Posted on by Jón Frímann

Two earthquakes yesterday and ground water heat map of Iceland

Here are two earthquakes that I did record yesterday. The earthquakes took place at Arnarvatns highland and in Krísuvík yesterday. The difference between the earthquakes is that one of them took place where the crust is old and carries the earthquake wave well. The second earthquake(s) took place where the crust is young, fractured and does not carry the earthquake wave that well most of the time. If a fracture area is not in-between the epicentre and the sensor in question.

The earthquake at Arnarvatns highland. The earthquake wave clearly shows what type of crust it has been going trough. In this case a old crust that carries the wave well in my direction. I cannot tell what way the crust fractured in this case, as I need a minimal of three geophones to do so.

The Krísuvík earthquakes. This is actually a string of many earthquakes. When this happens the SIL system that IMO has major issues with locating the earthquakes. As the S wave often get absorbed by the next P wave that follows the next earthquakes. Sometimes however the waves get separated at some distance. That often helps to figure out how many earthquakes happened at the same minute. What is also interesting about this earthquake is the fact that it is “noisy”. But a normal earthquakes has a clear P wave and clear S wave. But on Reykjanes and Reykjanes Ridge there are often noisy earthquakes. I do not know why that happens and I don’t think the reasons for noisy earthquakes are not at all understood (far as I know anyway).

This map here shows how warm the hot water is in Iceland. Where I live the hot water is about 66C warm. It is a deep magma that warms the ground water up to this levels. There is a good article on this process at Wikipedia here.

Text updated at 17:15 UTC on the 11th of December 2010. Spelling error fixed and minor text changes.

112 Replies to “Two earthquakes yesterday and ground water heat map of Iceland”

  1. @lurking old thread- thanks! Jón, that water heat map is nice. It more or less of course follows the geology, but even so, it helps to clarify the zones of activity. I was listening to a tech discussion program on the radio this morning, they were talking about communicating science. One gentleman said that the most useful thing that TV could do (or maybe some blogs!) was to present visual images striking enough to grab peoples’ interest and make them want to know more. Thanks Jón, Lurking, et al.

  2. I wasn’t aware water temperature was so consistent, is it monitored over time and would this be a guide to deep magma movement?

  3. I can explain the noisy earthquakes at Krysuvik compared to the Arnarvatn quake.

    When you have a fully solidified britle crust the quake will move uniformly since the material works as a homogenous trans-leiter. Think a metall body like a church bell.
    In new, or as probably in this case, partially melted and or differently heated materials you get a heck of a lot of difracting material intersections at Krysuvik.
    Think of it as water that has different temperatures, salinities and boundaries. Then throw in ice-sheets here and there for good measure. Then you magnify the problems with a factor of a hundred and then you get Krysuvik. All the noise you are getting are re- and de-fractions bouncing around between areas of fractures, magma, shallow moho, and areas of varying temperature and inhomogenous material density and reflectivity.

    When I constructed the algorithms in the program interpreting sonic marine data the hardest part was not to interpret the direct sounds and building 3D imagery out of it, it was to instantenously interpret all the myriads of false readings that any sound in the ocean produces. But we did it, and I guess you could “re-vamp” those algorithms into filtering away the readings in your noisy quakes.
    But as you said, you need more geophones to get the readinngs, when you do have those I would happily send a copy of the program to you (and help with altering the algorithms) and then we could build not only 3D maps of a quake, we would also get a high-def map of the crust with all it’s reflective features. Ie, a map with all fractures, probable reflective zones, and certainly all termo-variance-zones. Some of the changes are already done for the Mt Fako project.

    1. That might be sometimes the case. But the reality is that old crust also makes rather nosy earthquakes sometimes. Most of them however come from TFZ. But I don’t detect that area well due the fractures and distance from my station to TFZ.

      1. Yes, some old crust will be fractured to the point that we get noise too.
        The quake at Hveravellir is a perfect example of it in a way. To 3 sides you have homogenous crust, and in these directions the information goes well. Then you have the sprungur area to the northwest which gives off the pesky false reads. If you measured though those sprungur you would get a much noisier read then through the clear areas.

        So I was generalising a lot when I said that old crust is better. I should have said old unfractured crust 🙂

        By the way Jón, not “nosy”, it is “noisy”. Otherwise it has to do with the nose. And we do not want our quakes to start sniffing around with their olfactory organs do we? 😉

      2. It has been my experience since I started recording earthquakes (I started in 2006) that fractures between the active area and my location do not make the earthquake wave nosier. But instead the earthquake wave happen to be weaker when they reach my geophone.

      5. No, in this case we are using the same english. Even though it happens that people do not.

        This is the explanation of “nosy” from the link you gave:
        nos·y or nos·ey (nz)
        adj. nos·i·er, nos·i·est Informal
        1. Given to prying into the affairs of others; snoopy. See Synonyms at curious.
        2. Prying; inquisitive.

        So yes, that would be quakes that are sniffing with their noses where they do not belong.

      6. I did look better into this and fixed this spelling error.

        I am bit longer to respond as I am looking for a audio driver for a SiS ac’97 built in audio card. That search is not going too well. 🙁
        I am setting up a new earthquake monitoring computer for the new geophone that is hopefully going up next week (few weeks earlier then I did plan).

        But I still have the issue of getting a Wlan 2.4Ghz signal over ~1km distance. I am closing in on a solution. But nothing that I cannot implement until after the new year anyway. As I might have to get a custom build antennas to do the job.

      7. My big problem with english is to get the “to” and “too” correct… And some other gramatics… English is a rather sucky language 🙂

        Hope you find the driver and all the rest.
        Just holler if you need anything.

  4. Don’t worry about the spelling….
    Your English is better than my Icelandic ..(of which i have none…;( )
    Spelling is just a majority vote anyway and it changes with time. We would have a
    very difficult time reading old English… well i would, anyway.
    Everyone i know has misused the language and it’s supposed to be our mother tongue.
    As long as people get the idea of what is being said… that ‘s the bottom line.
    Don’t worry… forge ahead…
    and i didn’t understand about the different ground making different traces until You
    explained it…. It sure make sense considering what the ground is made up of.
    Here the second reading would have been interpreted as volcanic.
    and please forgive a stupid question…. does the heated ground make Your weather any warmer? or is it too far down. We have some heated areas but they are far from me.
    Best!motsfo

    1. Oddly enough, Old and Proto English is pretty close to Icelandic in it’s construct and alphabet. One is a mutant, the other is not.

      Guess which one is the mutant.

      2. English is of course the mutant, the French came to England and messed everything up. The Germanic languages were much closer to each other during the Viking Age.

      3. Äsch, it was the Vikings that got confused. First they exported our glorious forn-nordic directly to England, and when they got kicked out after the last taxation of England 1066 the Vikings from France (Normands from Normandy (Nordmandy)) brought french defiled forn-nordic… 🙂
        We should take back Normandy an England, getting both wine and beer that way… 🙂

        And of course getting America and Russia back is on the list… Muahahaha!

  5. Okay.. an actual question from the peanut gallery.

    It’s been about 20 hours since the deep quake happened. SIL has an issue with localizing some events… we have all seen it. Usually they get corrected when someone sticks an eyeball on it and fixes the interpretation.

    It’s still 42.1 km deep with a quality of 88.66.

    Ideas?

    1. It is a leftover in the system. In short, they didn’t bother to remove it from the list. It happens and is going to be a goner in few hours time anyway.

      The wave from in this post is from that earthquake. With the correct depth and size data. 🙂

      1. Nope, that is the reflection from the fracture. The actual quake is deeper. The P and S waves in your plot confirms this as long as this is from your Heklubyggd helicorder?
        Depth is (if it is Heklubyggd) 32km at 3.2M, if it is your other it would be 3.6M at 37km.
        Fun though that you got the reflection and not the original. Must be something down there that is in the way and is sonically deadening. I think it might be indicative of a slab down there. But we would be needing better readings to confirm that.

        But the reason for it not being removed is that it is a weekend. I guess they have only skeleton staff, if at all, at MET. 🙂

      4. In the earthquake locations we use degrees. In this case the degrees are 0.565 degrees. If you look at the picture you got the location of the Hvammstangi station and the location of the earthquake.

        It’s all there, as it needs to be.

    1. I did manage to get the sound driver working using a different realtek audio driver. So I don’t need to use this one.

      Thanks for the suggestion.

  8. Very much appreciated.

    This leads me to my next question, it’s a rather simple one (stupid in fact) or quite complex, depending on your (the reader, not any one in particular) level of knowledge.

    In my case, I fall into the second category, since I have the question.

    On the seismic moment plot, the value being plotted is given in newton-meters. (sometimes dyne-cm). In my power calculations, the result is in Joules. The two are synonymous, yet one is a vector, and the other is a scalar. If the conversion of the quakes to a unit reflecting direction and size (vector components) is what is being done, are they summing the direction of the slip? Or is it just a mechanical representation of the energy that occurred, since a quake involves a mechanical displacement of some sort? If so, then how far off is my representation of the quake energy? Should I divide that power level by the equivalent area that is used in a comparable plot to get the same scaling?

    If you have read this an are puzzled, don’t worry it isn’t really that important. If you are reading this and are laughing your head off… your welcome. Please give me a clue when you get a chance.

    Physics was so long ago…

      1. Thanks for that.

        I’m still a bit perplexed by the idea of summing a vector and getting a scalar like they have going on in http://hraun.vedur.is/ja/vatnajokulsvoktun/grf_uppsafn.html, but it all they are doing is tallying up the energy release in that box, it makes sense.

        If that’s the case, I should be able to replicate that plot for other locations and be pretty close. That is, after I verify and make sure my spreadsheet formulas are correct.

      1. Yes, it is probably just a tectonic quake normal to the area, even though a rather deep one.
        But… And I hate myself for even writing this, I have a feeling about Þeistareykarbunga. Normaly I try to keap my “feelings” away from my reasoning, but this dormant volcano just keaps nagging me. It would be easier if I or you could take a look at the waveform and say that it is just the normal tectonic quakes.
        I know I am just being silly, it is not even a quake-swarm we are talking about, and nothing shows on the tremor-plot. Silly me.

      2. Your unease over Þeistareykarbunga intrigues me Carl. Some would call it intuition and as we all know, intuition is the subconscious mind’s interpretation of data that we are not wholly consciously aware of and can express.

        Located towards the northern end of the EVZ, Þeistareykarbunga differs from the other large volcanoes in that they all have had many eruptions; small, large and huge, in the time since she last erupted. Yet she is subject to the same forces as they, forces that have made them erupt a multitude of times, but not her. Why is Þeistareykarbunga so different from Krafla, Askja, Bárðarbunga and Katla (I’m limiting myself to naming the large central volcanoes)? It’s a bit like turning on all the hot plates on the stove only to find that the water in one pan will not boil even if the light indicating that it’s on glares a brilliant orange, isn’t it?

      3. And it get’s even weirder with that one. The chemical composition is totally different than in all the rest of the volcanos, and it is more like the Hawaiian volcanos when/if it erupts. It is a very different beast all together.
        And since I am one of the hardcore scientific types I try to not have intuition, unless it is a provable idea that I am intuising (or how the heck one spells that one).

  10. My hunt for Kistufell and Þeistareykarbunga information dug up this nice little article on chemical compositions in icelandic lavas. It is veritable whatswhat of the icelandic volcanos and lavas. I really itch to dig away at Þeistareykarbunga after reading this. Why on earth haven’t anyone started a Rare Earth Mineral mine there? Just the Vanadium makes it worthwhile. And the cat in the article is cute.

    http://www.geokem.com/OIB-volcanic-iceland.html

      2. Yeah, I’ve read that one before. The re-read is very enlightening. (after having read other stuff since then)

        One thing that this may have an issue with, is that there it still evidence of a hotspot that treked across Greenland towards Iceland’s general vicinity.

        Stupid question #2.

        What value is the magnitude on MET’s site reported in?

        Mw/ML?

      4. An also the distance is not that great between Bardarbunga and Kistufell. The difference if it was under either of them (or inbetween) wouldn’t be that great.
        I just noticed that they pointed to Kistufell instead of Bardarbunga. Myself I do not really wish even to have an opinion.

      1. The same applies to Skrokkalda, Mökollar and Bruarjökull – all of them are around Bardarbunga. And those eqs today NE of Bardarbunga? What’s up?

      3. I did not refer to the overall level (average signal value), but the variability of the signal around the average. The were no eq swarms to explain the increase in the variability.

      5. But something is up with Bardarbunga, but what time will only tell.
        We do after all have a small quake swarm at the Kistufell part of Bardarbunga fissure swarm. (Thanks Jón for explaining that it is a part of mighty B.)

      6. Yes. Check SKRO and GFUM GPS graphs. When SKRO fell back to “normal”, GFUM moved a lot…

  12. @Lurking,

    I just got through catching up and your question made no sense to me at all. LOL Well, maybe a little bit if I knew what scalar meant. That is a new word for me. I have had some physics, but not very detailed except for the class Electron Optics. Don’t ask. LOL

    @Jon Frimann, I like seeing the graphs of the quakes even if I don’t understand much of it. I do have some knowledge, but not much. Geology 101, as it were, doesn’t give much detail and it was “gasp” in the ’70s when I took it!

  13. @Diane N CA

    “Scalar” is just a value with no direction assigned. 40mph would be a scalar number.

    40mph at a direction of 240° or “east” would be a vector type of value since there is a value and a direction.

    It comes up when your doing things like solving reactance equations or other things like that. I’m pretty sure that it would have crossed your plate in a subject like Electron Optics, but you just didn’t notice it. Scalars and vectors are like that…. sneaky.

  14. Do they think the plume tracked over from Greenland or did the ‘land’ move across the plume?
    to means directional
    “to the store”
    too means also
    “i’m going too”
    Best!motsfo

      1. Before reading the document linked by Peter, I don’t see how the plume could move (relative to Iceland). Continents move due to spreading at mid-oceanic ridges. Iceland sits squarely on such a ridge with one half going west, the other east. How long-lived are mantle plumes? The Midway – Hawaii chain argues tens if not hundreds of millions of years. But is this true for every plume and if not, could there have been a now-extinct one under Greenland or must it be the one currently under Iceland and if so, how on Earth did it end up under Iceland?

        I will now proceed to the paper provided by Professor Cobbold to be suitably chastened.

  15. @Diane N CA How about mid-60’s for 101….and no physics at all, just High School Chem. ..and you’re lost sometimes?? But I’m learning concepts, if not how-to’s.

  16. @Birdseye,

    Let’s see……highschool chem, college chem 2A and chemical calculations, electron optics for electron microscopy course, conceptual physics in college (no lab), physics 51 for electron microscopy course, I took geology because I wanted to and I was going to take minerology, but I didn’t have the time, yada, yada, yada…..You see, I was in college for 16 years!! I remember some of it, but when it comes to physics and chemestry, anything to do with the math part is not part of my memory and I took 8 math courses in college! I did like using the electron microscopes, but not the high stress of the course itself. It was supposed to be a two year course. Took me four. Tough course. One person went to Berzerkly after taking EM and they had to take physics again because 51 wasn’t transferable and it was the same as what we had so in a way it was a waste of time for them, but the good part is it reinforced their knowledge.

    I have to tell you all something funny: when I was taking conceptual physics, the prof showed a film from Nova about the sun and the theory of nuclear fusion supposedly going on with the sun. I enjoyed that film a lot and then some guy pipes up after the film and asks, “You expect us to understand that?!” I just shook my head and wondered where he came from. It’s like the gal in one of my classes who asked the prof in the second classperiod, “Um, you’re giving us a lot of information. Can you tell us anything about what’s going to be on the test?” I leaned over and said, “Know everything!” I told one of my former profs about that and his response was, “Yep, yep. Don’t give me any relevant information. Just tell me what’s on the test.” Sorry to be so OT, but I thought you all here might get a laugh or two.

    2. Sounds familiar. I studied physics as my major, and chemistry as minor. Later I found myself teaching physics, and got heavy critics for “not utilizing old exams”!

  17. OT or not, it’s the way that people think. Been that way for a long time.

    I did two tours as an instructor teaching electronics and electronics theory… how to troubleshoot and other thrilling things like that. I had students of the same mindset. Just wanting the minimum to get by. The only problem is the military uses criterion based testing. If you can’t demonstrate an acceptable working knowledge of what you are taught… you don’t make it. Period. Academic Review Board time to see if we can find something better suited for your skill set.

    1. I’m glad y’all are so smart!!! Now, what is that crazy orb over hekla?

      Enjoy reading everyone..

      2. Jón, where you live at lat 65.5, the Sun can only get a single degree above the horizon at noon at this time of the year. You have, what, 20 hours of night, 2 x 1½ for dawn and dusk and a single hour of daylight, yes?

      3. Hm, Henrik. Hvammstangi is at 65,2. And believe me, at these degrees we get the sun higher then 1 degree during the day.
        He would have 10 degrees and 1,5 hors dawn and dusk with 2 hours of sun.
        At least that was the figures in my old hometown of Luleå… which is more to the north then Hvammstangi.

      4. The sun gets about 12 degrees above the horizon at noon. But not a lot more. But the lowest point is on 22 December.

        We get about 4 hours of daylight at this time of year. I am unsure how long the dawn and dusk is here.

  19. Now it is flowering in Hell…
    2 quakes at Prestahnukur:
    Monday
    13.12.2010 12:10:20 64.611 -20.552 12.2 km 1.7 77.62 18.1 km ESE of Húsafell
    Monday
    13.12.2010 12:08:30 64.595 -20.592 2.4 km 1.8 64.87 17.5 km SE of Húsafell

    I would give my right pinkie to have a gps-read of the area right now.
    What did you get of these Jón?

      1. No, I was not.
        But it was not so very forth-coming. As far as I could find it did not go into detail of what kind of micro-quakes was tectonic or magmatic. It was more of a “lets sum up the activity and see where the activity is” than a try at explaining what is happening. But my icelandic might be to bad to get the finer points.
        Thanks for the nice link!

  23. Yep, I think you can also see them at Jón’s Hekla helicorder, 3 little spikes before the major boom. 😀

      1. Interesting, what would this mean? Does it have a tectonical or a magmatic origin. For now it seems dat an imminent swarm not the case. But it is at the same depth as we’ve seen so many quakes last month. So my guess, magmatic?

    1. Could you explain to me what P and S-waves are? And what information you can distract from them?

      2. Also remember the effects of the internal density and composition of the path the waves propagate in.
        Adams-Williamson formulations work the best for this since they are relatively simplistic.
        But do not take it to seriously since it has the drawback of being meant to use on exactly spherical obejcts and earth is not. So over larger distances the margin of error increases.

  27. Hmm, for the Sun to get 10 degrees above the horizon at midwinter solstice, you’d have to be at lat 90 – 23.5 -10 = 56.5 or in Edinburgh, Scotland. Where I live, a shade below lat 60, the Sun rises no more than 6½ degrees above the horizon at noon, December 21st. But you don’t have to trust me, trust the maths and the maths says it’s 1 degree for Jon att midday, Midwinter solstice.

    Carl! I too have lived in Luleå (1964-6, Repslagaregatan 3).

    1. And the sun measurement from my home at 63,4 today at high noon was 11 degrees…
      I think this is the case where I am going to go with observation over math 😉
      But… the math is correct. I am now officialy scratching my nogging wondering what the hell is wrong with things.

      Ah, I lived there untill 87.

      1. 😉 Yo’re not much of a sailor are you Carl! Every competent sailor knows that you have to allow for atmosperic refraction and for that reason refuse to take the position of any star not more than 20 degrees above the horizon. And an error of some ten degrees, dear me! 😉

        Jokes aside, atmospheric refraction is never more than just over half a degree, meaning that when we see the Sun on the apparent horizon, it has in reality already set.

        Another way to approach the problem would be to use the distance from the Arctic Circle (lat 66 degrees 33 mins) and add the 29 minutes of arc caused by atmosperic refraction at ½ degree above it. Doing this for the Jón (lat 65½) at Midwinter Solstice yields a generous maximum value of 1½ degrees above the apparent horizon or 1 degree above true.

      2. Well, I have survived an atlantic solo crossing… 😉
        But I guess I am a bit of a GPS-generation sailor by now. Haven’t taken a solar-bearing since I was a cadett at Falken.
        Jón is not at 65 1/2, he is at 65 1/3 🙂

        The oddest I’ve ever seen sun-wise was a morning with four green suns in a diamond shaped configuration.
        If you ever see that one, get religious. 4 hours later I was in a hurricane north of the carribean islands. 5 hours later I learned how to basejump a 50 fot ketch of a wave and how to surf down a tube with it.

  28. I currently don’t have the time to write about this earthquake. But I did record it on both of my stations. I will provide the high resolution image later today with a blog post about this event.

      1. I have finished with the school. I was preparing and am going to install a GSM antenna for my dad in order to try get a GSM signal to him. But currently there is no signal. I am building a passive antenna for to do this.

        But I did build a GSM-900 (900Mhz) antenna in the school in order to do this. I think this work, at least I hope so.

  29. Carl, are you still up near Lulea? I spend a fair bit of time between Skelleftea and Arvidsjaur.

    1. Depending on your definition of near. I still live in northern Sweden, but about 270km to the south.
      But I have a tendency to be flying around a fair bit.

      Now comes the question, between Skellefteå and Arvidsjaur there is pretty much nothing else then mines and mooses grazing on german tourists, what the fudge are you doing there? 😉

      3. Hällnäs 1966-70, -47 grader i skolan vid Hjuken och tio dagar i sträck under -40. Räknas det, eller är jag trots det att anses som schläppträskare?

      4. Efter det så är du att räkna som hedersvästerbottning i alla fall, plus då Luleåvisterlsen 🙂

        Vi är inte många, men vi tar så sakta över världen!

        (Sorry for all this OT in Swedish, we are just discussing our world domination)

  31. It’s me again…. brain pickin’ time.

    hraun.vedur.is has these two events listed. ( no specific reason that I chose them, they were just handy)

    36 20101213 125518.541 63.90093 -22.04531 4.609 1.61 1.09
    37 20101213 125809.361 63.89893 -22.04381 4.990 2.80 2.70

    They equate to:

    Monday
    13.12.2010 12:55:18 63.901 -22.045 4.6 km 1.6 99.0 1.8 km NNE of Krýsuvík

    Monday
    13.12.2010 12:58:09 63.899 -22.044 5.0 km 2.8 99.0 1.7 km NE of Krýsuvík

    Now, in the first set, the last column is tagged as ML, and the next to the last column is tagged as just M.

    This tells me that the web interface at en.vedur.is is reporting the size of the quakes in M. So… which M is it? Mw? Me?

    Even a link at a reference that would state it would be appreciated. My gut feel is that it’s Mw since that’s supposed to dovetail into the Richter scale.

    1. Duuuuuuuude!

      I think I have a reprieve… of sorts.

      Rather than hitting the MET site every few hours and copying the new quakes into the spreadsheet, I have managed to locate the data in flat file format. I’ve been doing this since April… and it really… umm. “is unpleasent.”

      I ran a test of my graphs on the run up phase of Eyjafjallajökull… the part of the show that I missed. It looks promising. That was one pregnant puppy before it went off. I have to work on getting the timestamps to translate properly, but this is gonna be nice. 😀

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