Posted on by Jón Frímann

New harmonic tremor spike in Katla volcano

Today around 16:00 UTC there was an new harmonic tremor in Katla volcano. This harmonic tremor has two sources. Hyrdothermal activity under the glacier, or magma moving deep inside Katla volcano (without creating many earthquakes in Katla volcano). It is unclear what is the case at the moment.

This spikes are so far not related to glacier floods from Katla volcano. But that sometimes also happen without an eruption being involved.


The harmonic spike can be seen here. Close the end of the chart. It is different then the background noise as it is more powerful then the background noise. Copyright of this picture belongs to Icelandic Met Office.

It is impossible to know what happens next. But it is also important to be aware of the fact that earthquake season is starting in Katla volcano. But that is normally from end of June to beginning of October (or when it starts to snow again in Iceland). So more earthquakes are going to be seen this summer also because of more SIL seismometers around Katla volcano.

So there is no reason to panic about Katla volcano at current time. But it is worth to keep watch on it anyway.

Notice: Updates might be an little few due the fact that I am now working all day during the week and I am tired in the end of the day with no energy to write new blog posts. But I am going to do my best anyway.

145 Replies to “New harmonic tremor spike in Katla volcano”

  1. Of course my pea sized brain with the volcanic acumen of a small child wants to speculate how all these events are tied together or what one might see in the run up to an eruption, but I’ll leave that the those with more insight.

  2. Jon Thank you for these notes. I will watch with interest. As there is no detailed knowledge into Katla’s modus operandi this will be an interesting and possibly very long watch. However watch I shall and also learn as I wait.

    Two more EQs this morning in the SW of Myrdasjokull . Katla is being a very teasing Lady.

    Jon no need to apologise for tiredness after a hard day’s work. I for one, am very happy watching the discussions on here between your informative blogs. I am sure should anything start happening in Iceland that YOU find interesting I am of the mind that tiredness would be overcome by your enthusiasm.
    Thanks again Jon for all your time spent sharing your enthusiasm and knowledge.

  3. It will indeed be interesting to see the lead-up to an eruption at Katla.
    However as the last eruption was a while back I believe we will see quite large or many earthquakes before she decides to bust open.

  5. And I wouldnt be surprised if we will see the eruption starting at Godabunga since there has been alot of deep seismicity at that location.

    1. @ Daniel. Yes! from the locations WSW & SW ..ish of the main caldera I was thinking the same. So interesting to watch and surmise, yet I do not expect the ponderings of this rank amateur to be accurate or to hold any true scientific proven logic 🙂

    2. Daniel, one of the fascinating aspects of the Eyjafjalla and Katla volcanic systems is that the conduits aren’t perpendicular to the surface vents but slant at an angle eastwards as measured from bottom of mantle. In the case of the Godabunga cryptodome, the conduit is thought to branch off from the main one at a depth of about 10 km below Eyjafjallajökull. (Pity the Sturkell & all paper on E&K where all this is detailed is now pay-to-read $35…).

      Very deep earthquakes (15-25 km) directly below Godabunga could very well be part of Katla’s conduits although it’s fair to say few people know for certain.

  6. I read many of the papers linked here in an earlier entry. Katla is one mean “fat old lady”! She’s been active at least for approx. a million years already, and been a frequent contributor to the volcanic activity in Iceland. The main caldera is 9 km * 12 km, hinting to a VEI7 caldera collapse eruption somewhere in the past. It remains to be seen whether the failed eruption of 1999 affects the size of the coming eruption. However, be it an average or above average eruption, we’re heading for interesting times!

    1. Ah! Provided the caldera was formed by a collapse into an emptied magma chamber, yes. However, it seems that most subglacial volcanoes have these “pseudo-calderas”, very large craters (much too shallow to be calderas proper) that result from the interaction between basaltic to andesitic magmas with the thick ice sheets covering them. In order to have a caldera-forming eruption, the magma has to be far more viscous, dacitic-rhyolitic, else there won’t be sufficient volumes under sufficient pressure to create a VEI 6-7 caldera-forming eruption.

      Jón, correct me if I’m wrong, but aren’t Askja, Tindfjallajökull and Torfajökull the only Icelandic summit calderas to have formed this way?

      1. Caldera formation events in Iceland happens when basalt magma gets into contact with rhyolite types of lava inside volcanoes.

        When Askja was formed, this is what did happen.

  7. For anyone like myself who wants to read as much as they can about the glacier and bed rock features of Myrdalsjokull this is quite a good link to start.
    http://www.raunvis.hi.is/~mtg/pdf/Jokull49_HBetal_Myrdalsjokull.pdf
    e
    It details the topography and explains the possible paths of glacial outbursts , “jökulhlaups”. This rapid flood of melt water is the most dangerous aspect of any eruption under any glacier for the local population. So there has been much study and many papers on this most Southern Glacier in Iceland. I write this for those like myself who are interested but not expert. My advice for anyone is to Google for information but be aware of the sources and to use your better judgements. Many articles have much misinformation and were hastily cobbled together during last year’s Volcanic ash frenzy.

    1. Looking at Jón’s helicorders, the 2.8 though deep is unfortunately a textbook example of a tectonic quake with superbly defined p- and s-waves.

  9. Katla is preparing a party.
    When it will take place, this is up to Mother Nature.
    But it will be a party, indeed.

  10. Jón, great post emphasising the most likely explanations – seasonal hydrothermal.

    1. Only green, red is already heading down. Maybe weather/sea effects. When the eruption starts, it will shoot towards the sky like a rocket.

      1. The actual weather for south iceland is warm and sunny. Almost no wind actually. And bad weather influences the highest freuquencies (2-4Hz, blue) stronger than the lower frequencies as far as I know.

  12. A CME propelled toward Earth by the “solstice solar flare” of June 21st may be moving slower than originally thought. Analysts at the GSFC Space Weather Lab have downgraded the cloud’s probable speed from 800 km/s to 650 km/s. Impact is now expected on June 24th at 0700 UT plus or minus 7 hours.

    It may be have effects on Katla.

    1. A polar bear who farts on the north pole may also have effects on Katla… There is no proven theory that the sun has influence on volcanoes…

    3. Um. No. Worst case scenario, the polar bears get a pretty aurora borealis and a few people find it difficult get signal on their phones. Besides which, yesterday it was reported that the Sun’s geomagnetic field was quiet to unsettled, and while there was a halo coronal mass ejection observed, the Earth is only just in the way of it. I very highly doubt it would be strong enough even to knock out many communications, and the notion that a CME would physically affect anything, such as a volcano, has such a small probability (bearing in mind that quantum mechanics tells us that almost anything is technically possible) that it’s probably akin to a grain of sand on a beach somewhere blowing up the planet as soon as I click on the “post comment” button. The chance is so close to zero we can’t comprehend it, but nothing can be ruled out entirely.

      Sorry for the physics lecture, anyone who’s reading this, but as a physicist I really have no time for pseudoscience. Hopefully this has cleared a few things up. 🙂

      1. No worries a lot more interesting read then the pseudoscience stuff which is more along the lines of scaremongering.

      2. :…it’s probably akin to a grain of sand on a beach somewhere blowing up the planet as soon as I click on the “post comment” button. ”

        Happens to me all the time over at BigThink (Eruptions! blog). It’s to the point that I fear clicking that button, not knowing what the gnomes are going to turn my post into.

      3. I think the gravitational force of NATO pulling out of Libya given its accelleration quotient is actually more likey to affect volcano’s that CME’s

      4. That is absolutely correct. The worst a CME can do (highly theoretically speaking) is to spontaneously turn the mass of the hydrogen plasma into energy because of the e=mc^2 equation and heat up the ground enough over what happens to be Myrdalsjokull to vaporise it and allow a path to the surface for the magma, but the scenario itself is exactly as unlikely as it sounds, though not utterly implausible. However, NATO pulling out of Libya would alter the gravitational pull of all the magma in the planet, so there’d be a very slight shift globally. If you got the whole of NATO stood on Myrdalsjokull, the magma might be pulled slightly towards the surface on Katla. By, perhaps, a couple of nanometres. Ha ha ha. 🙂

      5. Sound like you’re getting into the realm of the Infinite Improbability Machine from the Hitchikers Guide to the Galaxy! Katla will go when it goes!

  13. What’s going on at the Eyjafjallajokull webcam – I can’t tell if it’s mess on the camera or brown clouds being blown through the Porsmork valley!

    1. Have you a link I’ve lost it somewhere lol. I would expect it’s either cloud or some grims ash floating about.

  14. @Tony M: just a rainy day in Porsmork with the chance of some sun stripes (would give alot to change my current location to this fantastic valley)

  15. Sending some diocalm and Gaviscon for Polar bear’s bad wind that may affect Katla’s harmonics…….Just in case!

    2. (snigger)

      But wouldn’t Gaviscon induce constipation, i.e. a build-up in pressure?

  16. Well, there was indeed a quake, but poorly constrained:
    Wednesday
    22.06.2011 17:16:07 63.628 -19.203 2.2 km 1.7 88.84 2.7 km ESE of Goðabunga

  17. Yeah, a CME – nice one for the next 2012 movie. Maybe the CO2 from my car when I drive to work tomorrow will definitely induce a radical climate warming, sea-level will rise, that way more water will push down the continental crusts, that will cause their subduction and change mantel-circulations, what will increase the hot spot under Iceland and not only make Katla pop but the whole Hengill system blow… Sorry for that… 🙂

    1. Please no. My next hikes should be in the Hengill and Takgil (Myrdalsjokull) area. I dont want any of these volcanoes to erupt when I am there. But I am not really afraid of Hengill, the volcano shows little inflation, and always with lots of earthquakes weekly, for years. Katla, yes I have fear of it, when the eruption starts it might send a massive ash cloud, if like Grimsvotn it will turn day to night, even where our home is located, for about 3 days (if the prevailing winds blow).

    1. This solar eruption is a very common one. This will not cause even a european-wide northern light. A C7 flare is nothing! A major flare is more interesting, and a X flare even more. But still, even a strong X flare, the likes of 2004 or 1989 flares, are nothing compared to the 1859 event. That flare became visible to naked eye, as a burst of white light. Can you imagine that? That would be a catastrophe for our civilization, because of the damage in power grids and computers. My laptop would probably burn, as would many around the world. But still the volcanoes would be without any effect (as were after 1859). This can happen at anytime, and not necessary in solar max, but its pretty rare, and nowadays we will have notice a couple of days before. The flare would however have an effect on people: you become astonished with the lights above you at night.

  19. Not saying a solar eruption wouldn’t have consequences, but if we had a fat one, the first concern wouldn’t be it’s effect on volcanism. Our society has become very vulnerable due to it’s high level of technology, even an event with a probability of 1/100 per year is persued as a cataclysm (see recent earthquakes and tsunamis) and referred to as ‘biblic”. I take any natural hazard seriously, but even though stay more afraid of Campi Flegrei than average CME’s… Although very interesting to think of any kind of scenarii. Just love it.

    1. Lets see history. History is always a great teacher.

      Since 1000 we had (in Europe):
      – apparently only one huge solar flare event, in 1859 (burns electrical systems)
      – several volcanic winters (apparently in 1314, 1477, 1600, 1783 and 1815), thats an average of 1 per 200 years! This caused widespread famine, and would be a disaster. But nowadays, with our massive production of food, it would take a really big eruption to cause some collapse. But even a small, worsens the economy with obvious consequences.
      – several earthquakes (only a disaster to coast because of a tsunami). We only had about two in Europe in 1000 years. In the US, about the same, in recent centuries, only the New Madrid quakes
      – plagues, several small ones, and some really devastating. Two at least, Black Plague in 1345 and Spanish Flu in 1918. But cleaning conditions at that time were also pretty bad.
      – No meteor strikes in 1000 years in populated areas. So I wouldn’t worry about this too much.

      So, from what we have only volcanic winters seem to be the most frequent global disaster events to civilization.

      1. Unless you are in Japan. They not only have to contend with Godzilla, but also the Fukashima power plant… BTW, the experiment to filter out radioactive material from the water to then be re-used as coolant failed. Okay, not failed, but failed to meet their expectations. (didn’t pull out as much material as they expected) They figure that at the current rate of pumping the reactor area will overflow by the 29th of June. They plan of trying to push that date out by using another storage tank to hold the contaminated water. The NHK news stated that the filter system could only reduce the water contamination to 1/100th of what it had (high contaminated water). For the low contaminated water, they were able to get 1/1000th.

        Dunno.

        And, they got another quake nearby. An M6.7.

  20. @Irpsit: it’s always kind of strange anytime a volcano gets active in Iceland. I love Your country for being THE symbol of nature’s untamable power, and for this I love to follow what happens, but I always feel very sorry for You guys that have to directly deal with the consequences. I admire Icelandic people a lot for their maturity in the way You live with Your environment.

    1. Takk fyrir (Thank you). I am not Icelandic despite that i live here. But I do admire their (historical) resilience. A minor volcano here is watch with as much worry as is a common storm: Icelanders don’t really worry about volcanoes, unless its a “Laki”.

  21. Sounds very impressive, indeed. Add meteorites, biological stuff and all the potential due to our “silly” human nature… We should all meet and write some nice stories for really scaring movies, could maybe make more money than as scientists… Sorry for having left the topic of the post a little much.

  22. A little off topic, but where can I find strain charts for Katla? If there are any.

  23. @Geoloco and Irpsit
    I am sure you both sound far too young to remember the eruption that threatened the harbour at Heimaey. The fact that the locals there fought the lava flows and won, to me, sums up the passion and strengths of the Icelandic peoples.
    I remember it well and was so impressed by their resolve to save what they had and survive this natural disaster.
    There really is something special about Iceland and her peoples.

    PS. Maybe I shall hold back on the Gaviscon and let nature take it’s course!

  26. @Diana: We sound young – tell this my wife when she smiles at me looking at my grey hair and telling me how old we have become… Age is relative. If You are under 70 I’m sorry, but I can’t accept this kind of comment … 🙂 In Iceland they where cleverer as our Italian mates, who once tried do hold back lava with concrete blocks – was interesting to see them swim away on the flow… My Italian friends, part of them high class mineralogists, where quite ashamed…

    1. It must have been like trying to stop water flowing by using water balloons…

    2. A lady does not divulge her age. I agree, irrelevant here. I am still as I was at 18 but maybe a little more wise!
      I cannot believe your Italian friends. The little Dutch boy’s finger was more effective!
      Did anyone manage to get measurements of pressures incurred at the moment of impact ? How did the composition of that particular concrete mix react to the high temperatures? Were the blocks loose or mortared together? If mortar was used what type was it? …:)
      Maybe they had been inspired by a very bad Hollywood disaster “B” movie

      1. Yeah well, “the only people who never fail are those who never try” 🙂

      2. From my iPhone I didn’t see this comment of Yours. In fact there was a lava flow separating in several channels, and one of the channels lead to potential dammage. So they just “threw in” some concrete blocks, I imagine something like the blocks they sometimes use to separate the highways, hoping they would “agglomerate” and “stuff” the channel entry. I agree with Jenso, sometimes You just have to try, but in this case the result was predictible. There are moments where You just have to show the touched populations that You do something. It count’s for them to see that at least You tried and didn’t let them down. Nevertheless, from a scientific point of view, we can’t hold back a tender smile…
        Oh, aha, yes, well, with Your 18 You’re a little young for me… 🙂

      3. Did any of the concrete ‘explode’? It sometimes happends when i gas cut steel over concrete & a large molten blob of steel lands on it.

    1. Ha! Surprisingly being from the UK, I’m unable to view a BBC Worldwide webpage! Unbelievable!

      2. We’re sorry but this site is not accessible from the UK as it is part of our international service and is not funded by the licence fee. It is run commercially by BBC Worldwide, a wholly-owned subsidiary of the BBC, the profits made from it go back to BBC programme-makers to help fund great new BBC programmes. You can find out more about BBC Worldwide and its digital activities at http://www.bbcworldwide.com.

        Yup we are British! We pays our dues and Taxes and keep our upper lip very stiff!

      3. Oh yes – reminds me of working nights and actually being able to listen to the BBC worldservice on MW/LW – it was broadcast for the UK to hear at night only when Radio 4 had finished with “sailing by” and the national anthem…. very interesting – pity we couldn’t hear it during the day!

    2. Well its not as bad as the germans when they try to picture our midsummer´s festivities here in sweden.

      And for the life of me I can not see how this would have anything to do with IKEA.

      http://www.youtube.com/watch?v=8I5BGsK5ZAU

      (Sorry Jón for the way OT. Ill get right back on track with Katla now. 🙂 )

      1. Definiely not a genuine Swedish celebration. The fish is fresh.

        Sorry for another OT. Many thanks to Jon and the contributors for knowledgeable info on the volcanoes!

      5. Glastonbury music festival near me this weekend, part of it can be seen (sometimes heard) from the top of Glastonbury Tor. Way off topic i know!

  29. Well I was concerned that you would get the wrong impression of Swedish midsummer.
    The truth is that we have ALOT more alcohol than what was shown in the video. 😉

    Jokes aside..It will be very nice to have a day off tomorrow. Lets hope Katla remains calm. 🙂

    1. I’m so dissapointed now. I always hoped that buying some furniture at Ikea and eating their frozen meat-balls and cakes would make me half a viking or a quarter Thor. I’ll give this up now and go back to eating chocolate, cheese I have cut with the army-knive and running to be right on time after having looked at my precious watch that I got from grandma Heidi and grandpa Peter.

  31. @Renee:
    Good to have you back.
    @Daniel:
    Don’t forget that the great play by Strindberg, Miss July, takes place in a Swedish midsummer. Funny things happen in a Midsummer night, when the fairies are celebrating…

  32. hi all. watching the Katla cam earlier and noticed something strange. what seemed to be a cloud of steam, or stream of water, or whatever, shooting from the mountain/glacier far in the distance. I captured the images and made a gif out of them. what do you reckon? I had someone on another forum say it was sunlight, but I don’t think it is.

    1. Thanks, Mark, for your observation and gif (only wished I could produce them myself). 🙂
      I can see what you mean. Clouds and haze have played this kind of trick on me before, but we must keep a watch to see if this goes on.

      2. Yeah RR, I know, me too. It was the speed of this incident that had me thinking. it was all over in no more than 4 minutes, as you can see from the times, and the area looks as if it was being hammered by heavy rain at the time too by highish shower clouds.

        Maybe it was an unusual cloud/mist formation. Just thought I’d share it with you all.

  34. We just had an earthquake here. Not much. Just like a lorry going past. Devon, England. Definitely not volcanic though.

    1. They mentioned it on this evenings local news (mag 2.3 i think it was), living in Somerset i felt nothing (as you would expect).

      2. Yes. the time descrepancy is our time as British Summer tTime (BST) while the data is reported in UTC or GMT.

  36. I see Etna is beautiful looking 2night. Can i just say thankyou to the guys from ruv for getting Katla back on line.

    1. These are just clouds. Don’t forget that Katla is pretty high and the climate on top can be pretty harsh (also due to the glacier). When Katla starts, it will most likely not just steam a bit, but give a fully blown volcanic eruption.

  39. first post from someone who knows nothing ,but reads a lot on here ,thank you jon
    for you hard work
    has anyone looked at the charts this morning ,

    1. Diana, ever since the eruption at Eyjafjallajökull it lets of some steam from time to time. The ground is actually still pretty hot and occasionally there is a bit of steaming. I guess it will take some time before she cools off completely.

  42. @ Daniel
    Thank you. I have been reading through past comments. I am sorry to have got overly enthusiastic. Common sense should tell be that there would still be steam from a recently erupted volcano surrounded by ice!! DOH!!
    However I have at least had a “dry” run through making a video quickly and getting it posted ready for when and if I see proper eruptions.
    I apologise again for my very amateur mistake!

    1. Absolutely no need for apologies. I have posted many posts like the one you made. 🙂 We are all (almost all) amateurs and we are here to learn.

      And as you said. If anything you will be able to make a quick video now when Katla erupts. 😉

    1. More than likely, it’s from last night’s earthquake in Alaska.

  44. The strong spike seen last night was the Mw7.3 earthquake in Alaska. It can also be clearly be seen on my webicorders, the P wave did arrive around 11 min later in Iceland after the earthquake did happen at 03:09 UTC.

  46. In don’t know, wasn’t there. Heard about it from my Italian colleagues.
    From a mineralogical point of view it seems quite understandable that you have this kind of reaction when You think of the temperature of molten steel. At least You’ll never see me built a fire-place for Sunday-grilling out of concrete… 🙂

    2. My mate also used to get the ‘exploding’ concrete thing when he worked in an aluminium foundry & molten aluminium would sometimes splash on the floor. Anyhoo i guess most of us on the ‘Iceland volcano sweepstake’ would back Katla erupting next (think at the time i said i’d back any Iceland volcano that we weren’t talking about at the time).

  47. Well, in fact there was a lot of steam yesterday and today there is quite a column of steam. Quite a sighting! And I have not seen such a big steam column since last July!

    Yesterday should have been a column for a while up to 1km high (it was as tall as the height of the mountain), today around 200 meters maybe (still well bigger than the normal average that I see it every sunny day from my home in Grimsnes).

    You can see it right now, but not very well, in the webcam. Thats because the column is blown from north to south, so you cannot see it very well in the webcam. But from where I live, 80km west, a different perspective, I can clearly see the volcano and a big steam column blown southwards towering above the glacier-covered volcano.

    I remember one month ago, watching at the same time 2 volcanoes plumes, the small steam still coming from Eyjafjallajokull, and the big ash one from Grimsvotn (with lightnings). Its crazy to see this stuff from your kitchen window!

    I just hope this strangely big steam column does not mean renewed activity at Eyjafjallajokull or Katla.

    1. Does either volcano tick the boxes. Does any have increase in EQ’S compared to the avg amount at this time of year? increase in strain or tremor’s? increase in movement, with it going up or down?

      I do not know these answers, could someone with a bit more knowledge, tell us?

    2. Dear Irpsit,

      Does the steamcolumn comes from the Eyjafjalla? You didn’t mention it in your post, later on you mention Eyjafjalla and Grimsfjall; so I got confused!
      Like to hear from you; thanks in advance!

      Kind regards,

      Henk Weijerstrass
      Zwaag (Holland)

      1. I’m not an expert, but what do you guy’s think on this tremor. It’s around Eyjafjalla. I think it looks like the was a bit of magma movement. But it has gone back down now.

    1. That’s strange, I thought they had fixed it. Now 2 days later it’s down again.

  50. Sorry if I was confusing. The tall steam column visible these last 2 days was from Eyjafjallajokull. This volcano has been steaming often ever since its eruption last year, but 2 days ago the steam plume was quite surprisingly big. Now it reduced back to previous size. From where I live I have an excellent perspective from Eyjafjallajokull, Katla and Hekla.

    There is nothing going on in Katla or Grimsvotn, in fact volcanoes do not erupt by sending steam first – instead, the steam appears after the eruption is finished, sometimes for years. Don’t expect to see anything else than earthquakes before Katla or Hekla blow.

    2. Yep I know this, was still wondering about this red tremor from Eyjafjallajokull, it’s not very big but it did rise up a bit then drop back down quite suddenly. Was just wondering if that could have been some small magma movement there.

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