Posted on by Jón Frímann

Frost earthquakes around Eyjafjallajökull volcano and Mýrdalsjökull

Over the last few hours it has been getting cold. The frost has been getting down to -10C and even colder in the higher areas. This has started a interesting events that takes place in Iceland (this might happen elsewhere too). But the events that take place here are frost earthquakes. This are not real earthquakes, but a event that the frost creates and are in fact false earthquakes. Most of them are too small and too poor in terms of quality to be located by the SIL network that Icelandic Met Office has. But when there is a sudden drop in temperature the frost earthquakes can appear on the SIL network, but with a extremely low quality. The driving force behind this earthquakes is water that is freezing in the ground and in rocks (cracks).

During the next 24 hours or so there is going to be a cold snap in Iceland with temperature going down to -20C in some areas, and even lower at glacier and higher areas. So we can expect a lot of frost earthquakes (false earthquakes) in that time. So the Icelandic Met Office maps might start to look interesting and with a lot of earthquakes in the next 24 hours.


Picture: Icelandic Met Office Picture saved: 6th January 2011 at 20:39 UTC.

Frost earthquakes on Fagurholsmyri SIL station close to Öræfajökull volcano and Esjufjöll volcano. This frost earthquakes are not located by the automatic SIL system.

The weather forecast in Iceland: Temperature

Iceland news about this. Use Google translate at own risk.

Frostbrestir í Eyjafjallajökli (Vísir.is)

Text is updated at 22:46 UTC on 6th of January 2011. News link is added.

63 Replies to “Frost earthquakes around Eyjafjallajökull volcano and Mýrdalsjökull”

  1. Jon, 16 of those earthquakes are deeper than 4 km. Are these false readings?

    1. If the quality is lower then 50.00 then it is a good chance. The better the quality number is, the better the chance that the earthquake is correctly located by the automatic system. Earthquake that have 99.00 in quality have been manually reviewed by a seismologist at Icelandic Met Office.

    1. The problem with these quakes is that they are hard to locate. So depth and position might be wrong. And most of them will probably disappear, when the quakes are reviewed by experts.

    2. This is blog is complete nonsense and ungrounded. (don’t take it personal. 😉 )
      Earthquakes in Katla volcano are very common. EQ’s with the magnitude 4+ have occured in the past century without anything happening. As long as there is no inflation and no real EQ swarms I wouldn’t worry about an eruption in the near future.

      Though some of these deep earthquakes may be precursors to what will be a new period of inflation, but it could also just mean nothing at all.

      1. Not that my opinion matters much because I’m only one person, but I like the blog the way it is. The geeks as well as the comedic scientists and their theories are highly entertaining. It’s like a volcanic soap opera.

    4. Yes it was hilarious, but on the other hand, it is easy for us to laugh since we have a bit of knowledge and have been studying it hard. Ontop of that we have Jón with good info on what is happening.
      So we know that part of the increase of quakes are due to better and more SIL-equipment, we know about frost-quakes (happens in northern scandinavia too), and about other things. But if we didn’t we would also go more wrong (and we, or at least I, do go wrong from time to time).
      I am just surprised that they don’t go off more. I thought a good survivalist blog-post would have contained Katla as a part of “The Man” testing new weapons 🙂

      PS, we’ve had a case of spontaineous bird-death in Sweden now. Same species of birds, same tiny area with a bucket load of dead birds. Apparantly they all died from blunt force trauma that some scientist dude said was caused by fireworks. And there was when even I started to say things about “The Man”. If they would have died from fireworks it should have been on new years eve, not five days later… DS.

      1. Well… the one “theory” that will be popping up soon, is that they collided with a UFO or some new Chinese Stealth aircraft….

      2. The thing that bugs me is that we now (as far as I know) have two cases in the US and one in Falköping Sweden. And sofar I have not heard one good theory.
        What even bugs me more is that even I can’t come up with a good theory, or even a way to cause that to happen myself. And I have a wild imagination comming up with weaponry. Something tells me this is not the last time we will hear about something like this, hope I am wrong though.

      3. Well, the best (and most likely) idea I have heard is in answer to the question “Why do dead birds fall from the sky?”

        Answer: “Because they are dead.”

  3. As a whise man said (Lurking) we will get technology skew in our data for Katla and Eyja. We also have those pesky frost-crackings in the ground. But even after counting this we have had a bit more of the real quakes the last day.
    Either we are having a small quake-swarm (we have seen larger) or something else is happening.
    If it is not a small quake-swarm, here is what I think is happening based on my experience with large integrated measuring systems.
    We all know that they have integrated new and more sensitive equipment during the last few days. When they brought them online they have to be finetuned to work properly with the older, not so sensitive, equipment. And here comes the rub I think. The programs they are using are tuned to the old equipment, all of a sudden that same program gets data from more sensitive equipment (shows as harder energy levels) and the program quite simply takes these data and believes it is seeing stronger quakes than there really are.
    Let’s say that we have a 0,2 quake recorded at one of the new ones (the old wouldn’t have seen it), and when that data is received by the program it will believe it to be stronger. Let us say that the new equipment is ten times more sensitive than the old, that means that the program will put it up as a 0,8 to 1.0 (ten times the powerlevel).
    This is just a theory, but I have seen this happen in a lot of other systems. If I am correct they will tune it quickly and it will go back to normal.

  4. Yes, but still the levels of the different stations would be different. If they remembered to take that into count in the automatic program then all is fine, but if they didn’t it would make the problem I mentioned above. I’ve noticed this on other automated measurin systems before. I know, those where not SIL-systems, instead those where hydrophones, but the difference is pretty much nil since we are talking about wave-forms (sound in a sense).

    For those not so savvy in tech, what we area talking about is the level of sensitivity in a “microphone”. The more sensitive a microphone is the higher output it has, that is why two different microphones hooked up into a mixer-table will give different volumes at the same settings according to their sensitivity. In a sound studio you tweak the gain potentiometer on the input to correct this. The principle I am talking about here is exactly the same, if you do not tweak the gain on the microphones (SILs) the more sensitive ones will send in a higher volume into the system. And “volume” is a key-ingrediant when calculating the force of a quake.

    Probably they remembered to correct the input “volume”, but if they didn’t it would make a lot of small quakes into large quakes. But the only way to be certain would be to look at an old station and a new one to see clearly if it is the case, something neither Jón or me can do.

    1. I often see small earthquakes close to my Hekla sensors with a sharp spike. But they are still just ML0.2 or ML0.6 in size. Today I got one small earthquake like that.

      1. Yes, but your sensor and your software is made for each other, correct?
        If you then put in one that is ten times as sensitive the same software should be seeing it as a larger quake.
        As I said, I am far from certain that this is causing all the extra (non-small) quakes we are seeing, but it might be an explanation.

      2. The software and the hardware is made to work with each other as always. But this software can be used with seismometers that have 20 second long period and are able to detect earthquakes that happen other side of the planet.

        Seismometers measure energy and ground displacement. Nothing more.

    2. Over a period of a few days or weeks, we’ll be able to do a raw “quake per unit of time count” and compare it with the time before the new sensors went online. The slope change (before and after) will demonstrate the effect that the sensors have on what is the new normal is.

      1. For now I will just stop counting anything below 1.0, might be best anyhoo (attack of canuckianisms) since nothing under that has much of a meaning.

        By the way, new world record of manmade quake without a nuke. 3,4 quake registered for 20 seconds at the Aitik mine. Continous serial blast in a day mine.

        Aitik (and we wonder why others get scared when swedes say the word mine…) When visiting the site below, click on “Sprängning i Aitik” for a video of the record blast.
        http://www.boliden.com/www/bolidense.nsf/dcf92b4a139e3756c1256d9600213f86/b36b74b026017415c1256dbe00295bfb?OpenDocument

        Yepp, I wanna do that to a certain volcano in Iceland… 😉

      3. Oh… You know, that would be a wet dream, at least as long as the new magma has the same chemical composition.
        But in this case the volcano hasn’t erupted since time immemorial.
        And in reallity, if and when we get a permit we would still be doing it as a much smaller operation. The reason for this being the problem with hireing enough people to run the operation, after all we would need a refining plant and a foundry pretty much onsite.

        But… if you got the volcano going the benefit would be that it was allready melted… 🙂

      1. Aust is interesting. Did you want to know that I think the old lady will whistle a tune before long ?

      2. Kind of my thought too, most people seem to bet on Godabunga, but in my (non volcanologist) opinion there seems to be more data supporting something happening around the Aust part of the Katla Volcano.

  9. Interesting. Today we note no quakes since midnight. So…

    (a) has it warmed up in Iceland? Nope. Overnight temperatures were bitter as arctic flow established itself, so why no frost quakes at a time of diurnal minimum temperatures?
    (b) has the website not been updates? Possibly, last quake showing at 00:23

    1. I don’t know either. Could Eyja have really been collapsing slightly into it’s magma chamber now it is emptier? Could cold weather causing faster cooling been the final straw de-stabilising it? I guess that would have shown a corresponding deflation on GPS though.

      Perhaps ice cracks as it drops through a certain temperature zone e.g. as it gets colder than -10 degrees. Beyond that, perhaps it either isn’t going to crack, or has already done so. That doesn’t make much sense for some of the deeper quakes though as there would be a very long time lag for the low temperatures to reach those depths, even if they ever did.

      Perhaps IMO had a data processing problem as a result of alterations when adding in the new seimometers?

      Does anyone else have any ideas?

      2. No, there has not.
        The deflation you are seeing is all happening during and right after the eruption, then it ended. The same is also obvious when looking across the board of sensors.

        The deflating ones are SVBH, THEY, FIM2 and SKOG.
        The inflators are SOHO, DAGF, HAMR, BAS2, ENTA, GOLA and AUST.
        The rest are stable.

        It is the normal process of a volcano that has erupted but is still in some senses of the word actice. Som of the sensors are also indicative for Katla. AUST for instance is a sign of immanent eruptive capabillity of Katla.

      3. If look at the last few digits of stations around Eyja, you can see a sudden drop, this was around the time of the unusual earthquake swarm around this area, that’s what I was referring to.

      4. Yes, but it is still just a small shift and it is during severe storm conditions. I would just wait a bit.

        The “swarm” of quakes is probably not an increase since the IMO have inserted more sensors into the system, and are experiencing severe integration problems.

        But, I would say that Eyja is not going to do anything for quite some time. All the evidence points to the other end of the Katla caldera as a center of activity.

      5. I agree with you on that, we’ll just wait and see what this beautiful country has in store for us. 🙂

    2. There is a severe storm going over Iceland actually. This creates a lot of noise on the seismometers and makes so much background, that all the small quakes get lost in it. Have a look on Jóns helicorder, IMO has the same problems. We don’t see any small new quakes, since the storm started.

      2. How do people in Iceland cope with the weather. We have difficulty heating our houses below about -8C as they lose heat faster than we can heat them, and our gales cause lots of damage, yet are nothing like the strength of gales Iceland gets. I presume Icelandic houses are built better?

      3. Weather like this is not unsual in the winter here in Iceland. Especially storms are common. And of course the building code for houses is adapted to this. For example we have only metal roofs here – so there are no tiles flying from the roofs.
        And heating, well, a lot of this simply comes from the ground 🙂

      4. Weather here torrential rain – can’t see across the road. Lots of flooding and it has not got light all day, but we don’t get your awful winds very often.

      5. Treacleminer; thing is that you “islanders” have a wish to punnish yourselfs. It is easy to survive with insulation and good heating in every room. A warm waterbottel in the oven is not, and has never been a good idea to keap really warm.
        I employed a britt last winter straight out of Cambridge, but she left after just a couple of months due to feeling to much heat indoors.

      6. Yes, we don’t prepare for weather we rarely get, so when we do get it, we can’t cope it properly. Snow is a good example. We hardly ever get is, and when we do – even less than 1cm, traffic grinds to a standstill and we can get to work and the shops cannot get goods to sell. We go years without a frost hard enough to burst pipes, then when we get a strong frost, all our outside pipes burst and ones under roads; so many at once it takes ages to mend them and many people end up with no water supply. NI was affected most, but all over UK there were water supply problems due to burst water pipes.

      7. @Treacleminer:
        Thing is that I freeze in UK houses at plus ten, I find that the lack of central heating make them making my joints to ache… But I have probably gotten soft in the overheated nordic houses 😉

  13. Some of those Mila cams are getting a right old shaking. That storm you have there must be something!

  14. Cant add much here but I noticed something.

    I have never heard of the word ‘immanent’ until reading this blog. I looked the word up and it seems an immanent eruption is something that can be considered possible based on knowledge we have now. It could be millions of years away.

    Imminent sounds like the better word?

    http://dictionary.reference.com/browse/imminent

    1. Dang, Andy! I never even thought it could be something else than a typo of ‘imminent’, but indeed, it is a valid word in its own right. You live and you learn…

  15. But why the rash of quakes all around Myrda and Katla and not just right under Eyja if it is suspected to be deflating, and if its frost quakes, why not also all around Iceland where there is a spike in low temps? The rash right now is appearing only all around Myrda, so I like Lurkings explanation the most as the major contributor.

    At the minimun, IMO is doing rea time testing/debugging of software/hardware integration perhaps while there are key events happening where scientists need to interpret the data. However, they can’t right now as they can’t hold constant or remove the effect of these other suspected variables within a reasonable level of confidence.

    This is par for the course though in software/hardware. Just think what a huge real time experiment MS operating system is by necessity. There is no way you could do anything other than using us all a testers and this is why Iran’s nuke program and Siemens maching logic controlls were so flawed in the first place, they used Bill Gates’s crap . Stuxnet wins the day you Nazi S*** head Mullahs.

    Now Ron, be polite to these people

    2. Why you don’t see this all around Iceland? Because the region around Eyjafjallajökull and Katla has much more monitoring equipment in position than any other corner of this country. And they just added more stuff, financed by the British Geological Survey. If you look closer, you will find more. Thats an old story.

      1. Perhaps, and I am not up on the density of sensors, but if you look at the IMO quake map, all the quakes are visiting the Myrda Tavern and drinking heavily and the other bars in iceland and ghost towns, so why not some pattern that follows the density of sensor, this variable of course posited to be the main contributor.

    3. Or, perhaps its a collusion of all these suspected variables making a big vegetable soup of mixed signals confounding any attempt to posit anything with confidence. No paradigm shifts here until the methods and data can be aligned.

  16. IF you really want to abbreviate Mýrdalsjökull, then please at least use ‘Myrdal’, so it’s a word with a meaning…

    1. Or how bout just, “M”. I surely don’t want to offend the delicate sensitivities of anyone else.

  17. Estimated thickness of ash-layer from the eruption in Eyjafjallajökull
    http://www.vedur.is/vedur/frodleikur/greinar/bigimg/2076?ListID=0

    From an article re. melting glaciers after the ash fell.

    Thin layer = more ice melt down as see in Jökulsá á Fjöllum (north of Vatnajökull) that equals 1,2 meters of ice in the area that supplies water to the river. Same applies to Skaftá. Exception is Langjökull, where the melt down is apparent to the south (less porous ground to the south) but not north – it’s still evident that Langjökull has lost a lot of ice last summer.

    Thick layer = no melt down, as in Eyjafjallajökull and north of it.

    http://www.vedur.is/um-vi/frettir/2011/nr/2096?ListID=0

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