Quiet time in earthquakes around and in Iceland

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Currently there is a quiet time taking place in Iceland. This sometimes happens. It does not mean that all activity has stopped. But it just means that the most of the earthquakes that are taking place are so called microearthquakes and that they are less then ML3.0 in size. But the thing about microearthquakes is that they are not useless, as this (pdf, English) report from Icelandic Met Office shows.

While it is quiet as it is I am going to relax a little. So that I can take on the busy times better.

30 Replies to “Quiet time in earthquakes around and in Iceland”

      1. Oh I’m not doubting the lack of activity. It’s just that in Iceland quiet is abnormal… seismically speaking.

        Occasionally, I’ve run FFT’s against the quake data and (naturally) keep seeing periodicities pop out. Nothing consistent, but 54, 27 and other multiples close to 9 (days) keep showing up. Could be a vagary of what I’m doing, could point to some oddity in the way Iceland works. (note, this is not firm, some of those numbers have to be wrenched into place)

    1. This is the strain related to both Eyjafjallajökull and maybe Hekla volcanoes. This drop in strain might be related to changes in those volcanoes. Maybe a new eruption is being prepared in either one of those volcanoes. But that is just a speculation on my part. Only time is going to tell us what this means.

      1. And the answer is… In either one minute, one hour, one day, one week, one month, one year, but definitly within 50 years… And nobody can do a better prediction than that of Hekla.
        There are no warning in good time on this one.

      2. It is the same strain-meter that showed signs before Hekla bopped last time, but and it is a big BUT, it also had a large quake at the same time. If it does like that and band a M4+ than it is time to run for the hills because last time it erupted just a few minutes after. Hekla just needs one beer…

        We might just be sitting here and looking away for five minutes and come back and the eruption is in full swing.

      3. That station was the station at Búrfell, that station is quiet. So I am guessing that this is related to Eyjafjallajökull changes, not Hekla. If that is the case to start with.

  1. I am seeing on my Hekla geophone few low period earthquakes. I am unsure where they are coming from. But I am assuming Goðabunga until otherwise is proven.

    1. They are visible on some tremor-charts to. They are 3 sharp lines, they are showing on all plots around Myrdalsjökull, most clearly on Lagu-Hvolar. But they the same 3 distinct lines are possible to see as far away as Gygarholskot-SIL and SAU + SAU.
      Here they are on HVO:
      http://hraun.vedur.is/ja/oroi/hvo.gif

      And of course they are the sharpest and most powerfull on GOD.
      http://hraun.vedur.is/ja/Katla2009/oroi_god.html

      So I think you are very much right and it is some slight movement under Goðabunga.

  2. My question is how long do you think that the inside the earth will continue to produce earthquakes and super eruptions? It seems to me that the time for giant eruptions are waining for the inside is cooling down. Does anyone have any way of comparing temperatures of lava that is erupting now compared to years ago?

    Thanks dragondp

      1. No, it is known: By interaction of radioactive decay heat (from radioactive isotopes inside Earth’s core) and magnetohydrodynamic forces. That’s one hell of a kettle boiling, and it will still keep boiling vigorously for a few gigayears from now on… So, no worries, it is not going anywhere soon!!!

    1. @dragondp : I’ve posted this question before, and it seems that temperatures underneath are pretty much the same of those from Pleistocene. So, there is no waning, just a change in concurrent conditions for something in a large scale to happen in our life-time span. We must be patient and be happy to see Eyjaf’ kind fireworks or some more explosive ones like Merapi’s VE4 in a short term period. But hear what more knowledgeable people have to say.

    2. The interior of the earth is slooowly cooling down. But it is a very slooow process, since radioactive decay is constantly producing additional heat. Long half-life isotopes of many elements incl. uranium, potasium, and many others will provide additional heat for a long time to come. Therefore, we are going to have plate tectonics for a long time to come and won’t suffer the fate that befell martian plate tectonics and volcanism.

      1. But it will never cool down enitrelly since the tidal effect causes frictional heat.
        But otherwise I totally agree with Holger, it is sloooooooowly cooling off, and then I mean slowly even in geological terms.
        We will never see a difference and there wont be noticable difference in a million years either.
        It should have cooled off enough to hinder eruptions at least a bit around the time earth is swallowed by the expansion of the sun as it turns into a red “giant” in 1 or 2 billion years time…

    1. That would be weather related, the warm water in the crater is steaming in the cold. It is after all 8 – 10 degrees below zero centigrades ontop of Eyja now.
      Although I feel that it is warm there, I have minus 28… And that is 8 degrees colder than in a freezer. Warm water when it is minus steams a lot and that is what you are seeing.

  3. You can clearly see a “line” of earthquakes today: Rekjanes, Thingsvellir, Langjokull, Blondulon, and there there there seems to be a line of earthquakes to north of Myvatn.
    Maybe this is a old fault?

    The pattern seems more than a simple coincidence. I strongly think tha the fault that runs between Thingsvellir to Langjokull continues north to Myvatn, where the earthquakes are now occuring. Or maybe not the same one, but a parallel one, like the several ones existing in Reykjanes.

    1. This is just a pattern that you are seeing. It doesn’t mean anything. If there is a earthquake on a fault line you see it. But it is not going to cross all over Iceland as you think that you are seeing. The longest fault in Iceland are maybe 15 to 20 km (Mw6,3 earthquake). I do not know how large the fault line is from a Mw7.0 earthquake in Iceland. But that is just because how rare those earthquakes are.

      There is a new earthquake swarm north of Iceland taking place now. It is not far from Kolbeinsey island.

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