Posted on by Jón Frímann

Large earthquake swarm in Katla volcano

At 02:45 UTC a large earthquake swarm did start in Katla volcano. I do not know if this an start of a eruption in Katla volcano or not. For the moment it is too early to know for sure. I have to wait few more min before that becomes clear on the harmonic tremor plots. The largest earthquake so far according to the automatic SIL systems is a ML3.9 earthquake.


The earthquake swarm in Katla volcano. The second green star is from a fake ML3.3 earthquake from yesterday. Copyright of this picture belongs to Iceland Met Office.


The harmonic tremor plot on Slysaalda SIL station at 03:04 UTC on 5 Október 2011. Copyright of this picture belongs to Iceland Met Office.

It takes a few moments to become clear if Katla volcano is starting a eruption or not. I am going to post updates as this situation changes if I have too.

493 Replies to “Large earthquake swarm in Katla volcano”

  1. Seems like emsc has nailed the magnitudes of the larger boys right.
    First one M3.9, and second one M4.1

  2. Although the pattern of quakes indicates, to me, an acceleration of the movement towards eruption, there has not yet been very large signs of deformation and inflation in viewing the GPS data … so it can still have a ways to go before eruption.

    However, in squinking at the GPS data looking for clear, unambiguous indications of inflation, there are some signs of inflation, but I do feel like I have to squint too much to see it .. and nothing very large such as was seen with Eyja.

    Interpreting the gps changes for the important ENTA and AUST locations is a challenge, since some gps changes there are due to the glacial floods, but how much is a question.

    So, based on gps, I can’t see a likelihood of immediate eruption .. even though the quake data is calling for attention.

  3. By the looks of the plot map, she hasn’t slowed down any. And isn’t tremor trace SNB starting to show a harmonic tremmor?

  4. 05:55:46 63.651 -19.062 1.1 km 2.2 90.01 8.1 km NNE of Hábunga

    05.10.2011 05:52:54 63.641 -19.108 4.7 km 2.2 90.01 6.8 km N of Hábunga

      2. I would guess that they are located in Reykjavik and so should be out of any possible danger. The IMO web works again, i think there are just to many guys like us silently watching Katla. : )

  11. Upa!!!
    Seems that Katla make some aerobics this morning!
    And it didn’t stop yet. Btw IMO is up

  15. IF Katla erupt that is so clear that no one has to ask! As long as you ask – is Katla, Hekla …. not erupt 🙂

    1. It is just a guess of the depth when the automatic system can’t figure it out reliably.

  18. What was the time window between Eyja-Katla according to Pall Einarsson if they are “linked”? Maximum of 18 months? April 2010 to october 2011… 🙂

    OT – Some “stretching exercise” going on in Turkey. Always worth a look… Even if nothing very bad at the moment (some 3s).

      1. I saw a study about the zone concerning Istanbul (not where the quakes are happening now). It was about the transmission of stress / pressure in the fault. According to it (sorry, don’t remember the reference and have no time now to search for it) it “travels” from east to west. Next epicentre, if their calculations are right, would definitely come close (4 to 40 km) to Istanbul. And we’re talking about a mag 8+ event, clearly. And if we let ourselves go and use the term of overdue – yes, seems that it can happen any time. Sad things to come overthere. I’m not sure about where we stand in the southern zone, but who could forget the pictures of the last strong one in Izmir…

    2. Don’t quote Professor Pall-Einarsson please. Once upon a time he was a well-respected scientist, but now he’s got a thoroughly unscientific bee in his bonnet about a link between Eyafjallajökull and Katla. It’s as scientific as saying that as Man U won the Premier League, Chelsea will win the FA Cup this season because the clubs have a secret agreement between them – coincidence is NOT causality!

      2. Vik should be safe, because the people can get to higher ground.

        I would bee more uncertain/worried about the people currently travelling over Myrdalssandur (The Floodplain between Kirkjubaerklaustur and Vik)

      3. Myrdalssandur is officially closed as is complete Fjallabak. Due to northern winds, strong in force, I guess snow has set to come in. Leaving tracks unusable by normal 4×4’s. And soaked, immediately, so the ground will become softer.

        @propensity: Where did you find that conductivity is increasing? I cannot.

  21. Knew I shouldn’t have gone to bed at midnight – anyway first look at ipod this morning and I can see you have all been up keeping an eye on things and analysing the info. Not going far today – well only a brief trip into the non volcanic dales

  23. Exciting!! My bad luck I’m at work at the moment, and a dentistapointment in the afternoon.
    Please, please Katla, wait until I’m home… 😀

    Will read the comments wenn I’m home and online again. Thanks for keeping watch.

      1. @ Christina: I know … only, I’ve got one of probably the last ones who “only” are used for telefon and sms… 😀

        But I’m home now and trying to catch up. (and thanking K. that she waited *s*)

  25. but from records, this is the greatest earthquake swarm happening in Kalta ya? When it erupt in July (sub glacier), those it shows such signs as well?

    1. Strongest I’d say (in magnitude), but not in number of quakes.
      Yes, there were “signs”, but not exactly of the same sismic signature.
      I guess we’re all so keen on seeing what really could happen there that a lot of us would tend to say “this is is, this is the sign that eruption is imminent”. But in fact, as Jon so often says so well, it is a wait and see situation.
      Not easy to stay concentrated on other things. There are so many questions that would be answered. How many times did we torture our brains painting scenarios about Katla’s next “real” eruption. I just hope Icelanders can keep their people save, so we can “enjoy the show”.

      3. Red sky in the morning, shepherds warning.

        Its an old saying, meaning bad weather is on the way

      4. Also .. red sky at night, shepherd’s delight .. then never sure really what sort of weather shepherds liked..

    2. red sky in the morning
      Means lots of dust particles in the air to your east… (between you and the sunrise to the east)
      Generally meaning a warm air = nice weather to your east

      the red sky at night
      similarly
      Means lots of dust particles in the air to your west (between you and the sunset to your west)
      Generally meaning a warm air = nice weather to your west

      shepherds delight/warning is a nice rhyme that is based on having a prevailing westerly wind bringing/blowing away the nice weather.

      a clearer rule would be ‘looking at red sky with the wind in your face – nice weather coming, with the wind at your back nice weather going’ but it doesnt rhyme so well.

  27. haha u guys really cheer me up abit. I am really tense now cause I am going to Iceland in 3 days time!

    1. Most wonderful piece of our planet. Go if you can.
      Just wish you not to suffer consequences of the potential event.

    2. June have a great time. Unless you are planning to climb a volcano, you will be fine. Just take a tin hat, follow local advice and don’t forget to take your mobile phone and video camera (inc, chargers for them). I am really envious.

    3. Do go to the Bláa Lónið and take a bath. It is spectacularly beautifull. One of the miracles of the world. Really, it is the nicest industrial accident ever! 🙂

      Don’t forget the tin foil hat so you do not need to listen to the crazies waiting for the end of the world 🙂

    2. But which webcam? Ruv has taken its Katla cam offline so maybe it is faultu or undergoing maintenance.

  30. I’d guess that, weather dependant, the IMO will ask for the coastguard plane to fly over Mýrdalsjökull at some point today. Wouldn’t mind betting that there are some new features/very big holes on the glacier! 🙂

    2. Its snow. The temperatures dropped two or three days ago, so we have the first snow in the highlands and high peaks.

  33. For people wishing to monitor Mukalvisi conductivity, go to IMO home page, select blue hydrology tab, another tab will open on your browser, on that page select myrdalsjokull, then select Mukalvisi river, you will see charts for conductivity, water temperature etc. Hope this helps.

    1. Sorry I missed out a step, in Hydrology tab click on a dot on the map, this activates the page whereby you select Myrdalsjokull then Mukalvisi. Links direct to this page don’t work hence the instructions 🙂

  35. No eruption yet. But they are also saying Icelandic media that eruption is not starting in Katla volcano.

    As that might well be. It is clear that Katla volcano is heading for a new eruption event soon. But when is always the question.

    1. At least they show guts to be so clear about that. Chapeau, I would formulate things with a lot of caution at this very time.

      5. It’s just spikes created by the eartquakes, the spikes in the green band is interesting though

  40. according to http://www.icelandreview.com :

    Sharp Series of Earthquakes in Katla Volcano
    A sharp series of earthquakes began shortly before 3 am last night in the northern Katla caldera below Mýrdalsjökull glacier in south Iceland with the first quake measuring well over three points on the Richter scale, according to earth scientist Benedikt Ófeigsson who was called out to the Icelandic Meteorological Office.

    Mýrdalsjökull. Photo by Geir Ólafsson.

    Ófeigsson said a few other earthquakes measuring around three points on the Richter scale followed but then the seismic activity subsided, only to pick up again at 3:30 am and again at 5:30 am, but in both those instances the earthquakes were weaker than during the first series, visir.is reports.

    Therefore, it was not considered necessary to alert the Civil Defense Department, Ófeigsson explained, although the events of the night will be reviewed there this morning.

    The inhabitants of Vík in south Iceland have practiced evacuation in case of an eruption in Katla, as a glacial outburst from Mýrdalsjökull might flood the town.

  42. This fits perfect :

    42nd Nordic Seismology SeminarReykjavík 5 – 7 October 2011
    The conference will be held at Orkugarður, Grensásvegur 9 (see Transportaion).

    Organized by: Icelandic Meteorological Office, Institute of Earth Sciences, University of Iceland, Iceland Geosurvey and Reykjavík University.

  45. I think that we will at least have a few more swarms like this before an eruption, but when that is said, I also think we are gonna see another swarm within the next 24 hours…

    1. Maybe, only thing we can do is wait 😛
      Wouldn’t be surprised if there would be a new swarm

  48. Was just about to do some housework when I come across checked the sites to find out Katla is stepping it up a bit… ahhh distractions must keep an eye on cam lol…..

      1. Ok I will take that in to account next time, but the tremor is still up on Slysaalda, Láguhvolar and Rúpnafell

  50. Does anyone noticed this brotherhood??

    2011-10-05 04:13:33.06hr 13min ago 75.71 N 7.73 E 2 4.7 GREENLAND SEA
    2011-10-05 04:11:51.06hr 15min ago 63.65 N 19.10 W 1 4.1 ICELAND

    And yes I suppose that a new swarm is starting…

      1. lol .. that’s technically right. And I knew that but….

        It’s a second time when there is an seismic movement along the Atlantic rim (last time if I remember well) was south then Iceland, now is Iceland then north…
        Maybe a boiling/stormy asthenosphere?

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