Posted on by Jón Frímann

Interesting earthquakes in Bárðarbunga volcano system (Hamarinn volcano)

At 02:06 and 02:07 UTC there where interesting earthquakes in Bárðarbunga volcano system. What makes them interesting is that fact they did happen at 0.6 km depth one of them. But this area did see some volcano related activity (speculated) earlier this summer, that did result in large glacier flood. But it has been suggested that a minor eruption took place there around 10. July 2011.


The two earthquakes can be seen as spikes at the end of this tremor plot from Icelandic Met Office. Copyright of this picture belongs to Icelandic Met Office.

What makes this earthquakes so interesting is that they seem to have a low period component in them. But it was seen on the Kálfafell SIL station, and other SIL station that was decent distance from the source of the earthquake.


The two earthquakes can be seen as spikes at the end of this tremor plot from Icelandic Met Office. Copyright of this picture belongs to Icelandic Met Office.

Currently there is nothing that suggests that a eruption is about to start in this area. But that can change without warning given the current status of Hamarinn volcano system.

54 Replies to “Interesting earthquakes in Bárðarbunga volcano system (Hamarinn volcano)”

  1. Jón, yet a third one was recorded by IMO sensor, but also poorly located.

    1. There is a ghost in the list.

      2011-08-01 02:07:52,2 64,627 -17,436 0,6 2,2 90,03 4,6 km ASA af Bárðarbungu (real)
      2011-08-01 02:07:51,8 64,554 -17,508 8,4 2,3 42,59 9,6 km S af Bárðarbungu (ghost)
      2011-08-01 02:06:37,1 64,629 -17,435 0,9 1,4 60,88 4,6 km ASA af Bárðarbungu (real)

      I have marked the ghost one above.

  4. I am going back to this post from…
    Ingemar Johansson says:
    July 28, 2011 at 16:49
    Hi John.
    Do you have any idea about the very regular short period spikes in the tremor graph of ALF are caused by?A spike every 4-4.5 hours for at least the last two days. They are also triggered by alert system but seldom localized. I have used the Fbreaktime to calculate the last 4 events (today 0201, 0612, 1028, 1512UTC) and have calculated with epicenters to be (fixed depth 4km) 63.50-19.09, 63.50-19.09, 63.51-19.10, 63.50-19.09, about 5 km east of the station ALF. All almost at the same spot. Are these man-made detonations or natural, if natural how come the regularity in time?

    This is still happening. It shows very nicely today as things are quiet ( Apart from the wind!)
    http://hraun.vedur.is/ja/oroi/alf.gif
    It is as Ingemar says, very regular.
    “The Pulse of Myrdalsjokull” !

    Now I also find this graph interesting.
    http://hraun.vedur.is/ja/myr/myr_num.html
    The red line! Please which area is this? If it is the west side of Vatnajokull then could this be why the SIL stations, as Askja, Skkrokald and Vatnsfell have been showing odd activity ? Could this be related to Hamarinn or is it Askja?
    Apologies for sounding muddled but as usual I am a little confused!

    1. The red line says that it is Myrdalsjokulska so I’m guessing it’s the icecap area above Katla and Godabunga.

      1. No, I misread, it says Myrdalsjokulaskja so it appears to be an area encompassing both Myrdalsjokull and Askja which is a very odd shape to pick.

      3. Wow! Thanks for that link!

        http://hraun.vedur.is/ja/myr/myr_reg.html

        The submenus have the data plots I so much wanted to see! I didn’t know it already existed!

        Last weekend, I actually created by own 3 areas in Google Earth similar to the ones shown at the link, so as to get the coordinates to deliniate the areas, but could’t find the link to access historical raw data to plot the quakes in each region and compare on plots one over the other … but it is all here!!

        (btw What is the link to the raw historical data (back over several years) for Island earthquake data?, Anybody have that secret info?)

        I could see the progression of number of quakes shift from Eyja to Goda (last year) and in the past 2-3 weeks to from Goda to Katla by animating the weekly EQ map-graphs over a period of 2 years, but the link you gave has the better visual of x-y plots of numbers of quakes by day, by years for 4 areas!

        The full effect is not optimally shown, since the plots are 1 year at a time per web page … but when I have the chance, I’ll splice them together to get the full effect and post here.

      4. tony, in icelandic, askja is not only the name of ASKJA the volcano, but the type of volcano crater also. katla has a caldera, and the icelandic name for caldera is “askja”.

      5. @ Irpsit many Thanks I now understand . It was the word askja that confused me.
        @Watchman. Many thanks I am slowly adding new words to my Icelandic vocabulary.
        When I visit Iceland I will be fluent in Volcanic words but will be unable to ask for the Ladies room or other such vital directions!!!

    2. I did in part answer this one earlier.

      The red line is the collected number of earthquakes inside Katla volcano caldera. As can be seen there, this year it has many more earthquakes compared to last year.

  6. There is a harmonic tremor spike taking place on Skrokkalda SIL station. I assume that it is from Hamarinn volcano. The glacier flood is over according to the news, it did end during the night.

      1. this is too big to be from Japan is´t it?… and would be seen more clearly on other SIL-s if it were so, right? This tremor has something to do with Hamarinn on my oppinion. (or Hofsjökull?) (on the funny side, my captcha for this comment was “crater” :))

      2. There was the earthquakes in Japan and then a harmonic tremor spike it seems. That did start around the same time as the earthquake waves from Japan arrived in Iceland.

        That is why this got all mixed up.

      3. How about the alignment of the latest earthquakes near Bardarbunga? Isn’t that something to worry about? It exactly follows the path of the Veidivotn and Loki-fissures. Also, the earthquakes have a depth of 19-25km. This combined with the fact that it creates low-frequency tremors and are therefor long period earthquakes would mean that there is flowing new magma into these systems?
        Just guessing here.

  7. Ongoing swarm in Azores: 2011-08-01 18:17:18.0
    52min ago 38.55 N 29.97 W 15 ML
    4.2 AZORES ISLANDS, PORTUGAL 2011-08-01 18:38
    2011-08-01 17:45:01.0
    1hr 24min ago 38.52 N 29.90 W 10 ML
    3.4 AZORES ISLANDS, PORTUGAL 2011-08-01 19:01
    2011-08-01 17:34:49.0
    1hr 34min ago 38.62 N 29.88 W 5 ML
    3.2 AZORES ISLANDS, PORTUGAL 2011-08-01 17:55
    2011-08-01 17:03:50.0
    2hr 05min ago 38.52 N 29.90 W 14 ML
    3.5 AZORES ISLANDS, PORTUGAL 2011-08-01 17:21
    2011-08-01 16:52:11.0
    2hr 17min ago 38.62 N 29.88 W 11 ML
    3.3 AZORES ISLANDS, PORTUGAL 2011-08-01 17:07
    2011-08-01 16:36:23.0
    2hr 33min ago 38.32 N 21.75 E 8 ML
    2.7 GREECE 2011-08-01 17:15
    2011-08-01 16:13:48.0
    2hr 55min ago 38.48 N 29.88 W 5 ML
    3.2 AZORES ISLANDS, PORTUGAL 2011-08-01 16:36
    2011-08-01 16:06:49.9
    3hr 02min ago 32.44 S 178.90 W 34 M
    4.7 SOUTH OF KERMADEC ISLANDS 2011-08-01 17:40
    2011-08-01 15:53:28.2
    3hr 16min ago 38.27 N 21.75 E 10 ML
    2.0 GREECE 2011-08-01 15:55
    2011-08-01 15:49:56.0
    3hr 19min ago 38.60 N 29.87 W 7 ML
    3.6 AZORES ISLANDS, PORTUGAL
    http://www.emsc-csem.org/#2

    1. Luckily this is an area known for it’s many tectonical earthquakes so no volcanic activity to worry about.

  8. Please could someone clear a confusion. Given that Katla is a central caldera, are Haabunga and Godabunga separate vents within the main caldera (as Halemaumau is to Kilauea) or are they separate entities in their own right?
    Jon, this is a cracking site!
    Thanks

    1. As I believe Haabunga and Godabunga are mountain tops on the rim (Godabunga is just outside) of the caldera.
      I could be wrong though.

      1. Thanks Pieter
        A good bedtime read:
        http//www.raunvis.hi.is/~mtg/pdf/Jokull49_HBetal_Myrdalsjokull.pdf

  9. I want to write something. But I am just so tiered at the moment mentally, so it is going to wait until I feel the energy to write something soon.

    1. Take your time, personal comfort goes first. Get some sleep and once your refreshed and wait for the right moment. 🙂

  10. So today we had an interesting day.
    Harmonic tremor at Hamarinn, while the earthquakes there yesterday formed a line along the Bardarbunga fissure system. And a notorious inflation rise, in the two stations near Hekla.

    I really think we are getting really close to an eruption of Hekla.
    Everyone is distracted and waiting for Katla, but I think it is Hekla and Hamarinn which are really close to an eruption.

    Hekla usually does not give much warning beforehand, but now we have just detected a sudden inflation in Hekla for the second time in recent weeks (and now not only in 1 station but 2!), and this is just after a few earthquakes that happened close to Hekla in the past week (that had magma signature, according to Jon). This, for me, is signs that magma has been moving and filling the deep chamber in Hekla, and it will be just a matter of time (usually within a year) before Hekla erupts.

    About Hamarinn, we do know that the volcano has had some recurrent subglacial activity in recent years, it could be that small amounts of magma are released, thereby causing minor floods. Yet, it has been a long time since its proper larger eruption. And all that we are observing, could be signs that the Bardarbunga system is gradually getting close to a larger and more conventional eruption. When? No one knows, but I reckon sometime in next years or couple of decades (which is geologically very soon, of course).

  11. Inflation in Hekla is +15mm in Isakolt, and +20mm in Haukadalur, since yesterday. Any thoughts?

      1. Hekla is ready for an eruption any time now, local farmers say that water levels in smaller streams close by have receded noticeably this summer

      2. It is always prudent to take note of local farmer’s comments. They know the land intimately and will notice small local changes. They may not always be right but then nor are the experts. Small details noted now could be useful signals for future eruption predictions.

      3. Well this indicator of inflation that Irpsit talks about is still showing today

  12. Tuesday
    02.08.2011 04:24:14 63.651 -19.373 1.1 km 1.9 80.14 6.1 km ESE of Básar
    Tuesday
    02.08.2011 04:24:13 63.691 -19.246 0.1 km 1.2 35.22 5.7 km N of Goðabunga

    do you think one of these is a “Ghost”

  14. Anyone know what is going on at Eyjafjallajokull? On the webcam it looks like there is a huge mud flood to the left of picture, and there is what looks like steam rising from it. I’ve tried looking on the met office website, but can’t seem to get a connection.

    1. Maybe still hot ash from the old eruption site washed down by the recent storm. Thats my guess.

    2. Yes I see what you mean. But, I think it is probably the sunlight through the clouds, the sunlight is making the ground look lighter, as the sunlight moves along it makes it look like there is mud moving.

      The English version of the site is down, you can still view it in Icelandic.

    3. I do not see any mud flood and none has been reported so far. There is also nothing on sensors indicating that anything is going on at current time.

  15. Does look a bit like it but maybe its deceptive. I am sure some news would report it if it was.

    1. I don’t see anything that looks like a flood. I think that was an optical illusion played by sunlight and the camera low resolution (which makes look like the soil is moving).

      The flood last year happened precisely on the outlet glacier falling from the ice cap, that you see on the middle of the webcam (view from Thorsmork)

  16. Thoughts on using ISAK and HAUD for measuring Hekla inflation.

    ISAK GPS is about 15 km from Hekla on the other side of a river near route 32.

    If I had included it in with Hekla GPS units in the following link, it would be seen way far off in the top right, near the compass, on the other side of the river.

    http://twitpic.com/5w42j2/full

    For direct viewing of the GPS location in Google maps or Google Earth or similar mapping program, the coordinates for ISAK are …

    64.119328479 N 19.747177587 W

    HAUD also is about 15 km from Hekla, which is why I didn’t include it at the link above with the Hekla GPS.

    HAUD coordinates …
    63.968548475 -19.964362503

    So, because of the distance for Hekla, HAUD and ISAK may not be the best GPS to use to measure inflation or deformation of Hekla. At the least, the distance must be considered, so as not to mistake the GPS changes as measuring deformation or inflation of the Hekla volcano itself.

    But the placement of HAUD and ISAK GPS units must have been done for good reason, as well as their inclusion on the Hekla GPS plots web page at …

    http://strokkur.raunvis.hi.is/~sigrun/HEKLA.html

    I wonder if they are strategically placed on or near known fissures associated with Hekla?

    1. There are 6 GPS stations in the Hekla observation net.

      FEDG = Feðgar elevation 503.63
      HESA = Hestalda elevation 529.98
      NORS = Norðurbjallar elevation 560.38
      MJSK = Mjóaskarð elevation 770.46
      GLER = Glerhaus elevation 444.99
      HEKR = Heklukriki elevation 733.84

      ISAK = Isakot is more likely included as a “reference point” since it it one of many stations that are certain to be connected and sending data every day.

  17. I saw the effect you referred to, but the landscape appears now as it did before. I suspect it was a trick of the light, as Bemused has suggested.

    1. Þriðjudagur
      02.08.2011 20:50:38 63,633 -19,298 1,1 km 1,6 90,01 2,5 km VSV af Goðabungu

      1. Yes, Jon, this shows well up on all IMO charts. However the event around 22:30 hrs tonight (likely also showing on your geophone) does not appear on but one IMO list: In some remote corner of this web (http://hraun.vedur.is/cgi-bin/myrseism.cgi – select “Óyfirfarið”) this was at time GMT 22:30.52.3 POS 63.552 N -19.244 W, Depth 8.4 km, Ml 0.4 Quality 19.15 !!! Is this not some interesting event, possibly “new” Magma on the move, what do you think ?

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