Posted on by Jón Frímann

Minor earthquake cluster in Katla volcano caldera

There seems to be forming of minor earthquake clusters in Katla volcano caldera. But this has been following growing number earthquakes in Katla volcano caldera during past few weeks. This is most likely an signal of increased activity in next few weeks to months. But the increase does not have to been slowly up. It can be sudden as did happen in July 2011 in Katla volcano caldera when earthquake activity did increase suddenly and there was an small eruption without an warning.


Current earthquake activity in Katla volcano. Note the small cluster of earthquakes close the area where an small eruption took place in the year 1999. Copyright of this image belongs to IMO.

There has been some small cluster of earthquakes taking place in Katla volcano caldera. I am not yet sure what that means at the moment. However this might be clues to minor dike intrusions into Katla volcano caldera. But without more data, it is impossible to be sure on this detail at current time.

Last night there was an change in harmonic tremor on two SIL stations around Katla volcano. But due to high wind noise I am unsure what was going on. But it is possible that this was an small dike intrusion taking place close to Goðabunga part of Katla volcano, or this was an minor glacier flood that was taking place under the glacier. At current time I have no good idea what was going on.


The harmonic tremor on Smjörgil SIL station. The signal is unclear due to high wind noise. Copyright of this picture belongs to IMO.


The harmonic tremor signal on the Goðabunga SIL station. Due to high wind the signal is unclear and hard to see. Copyright of this picture belongs to IMO.

It is hard to know for sure what happens next in Katla volcano. But important signs can be found in earthquake patterns. But it is also important not to overlay broad interpret the data in the favor of an eruption taking place. As it is impossible to know for sure when Katla volcano erupts, and then how big. All we might get is an new small eruption like in July 2011. As Katla volcano can also have small eruptions like big ones.

29 Replies to “Minor earthquake cluster in Katla volcano caldera”

  1. Thank you, Jon. I’ve been watching these and wondering what is going on. Nice to know your opinions!
    All the best.

  2. As I said before, are a little deeper than the last few months, but need a bit more depth to be a clear new magma input, that’s what I think

  3. So has Katla had a steady flow of earthquake clusters like this in the past 50 years or is this unusually high? If I’m remembering correctly, this amount of earthquake activity is unusually active.

  8. Hi Jon,

    I wonder if you might consider putting arrows on the interesting bits of tremor plots? I like to think that I am getting quite good at looking at them, but it would be nice to be reassured that we are looking at the same things.

    Thanks! 🙂

    1. I would love to do so. But I do not know how to do this properly in GIMP (an image program). I have been looking for an way to do this for some time now. But so far no luck.

      Any help and suggestion on how to do this are welcomed by me. 🙂

      1. The easy way is to insert it into something Powerpoint (assuming you have it) to put arrows in, then re-save as a jpg.

      2. Hi Jon,

        First I would like to thank you for your blog. I’m reading here on regular base with great interest. Keep up the good work 🙂

        On the arrow in the gimp, you might do the following.

        – Download the file arrow.scm from http://registry.gimp.org/node/20269 and copy it in your script folder; \.gimp-2.6\scripts
        – Start the gimp and load your picture
        – Use the path tool (short-cut B) and mark two points. The first one will be the direction of the arrow.
        – Then go to Tools – Arrow and a dialog will pop up
        – Play with the dialog settings to create the arrow you want.

        Grtz,

        Chris

  9. Hey jon im just passing by to say i like your work and i wish you the best!
    Hugs from Brazil! (we dont have any volcanoes or earthquakes here lol =/)

  10. As an easy workaround you can download a dingdat font, like this one (free)
    http://www.dafont.com/pointers.font?fpp=50
    You can use them the same as when you type normal letters in Gimp, just choose this font and type the one arrow you need or like. After that you can change the color, size and even stretch the arrow you just typed, copy and past it to use it again in another place, turn it into the direction you want, etc., etc..

    There are also many videos in youtube that show you how to do tricks in Gimp

  11. The Mid Atlantic Ridge in in a decompression phase now, so one could assume the plates Iceland sits between are drifting apart at a greater speed than usually.
    That probably explains much of the EQ activity lately, like the ones at Veidivotn.
    http://volcanocafe.files.wordpress.com/2012/02/120218_1545.png

    Every time this happens it increases the possibility for fissure eruptions.
    I think the areas to watch over the next months would be Bardarbunga and the NE area, like Krafla and Theistareykjabunga.

  12. OT: anyone who is following the GPS data for El Hierro needs to be aware that is from October 2011 so does not show the displacements prior to then.

    1. 2 deep quakes at El Hierro today: 33.3km and 34.1km, both low magnitude at 1.3 mbLg each.

      Are these a new injection of magma / or an indication that more might be on the way?

      1. It might be new magma. But the question always is this. Is the magma going to reach the surface, or just stay down there and cool off into an new rock sill that might never get exposed to the surface.

        Nobody has an answer to that question at this moment. So we just have to wait and see what happens next.

      3. The latest helicopter video show a lot of dark stain now in the water.

        I guess that this is volcanic ash.

    1. Thanks for the link. But I do not think it is for me. As all I want to do is to build electronics, write books and watch earthquakes and volcanoes.

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