Posted on by Jón Frímann

Analysis of the Helgafell mountain earthquake on Reykjanes

Icelandic Met Office has posted an interesting analysis of the last weeks earthquake on the Reykjanes. But this earthquakes where connected to Krýsuvík volcano activity. By relocating the earthquakes, it is possible for Iceland Met Office to see better how long and how deep the fault that created this earthquakes is. In this case, it was around 2 km long and the movement was east-west, like the one found on SISZ.


The re-located earthquakes. The green ones are normal locations, the orange ones are re-located earthquakes. Copyright of this image belongs to Iceland Met Office.

The orange ones are re-located using relative locations. I am not sure how this technique works. But it often gives better image on what is going on with the earthquakes. Both in terms of the fissure making the earthquakes and the depth where they are taking place.

The fissure in question was on N-S axes and is inclined about 70° in west direction. According to IMO, the aftershocks suggest that movement of this fissure was right slip, along with minor drop in it. That means this according to IMO. The west part of the fissure moved to north and down, while the west part of the fissure moved to the south and little bit upwards. According to IMO. This movements happens in SISZ on large fissures there (when they break).

I am currently waiting for more earthquakes in this area. This activity is not over in my opinion any time soon.

Source of data: Week 9 – Iceland Met Office (Icelandic).

Other: I am sorry for lack of updates. There has not been anything special going on and I have been working on confirming getting an apartment in May 2012.

Blog post updated at 09.03.2012 at 17:37 CET. Fixed spelling error.

42 Replies to “Analysis of the Helgafell mountain earthquake on Reykjanes”

  4. There’s a strong solar storm hitting us this morning between 6am and 10am, it will be interesting to see if
    that leads to any seismic activity as it imparts that energy into earth.

    1. Not seismic activity but may affect GPS measurements giving wrong values on the GPS stations.

    2. Sorry, but this is not a strong solar storm – we had already stronger ones this year. And no, the sun has no effect on the seismicity of the earth.

  6. @CHRIS The storm hitting us today is from an X5 class flare, so it is pretty strong. The one earlier this week was from an M class flare as was the one last month.

    Check out spaceweather.com and also the KP INDEX if it hits 7 that will bring Aurora to Southern UK.

    1. You are right – I rememebered a flare from january in the wrong category. But this will also not cause any change in the seismiscity of the earth. I can however cause troubles with satellites.

  7. What’s up with Eyja? 2 quakes not far from each other at Básar, low quality though.
    Anybody any ideas?
    Henk

  8. Very good article and very interesting for me, thanks Jon.

    You write :
    “The orange ones are re-located using relative locations. I am not sure how this technique works.”
    Maybe I know this technique.

    20 years ago, I’ve work on “méthode des doublets” (in french).
    It means to analyse P and S waves, compare differences of arrival time using wave form.
    We had a very good geophone network well located, and local seismic crisis in France with a few houndred of microseisms.
    In France means low intensity (like the “big one” Ml 3, and the other Ml 1 or less).

    To resume, with this little differences, we relocate every seism vith 1 or more other, and you repeat more and more until …
    … you define the fault geometry in 3D, and the comparison with other methods was very good.

    I hope you understand what I write (it’s more easy to explain in french …).
    Anyway, thanks to you, I feel younger of 20 years !

  9. Well Katla 2 earthquakes with a little more quality to 11.6 km
    2012-03-08 18:19:54,8 63,626 -19,224 11,6 1,9 80,84 2,0 km SA af Goðabungu
    2012-03-08 18:02:17,1 63,592 -19,107 11,6 0,2 70,86 1,4 km NNV af Hábungu

  10. There is an fake earthquake in west Iceland. It did not appear on my geophone at Hvammstangi and is clearly an fake earthquake. I base that on the data from Ásbjarnarstaðir SIL station.

      1. The spike is too big. But now there is an spike taking place on other SIL stations also. So I do not know what to make out of this at the moment.

    2. It is only 47.6 quality but that is not a cetainty that it is unreal. Alas I dont think their geologist review them at night.

  12. Interestingly, although we have a excellent Civil protection service and search and rescue teams, no response plan exists for most of the country.
    It only exists for Eyjafjallajokull and Katla, not even for Reykjanes, where two thirds of the population live.
    I read about this some time ago and from what i could tell someone wrote a report detailing all the possible dangers of volcanic nature that might pose a threat to the Reykjanes area, but it scared some people so it never saw the light of day.
    This is something that needs to be fixed.

    If something major happens, and it quite easily could, then we will have a elite force of highly trained people running in circles, clueless of what to do.

  13. I am planning on writing about the Mw6.8 earthquake that did happen this morning in Vanuatu. But at currently I do not have the time to do so. I hope to write about it later today.

  14. I hope I don´t sound like a nitpicker when I correct your English and I hope you can just appreciate it. I think you should use the word Analysis instead of Analyze. Analyze is the verb form. It’s just that you use the word alot. OK? I hope so.

    3. Thanks for this. I will correct this. I am no master in English yet. I still have not yet gotten my 10.000 hours before I get into that level.

      1. I see some people take this an insult but that is not at all my intention. Even after having lived the last 25 years in Spain, I really appreciate it when somebody corrects my Spanish. I have been a follower of this blog ever since the Ejafjallajökull eruption and I have noticed that Jon wants to improve his English so I just thought he would even prefer to know. The way everyone expresses themselves here is appreciated by me and some neat words turn up at times. I have spent my life making up new words all the time. It is important to me that you understand that I have no pretentions and don´t feel superior.

      2. This is how the internet is. Nothing can be done about it. But I am thankful for corrections when I get them. As I am no master of English yet.

      4. buenamusa. I noticed you said Ejafjallajökull i your comment above 🙂
        Its actually Eyjafjallajökull.
        Just teasing 😉

      5. 😳 I didn’t notice that one either. A trip to the opticians seems to be in order for me.

      6. I even have to correct my own English lol. It´s pretensions and not pretentions. Geez I´m forgetting my own language since I use it so rarely. Anyways I won´t go on anymore about this, I just had to fix this because I might not be able to sleep over it. lol

  15. I’m on your side there Jon, I couldn’t speak icelandic or even get close. I have no trouble with what you mean so dont take it
    to heart. There’s far more serious stuff in here to worry about!

  16. As an interested novice I very much appreciate everything you write and have no problem understanding you.

    1. No problem. Thank you for letting us know, but look forward to the next post when you have the time / energy.

      2. Yes it is, beautiful, mysterious, dangerous.
        Absolutely perfect.
        Hope it stays that way for ever.

    2. I enjoyed those glimpses very much thankyou. We are totally in synch with nature, which is why we live in the
      Outer Hebrides, and neither Mary nor I would swap it for anything, we would come and visit Iceland if means
      allowed, but I imagine you would need quite a bit if time there to fully appreciate what is around you.

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