Posted on by Jón Frímann

More intraplate earthquakes north of Langjökull / Hofsjökull volcanoes

Earlier this night (around 19:19 UTC 28th of October) more intraplate earthquake did start happening north of Langjökull / Hofsjökull volcanoes. The earthquakes are in the same place as before. But please see my earlier post for information about the earlier earthquake swarm at the same location.

Currently it seems that the earthquake swarm is growing in size and frequency of earthquakes. But the earthquakes appears clearly on my Hvammstangi station. The web page for my geophones can be viewed here. The distance of this earthquakes from my Hvammstangi station is about 40 to 80 km. But no more then that I think.

So far all the earthquakes have been less then ML3.0 in size. But if the swarm gets stronger that might change with out any warning. This area of Iceland is unpopulated so it is unlikely that anyone is going to feel those earthquakes at current size levels.

39 Replies to “More intraplate earthquakes north of Langjökull / Hofsjökull volcanoes”

  1. The strongest earthquake so far according to the automatic SIL system that Icelandic Met Office has is ML3,7 in size at this location. It did appear clearly on my geophone. Both of them.

  2. These intraplate activity is confusing to me… can anything happen in this volcanos? I’m hasking because these tectonic tremors can instable the magma stored in volcanos or not? sorry if i’m stupid…

  3. Interesting how the swarms keep getting stronger.
    Have you seen familiar intraplate swarms in the past Jón?

    1. Not at this location. But few years back there was a swarm a slight left to where the current swarm is taking place. But I do not think that earthquake swarm was a intraplate earthquake swarm like this one. Those earthquakes where more connected to the north Langjökull volcano, see here http://hraun.vedur.is/ja/viku/2007/vika_48/index.html#mark

      Last intraplate earthquake swarm took place in 2006, then in Westfjord. In the most east part of them. See here, http://hraun.vedur.is/ja/viku/2006/vika_36/index.html#mark

      1. Thanks! That indeed looks familiar to this one.
        Oh and by the way, for all of you, there is another Dutch site about iceland which has a great earthquake (M >1) archive! It’s in Dutch but I think it’s rather self explanatory. Earthquakes going back to 1995, click on EQ’s to get a detailed view of depth and location:

        http://ijsland-enzo.nl/ijsland/actueel_aardbeving.asp

        (To go back in time, click on one of the numbers (days) and change the date in the adress)

        http://ijsland-enzo.nl/ijsland/actueel_aard_animatie.asp > Earthquakes 1995-2010 animated.

      2. Those charts are cool – thank you Pieter. It’s good to be able to see more than 48 hours data at a time.

  4. Magnitude ML 3.7
    Region ICELAND
    Date time 2010-10-28 21:10:35.9 UTC
    Location 65.17 N ; 19.61 W
    Depth 1 km
    Distances 159 km NE Reykjavík (pop 113,906 ; local time 21:10 2010-10-28)
    90 km SW Akureyri (pop 16,563 ; local time 21:10 2010-10-28)
    63 km S Sauðárkrókur (pop 2,682 ; local time 21:10 2010-10-28)

  5. Another 3+.

    28.10.2010 21:36:45 65.142 -19.575 1.5 km 3.1 90.04 30.5 km N of Hveravellir

  8. Well, how about that. An artificial reservoir.

    Based on http://www.karahnjukar.is/files/summary.pdf it has a “usable volume” in the range of “2,100 GL (million m3)”… which works out to something above 2.22 x 10^9 metric tonnes.

    I guess that and normal MAR stress can trigger a quake swarm.

    1. This is a different artificial reservoir. This one you are referring to is located close to Vatnajökull in east Iceland. This man made lake was created in 1991 where the current earthquakes are happening now.

  9. WHOA!!!

    Two more, but about equidistant to the upper corner of what may be the top of the Tröllaskagi.

  11. On my geophone I am seeing more earthquakes then appear on IMO automatic maps. I don’t know by how much. But for every two earthquakes that appear on IMO map I am seeing about three more on my geophone at Hvammstangi.

  12. That plot does look pretty straight, Lurking – as can be inferred from the IMO surface plot. Since it’s claimed to be tectonic, let’s indulge in some contra-factual speculation: For argument’s sake, let us assume that this turns out to be a volcanic or volcano-tectonic event and we’re watching the very first stages of the formation of a new volcano proper. If I am not mistaken, mankind has only ever seen cinder cones form, never new strato- or shield volcanoes.

    What would such an event be like? Would it start with a large, long-lasting effusive eruption (years or even tens of years on-off) that built a recognisable volcanic mountain? Or would it first create a magma chamber for itself and the first eruption be an explosive event followed by an effusion of andesitic-dacitic-rhyolitic lave that built a cone? I have to admit, I’ve never come across a description of how a new volcano – as opposed to cinder cone – is born. The closest I guess, is the lava dome at Novarupta, if that can be classed as the birth of a new volcano.

  13. This could be the continuation of the fissure/fault that runs all the way between Thingvellir to Langkojull, and to the north, in the direction of Myvatn. Look how aligned all the earthquakes are happening along a \line\, even between Reykanes all the way to SW of Myvatn! This is even parallel to all the Hekla, Grimsvotn, Katla fissures!

    However the strange is thatseemingly there is no geological evidence in that zone, north of Langjokull and Hofsjokull. Maybe it’s a old fault, or a newly forming one.

  16. This was posted over on BT, just in case some of you are interested and missed the post there.

    PRINCESS FRITO on October 29, 2010, 2:24 AM

    “There’s a Canadian documentary called “Geologic Journey” that is in its second season. It’s hosted by geologist Dr. Nick Eyles of the University of Toronto.

    http://www.cbc.ca/documentaries/natureofthings/geologicjourney2/episode-guide.html

    In tonight’s episode #2, something really caught my attention: he said there’s a cycle of increased tectonic and volcanic activity that ramps up every 10,000 years, and he pegged this year as the start of a new cycle of activity.

    The episodes are viewable online once they’re aired on TV so only episode one is available at present. It covers Iceland. Episode 5, once it’s available online in about 4 weeks, will cover Indonesia.

    If anyone is interested, please bookmark the link. I’d love to hear people’s opinions of this series as they air.”

  17. Magnitude ML 3.4
    Region ICELAND
    Date time 2010-10-29 10:30:48.7 UTC
    Location 65.16 N ; 19.58 W
    Depth 1 km
    Distances 159 km NE Reykjavík (pop 113,906 ; local time 10:30 2010-10-29)
    90 km SW Akureyri (pop 16,563 ; local time 10:30 2010-10-29)
    65 km S Sauðárkrókur (pop 2,682 ; local time 10:30 2010-10-29)

  18. Date Time Latitude Longitude Depth Magnitude Quality Location
    Friday
    29.10.2010 10:41:12 65.136 -19.596 9.6 km 2.9 34.28 29.9 km N of Hveravellir
    Friday
    29.10.2010 10:35:25 65.143 -19.557 4.9 km 3.0 61.16 30.6 km N of Hveravellir
    Friday
    29.10.2010 10:30:48 65.159 -19.580 0.6 km 3.4 90.01 32.4 km N of Hveravellir
    Friday
    29.10.2010 10:26:15 65.140 -19.573 1.9 km 2.8 90.06 30.3 km N of Hveravellir
    Friday
    29.10.2010 10:23:45 65.145 -19.588 4.3 km 2.1 50.73 30.9 km N of Hveravellir

  22. There seems to be a period of 60 years of more intense volcanic activity in Iceland, every 135 years.

    Last times were probably around 1859-1919 (major eruptions of Askja, Bardarbunga and Katla) and 1724-1784 (major eruptions of Krafla, Öræfajökull, Hekla, Katla and Laki). If you go further back we find the major eruptions of 1477 (Torfajokull, Veidivotn and Bardarbunga), 1362 (Öræfajökull), 1104 (Hekla) and 934 (Eldgja) within these intervals. Even the last episodes in the Reykajnes peninsula match in these peaks of volcanic activity in 1340 and 1211 or from other dormant volcanoes.

    The pattern does not seem exact. Or maybe it is a coincidence, but some geologists give serious attention to this possible cycle. According to the pattern, the next peak in volcanic activity is somewhere between 1994 and 2054. Probably around 2020-2040.

  24. Well… the area does have lakes. So I went and found the closest one and threw it into the plot. I don’t know if this is the reservoir that was mentioned earlier, but it’s possible. All I had was one of several bodies of water in a shape file, and this one was the closest. You can see it as the red figure at the surface.

    Zoomed in pretty tight, these quakes make an interesting pattern. There is an upper group and a lower group. The upper group seem to lie on centroid that has a horizontal drop of ROUGHLY 10° to the North. I have no idea if this indicates a fault plane. It’s just a trend in the group.

    The batch of quakes in this plot are from 10/25 to present.

    View North

    http://i52.tinypic.com/o6zm0i.png

    View East

    http://i53.tinypic.com/zockcx.png

    Perspective View, oriented so that you are looking end on at the apparent centroid of the upper group of quakes.

    http://i52.tinypic.com/2sbwqd3.png

    Enjoy!

    1. @ Lurking.

      If it is indeed as you say that the quakes are grouped in two different groups then the argument that the EQ´s are due to an old faultline gets even stronger. It is most likely that they are tectonic and that it is just a small “creaking” noise we hear.

    2. Lurking, FYI: http://earthquake.usgs.gov/earthquakes/recenteqscanv/

      Interesting side note on developing EQ story:

      There has been 6 EQs ranging from 3 to 3.9 along the Laguna Salada Fault with the last one touching the top of the EF (3.9). I have not seen this before where the swarm hits the EF. Do you think this is more evidence of stress waves moving further northward. I don’t think sceismologists would call the 3.9 today adjacent to the terminus of the EF an after shock of the 7.2 on April 4 near El Major. All this follows the 6.9 near La Paz, Baja (I vacationed in La Paz with our sailboat and loved the wind, blue oceans and the quaint town)

      Its not the EF, LSF, SJF offsprings of the SAF that I worry about. These are newer, smaller, more active indications of the plates grinding it out. I do worry about their potential effect on the mother SAF. I have several friends who live near the southern end of the SAF, including Palm Springs, Riverside, etc. We also have 2 cabins in the mtns near Palm Springs. I fear I will go up there someday soon to find them severely damaged.

      Ron (tucked safely away in Phoenix, AZ)

  25. RonF [21:16]

    I can’t quite say. I have heard the story of the geologist who was tasked with the Salton Sea as his realm of study who suddenly pulled up stakes and transferred to the rather mundane State of Florida after doing a few years of work. The reason that is inferred by the story was that something there did not sit well with him and he wanted his family away from the area. (or it could be that Florida was a geologically more interesting place)

    But this is just a story.

    I have pondered… mused, ruminated kicked around the idea of snapping a few concrete paving stones into the rough shapes of the fault blocks of SoCal to see how they mesh/grind… then I realized that I have no way of verifying the dimensions or getting any sort of ballpark measurements off of them.. and that to do so would firmly place me in the category of the mashed potatoes guy from “Close Encounters of the 4th Kind.” I’m not that crazy.. yet.

    As for “stress waves” (the wacky theory), there may be another set moving north from the Rivera platelet… might not be. I’ve noticed that the newest quakes there are further South. Could just be a re-aligning… dunno. I read somewhere that the small pieces like Rivera tend to rotate in place as they grind between the bigger plates. It might be that. (Side note, NW Washington State seems to have done this in the past… based on magnetic alignments of the rock)

    One thing to keep in mind. Elsinor, San Jacinto, Laguna Saluda and the rest have not piped down since the Mex Quake.

  26. Okay… long day of cursing traffic and dodging police intervention. (traffic blocked due to “home invasion” / “domestic violence” incident… next to the Interstate)

    Time vs Depth vs Magnitude for the “N of Hveravellir” swarm.

    http://i55.tinypic.com/2vdl5pi.png

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