Posted on by Jón Frímann

A ML3.7 (automatic size est.) earthquake happens on Reykjanes, close to town called Grindavík

A earthquake that had the automatic size of ML3.7 did happen at 22:14 UTC on the Reykjanes. This earthquake was only 2.6 km away from a town in called Grindavík. The earthquake was felt well in town according to reports that I got over Facebook.


The ML3.7 (automatic size) earthquake location. Copyright of this picture belongs to Icelandic Met Office.

So far no aftershocks have happened where the main earthquake took place. But that might change at any time.

290 Replies to “A ML3.7 (automatic size est.) earthquake happens on Reykjanes, close to town called Grindavík”

  1. That was fast to get it up so soon Jón!
    Nice work, and even nicer catch!

    You know, it was prophetic your comment that it was very calm and you where getting a pause. 🙂

  2. Ey, is there any volcano there? And has there been more activity this year than previous years?

    2. Yes there is no less then two, or one depending on how you count them.
      You have the Reykjaness volcanic System that spans from the tip out downwards. Had a bunch of subsurface aquatic eruptions during the years and produced islands now and then. The other (or the same depending on source) is the Svartsengi volcanic system that strectches over parts of the Reykjaness Peninsula from it gets out of water up towards Krisuvik volcano.
      It erupted wildly between 1179 and 1240 with both large lavafields being produced as large tephra production. So almost 800 years of dormancy.

    3. The closest named ‘volcano’ would be Krýsuvík as far as I know. But the whole Reykjanes peninsula is a fissure zone, which is part of the mid-Atlantic ridge.

      1. You have the Svartsengi volcanic system, with a bunch of small shield volcanos, crater rows and fissure-vents. The most famous of the fissure-vents is named Svartsengi which the name is derived from. Some though bunch Svartsengi together with Reykjanesshryggur and call it the Reykjaness volcanic system, Some devide it into two volcanic systems.
        This is the same as when Krysuvik started quakeing, no one had heard of it before 🙂

  3. As a relative “newb” to volcanism and tectonics (with regards to geological time-scales, if nothing else!) is activity in South West Iceland on the increase, or just about normal?

    I ask because last year’s eruption got me interested in volcanoes, but I think there was a swarm of quakes going on somewhere in the south west earlier this year, which was when I started following this blog.

    There also seems to be more reporting about Icelandic volcanoes in the media here in the UK, but I would guess that is to be expected as potential doom sells very well!

    1. First of all, disregard the media in the UK for obvious reasons… 😉

      Yes there has been a marked increase in the area.
      From 2009 and onwards there has been repeated quake-swarms in the Reykjanesshryggur volcanic system around Geurfuglasker, it might erupt soon, and it is an area with active volcanos.
      Then you have Krisuvik with numerous quake-swarms and GPS uplift and water coming and going in Lake Kleifarvatn.
      Then you have Hengill (brute of a volcano) that has had its root filled with magma and some small quake activity, but not likely to go in the next few years.
      Svartsengi Volcanic system has been dormant for a long time, untill it had two quakes today.

      1. A healthy disregard for the UK media is a good plan for any topic, not just volcanoes! 😉

        I’ll look into the names that you mention more tomorrow, but I think that it was a swarm at Krisuvik that brought me here (somehow!). Thank you for your response – so many volcanoes to learn about and so little time. And that’s just in Iceland, never mind the rest of the world…

      2. Iceland only have 93 active volcanos, or some such…
        And when you look away another one pokes it nose up unanounced and unvanted.
        The joke goes, “there is no volcano here”, “no, not untill yesterday”.

    2. Cathy, Yes it was probably the Krisuvik swarms back in March which brought you here.

      World press in good in that on the right hand, far down past the ads, there is a list of key words or “categories” which can be clicked on to bring up all posts tagged with that word. (Much better than “Big Think”, in my opinion, for searching.)

      If you click on Krisuvik, you will be brought to all posts tagged with Krisuvik … as in the following link …

      http://icelandgeology.net/?cat=37

      And you can then review the posts on the Krisuvik swarms as described by Jon, and commented on by others.

    1. But those are the ones that are subsurface out at Reykjanesshryggur, the last on land was in 1240.
      There is a paper somewhere that I have that divides it into two separate volcanic systems since the lavas are different in chemical composition, and the distance between the two centers of activity.

      1. Yes, There are two other volcanoes out to sea from Reykjanes Ridge. But they are unnamed besides the islands that they have created in a eruptions in the year ~1000.

        But I think that GVP is referring to the volcano that is both below and above sea levels in this area.

      2. Problem is that they have have Geirfugladrengur and Nyey and all the others out at Reykjaneshryggur too in it. So I would say that they have baked it together.
        I think this is a case of GVP being a bit confused, and I can understand them, many things are very unknown about these volcanic systems.
        In one place they talk about Reykjanesshryggur, next sentence Reykjaness Volcanic system (the one at the tip) and then they bake it together with the Svartsengi.
        If I remember the article correct the Reykjaness Volcanic System had mainly tephraitic eruptions, and Svartsengi produced lavafields through fissure vents.
        But I can’t for my life find the article now. One of the moments I wish I had edeitic memory (photographic memory).

    1. Will probably come sooner or later, but this might also be a part of a quake-swarm. There has technically been quakes at the spot for a few days, so this might be a signal that there could me more mid-sized quakes.

  9. yebb. finally. lets hope its the rest of them. must not be comfortable to try to sleep in this shaking… 🙂

  11. It and the follow up ones (eg. 3.2 @ 6.2 km SW of Krýsuvík) look to me like tectonic responses to the magma injection under Krýsuvík, which we’ve been seeing last few months.

    Does anyone know if there are inflation data for Krýsuvík volcano?

  12. Wednesday
    17.08.2011 01:35:17 63.537 -23.673 1.1 km 3.1 64.72 8.4 km NE of Eldeyjarboði
    Wednesday
    17.08.2011 01:34:24 63.854 -22.168 1.1 km 3.2 90.04 6.2 km SW of Krýsuvík
    Wednesday
    17.08.2011 01:34:23 63.887 -22.293 1.1 km 3.3 43.98 1.9 km SSW of Fagradalsfjall
    Wednesday
    17.08.2011 01:34:23 63.850 -22.386 5.7 km 3.3 90.05 3.0 km ENE of Grindavík

  14. Not to be “that” guy but technically can these be called aftershocks? If the origin is magmatic it is just an EQ swarm isnt it? And the large M3.7 set it off.

    Aftershocks would be present if the quake was tectonic in origin right?

    Just thinking out loud.. 😉

    1. Looking at Jon’s helicorder data it seems to my eyes, that both P- and S-waves can be detected clearly, i.e. the quakes were indeed tectonic. Jon, please confirm or correct me.

    2. Being that guy I think it is the question about the “hen and egg” again 🙂
      We are after all taking about one of the weakest spots on the planet. These quakes are heavy enough for them with time to become magmatic, even if they might not have been in the beginning.
      We have magmatic upwelling ongoing at (minimum) Krysuvik, and a heave afterchock has allready happened there.
      If this continues for a while it will turn into a quake-swarm, and at these magnitudes there will most likely be soomething coming up somewhere. Or lake Kleifarvatn flushes the toilett again.
      This is not good I think.

  15. I stayed on the beautiful camping in Grindavik for a few days (half july). I had planned to stay there a few days to visit Krysuvik and Kleifarvatn. But, because the weather was so beautiful (sun and no wind) I decided to visit Krysuvik on my way to Grindavik and visit Kleifarvatn a few days later, which I did. The boiling mudpots and beautiful colors of the ground left quite an impression with me.

    Something else:
    A few day ago I read a blogpost – by Irpsit if I remember well – about Kerlingarfjöll.
    I’ve been there too the 14th and 15th of july and had superb weather! Made a lot of photo’s there and a few short films. For me it is the most beautiful geothermal area of Iceland with a lot of walking/hiking possibilities.
    So, if any of you wants to get some really beautiful pictures, just send me an email Emailaddress: henk.maukie@hotmail.com

    Henk Weijerstrass
    Zwaag, Holland

  16. While I am at it, I love how Jóns Helicorder shows clearly how large the difference is between a 3,7 and a 3,3.
    Most people have a problem understanding how enormous the difference is between a lets say 2 and a 3. Look very carefully at Jóns Helicorder and I think you will understand. Now think about the normal piddly quakes at Katla that are below 1. I think now you will understand what it will take to open up that volcano. Here you are seeing the quakes that are needed, and still it would need a lot of them.

    Jón, I think you should add this picture from your Helicorder to your former blogg post. I think it would help people to understand much clearer the energy level increases in the magnitude scale.

      1. If I have understood it correctly, yes.
        Sofar they seem to be purely tectonic, but since this is a fragile spot I do not think they will be for long if it continues.

  17. And on the topic of scales just to add some perspective.

    Each step in the richterscale represents a very large increase in energy. At lower magnitudes this is not as much as on the higher.

    A few examples. The difference between a Mb1.0 and a Mb2.0.
    Mb1.0 = ~500g of TNT
    Mb2.0 = ~15kg of TNT

    Each step in the richterscale is about 10 fold correct?
    With that in mind imagine that a Mb1.0 EQ released 100 (energyunit).
    Mb1.0 100
    Mb2.0 1 000
    Mb3.0 10 000
    Mb4.0 100 000
    Mb5.0 1 000 000
    Mb6.0 10 000 000
    Mb7.0 100 000 000
    Mb8.0 1 000 000 000
    Mb9.0 10 000 000 000

    I know these figures are not scientifical per se but gives some perspective between magnitudes. The difference between a Mb1.5 and a Mb3.7 doesnt look like much but the difference in energy released is quite astonishing.

    This is of course if I am correct in what I am saying but I dont think Im too far off track. 😉

    1. Haha, modesty in the morning? To little coffee, not good for us small swedees!
      🙂

      You are absolutly correct, you even got the offset correct for the low-level quakes. Below 1 the scale just becomes ridiculously energy-deprived.
      A 0.1M should be 10 of your energy units, but they are close to 1 instead.
      Richter-scale is bad at week piddly quakes. But on the other hand it was never designed for those ones.

      1. Technically yes, but it is pretty hard to get the head around it.
        And to be even more precis, 1 to 2 is 32 and 1 to 3 is 1024 since 32×32=1024.
        But to just add a zero between the steps give a “good enough” table that is understandable. Thing is that I have noticed that people tend to think it is just a doubling in energy between the steps.

      2. The earthquake energy goes up around 32-fold for each unit, but the shaking (that you can see in seismometers, for example) grows up 10-fold.

  18. That’s seems to be not >exactly< right, a 0.0M should be 10 of the energy units, a 0.1 is approximatly 12.6 energy units, and a -1.0M is 1 energy unit. The formula seems to be E.U.=10^(1+value(M)), isn't it? 😉
    I just read this blog for some days now, and i like it, especially Jon's moderation of the blog, and also Carl's explanations (chapeau!), to say that.

    1. Yes well as I said. I might not be exaclty correct but the point was (excluding the exact mathematical formula) that the difference between two seemingly small earthquakes is actually quite large.

      We see alot of Mb1.0, Mb2.0 and occassionally a few Mb3.0+. Seeing it like this and we all have the large quakes in the back of our heads (japan, chile and so on) they seem small. But when you look at it closer the energy released is tremendous and the difference between the smaller Mb1.0´s and the recent Mb3.7 is many times larger than one might first think.

      🙂

  19. This is a bit OT but has to do with volcanism in Iceland.

    The area where the infamous Skaftar fires occured in the late 1700´s is obviously volcanically active. Now we never see any quakes in this area. No magmatic nor tectonic quakes.

    Why is that? I would believe that this area should be quite active from time to time.

    Is it due to a “rubbery” (in lack of a better word) litosphere? Is it really a aseismic area (find that hard to believe).

    I have been thinking since the eruption of Laki was one of the largest ones and on top of it all there is a tectonic ingredient to the area as well since the MAR actually runs right through this place.

    1. One thing is sure: Magma production during the Laki eruption was so big, that coolig of the new rock must have taken years or even more. That could have affected the properties of new base rock created, i.e. rock being “softer” or allowing more movement without breaking (and causing quakes).

      1. Is it possible that the Laki (etc) magma would have “welded” the regional rock into a solid lump which would not allow for small movements? The MAR movement would either take place elsewhere where rock is more fractured or it would be taken up in elastic stress until the lump cracks with a large bang?

      2. Well most of the magma was deposited on the surface as a giant lava field (12 cu km if i remember correctly). The residual magma which would have “welded” the fissure is simply not enough I think. One of the reasons there was such a large lava flow was the size of the fissure. Over 20km with fissure vents.

        And on top of that I dont believe a small (in perspective) welding like the Laki fissure would be nearly enough to stop the movement of the MAR. Not even locally since the southern and northern split would tear that weld.

        My guess at least. 😉

      3. If it was welded it would just break within years. No the time it takes for it to become cool enough to be hard and brittle is pretty long.
        It has instead become rubberbanderized (gummibandiserad) or what the heck one should call it.
        Ductile is the scientific word for it. And as a ductile area it stretches equally well as the rest of the fracture zone (GPS proves that), but it just stretches and stretches like a a rubberband untill it goes “snapp” and it rips open like nasty velcro and out pours cubic-kilometres of lava.

    2. Crust becomes more ductile the hotter it is. On the surface this area is pretty cool, but not that far down the temperature goes up, and the deeper and hotter it gets, the more energy it takes for the rock to break. Think about a rubberband here, in room-temperature it just stretches when pulled, when frozen it snaps.
      There are more reasons for it to be quiet too.
      The area is surrounded by fractures, new and old, then you have the fissures themselves and so on. Every fracture tends to work like a thermohaline or saline does in oceanic water. Or for that matter a common mirror. It diffuses and reflects away the wavefronts when they hit the fracture, how much depends on several factors.
      So basically you have an area that works like a sound-proof room, the hot ductile material works like the dampening and the fractures like the walls that reflect the sound.
      In the end pretty much nothing get out of there noisewise.

      There is also no equipment inside the area listening, and this is a big oversight from the IMOin my opinion. Correctly placed inside “the zone of deadly quiet” a SIL-station could hear what is going on. There really should be one there because we are talking about perhaps the most potentially dangerous place in the entire Iceland. But I am not a volcanologist… Just a retired expert on listening devices…

      So, the answer is that it is aseismic in a way, but it should be rich in tremoring. But as with any rubberband, when stretched enough it breaks, and here the break is an eldgja or Laki event.

    1. I think it might be a good idea if you explained what those are a bit and how those ones in this case says it was tectonic and not magmatic, and how a magmatic quake might look like. I know you have done so before, but there are some newcomers I have noticed.
      Hope you are feeling better today.

  22. Regaring the rubberbanderized area NE of myrdalsjökull. There is a good paper written about the basics of Icelandic geology. I recommend people to read it. Couldnt find a link but search on google for “Pall_Plate boundaries, rifts and transforms in Iceland.pdf”

    Based on that paper the spread vector for the area in question is 22.4 mm/year in a 100 degree direction. Laki had an eruption in 1783 which ended in 1784. Now that was 227 years ago. 22.4 mm/year would mean that the area has spread an approx 5 metres (around 16 feet).

    Wonder how much strain the “rubber band” can stretch before snapping.

    1. Between 5 and 7,5 metres if you recalculate it from the lava-flooding episodes that have happened there. We have just entered the period when it is starting to get dangerous.

      3. Eruptions in that ice-free area occurred in the following years:
        870 (Vatnaoldur, Bardarbunga)
        934 (Eldgjá, Katla) 64 years of interval
        1290 (Bardarbunga) 364 years interval
        1350 (Bardabunga) 60 years interval
        1477 (Veidivotn, Bardarbunga, and Torfajokull) 127 years interval
        1717 (Bardarbunga) 240 years interval
        1783 (Laki, Grimsvotn) 66 years interval
        1862 (Trollagigar, Bardarbunga) 79 years interval

        2011, so far 149 years interval

        Eruptions seem to be quite irregular there, and some are small, other huge. They also happen in different fissures from different volcanoes. I think sooner or later there is going to be another great fissure there, but it is difficult to know when.

      4. That means on average 143 years with a standard deviation of 116 years. Most probable range is thus 30-260 years between eruptions. It may be we will never personally see another large fissure eruption in Iceland…

  25. A couple of small quakes just took place on the edge of the Torfajokull caldera.

    1. Very low quality, extremely weak. Probably just one quake and a shadow.
      Another of those 3 squarecentimetre rock that breaks style of quake.

      To put it into perspective.
      Tonights quake at Grindavik had 32768 times as much energy in it.
      The Japanese quake had 1 099 511 627 776 times as much energy in it.

    1. This is for those who like extremes… ;o)

      Check the link above, chapter 22 on mantle plumes. On page 636 there is a schematic picture of the icelandic mantle plume. Gives a feeling about the forces that created this volcanically very lively island!

      1. @Jack. Thank you so very much for that link. It has explained Hot spots and plumes and answered so many questions I have had since I first started studying Geology over 50 years ago!. What huge strides have been made in the understanding of the Earth’s “engine” since then.
        I now have a deeper appreciation and understanding of the complexities of assessing volcanic activity in Iceland.
        It has also enhanced my understanding of the inter-relationship of plant and animal evolution, climatic changes and plate tectonics.
        I wonder if humans will be as successful a species as others who managed to adapt to these changes for millions of years!

    2. wooo, thanks for that link, even when some tables are out of date (e.g. world population or energy use EDS24), most of the content is beyond timescales of humans (for now).

      EDS_24 p30
      EASTER ISLAND, EARTH ISLAND
      The history of Easter Island shows the effects of overuse of natural resources
      and disregard for the limitations of a natural environment.

      Sorry to play the “depressive” mind again (sometimes i cant hold back).
      But its time… 4 years for a fb fraud but not 1 year for inside trading or the other free running politicians (murders, NATO).
      I dont get how you can be fine with our situation, we are paying their 10th car or 3rd house while all 5-10s dies a child from hunger or 10.000 each day loose their eye-light, because of not enough Vitamin A. We could fed 12 Bn people with the space to grow but nah we have to fill our 200PS cars, with “food”. (ahhh shit world).

    3. Excellent link! I have it fav’d in my browser now.

      YIKES! … the first “word” in my Captcha verification looks like a seismogram and not like anything English at all! Never saw such as that before. Is it some kind of omen or warning? :O ….

      http://i56.tinypic.com/2mhx9v5.jpg

  28. Folks:
    What a great job you are doing at this blog!
    Anytime I have a question, it immediately appears discussed in depth.
    Hope Jón may soon get better from the cold, but I would also like to thank Carl, Daniel, Chris, Jack, Irpsit, Pieter and all the “other lurkers” for the excellent debate.
    It’s a pleasure just to enjoy lurking from behind!

    2. And thank you for your comments, insights and really good questions.
      And of course warming all of us from Sweden in the middle of the winter with thoughts of Rio and women (and men for those who prefere them)… 🙂

  29. Well, I can only agree. I read this blog several times a day. Seems like I know you all a bit 😉 And nobody knows I am reading this 😉 So, thanks!! For this great blog!!

    1. Well inflation doesnt nescessary have to be accompanied by tremors. And if it is the chances are that the noise from the slow movement (compared to instant movements) simply drowns in the background noise and other events.

    2. This is scary… SKRO is 25 km from Hamarinn and 40 km from Bardarbunga.

      If it is really Hamarinn inflating, the rise corresponds to a magma inflow of at least 0,04 km^3/week. Or if it is Bardarbunga, it means 0,1 km^3/week!

      1. That would indeed be scary. That huge amount of magma wouldnt stay contained for long.

      2. Typically only a minor part of the accumulated magma erupts. Atypically, if a major part erupts, it likely leads to a caldera forming event.

      3. It could be a case of what I termed “Hyper-inflation” (I forgot the technical term for the ground-deformation) that some volcanoes have during the last weeks or months before an eruption.
        Classical example if I remember correctly was Mt Saint Helens.

      3. My revised estimate gives 0,16 km^3 of total accumulated magma. Hamarinn may already be capable for a VEI3 …

      4. Or, it may still be Bardarbunga, although it is also seen at Hamarinn. In that case it amounts to 0,9 km^3…

      5. The Hamarinn volcano appears to have been influenced by the large Grímsfjall volcano eruption this spring. But I am going to write a blog post about it soon.

        In what way I am not sure yet. But I would not be surprised if there was a larger eruption there soon. Rather then the small events so far.

      6. Now is this inflation something to worry about on a short term? Speaking of Days?

      7. Likely before Christmas, as the inflation is so rapid it cannot simply last for a very long time.

      8. Found this on my travels,

        http://upload.wikimedia.org/wikipedia/commons/b/bc/Volcanic_zones_of_Iceland.svg

        and

        http://hisz.rsoe.hu/alertmap/site/?pageid=event_desc&edis_id=VA-20110715-31586-ISL

        In September 2010, an earthquake swarm occurred near Bárðarbunga, with over 30 earthquakes recorded on 26 September, the largest quakes measuring 3.5 and 3.7 on the Richter scale. Is this the area where the inflation is taking place now, also see the link below.

        http://www.geo.mtu.edu/volcanoes/iceland/vatnajokull/gvn/notice.001.html

        Could it be that this area rise that quick?Everytime Grimsvotn goes up, Its waking up the rest of the family?. My guess that Katla is next in is out the window.
        I read if either of these volcanco goes, the local dams and hyro plants could have everything changed on them?

      9. Well Katla doesnt have any connection with the volcanoes beneath vatnajökul icecap. And Grimsvötns connection to Bardarbunga central volcano is still a theory and as far as i know have never been taken as fact. If it were so even then I would be inclined to believe that Bardarbunga affects Grimsvötn and not the other way around.

  31. I have a question. I noticed some times already that the IMO reviews only the smaller earthquakes in a swarm and not the larger ones. Also with this quake swarm at Grindavik they reviewed all the quakes but not the ones larger then 3.. Is it more difficult to review a larger quakes or not?

    Sander

  32. Good question. Looking forward to a good answer from someone also. 😉

    Maybe they dont need to check the larger ones since they already know it happened and where. I mean the signature of the EQ is probably easier to see.

    1. And before any mistakes happen with reading the graph. The scale is different than normal plots. This GPS stations has gone up at least 4 meters (!) since 1998 and probably more before that.

    2. Do we have a candidate here for the next major fissure eruption in Iceland?

      1. If we assume the instrument is working as intended the next question is over how large an area? Then, is there any other process, geological or meterological, that may explain such an uplift? If it turns out to be over a large area and there is no explanation other than magmatic intrusion, then I’ll get excited. Very!

      2. As Carl stated earlier, IMO is stupid if they do not follow more closely this area (all the fissures between Myrdahlsjökull and Vatnajökull). One reason for this is, that the fissure eruptions do not seem to give any warnings. According to http://en.wikipedia.org/wiki/Laki the eruptions started with phreatomagmatic explosions. No earthquakes are mentioned. Or, does any other know more about this?

  34. Haven’t seen the article yet, but according to BBC digital tv text page 154 (?UK only?)
    the journal Geology has an article stating “another ash cloud soon “unlikely”, and UK unlikely to see another gigantic ash cloud (ref Eyja march 2010) in this lifetime, ash clouds as those of 2010 only occur on average every 56 years”.
    Yeah, yeah no-ones told our Icelandic ladies!!!

    1. Love that kind of reasoning:

      “The average life span for men in Sweden is 78 years. This means that you’re guaranteed not to die before your 78th birthday and unlikely to live a day longer”.

      Pschuiit! Only fools use statistics in the manner of that article.

      1. Haha, well…
        Ahem…
        I should probably shut up and put on my fools hat and celebrate my exactly measured remaining lifespan.
        Thing is that the statistics are correct, it is just that people miss the inferred words “on average” and “statistically”.
        I actually liked the article. For being a british article it was fairly un-alarmistic, and actually used correct numbers and facts.
        According to swedish statistics I have exactly 1,78 cildren and eat 3,7 sandwiches for breakfast. I also take a dump in the 1,4 toiletts I have. I am also divorced 0,6 times from my 1,3 wifes.
        Swedes = anal? No way..! 🙂

  35. @ Pieter: that link looks interesting, UP has gone from -180(ish) to 200mm. As you say around 40 cm. What does this mean for the volcano to the leyman? (like me).

    1. Well it means that magma is building below. There is an inflow from somewhere which makes the ground bulge upwards. Often both North and East components show a trend aswell although smaller.

      What it specifically means for the volcano is pretty much that if it continues it will break open causing an eruption of some sort.

      But many things can still happen.

      Magma can find other paths as the pressure increases which can result in a deflating or stall the inflation for some time.
      The inflow could slow down causing the inflation to stall or progress slower.

      So I think its too early to tell what will happen. Its a wait and see game as usual. Keep an eye on GPS, tremors, EQ´s and so on.. 😉

  37. On how long time has this rise been going on? Days? Weeks? Years? Cause 40cm seems like a lot if its only short time..

    1. Since 1998 the uplift has been 40cm. This means an average of about 3cm a year. Whatever happened before and for how long this has actually been going on, we can’t know because there are no records before 1998 at this station.
      We can speculate, did it start right after the latest subaerial eruption in 1910? Then the total uplift would be 340cm (highly highly unlikely 😉 ), but let’s say it started in 1990. Then it would be a a nice and steady 64cm. We just don’t know!

      For comparison:
      Grimsvötn had inflated about 35cm before the 2011 eruption. This of course was right on top of the volcano(=inflation source), and Jokulheimar probably is not on top of the inflation source. This means that the actual local inflation at the volcano itself could be even higher.

      Just jibbering a bit, don’t take it as a fact at all. This is just my interpretation of the data.

  38. I have a couple of comments.

    HAMA & HAFS are probably more for the Grimsvötn eruption, it even stoped in its track after that one.

    I also have a comment on Skrokkalda and the other GPS-stations. It seems like some sexual-trend here to ONLY look at the UP-factor. The other two are sometimes even more interesting.
    Take for instansce SKRO. First of all, there has been no change in movement speed and pattern for the east/west and the north/south component. Ie, it isn’t being pushed in a new direction by a swelling body of magma changing the topography of a volcano. Compare this with the movement pattern for Austmannsbunga in Katla.
    http://strokkur.raunvis.hi.is/~sigrun/katlajul.png
    The movement from day to day in AUST is larger than for months at SKRO, and much more irregular.

    Secondly, and this is VERY VERY interesting. SKRO placed in between two faultlines, on running up by Langjökull and one through Vatnajökull. So it should be moving slowly to the east. And it is… Okay, I have invented the wheel, I know. But my point is, the inflation should deform the mountain so that the east movement stops or reverses. Simple mechanics.

    I am as you notice not convinced about some imminent eruption or superinflation. The rapid lift at HAMA is probably Grimsfjöll eruption, remember that we noticed a heck of alot of odd things in January that pointed to a connection between Hamarinn and Grimsfjöll, and Hamarinn and Bardarbunga.
    The JOKL is rapid, but over a long time, and remember that this part is uplifting constantly. But the POINT is that the uplift stopped dead in its track when Grimsfjöll erupted.

    Yes Hamarinn is showing signs and portents, but it does so very often, and it is normally related to activity in Grimsfjöll or Bardarbunga. But remember that it is quite some time since Bardarbunga was active, which is naturall if there is a connection between these 3 volcanos. Grimsvötn is relieving preassure so often that Bardarbunga cannot erupt.
    And that perhaps explains why Bardarbunga stopped erupting (at least visibly) and why Grimsvötn is erupting like clock-work. It really seems logical that a conduit opened up between Grimsvötn and Hamarinn, and Bardarbunga is connected to Hamarinn through a dyke, then Grimsvötn is pretty much keapt open semi-permanently since it is getting the magma from two massive volcanic systems. Remember that with a open conduit system the pressure required for an eruption would need to be much higher than in Grimsvötn, so it can not erupt.

    I am rambling now, I do not think Hamarinn is the real culprit, we are looking at old figures, and the last few days are just localized movement where the station is. Same as we are seeing at pretty much all GPS-stations when they run away and then just schlurps back after a few days.

    1. I forgot…

      All hail he who should be hailed.
      The connection was in my eyes proven by Lurking during the run-up to the Grimsvötn eruption. He made insanely accurate quake maps spanning years that in my eyes proved that
      A) There is a connection from Bardarbunga to Hamarinn.
      B) There is a connection between Hamarinn and Grimsvötn.

      With the tremendous amount of data HE (not I) deduced this and proved it with his imagery.

      A logical conclusion of the Lurking-theory is that what we probably are seeing at SKRO when it has those harmonic tremor spikes, and swelling episodes is Bardarbunga erupting sideways into Hamarinns magma-chamber, which is then mixed up there, and then it is pushed on towards Grimsvötn.
      It is the most logical conclusion, fits the data, and follows the images of the conduits.

      Talking about which, what happened to Lurking?

      1. If this station:
        http://strokkur.raunvis.hi.is/~sigrun/HAMA.png
        Is anyhow influenced by Grimsvötn it would have been visible by significant deflation in 2004 and this year. And about the other directions, they do all confirm the Hamarinn theory. If indeed Hamarinn would be inflating, a station located N-W of Hamarinn would move N-W faster. All stations located N-W of Hamarinn ARE actually moving N-W:

        -Skrokkalda
        http://strokkur.raunvis.hi.is/~sigrun/SKRO_11.png
        -Jokulheimar
        http://strokkur.raunvis.hi.is/~sigrun/JOKU.png
        -Hamarinn itself
        http://strokkur.raunvis.hi.is/~sigrun/HAMA.png

        This goes, as you said, AGAINST the natural S-W movement. In other words:

        -Something is moving these stations another direction they sould
        -This direction is exactly away from the volcano in the theory
        -We have had multiple glacial floods from several cauldrons the past year
        -We have seen increased seismicity in this specific region. (last year was highest since 1996)

        I’m not stating anything but that there has to be some anomaly down this area. What it is, I don’t know, but it’s there.

        Oh and about the connection with Grimsvötn? Sure, could be, could just as well be nothing. A nice line of earthquakes can mean anything. For all we know it could be stress created by an expanding volcano before an eruption (Grimsvötn) causing small fault lines to slip. I think it’s too soon to really draw conclusions on this matter because we have so little evidence. (no offense to Lurking! his plots are more then interesting)

      2. http://hraun.vedur.is/ja/vatnajokulsvoktun/gps_skrokkalda.html

        Normal movement, no movement to the west at SKRO
        http://hraun.vedur.is/ja/vatnajokulsvoktun/gps_skrokkalda.html

        It was more than that with the plots in question from Lurking. It was timing and a bit more.
        I am one of the hardest to convince about anything, I am a pain in the ass. But that mapping he did was accurate on a scale that you do not normally see with volcanos. He by far surpassed anything seen in the literature about Vatnajökull with them. And a set of picture perfect dykes are most likely a set of dykes. Either his data was flawed (IMOs official list of quakes), or it was correct.
        Another little piddly thing, anyone seen Bardarbunga erupt lately? At least IMO has no eruption on its list of eruptions… 😉
        I am going to say that as theories go it is more likely than any other I have seen for the area.
        Numbers never lie, you can over-interpret them (which we might have a bit), but in the end the numbers add up.

      3. The plots you have there are on a scale of 3 months. It’s obvious when looking at the larger plot, that in such a small period there won’t be any significant movement. And even looking at this scale, if things would be normal, wouldn’t the data suggest that it’s moving south-west as the faults do? No, their more or less stagnant, which would mean a force is holding them from moving that way.

        I’ve also seen those plots and they couldn’t convince me. You know that dikes are actually the same shape as fault planes, so with this data you can never ever distinguish those.

        I’m not expecting an eruption from Bardarbunga either, I’m not expecting anything at all because I’m not a volcanologist. But historical eruptions at the site of Jokulheimar have been present as this area is discribed as part of the Veidivötn fissure system. Now I don’t want to sound like a farty old doom-nOOb, but if I’d have to guess I’d say that I will witness an eruption in this area in my lifetime. And when I say eruption, do not neccesarily think of a giant eruption like the Veidivatnahraun or Thjorsarhraun, because small eruptions do also occur.

        Yep numbers add up, in this case to 40cm of inflation, and N-W movement. Interpret it as you want. 😀

        (My tone might sound a bit harsh, sorry for that. 😉 I neither have a clue in most cases, I just like spin my mind now and then. 🙂 )

      4. Amazing connection – I too was wondering why there was still so much tremor / unrest seen at Grimsfjall station, yet eruption was over in just days (!?), maybe it just found sideways exit. I think Grimsvötn is fed only by itself.

        http://hraun.vedur.is/ja/hekla/borholu_thensla.html

        Another minor “abortion” of the Greater Hekla Region or do these “transient” (pressure waves) come down from Hamarinn area (or even the “Rubber” area).

        My comment re them recent sharp quakes in “south side” of Reykjanes rift is, can we expect them also in Hella area or Eyja / Katla areas as well. It seems to me there might come more of these.

      5. Hekla is not on the rift zones. It is a stand-aloner…
        It is not affected by Hamarinn. This is caused by Hengill, there is a clear time-causal connection between Hengillarea-quakes and The current set of transients. There has been other transients caused by earthquakes at Hekla, they behave slightly different.
        But they are all sign of tremendous strain in the Hekla volcano. But as long as there is a causal chain from Hengill it should not set off an eruption, unless there is major Hengill quake, and I mean at least +3,5 minimum and most likely above 4.

    2. Carl, you’re correct in the case the spreading of the american and eurasian paltes does not mask the west-east movement. Remember, those readings are relative to Reykjavik, not absolute readings.

      1. In more detail: It could be that the relative movement between Reaykjavik and SKRO covers the absolute movement of SKRO perfectly. And you’d see nothing in this case, while Hamarinn would continue inflating happily…

      2. I know, and I do my very best to remove that movement out of the equation. Obviosuly I do not do a proper recalculation of. I only detrend the GPS:es for Hekla, but that is done automatically by my computer. I am fairly lazy after all.
        I though wish that IMO did use one of the stations on each plate as a reference and then did recalculated movement maps like Sigrúns Austmannabunga-map. Because it would at many times be better to see local movement then Reykjavik-referensed movement.

    1. It is small compared to the others I have on file.
      I think this one is caused by Hengill directly. But notice that it started with a small up, before falling.
      Last two started with quakes around Hengill area. The first was a mid-sized and happened withing half a minute after a Hengill quake, the second happened just before the small swarm at Hengill.

      My guess is that the tension is high over at the Hengill Sprungur and that when there is release there it affects Hekla quite a lot.
      Remember that this is an area that can throw off 5+ quakes. If there was a large quake in that area it would probably make Hekla erupt.
      By the way, Hekla seems to have stopped its uplift, perhaps due to systemic maximum filling, the filling is though very large now at Burfell/Isakot. Equal or higher than the numbers for Skrokkalda.

      But, just to be clear, the current activity seems not to be caused by Hekla, it is more likely caused by Hengill, but affecting Hekla.

      1. Yep I’ve been wondering about that scenario too, a large earthquake (M5+?) in the SISZ, followed or preceeded by the eruption of Hekla. As happened in 2000. I’ve also check back the files a bit, and previous Hekla eruptions were accompanied by rather large earthquakes. The one in 1946-47 was preceeded by a M5.4 and a M4.0 beneath Hekla.
        And half a year before the 1913 eruption a M7.0 occured about 18km S-W of Hekla. Etc etc etc…
        There have been some pretty nasty earthquakes in Iceland actually!
        Take a look yourself:
        http://ijsland-enzo.nl/ijsland/actueel_aard_historie.asp?jaar=1800
        (Dutch site, speaks for itself)

      2. I have that list in english (thank god).
        Dutch is the hardest language I have ever tried to get my grips on, I just gave upp learning after the Rabobank cycling-term arsgespuiten… 🙂

        In 2000 it followed after yes, but the causal quake was a meesly 2,5 quake.

      3. You think so? You are from Sweden right? I had no problem making something out of Swedish when I visited Boras and Göteborg. I recognized many words either from Dutch, German or English!

        There has been a study about the relation between the 2000 earthquake and eruption, but I must admit I do not really remember what the outcomes were.
        But now that I’m thinking, the M6.1 in 2008 should have done the job by that time right? The pressure beneath Hekla had already exceeded the pre-2000 value.

      4. I think my problem is that dutch is so like german and english (that I speak) that my poor head over-loads.
        I have heard that dutch-speakers have an easier time learning languages than others since all the sounds and many words are allready there. But the other way… phew… 🙂
        And yepp, statistics and coffee, can only be a swede 🙂

      5. Well another theory goes that not a single person outside Holland speaks Dutch, so we’re kinda forced to speak something else! Also we do have great opportunities to learn languages at school. At high school I had (have) a compulsory 2 years of German and 3 years of French, 6 years of , and I also took 6 years of Latin and 2 years of ancient Greek. Especially Latin is really usefull for all the south-European languages with little effort I can read some Italian. Though I do prefer the nordic languages! The rythm and melody of both Swedish, Norwegian and Iceland is so cheerful!

      6. add: 6 years of english.
        Forgot to mention that we also have the opportunity for many other languages such as Spanish or Italian.

      7. Same here, I think the dutch antillees speak dutch… No one speaks swedish.
        Normally we have an easy time with other languages, it is just dutch that gives me a headache.
        7 years mandatory english in basic school (out of nine), then 3 years at secondary level school.
        3 years french, 4 years of living and studying in Germany, 2 years latin, 1 year italian, and two years of spannish. I am confused in so many languages… Oh, forgot Basque, and for romantic reasons 3 years of yiddich with a maydele, and a smattering of Khi’zwahili.
        After that I stopped making sense at all.

  40. About Hekla-transients.
    Even though of them can be really strong, they are just signs that the mountain is filled to the brim and under large tension since it is like a fully blown balloon.
    The last transient before this one was the largest so far, but still not as powerfull as the eruptions transient 2000.

    At the onset of an eruption you would either see a quake at Hekla around 2,5, or a more powerfull outside, this will almost emediatly be followed by very large transient and hard harmonic tremoring would start at the same time. Then there would be a few quakes around 2 as the fissure at the summit rips open. All of this would happen within an hour.
    So, transient, Hekla is showing she is ready. Quake, transient + tremoring, more quakes… Well, run like hell… Run at stage two if you are there… When the ripping quakes come it is too late.

      1. Then the transient would be inversed Jack.
        These transient (except the one last night) follow exactly the pattern from the eruption, so it is the mountain trying to open.
        But something is missing in the equation.
        My guess is that Hekla needs a larger quake nearby or in it for a degassing event happening. But here I am just speculating wildly.

      2. If degassing is “the thing”, then some extra tension helps to prevent the onset of an eruption (everything else being equal), as higher internal pressure is needed for the magma to break free. That might actually explain, why Hekla has not yet erupted, although inflation is way higher than before the last eruption in 2000.

      3. Positive pressure would work as a counter-agent to eruptions. But we are have negative tension transients.
        Degassing is just a conjecture on my part.

        I have a different theory why it hasn’t erupted. Ductility of the rock. It has erupted a lot, and through that process the temperature of the rock is fairly ductile and can stretch more than cold rock. That also explains why it is so “tectonically dead”, since ductile hot rock is needing a heck of a lot of more energy to break compared to cold brittle rock.
        In a way that is bad, it would imply that Hekla over time can sustain larger and larger eruptions as long as the cycle of rapid eruption periodicity goes on.
        But, this is theories. Some of my theories will be tested if an eruption occurs as I think, others need totally different proofs.

      1. The factor on the tremor plot on the internet is 10, if I know the distance of the earthquake I can calculate it using my own formula.

        But I no good with numbers, so I don’t use numbers like normally is done. I am also no good writing down formulas here at the moment.

      2. Yeah I was wondering already how you could measure the size without knowing the distance of your helicorder. So you already guessed it was somewhere around Grindavík?

      4. I think that Jón by feel the force without equipment… I guess you could “just” see how strong they are after a while if you know where they are. But if I remember correctly Jóns software gives an estimate-value of the quake.

  43. Pieter;
    Regarding the SKRO-movement.
    We also found boguer-maps (or how it is spelt, I am tired now) that showed anomalies at the same places as the Lurking-plots. So there are more circumstancial evidence for it.
    Why I use the standard IMO GPS for SKRO is that something happened after the Grimsvötn eruption. It returned to the “normal” movement. Ie, before the eruption it was moving the other way, now it is not. Kind of indicative that SKRO is influenced like that.
    You should also remember that dyke-transverse movement of magma happens elsewhere too. Herdubreid-magma is moving towards Askja, and Hekla has an inferred dyke moving magma towards Isakot. Godabunga cryptodome is connected to Katla (probably) and might in turn be connected to Eyja (I do not actually believe this last part, it might be connected mechanically, but not magma-conduitic).
    Krafta and Askja are at a minimum connected mechanically, with a powerfull subsidation of magma from Askja during the Krafla-fires.
    So there is a set of volcanos connected in Iceland. So theorizing about a connection like we did now is not so unlikely. We also have the pesky Gjalp eruption that started with heavy quakes in Bardarbunga and then Gjalp went boom…

  44. Arsgespuiten???
    I need a beer!
    Keep doing the good work.
    I’ll try to draw Lurking back to where he belongs.

  45. $%&

    I just lost a hard drive. Data loss, if I don’t get the data on that drive back is I think minimal. But I am down 250GB. I guess that I have to buy a new hard drive, even if I am trying to save some money at the moment.

    I am not yet sure at the moment what I did loose. I am still looking into it.

  46. Good Morning all.
    I often feel so ashamed of the British education system, as the average Brit cannot even read and write English properly these days let alone another language.
    I had Two years of French and Latin in grammar school. No languages at all in primary schools. In the third year of grammar school I had to choose between Sciences, Languages or Arts. I think my Latin has been most useful as apart from the odd Holiday in France, I rarely use French. I did learn enough Spanish to get by on, simply by being in the country, the same with Welsh!
    My little Grandson is amazing, he can speak Norwegian, Swedish and English whilst poor Grandma struggles with Norwegian. It’s my memory that lets me down and getting my false teeth around some totally different phonetics 🙂
    Sadly Google translations are superior to my language abilities!!! (Hangs her head in shame). I so admire Icelanders and their Nordic neighbours for their excellent English.

    Poor Jon. First you are ill and now your Computer!
    At least all is quiet in Iceland right now. I do hope you get it fixed before Iceland becomes more busy.

    1. I would like to second what Diana said about the impressive language abilities demonstrated on this website. I think that Europeans are light years ahead of Americans in terms of teaching and learning languages. Here it is considered acceptable to learn no foreign language at all, and I believe that the US is the only country in the world that actively promotes being monolingual. It is truly shameful.
      Like most Americans I didn’t even have the opportunity to learn another language until secondary school where I started with Latin, soon switched over to French, and eventually added on Spanish and a smattering of Italian. But I am woefully ignorant of any Germanic or Nordic language, although both of my grandmothers spoke German. I have traveled a bit in Scandinavia, where I would politely ask someone if they spoke English, and would always get the reply “of course”. Now I would love to learn a Nordic language (although I haven’t declined nouns in decades!) but don’t know which one to choose. I am fascinated by Icelandic, as it seems to be a beautiful nature based language, but it is spoken by so few people that it would perhaps be a poor time investment. And unfortunately I have yet to visit Iceland….
      I came to this blog with an interest in Iceland and its volcanoes, but I must confess that what gets me most excited is when you all start talking about what the various words mean, and their relation to other languages, etc. The posters here have my deepest respect for their mastery of English! This summer I obtained certification in ESL (to hopefully teach English in France some day), and that course work introduced me to complexities of the English language that I was totally unaware of, so now more than ever I can appreciate the sophistication of the level of English used by the posters here.
      Jón, Carl, Pieter, Daniel, Jack, Renato, Diana, all the Icelandic posters and everyone else, thank you so much for this intelligent and entertaining forum!

      1. I think you’ll find that the greatest stumbling block is that AmE only has 33 phonemes (unique sounds carrying linguistic information) whereas a Nordic language such as Swedish has at least 45, not counting dialectal variations. Furthermore, Swedish does not have some of the phonemes of Eng or Icelandic (such as the two “th”-s in “THis” or “thick”). The sum is that you’ll have to learn to recognise and reproduce as many language sounds as you already know…

        A second stumbling block is that inflection sometimes is used to carry meaning, such as “anden” with stress on both syllables means “the spirit” and “anden” with no particular stress “the duck”. Then there’s all the idiosyncracies such as the use of articles and how sometimes what you have learnt to recognise as the definite, singular can turn out to be indefinite, plural.

        Though I’m delighted that someone would actually be prepared to endure all that to lear a Scandinavian language, I’d advise you to think carefully before you actually do it! 😉

      2. All this is true for Swedish, Norwegian, Danish and/or Icelandic. Finnish is totally different.

        The ones mentioned above are similar to central European languages, they use small words for designating tense, relation, etc. Finnish uses little endings which also can bend the main word. E.g. in German you have maybe 200 different possibilities with the small words before the main word, in Finnish you’ll have the same main word in over 200 different forms.

        Second major obstacle to foreigners in learning Finnish is double letters (vowels or consonants), which affect pronounciation. “Kato” means loss or failure, while “katto” means roof and “kaato” means fall or slaying. At least all Germans I’ve encountered and tested with those words, have heavy difficulties in hearing a difference between those three words.

        It may be due to this that we have a joka or saying here in Finland: “When all is said and done, and you go to heaven, only Finnish is spoken. Why? Because it takes forever to learn it!”

      3. What we should though admit Henrik is that we stink at teaching kids to do math, and we lag in hard sciences.
        Nowadays they can’t even do multiplication in their head. And no, they hardly even know how to use a calculator…
        Truth be known, we swedes are good at being bad at most languages, sometimes I think I am just confusing people in a multiple of languages.

  47. Well… dunno what I’m supposed to plot. So here is the Reykjanes over to past Hekla, all quakes, plan view, color coded for date (2011).

    http://i56.tinypic.com/2mds67a.png

    As for Hekla, as mentioned earlier, you aren’t gonna get much warning. It’s just gonna pop and go when it’s good an ready.

    The relatively large quakes on the south side of the MAR? Beats me. They don’t seem related (directly). If they put out focal mechanisms we might be able to get an idea… but they don’t, at least not to the public.

    1. Hello again!
      Coffee is on the pot and beer in the fridge!

      I do have a wish… for a plot.
      A 3d of the area Hengill up to Hekla. And if possible for as long as you have data…
      I am as you probably understand trying to understand why a quake at Hengill gives a transient exactly like the 2000 eruption. It is baffling me no end that a relatively small quake so far away gives that much reaction.
      Yesterday a small quake (o,7) gave a non-eruption transient, but that quake was nort-west of Katla.
      Good to see you again!

      1. I lurk, there for I don’t exist.

        “You heard that torpedo hit, and I was never here.”

        I will do the plot after work today. I will have to fold the most recent quakes into the archive set (1995 – 2010) and that’s a pretty large file.

        I haven’t really been anywhere, I didn’t think anomalies in the US Bureau of Labor and Statistics would be of much interest to followers of Icelandic quakes. (or odd periods where the HadCrut SST V3 quits looking like itself)

      2. I think it is more that I have been gone for quite some time. Had one of those moments in life when one discovers that one has tried to do good, but it came out as bad things whatever one did. So I soul-searched myself and sat at quiet and odd places of the planet.

        I am though curious what a HadCrut SST V3 is and what it looks like when it has quit looking like itself.

        Thank you very much for the hard job of making the plot! 🙂

    2. Regarding Hekla going pop, yes absolutly. We will get maximum and hours notice. I am just trying to collect data on something I think is the only small pre-warnings we get except from GPS-movements.
      My thinking is that the larger Hengill quakes could have something with it, remember that Hengill had a large quake “shortly” before 2000-eruption. The second is that I believe that the eruption style transient is a sign of tension-levels coming into “the zone”. But… It would still not say more than that the conditions is correct. At least untill after the next eruption when I can check my modell.
      As I wrote in another blog post, my modell has evolved far enough to work as a statistical modell for a prediction, so I guess we will now towards august nect year if I was wrong. Modell gave a date between december this year and may next year, and a bit of other stuff.

  48. Hi I love the banter just wish i had years of insight like you guys. With all this movement and inflation is there a possibility or has there ever been an occasion where volcanos have erupted together? Now that would be interesting. Thanks for a wonderful blog.

  49. Hi I love the banter just wish i had years of insight like you guys. With all this movement and inflation is there a possibility or has there ever been an occasion where volcanos have erupted together? Now that would be interesting. Thanks 

  50. Pieter, those earthquake summaries are rather interesting as they show that 1) the really big quakes are confined to two graben areas, Selfoss and Tjörnes, and 2) Medium size quakes follow the MAR with two notable exceptions – “Krafla” and “Eldgjá/Veidivötn”.

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