Posted on by Jón Frímann

Sharp earthquake activity in Katla volcano – Update 1

Tonight (20-June-2017) there has been a sharp increase in earthquake activity in Katla volcano. Largest earthquake so far had the magnitude of 3,6. At the moment I’m not sure about other earthquakes magnitudes. I’ll update this article once I have them. The current situation seems be less stable than it appears (based on IMO notice earlier this evening).


Current earthquake activity in Katla volcano. Copyright of this image belongs to Icelandic Met Office.

The harmonic tremor plots have not yet updated for the area around Katla volcano. They update only once every 30 minutes that leaves me currently without any harmonic tremor data at the moment. I’ll post an update once I have those updates.

At the writing of this article an eruption has not yet started. That might change without warning.

This article is going to get update or a new written as this situation develops.

Update 1

Activity in Katla volcano has gone back to background levels in the last few hours. This is the second earthquake swarm in Katla volcano in the last two days, the last one being on the 19-June-2017. Nothing unusual is appearing on the harmonic tremor plots at the moment.


The earthquake activity in Katla volcano at 21:35 UTC. Copyright of this image belongs to Icelandic Met Office.


The main earthquake so far with magnitude 3,6. This image is filtered at 1Hz due to wind noise. This image is released under Creative Commons Licence. Please see CC Licence page for more details.


The second earthquake activity. It is strange to look at on this plot. Seems to be one long continuous earthquake until it drops off. This image is released under Creative Commons Licence. Please see CC Licence page for more details.

Currently there are strong wind in south Iceland making it difficult for me to monitor Katla volcano due to wind and ocean wave noise.

This article was updated at 21:45 UTC.

18 Replies to “Sharp earthquake activity in Katla volcano – Update 1”

  1. She seems to be starting where she left of Jon I would think she is going to do something before much longer

    2. Maybe so maybe no. As I recall the last large Katla eruption was preceded by a sustained period of *felt* seismicity; houses were shaking in Vik and around the local area. The current seismicity isn’t anywhere near that strength yet.

      Of course there’s no guarantee the volcano will repeat itself; it’s big enough and active enough to have several kinds of precursory setup and eruptive style.

      1. Current earthquake activity seems to be a pre-earthquake activity before an eruption happens. There are going to be earthquakes in the magnitude range of 4,0 – 6,0 once magma starts to push up through the crust and the magma chamber starts to get empty.

        The problem is that what happens before an eruption in Katla volcano is not well known.

  2. Ooh booked to go to Iceland next month don’t know whether to be excited or scared now.

      2. Is it just me that finds that map excruciatingly annoying? The clickable hotspots are like 1×1 pixels, and some aren’t even clickable.

        To locate a specific station, this map is really useful: http://hraun.vedur.is/ja/skjalftar/silstn.html

        And then there’s this site with all the tremor plots [http://hraun.vedur.is/ja/oroi/allarsort.html], but I usually just type in “aus” in my browser and the cache memory finds the address for the aus.gif tremor plot [http://hraun.vedur.is/ja/oroi/aus.gif]. After that I simply type in whatever specific station i wanna check next, changing aus.gif to dyn.gif, von.gif, alf.gif … and so on.

      3. That is the problem with the English website. Everything works (besides the removed SIL stations) on the Icelandic website. I don’t know why IMO doesn’t update the English website.

  5. Still waiting for most of the earthquakes of this swarm to be manually checked.
    As of now the second “big” spike is set to magnitude 3.0 (manually checked), but the very first quake of the sequence looks obviously bigger in the Austmannsbunga drumplot. This EQ is however not checked yet. It should be a green star, imho.

    1. Sorry, my bad. The M3.0 is NOT manually checked.
      The M3.6 is the only manually checked earthquake in Myrdalsjökull since the start of yesterday’s swarm.

      Some more movement in the Katla caldera just now, by the way.

  6. Now it gets more interesting; not large quakes but at a variety of depths and at various points around the caldera. Not all at 0.1km depth any more.

    1. Some of them might be deeper than the usual near-surface ‘popping’, but is a bit hard to tell, since the magnitude 3.6 is the only corrected quake since yesterday’s swarm started.

    2. Now some more EQs are checked, and in deed you are right, Mike. For example, the first EQ of yesterday’s swarm sequence was a M1.9 at a depth of 14 km! That is unusually strong for such a deep EQ.

Comments are closed.