Posted on by Jón Frímann

Small earthquake swarm in Hengill volcano

Yesterday (17.01.2012) an small earthquake swarm started in Hengill volcano. This earthquake is in the area where Orkuveita Reykjavíkur (OR) has been pumping down cold water from the hydro-thermal power plant that they have in the area. So far the largest earthquake in this minor earthquake swarm is just ML2.0 in size according to automatic size estimation. The depth of this earthquake swarm is around 5 km.


The earthquake activity in Hengill volcano today and yesterday (17.01.2012 and 18.01.2012). Copyright of this picture belongs to Iceland Meteorological Office.

The earthquake activity in this area repeats it self regularly due to water being pumped down into the ground. This has increased the risk of large (Mb5.0 or larger) earthquake in this area. But it is impossible to be sure if such events take place. As this is most likely just going to speed up an process that is already in place by nature forces in Hengill volcano (earthquakes, nothing else). So for the moment, the only thing that can be done is to wait and see what happens next.

13 Replies to “Small earthquake swarm in Hengill volcano”

  1. The swarm looks very much like what happens at Clear Lake in California, USA. If you look at the daily quakes, the pattern is quite similar with many shallow (1.0-4.5) quakes taking place in the mountain surrounding the caldera. Clear Lake has never been active in historical time, but is definitely a Holocene center. If Clear Lake is a good indicator for what they’re experiencing at Hengill, you can probably expect this swarm to eventually become quite persistent. Clear Lake has had an ongoing swarm since they installed the geothermal plants in the late 1990’s! Fortunately, only wine farmers out there!

  2. http://icelandgeology.net/?p=1929
    here is a link to previous Blog Post and discussions about Hengil. Things have been much quieter there recently.
    Good luck and best wishes Jon for your new format. I look forward to reading more cool postings 🙂

  3. Never spotted a red dot there:

    Thursday
    19.01.2012 10:09:18 63.452 -15.295 4.2 km 2.5 71.59 89.0 km S of Höfn í Hornafirði

      1. There was another earthquake there last night. This was an isolated earthquake two days after the swarm that Jon spoke of.

  4. Thanks Jon for your widening area of interest. Greece and the Mediterranean are sometimes a focus of interest requiring a wider understanding. Germany and the Czech Republic have some interesting volcanic phenomena, which we know little about, but for now it is Iceland and El Hierro that are capturing our interest, and there is plenty going on there for us to learn about.

    Best wishes

    1. Interesting vortices. I have no idea of what they are.

      There were no never earthquakes detected in that zone out in the sea, although the area of those vortices is far from the mainland and earthquakes could go unnoticed. As far as we know this are is non-volcanic.

      However recently we have seen signs that indicate that there could be more geological activity that we dont know much about it, out there in the sea. Like the recent activity 90km southeast of Hofn, or some earthquakes that sometimes occur south of the SISZ quite out in the sea.

      Iceland has two volcano-tectonic rifts and several off-rift volcanoes, and even old volcanic rifts to the west and north (even active ones, like Snaefellsnes). It could be that maybe there are other volcanic systems further away from mainland that we are not aware of.

  8. I know it has nothing to do with the earthquakes in hengill volcano, but it seems that el Hierro eruption has stopped, but inflation has not got back to its formal levels, does that mean that he volcano has still some potentially eruptible magma or does it mean that the magma has cooled down and solidified?

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