Posted on by Jón Frímann

Current ongoing earthquake swarms in Iceland

At current time there are two main earthquake swarms taking place in Iceland. The first one is at Krísuvík volcano and has been going on since early this week. Currently there is nothing to suggest that it going to end any time soon. This earthquake swarm however sometimes stops for several hours and up to one to two days at the longest. Most of the earthquakes taking place are less then mag 2.5 in size. It is not clear why this earthquakes are taking place. This might be tectonic process or something to do with the magma intrusion that is taking place in Krísuvík volcano.

The second earthquake swarm is taking place at Herðubreiðartögl with earthquake taking place at Herðubreið at it’s north limits. Several mag 3.0+ earthquakes have taken place. This earthquakes appears to be due to tectonic process in the area. But I have heard theories that this process might have started due to influx of magma into the Askja volcano that is close to earthquake swarms in Herðubreiðartögl. At current time I cannot confirm that this ideas are correct or not. This earthquake swarm is ongoing and does not appear to be ending. But there are breaks in it that last from few hours and up to one day at the longest. Please note that Herðubreiðarfjöll is a central volcano that is active. It is not on the GVP volcano list for the area. This volcano is located inside Askja fissure swarm and has many active fault lines that cross it from north-south.

The newest earthquake swarm that appears to be at slow start is taking place in Esjufjöll volcano. But since activity started there in early October 2010 earthquakes appears to be on the rise in Esjufjöll volcano. It is worth noticing that earthquake swarms in Esjufjöll appear to start slowly but they due appear to peak after 20 to 180 hours after they starts. This earthquake activity is due to new flow of magma into Esjufjöll volcano.

49 Replies to “Current ongoing earthquake swarms in Iceland”

  1. What’s going on 20-30 km NNW from Langjökull? A nice quake swarm, average magnitude M2, depths ranging from less than 20 km to 1 km? Tectonics?

    1. There are fault lines there (big ones) that have the direction east-west. It appears they are active again. Last time (few years ago) there was a earthquake swarm in this area it lasted for two months without a break.

  2. Yes, that looks like a big swarm happening northwest of Langjokull. I was actually there this summer, it’s north of Husafell, its a nice forest area with remains of some large lava eruptions from the past, a few hot springs, and with valleys aligned west-east. If you climb there the mountains you can see those valleys going in the direction of Snaefellsnes volcanic peninsula. In the area, you find several volcanic peaks: ÖK, Eiryksjökull and also a caldera under the Langjökull glacier. It looks like this area is not that dormant after all.

    1. This is actually about 60 to 90 km away from Hvammstangi. But interestingly due to fractures in the crust there I do not see the earthquakes that well. But the distance is also a big factor in this.

  3. Today you can see a line of earthquakes forming between Thinsvellir, close to Reykjavík, and to the region NW of Langjokull, where there was the earthquake swarm. A few weeks ago, I mentioned this, when there was the other swarm N of Langjokull. Maybe the sucession of tectonic faults from Reykjanes and Thingsvellir, follows this path, northward.

  4. With all the swarms going on just now, certainly makes for interesting viewing!

    It’s like the whole of Iceland has woken up (earthquake-wise).

    1. I thought I detected a trend towards more tight clustering in time- then realised the time axes are different ( 1day ; 4days) .
      If you expand the time course on a cluster ( eg 9th Nov) do the EQs start deep and progress upwards or are they ‘random’?

      I cant see a trend to shallowing over the two plots.

      1. The second plot, the shorter time period, does have a slight upward trend… but it could easily be the human tendency to see what we look for. That’s why I didn’t toss in the trendline.

    2. This should not happen. I am unsure why it does. I didn’t find anything in the settings besides increasing the link limit from it’s current three (but I didn’t change it, just so you know).

      But I will just approve your messages if they have more links then three in it.

    3. I have increased the limit of links from three to four. So anything below four links is going to appear without getting stuck in the mod queen.

  7. @Renato Rio, my 19:08 post has the plots you are after… but it’s in the penalty box.

    Gonna have to wait for the referee to let it out of the box.

    I guess it iced the puck.

      1. I’m probably wrong, but something seems to be taking place between those earthquakes swarms.
        It looks as if magma is trying to rise under Husafell, but since it gets blocked, it is slowly flowing to Krýsuvik, via MAR. Is it too foolish to put it that way?

      2. Well… dunno about flow paths. That’s a pretty far trek.

        As you have noted, it is on the MAR. The problem is that the whole if the Reyjanes peninsula and ridge is a transition area. This is what makes it so dynamic. Further south along the MAR, it’s a normal oceanic spreading center… and a slow one as compared to the spreading rate of other ridges. Up in the interior of Iceland, it’s a continental spreading region, with narrow spreading zones mixed with ridge jumps, grabens and transfer faults and dike and sill formations. A generalized collection of just about everything you can geologically stick in one place with the exception of a subduction zone.

        My take is that it’s all tectonic in nature, with the caveat that if enough room is made between the two plates (actually, the North American plate/ Hreppar microplate boundary), then magma can seep it’s way up along the edges of previous dikes or along new fractures from the extension.

        I don’t know what depth the melt zone would be at, but you know it’s down there.

      3. You’re right. Tectonic in nature. But there must be some magma sneaking in through all these faults and dikes and whatsoever. We can see it in the plots.

      4. And I just went back and looked at the most recent MET plot.

        “Good Lord look at the quakes” came to mind.

      5. I’ve done some rummaging around.

        This set, up near 64.8N – 20.8W, is a little off the beaten path. There are two distinct groups there. The northern groups leans to the south, while the other group is sort of a collection of seemingly random points.

        This is also in an area of an “extinct” spreading center that traces in from Snæfellsnes to the northwestern corner of the Hreppar microplate. The western edge of that microplate traces south towards the Reykjanes (and the other quake cluster at Krýsuvík). The Northern edge (and the border with the souther edge of the Trollaskagi microplate) tracks towared the Bárðarbunga / Askja area.

        The really interesting part about this whole set-up, is that we have swarms at Krýsuvík, Northeast of Askja, and here at some obscure corner on an old spreading center. All of them near the extents of the little plate.

        Only two to see if that keeps me out of the penalty box.

        64.8N – 20.8W (since I can’t really pick a good feature as a name)

        View East:
        http://i51.tinypic.com/1pv3td.png

        View North
        http://i52.tinypic.com/4hw68n.png

      6. Lurking: I’m afraid to ask, but are there any register of plots on swarm threads taking place before large fissure eruptions? I wonder how would they look like.
        As for the last plot: could you “stretch” them to reach Askja coordinates?
        Thanks again.

      8. As for the leading indicators of large fissure events… the last time it happened no one was really looking at seismic data.. at least at the level that we look at it now.

        The residents and historians of Iceland would have better info on this.. provided someone actually wrote it down.

      9. So, we wouldn’t know what it would look like, if it were to happen. Hmm….
        You mentioned Trollaskagi microplate, and I remember having heard that there could be another plate at stake here.
        I’ve been reading about Erta Ale’s lava lake and what has been suggested to explain the constant convective forces driving rising lava which keeps the “wound open”, and I was wondering if the same processes couldn’t be happening here in Iceland, but in a larger scale. Not subduction, as you already said, but subsidence. If those tiny plates are sinking far beneath where mantle is soft enough to respond to the pressure, if MAR is gently spreading apart, couldn’t this whole process generate melts that keep coming up in waves, i.e. in Laki-type events?
        My point is: could the present activity reflect in a larger scale what happens to solidified magma sinking in Erta Ale’s lava lake? I don’t consider an actual fissure event, but just the “recharging” of dikes and other types of magma intrusions sneaking through all possible fissures and faults. Is that absurd enough for you?

      10. *sigh… if it’s not one thing it’s another. I was just ganked by my numlock key. three paragraphs down the tube. Gonna try and reconstruct it.

        “Not subduction, as you already said, but subsidence. If those tiny plates are sinking far beneath where mantle is soft enough to respond to the pressure, if MAR is gently spreading apart, couldn’t this whole process generate melts that keep coming up in waves, i.e. in Laki-type events?”

        If there was subsidence in play, I would think that there would be a significant signature in GPS that pointed at it. As it is, the whole if Iceland is busily doing the isostatic rebound dance from the last period of glaciation.

        A really telling example of that… one not involving precision instrumentation, can be found in a source link that Jón Frímann provided in the “Maps of geology in Iceland” post. From a caption of one of the photos off of that site:

        “Stóri Sandhóll, a marine terrace of Bølling age in Skorradalur. Behind, alpine scenery of the Skardsheiði massif”

        Stóri Sandhóll (The Big Sand Hill?) was formed by ocean water. A marine terrace is that relatively flat, slightly undulating region next to the beach that was cut by wave action. We have a few of them here in Pensacola if you know what to look at. Stóri Sandhóll reaches upwards of 150 m a.s.l. That’s current sea level. This time period is about 12.6 ka BP during the Bølling interstadial (warm period) prior to the Younger Dryas. During glacial max, the sea level was reportedly 300 meters below what it currently in. How much rebound had occurred prior to the Bølling I don’t know, nor do I know how far down it was pushed when the Younger Dryas returned the Northern Hemisphere to thicker glaciers and icecaps.

        My point here is that Iceland is still rising. You see it in the GPS every time you look at it.

        NOTE: The following is PURE speculation on my part, does not necessarily reflect accepted theory, and could be 100% wrong. I am not an expert, or a specialist in this field. I do not claim to be.

        (That’s for the media transients)

        I would think that before you had a Laki or Eldgjá level event, there would be precursor signals that would hint and what could be in the mix. I think that what you would see would be tell – tell quakes along a line of a dike swarm on a scale that has not been seen in modern times. This would likely be in conjunction with a massive eruption at one of the larger central volcanoes. Sure, we don’t have any readily available historical reports of quake swarms or seismic activity that lead up to the 934 or 1783 events, but that is what makes sense. (these reports may exist… but in an archive that only someone in-country and familiar with the language could find)

        Sure, those seismically silent regions are a bit deafening since we know what they are capable of… but for now, they seem like they are locked up tight.

        Lets hope they stay that way.

      11. Don’t you just love afterthoughts? I forgot this part… which was also part of the numlock gankfest.

        (oh yeah… “gankfest.” In online multiperson gaming, a gankfest is when you are stuck in a situation where the enemy has your spawn area locked down to the point that as soon as you spawn in, you die. Or, you have little time to do more that flail about until you die.)

        Anyway…

        Iceland is continental crust. Even the microplates are of the same material. Continental crust is less dense than oceanic crust, which is why subduction zones look the way they do. It doesn’t mean that continental can’t subside, the Jan Mayen micro-continent is fully 100% underwater with the exception of tiny Jan Mayen island. Eventually it managed to get welded to the Eurasian plate, so there is no telling where it will end up after a few million years.

        Reportedly… depending on which paper you read, Iceland is sitting on a hotspot. Currently Bárðarbunga sits right on top of where it is believed to be. This hotspot is caused by either a mantle plume (with shallower that others origins) or it’s caused by Icelands crust sittin on top of other (probably oceanic) crust. Much like two pancakes sitting in a sea of syrup. The melting the lower crust would probably be the source of magma in that scenario.

        Which is it? Beats me. I’ve read papers that make reasonable arguments for either scenario.

  8. I was looking at ths on the quake maps from the Meteorological folks in Iceland.
    Holy vibrate Batman! that’s quite a swarm. Hope nothing nasty pops,
    that pulsing has got me a bit concerned.
    I live in an area between the Cascades and Yellowstone. Partly why I have an interest
    in this….

  9. @Lurking: Beats me too. You mentioned: “This hotspot is caused by either a mantle plume (with shallower that others origins) or it’s caused by Iceland’s crust sittin on top of other (probably oceanic) crust.” What if this underlying crust is heavier and that both – hotspot and pancake microplates are working together? Wouldn’t that cause a havoc – an under-the-earth subduction sort of thing – the heavier sinking plate pushing downward and the hotspot holding it upwardly causing the plate to rotate and bend in swirling slabs? Remember Carl’s vortex theory?
    I don’t know about GPS and I think you are right: if there was subsidence, we could read the GPS data proving it to be so. But this is Iceland. It was not supposed to be there, yet, there it is.
    OK, you’ve already given much food for my thoughts and I begin to hallucinate.
    Thank you for the illuminating explanation, and thanks for the plots. I’ll be lurking from behind, since this is going to be a crazy week. But then, it will be over. And I will be back to tease you again with my dumb theories.

    1. Iceland is on top of a mantle plume hotspot, it has been scientifically proven. Millions of years ago it was beneath west Greenland (Disko Igneous Province), since then it has ‘moved’ (plates actually moved, plume didnt) east and formed the Greenland-Iceland Rise, and now it’s situated beneath Iceland.

  10. According to the news this morning. They believe that they earthquakes that are north of Húsafell are somehow connected to the earthquake swarm that took place below Blöndulón lake few weeks ago. What that connection is I am not sure. But this is interesting anyway.

    1. This makes sense in a way, if you draw a line between Blöndulón lake and the Húsafell earthquake zone, you get a line that’s parallel to Reykjanes peninsula. I speculate that these are related faults, and that there is transformal fault in between.

      1. Very interesting. Have to take a longer look later ( after I catch up with all the news….)
        Thanks for the link.

  13. hi guys, so according to all this data, is there any risk of eruption? or just normal behaviour…
    im an absolutely ignorant in this matter… thanks guys

    1. Sort of normal…

      The hard part is trying to figure out what forces are at play. I had a nice quake stack in that area until I took note of the stack associated with the April eruption… it looks quite puny by comparison. Event the activity over at Askja has a much more intense and clearly defined stack.

      I’m thinking “no” on the looming eruption idea.

      But I just plot stuff, so I can’t state that with any authority.

      1. Thanks about the explanation…. but please!, can you tell me what kind of previous-parameters or conditions occurs before having an eruption???
        I assume, that you guys are usually recording and collecting data from those gps, comparing them with old data collected before… and stablish how, when and where an eruption is comming… but
        is the eruption forecast so easy to predict… ?¿ or we are only capable to predict an eruption when it is already popping in…
        thanks people, im really learning a lot about this

  15. Their may well be hotstops , one because the ice is toxic, from fallout,with the change in the magnectic field thays why it may be getting hotter and melting the snow quiker.It may be only a short time before one volcanco goes,triggering a domino effect, is their any plans by your goverment for exovaction; I believe that might be a wise move if you live on the island.

    2. “…the ice is toxic”

      In order to be toxic, it has to be toxic to something. Toxicity implies a poison or contaminant. Other than possible contamination with the byproducts of an eruption I don’t see a connection here.

      “…from fallout”

      Fallout is a nuclear weapon byproduct. Ash fall from an eruption is… well, ash fall. Last I checked there were no ongoing ash column generating eruptions in Iceland.

      “change in the magnectic field thays why it may be getting hotter and melting the snow quiker”

      There are probably quite a few Icelanders lounging around out in the sun right now that would probably disagree with that melted snow idea.

      As for the magnetic field… well H2O is polar molecule. It’s going to try to orient itself with the prevailing fields. That’s why micowave ovens work. But microwave ovens reverse their field at several billion times per second in order to impart energy to the H2O. One magnetic reversal over a few thousand years isn’t going provide much energy to a water molecule.

      “It may be only a short time before one volcanco goes,triggering a domino effect”

      You are aware that this is Iceland right? That’s what Iceland does. Volcanoes are part and parcel of Iceland. Fissure eruptions and simultaneous volcanic eruptions happen there a lot more often in than elsewhere.

      An eruption on the scale that you seem to be inferring would probably make running a delay of the inevitable. Something on a scale that would require the evacuation of Iceland is gonna make the Younger Dryas look like a cold snap.

      My opinion?

      “Umm… nope.”

  17. The Last ones near Krisuvik are quite shallow, but the quality isn’t that good yet, maybe they get revised and we will get a nicer picture.

    Monday
    06.12.2010 18:43:38 63.852 -22.186 2.9 km 1.1 45.41 7.1 km SE of Fagradalsfjall
    Monday
    06.12.2010 18:42:52 63.874 -22.192 1.7 km 0.7 39.22 5.1 km SE of Fagradalsfjall
    Monday
    06.12.2010 18:31:57 63.903 -22.166 1.6 km 0.8 37.59 4.3 km S of Keilir
    Monday
    06.12.2010 18:25:58 63.830 -22.207 1.3 km 1.0 61.94 8.7 km SSE of Fagradalsfjall
    Monday
    06.12.2010 18:25:21 63.888 -22.150 5.2 km 0.6 66.73 4.1 km W of Krýsuvík
    Monday
    06.12.2010 18:24:15 63.877 -21.863 15.3 km 0.7 52.12 10.0 km E of Krýsuvík
    Monday
    06.12.2010 18:24:13 63.909 -22.129 5.0 km 1.2 90.02 3.9 km NW of Krýsuvík

  18. Jon:- In an earlier thread which is now closed, I understand you to have said that the moon has no effect of earthquakes.

    Please can you clarify this, because internet seems full of claims that the moon controls tides and sea tides are very heavy (heavier than glaciers) and control considerable sea pressure on rock, so high tides put stronger pressures on the earths crust and can trigger earthquakes in places where tectonic stresses are already close to breaking point, as the tides go out. Please can you clarify this.

    1. It is the physics of the the matter that is at play here. Rock is more dense and has more mass on m3 scale then water. So the gravity of the rock and the sun cannot effect it due to distance and size (the moon is small compared to Earth).

      This is why the moon and the sun don’t create earthquakes on Earth.

      1. But what I read was that tides could trigger earthquakes due to changing weights of water on the land in places where it is already close to cracking point – is that not true? The tides of course, are caused by the moon. I am not suugesting anyone is saying that the moon could pull or push magma via it’s gravitational pull. Is it untrue that sea movements causing sea water weight fluctuations can trigger earthquakes?

Comments are closed.