Krísuvík volcano / Kleifarvatn lake static image

Here is a image from Icelandic Met Office about the earthquakes that have been taking place in Krísuvík volcano over the past few weeks. This plot shows the latest 15 days.

This image is from Icelandic Met Office. Copyright belongs to them. The original copy can be found here. Click on the image for full resolution.

62 Replies to “Krísuvík volcano / Kleifarvatn lake static image”

  1. Those look like something that I might have spit out.

    So… I still can’t to a moment tensor, and don’t quite understand which magnitude value they are using to start the calculation with (they list M and ML in their data) Every time I do it I get a value out in left field by comparison to their data run,so I don’t plot them.

    Bad data is worse than no data.

    But I can sling a mean plot. Using the MET graphic for the boundary conditions, and data from the SIL listing, here is the what they plotted, but in 3D and 4D (perspective plot).

    View North:

    View East:

    Perspective (looking NNW):

  2. Okay… here is where I’m getting tangled up.

    The SIL list has two columns, “M” and “ML”. The “M” column is generally pretty close to what goes up on the MET website for the quake magnitudes. I have scoured high and low for a decent.. at least semi-close formulation to derive Mo. The only one I found that gets me halfway into the ballpark is from

    The document at

    Gives a reasonably good translation of a few of the Ms – Mw – mb – ML interrelationships… and yes, I do understand that there is the slight problem of shear modulus and fault area that I don’t have ready access to.

    But even with that problem, I should at least be able to get reasonably close to the Mo plot from MET.

    Here’s what I have…

    I’ve provided a snippet of the imported spreadsheet data so that you (someone) can see where my info sits and to possibly help me resolve my issue.

    Any help would be appreciated.

    1. I think I know what they are doing. (90 percent shure at least)

      Shear and modulus factors are beyond the grasp of them, only place where you with any certainty can factor that in is in mines or in areas where you have massive amounts of bore cores to study. This due to the need to know the material involved and the exact location, composition and size of the faults.
      So instead it looks like they are treating both the M and ML as outlayers and do a mathematical average on the difference on them. I think they work on that assumption at least.

      But they would probably give you the answer if you emailed them.

    1. Yepp, and that is where you get the summing over M and ML, since they treat them as the outlayers to be normalized. I summed the first posts of your “snippet” and got results (to few) that looked like it would fit a renormalisation curve compatible with theirs.

  3. I’ve done the email thing before on a different subject, got no response. (had to do with weather the quake depth is below MSL or the surface)

    I’m also not even sure that I’m doing this right. This is just the most recent incarnation of the attempt…. and the only one which yields data in the same power of 10 that the professionals come up with.

    I’ve done the straight energy conversion to Joules on past quakes, but if there is a “usual” way that its done, I would prefer to use that. When it was just Grímsvötn it was no big deal.

    Another aspect that I haven;t looked at due to this distraction, is a comparison of the area sampled to the Grímsvötn plot. That would determine if the two plots could be compared.

    Hmm.. I’m getting Captca queries now. Odd.

    1. Yeah, they are not good at answering mails.
      I sent one to the Energy department of Iceland and got an answer. I sent a really long letter and I received the very thorough, factfilled and helpfull answer of… “Takk fyrir.”
      Not even a signature… And then they wonder why no one does business in Iceland. 🙁

  4. So do any of you experts know what these plots are likely to signify going on?

    Hope all of you in Iceland survived your storms without to much costly damage.

  5. Well… I’m not an expert, but the accumulated moment tensor plot is similar in function to the one that is maintained for Grímsvötn.

    In Grímsvötn’s case, the idea is that if you compare the accumulated moment tensor since the last eruption with the moment tensor run-up prior to that, you can get an idea of where the volcano is at in it’s preparation for the next eruption.

    Personally, I think it’s a pretty nifty idea. It gives you a measure of how much seismic energy has been expended in a given region. This is the reason that I’ve been trying to figure out how to replicate the plot so that I can run it against areas of interest that come up on this blog or over at Eruptions. Currently all I am able to do is a straight Magnitude to Joule conversion.

    So far… I’ve found that it’s very likely that all of these computations are region dependent. At least that’s the only explanation that makes sense.

    As for the other graphs… the time v latitude or longitude would indicate if there is a moving magmatic mass or if there was some tectonic trend that tracked with a fault complex. The same thing for the depth. Quake count and Magnitude indicate if things are heating up or dieing down. I’ve done similar plots for other regions. They are great for speculation purposes.

  6. Hey…. Treacleminer, I think you just handed me a boon. 😀

    I am about one year shy of having all the data that was used in the post 2004 Grímsvötn graphic. And it’s clearly based off of the ML value.

    Now all I need to do is slice off a couple of hours to fiddle around with that. (wife had discovered that Christmas is near, so I have to deal with that too)

    1. @Lurking:
      Thank you so much for your plots. They are and will be always welcome.
      Tell your wife, in our name, that we are most grateful for your self-sacrificing work, and that we kindly ask her to be understanding towards the benefits you are granting us.
      Merry Christmas to you and your family.

  7. Hi Lurking, Please thank your wife for letting you spend the time to teach us all this and letting you do all these calculations and things which are so interesting to us.

    Merry Christmas to you and all you family, especially your patient understanding wife.

  8. Eh.. most of the thanks should be directed to Jón Frímann and his blog.

    He is the one doing heavy lifting with the blog and allowing me to stick my graphics here.

  9. I’m uhh… done for the evening.

    I found the flat file from 1995 to 2009, added 2010 data to it and now it tops out a bit over 255,000 data points.

    Even with a quad core 4 GB machine it chokes down when I do a sort. 😀

    1. Add 10GB of more ram and then it should be good. When using a quad core CPU then you can find out your actual speed by using this formula.

      number of cores * Speed.

      For instance I got a dual core CPU at 2700Mhz. That gives a actual speed of 5400Mhz (5,4Ghz).

      1. Yeah.. your right. I had to scrimp a bit to get this one up and going.. the last MB decided it was time to quit counting memory.

        I really wish Excel could use the spare GPU power. It’s a GTX 460 with 1 GB of Ram and fully CUDA capable. Some applications can use that as a coprocessor.

        Unlike my previous machine, I won’t have to swap out CPU’s to enable the other RAM slots. It was a 754/939 board and what exactly it could do depended on which chip you put in it.

        On the plus side, this one is fully 64 bit and running a 64 bit O/S… yeah, it’s Windows, but I have to stay in that realm due to job constraints.

        I was considering moving my Linux machine over to a 1U dual PIII box that I have. Right now it’s in an old AMD Thunderbird system (an quite happy at that). At least with the PIII box I can use the SMP kernal.

        Meanwhile…. since I had the data available. Here is Eyjafjallajökull to Katla, profile view looking north, all quakes 1995 to 2010.

        Of note is that around Jul 17, 1999, Katla had an “UNCERTAIN” eruption. It’s quakes would appear in this chart.

      2. Pretty nice, Lurking! One question – where do you find that dataset? Would have been cool to have done something similar, is it available for everyone? Can’t seem to find the data on


      3. Yes it is, but it probably isn’t something they tell everyone about. (not linked in on a web page anywhere) I found it by looking for terms related to it and hit a page that pointed there.

        Each year folder has the the by week files, and the one at the bottom is a one large flat file. (all weeks appended together) Its large for a data file… upwards of 250,000 records, well in excess of what older versions of Excel can handle. (65K records). It should be relatively easy to parse it into a MySql database or other package.

        The main problem I had was getting it into an ordered list and stripping out the individual headers from each week’s data.

      4. That was a noteworthy one. I think it actually answered something I have been thinging about for a long time, but not even dared stating since I didn’t have shredd of evidence.
        One thing is clear though, the amount of deep quakes needed is not so high apparantly. The deep quakes seems to be counted in the hundreds for Eyja, and they seem to be pretty spread out, compared to the mass of the “upper” quakes.
        This seems to be indicative that “old” volcanos keap their conduits open to the MOHO pretty well, and that we probably wouldn’t see a lot of deep quakes before an eruption at for instance Grimsfjöll, Askja or Krisuvik.
        I am pretty convinced that Katla erupted in 1999, but that it was just a small cough of an eruption. But on the other hand, anything below a VEI-2 would never break the ice.

        I will get back to my other theory now that you handed in my much needed evidence for my corny theory a bit later.

      5. Yeah, I noticed the relative of a well defined stack under Katla.

        The next thing I’m going to plot is the area under Hekla for that full time period. From the large plot it look like it might also lack a well defined stack also.

        But first… coffee.

  10. Jon: Thank you very much for this blog! It’s been a busy year. I value this blog very high, it’s one of those few pages I visit every day. Also, thank you to Carl, Lurking and Kultsi for your insights 6 contributions!

    Jon & Others: Have a Nice Christmas & a Better New Year 2011!!! Expressed this way, each one can hope what he/she wishes most.

    PS: My family too has discovered that Xmas is near…

    1. Thanks for sharing your knowledge with people like me!

      Christmas is near and a very busy time for me since I am the wife and mother of my family, I will check in when I find the time. Let’s hope for a quiet Christmas as far as volcanoes are concerned so the people in Iceland may have a peaceful time.

      Happy Christmas to all of you!

    1. Wishing everyone here very happy holidays! The full moon solstice eclipse was awesome, it glowed gold and copper then deepened to a deep amber up here (NE). Sounds like you might get some “fireworks” over there soon but I hope for the sake of Iceland people that it doesn’t get too bombastic. Skål!

  11. The only thing going on seems to be the anomalous tensor strainmeter values coming from Hella.
    It has now done it’s other shift in a row steeply up. The first one is not showing now, since they “normalize” it to zero when they do the day-shift. If I counted correctly the nanostrain value has shifted up 275 in 72 hours. With all the other stations trending downwards.
    The meaning of this? Not a single clue.
    I have also noticed a lack of equipment to measure strain, gps and tremor for the Vatnafjoll area. I guess that Jóns equipment is best placed for us (Thanks Jón).
    But it would have been nice to see the uplift for Vatnafjoll.

    1. I do believe that the Hella strain changes are actually due to changes in Eyjafjallajökull. But that is the closest volcano in the area to that strain station.

      Reportedly there where some strain changes on that station before the eruption started in March 2010. But I am currently waiting for the last episode of eruption at Eyjafjallajökull to start. As I do not think that volcano is over. It is on a break now from my point of view. I do expect that the a new eruption at Eyjafjallajökull might start without a lot of warning.

      1. I tend to agree with you on Eyja, it shouldn’t take much warning. But there should be at least some changes in GPS, but that could probably be ultrarapid and take just a day or two.
        But the Hella changes coincide with the Hekla-quakes, so I am not certain.

      2. Hella is also close to Hekla

        Ditto that Hella has followed Hekla but a large quake (~7R) is expected in the east after Suðurlandsskjálftar as it is believed that not all tension has been released

      3. Yeah, I read that report…
        Scary stuff in a way, because that might shake loose a few things. It could potentially affect Hengill, Hekla or Krisuvik causing one of them to go off. And Hengill or Hekla has a high potential.

      4. It is on the Weatherstuffs homepage somewhere. It is the report on the 2000 large quake in the southern parts of iceland. In that one they predicted that the (2000) pent up seismic moment was equal to a 7M quake.

      5. According to Dr K’s report from the AGU meeting, Sigrun(?) Hjaltadottir said that the magma rose by as much as 1.6 km per day directly from the mantle source 22 km below. Since the conduits are most likely still open, there is little reason to suspect a lot of earthquakes as a precursor of renewed activity, so I agree with Carl – the first signs would be (renewed) inflation and possibly tremor.

        If we pick up the first signs as magma starts to rise, it would take some two weeks (22 km / 1.6 km per day) before fresh magma would reach the surface. But how much of the “old” magma currently sitting in the pipe could be absorbed as inflation before an eruption occurs, being “pushed from below”? Are we talking about days or hours here?

  12. Good coffee…

    According to, Hekla had an event back in 2000.

    Start Date: 2000 Feb 26 Stop Date: 2000 Mar 8
    Dating Technique: Historical Records
    Volcanic Explosivity Index (VEI): 3
    Lava Volume: 1.9 x 108 m3
    Tephra Volume: 2.8 x 107 m3
    Area of Activity: SW flank

    This event should show up in the dataset. But one thing you need to remember, is that this was over ten years ago, and on a seismic network that technologically, is ten years older that what is in place now. So, while the coverage is there, it’s gonna have a bit less resolution that what we saw with Eyjafjallajökull.

    That’s my story and I’m sticking to it.

    Hekla area, all quakes from 1995 to 2010.
    Box 64.05°N – 63.9°N 19.85°W-19.48°W

    Note the area below 7.5 km. I think that’s important.

    Plan view, 1995 through 2001. Same box. The area south of about 63.94°N is mostly that group at or below 7.5 km deep.

    Perspective view, same data, view looking North East.

    Apparently, what happened is that something gave way and the magma originated from that area below 7.5 km down south. I’ve tried adjusting the color scheme to see if I could actually get some indication of a direction of travel, but that didn’t happen. most of those orange quakes happened in about 2.5 hours.

    See next post.

      1. Awsome pics.

        Is it me, or does Hekla seem like an over grown fissure cone system. It looks nothing like the central vent volcanoes.

  13. Well, that’s pretty raw… not only did I have to do a capcha, but the forum software added the http stuff to the link that I purposefully wanted as a non link. now I’m in the penalty box for four links.



    Just to round things out, here is a profile view of the same data, looking North

    And the view East

    I’m thinking that I might be in the ball park with this one. Note the red quakes down deep. That is likely the feed mechanism closing up or adjusting to the now erupted magma… or at least to the magma making it’s way out. Those red quakes occurred late in the game.

    Now… zoomed in in time, here is a time verses depth for those orange and red quakes.

    One thing is for sure… when it went, it went fast. It looks like the main event started at about 17:06, and was quickly followed by a near the surface quake at 17:09.

    After that things sort of went downhill fast.

    My guess… and remember, this is just me speculating.. is that the feed for Hekla came from southwest of the volcano, and arced to the east and north, up diagonally to where it finally came out.

    But this is just armchair speculation. It’s not my field of expertise.

    1. This is all good by me. As the nature can be destructive I will support all efforts to help people that get effected by volcano or earthquakes.

      That includes allowing people to post links to that type support web sites.

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