanket and a St Bernard dog complete with brandy Barrel. ROFL!
        😀

  33. Steam?

    At an ever increasingly active volcano, with a huge glacier on top of it?

    NEVER!!

  34. On a very serious note.
    @ All Icelanders here. I admire your country’s evacuation plans but it would be dreadful for those affected, in fact the whole country, should a massive eruption happen. Are you able to insure your property, livestock or other business, against floods and volcanic eruptions? It must be very difficult. Where would you stay if you had no family?

    1. Iceland has an emergency fund to cover the damage from volcano’s, earthquakes and other natural events. So all Icelanders have volcano insurants 🙂

    2. A. Would not want to be in the farmers shoes in case of an eruption, lifestock will be left at farms, worst case scenario put down due to lifestoc related health regulations (you can’t move sheep, goats or cattle between certain areas). Darkness will follow + most likely ash will be on the move for a long time.

      B. No insurance covers houses, business or lifestock though every year an amount is put into a certain fund that anyone can have compensation from be it because of a flood, avalance or eruption it will not cover all your loss or possible relocation.

      1. And that fund was used in 2000 when there was a huge EQ in south Iceland to cover for damages, it took months to get the compensation and also for damages for last years eruption in Eyjafjallajökull. It’s more complicated and less than people think

    3. @ Steinn
      That is partly correct, however you need to have a “normal” incurance for the insurance of “Viðlagasjóður” to take effect in case of a natural disaster.

      @ Diana
      Local schools are turned into shelters in case of evacuation. In 1973 the town of Vestmannaeyjar islands was surprisingly hit by an eruption at about 2 o’clock in the night and the 5000 inhabitants had been evaquated by morning. The inhabitants were placed in temporary shelters mostly in schools on the mainland. Many later moved in with relatives and “Viðlagatryggingasjóður” built quite a few houses around Iceland for other evaquees.

      1. Thank you for your replies. I remember Haemay well. I often wondered how those brave people managed to get back to living their lives and didn’t just abandon their home. It shows what a strong community it is.
        I feel a little more at ease knowing that there is help if needed. So difficult though to replace stock and to start again. But it is heartening to see how relatively quickly Surtsey was colonised by plants and birds. Nature has her bountiful side.
        I pray that with all this monitoring in future there will be perhaps more warnings and chance to have time for a little more preparation, not just for Iceland but in all areas of the world.

  35. You know, I have been observing the Helicorders Readings for a mere few weeks now. And although Jon has been ever so kind to answer my (Most likely daft!) questions regarding these readings, I have often wondered what an earthquake, or even a harmonic tremor would look like.

    Well, now I know. It’s huge! I didn’t know that the needle literally fluctuates into other hour’s grids for the day.. And the Red can be clearly seen over the last 48hours.

    No Way can that be background noise! :-O

    http://en.vedur.is/earthquakes-and-volcanism/earthquakes/myrdalsjokull/#view=map

  36. The latest bumps on Jon’s Helicorder look like small earthquakes from Katla. Or is it just noise?

    1. It seems on the first link you can filter the quality of the earthquakes. If you set “Gæði” to to 30 or above it should look the same as as on the second link. By setting it to a lower quality than 30 it seems it opens it up to earthquakes that may not be real at all since the quality is so low.

      1. Thanks G1 – that explains it.

        Improving my icelandic as we go – can knit a jumper from an icelandic knitting pattern and soon I will know more terms related to volcanoes!

  39. I think it’s not wise of these sites who are saying there is no chance of a eruption at Katla. Even though there’s no major major activity about, we shouldn’t just assume nothing is going to happen, and get people into a false sense of security that nothing will happen. It’s always better to be prepared and to know in the back of your mind an eruption could happen in the coming times, instead of it happending on such short notice! Even if nothing will happen, it’s good to tell people that anything could happen.

    So I thank you Jon for a very realistic approach to all the happenings in Iceland, and it’s no wonder that you have a million views, a number which will be increasing alot in the near future 🙂

  40. I have a feeling that Katla will erupt by September or October. Eyjafjallajokull also had about 3 months of earthquakes before. I expect more and more quakes around 3 and 4, with a build-up just before the eruption. But it could be that there might more “failed” eruptions and the real eruption only happen in next and after next year. Remember, that for a volcano that was 100 years asleep, its not 1 or 2 years that is going to make a big difference.

  41. Hi everyone

    (Just got back from work after seeing the 3.8 on the Icelandic Met Offices website).

    I think that the problem with looking at the webcam is that we can only see the image in 2D. As such it is difficult to see if the clouds are coming from behind Katla; are on top of it, or even in front of it.

    I think the webcam will come into its own if and when it goes up. Until then I think we need concentrate on the seismographs etc to tell us what’s going on.

  42. As previously stated. If she decides to blow wether it is a small eruption or a large one the current view on the webcam will be so much different.

    I personally dont watch the webcam since there is nothing to see at the moment. No seismicity that would indicate any eruptive event. If there is a large swarm and a significant increase in tremor I will check it out. But for now its just a nice landscape to look at. 😉

    And regarding tremor I think that the small increase at the moment will be dwarfed by the tremor signature of a full scale eruption. The jökulhlaup caused a large spike in tremor but even that would probably be small compared to the real deal. Just look at the tremor at the Eyjafjallajökull eruption.

  43. Forgot to log in…Jón remove my previous post if you want as it is waiting for “moderation”.

    As previously stated. If she decides to blow wether it is a small eruption or a large one the current view on the webcam will be so much different.

    I personally dont watch the webcam since there is nothing to see at the moment. No seismicity that would indicate any eruptive event. If there is a large swarm and a significant increase in tremor I will check it out. But for now its just a nice landscape to look at. 😉

    And regarding tremor I think that the small increase at the moment will be dwarfed by the tremor signature of a full scale eruption. The jökulhlaup caused a large spike in tremor but even that would probably be small compared to the real deal. Just look at the tremor at the Eyjafjallajökull eruption.

  46. The 3.8 is also visible on the BGS helicorder for Sornfeli (very long period) at 0206hrs BST

    2. I like it Renato when you’re kidding! But give a second thought to the poor stupid – sorry, simple-minded and uneducated journalists who read this blog, too!

  49. I know it looks like steam but it is just a funnellike cloudformation. 🙂 Starting to dissipate now.

  50. Remember all that if magma will reach the surface there will be an explosive event. So you will know it when she blows. 😉

Comments are closed.