Posted on by Jón Frímann

Sudden rise in harmonic tremors around Katla and Eyjafjallajökull

There is a sudden and sharp rise in harmonic tremors around Katla and Eyjafjallajökull volcano. I currently do not know what volcano is responsible for the spike in harmonic tremor. But this does not look like is a noise from the weather. But that can happen often this time of the year, as the wind forecast is good for all of Iceland at current time.

I will post more information if and when I get them.

SIL stations where the harmonic tremor rise can be seen.

Mið-Mörk
Eystri-Skógar
Lágur Hvolar (Currently most rise here for some reason)
Snæbýli
Saurbær
Ásmúli

Icelandic Met Office tremor web page.

56 Replies to “Sudden rise in harmonic tremors around Katla and Eyjafjallajökull”

  1. Jón, when you say a rise in harmonic tremors do you sometimes mean a rise in the 2.5-5.0 Hz band energy relative to the lower frequency bands?

  2. @Raving, I mean all the bands (0.5 – 4Hz). But sometimes just one or two of them changes while the lowest band (0.5 – 1Hz) remains unchanged. In this case, it is the 2 – 4Hz bands that are changing fast, and it is not due to a weather effect far as I can tell.

  4. Jón: Looks to me that there are spikes showing in other stations like Grindavik, Fagulsholsmyri, Bjarnastadir, Kaldarsel, Nylenda, Reykjanes… could it be some wider trend? I’m starting to understand what a spike means, I think.

  6. @Renato Rio, The station are esk, mid. But this is also starting to show on god but poorly. The source is from one central noise location. But where exactly is unclear at the moment.

  7. i think this is exciting.
    Wouldn’t it be great if Jon called the next eruption?
    i wonder who gives the Gold Stars out in Iceland.
    Best!motsfo

  8. Last time I did see this pattern on the tremor plots at IMO was when the Fimmvörðuháls eruption started. What is going on at the moment is however unclear.

  9. We are all watching and waiting with you Jón! Thanks for keeping us all so well informed – it will be interesting to see if, and where, some action happens.

  11. @Renato Rio, Most stations at south of Iceland are showing this spike. But that is the interesting part. Currently I have not recorded a single earthquake, and there is not a bad weather in sight far as I can tell. So I don’t think this is the weather.

    But I wonder if this is something that is happening at great depth under Katla or Eyjafjallajökull. Because the source seems to be there, but it is quite hard to confirm at the moment as there are no earthquakes at all that can tell me what is going on.

  13. @Renato Rio, I don’t think that is going to happen. As the decline has started now. Currently I don’t think this was the weather, but I cannot rule it out for the moment.

    Now I just wait and see what happens next there.

  15. I don’t know if it’s of any use to you, but measuring the percentage of signal change from 9/1/10 to the middle, top,. and bottom of where the trace is currently at, and then averaging those yields the following:

    esk 101%
    hvo 56%
    mid 226%
    sau 385%

    From that, and if the terrain had an even consistency (which it doesn’t) then I would lean towards whatever it is as being closer to sau. I know that it’s not the case, but like I said, this may or may not be of any use to you.

    (For the casual reader: the terrain is littered with sills, dikes, fissures, tephra form past eruptions, sediment fill etc. This means that the ground will no transmit vibrations evenly in all directions)

  16. It’s very interesting. But such increase of tremor in a wide variery of stations either means a big eruption coming, or just noise.

    However no major earthquakes yet, the earthquakes near western side of Katla continue constantly but stable. I expect a major earthquake just before an eruotion, otherwise it might be just a new eruption from Eyfjallajökull.

  17. Hi Jón Frímann.
    First … thanks for starting this blog. You are new to blogging but i think you are doing a very good job. In case we could maybe do the ash SEM thing again, could you maybe just give me a valid post mail adress and then i d put the money in an envelope and send it, so there wont be a “loss” and you would get your expenses returned 100%.
    Second: Is there a cam pointing to Katla atm? I am not getting an image with http://www.ruv.is/katla right now.

  19. During the last week there has been a swarm of earthquakes in a long, narrow region ranging from Reykjanes peninsula all the way to Katla, like it was a fissure system activating… May be this is related?

  20. I’d go with where the eq activity has been recently, Godabunga. Could it be the summer’s meltwater trying to force its way out from underneath the glacier or are you positive it’s magmatic?

  21. – Discovery News: EARTH’S PULSE FELT AT HOT SPOTS… Enigmatic volcanic hot spots around the world might be pulsating together — like a great planetary heartbeat — at the rates of five and 10 million years, say researchers from Norway, Hawaii and Australia… ECOLOGICAL EVIDENCE from Previous PLANET X Passages… National Geographic (November 19, 2008): “MYSTERIOUS ASTROPHYSICAL OBJECT that’s bombarding Earth with cosmic rays”:
    http://cristiannegureanu.blogspot.com/2010/09/earths-pulse-felt-at-hot-spots.html

    1. so this means that Alex believes in Planet X ((?))
      and who is this “Alex”???
      and why are i the only one to ask these questions?
      And are others thinking there is any credulance to the idea that all volcanoes
      are acting up from this planet X pass?
      Best!motsfo

      2. @Mots Fo: I found it better to leave to Jón, as the moderator, the suitable response to that. No planet X believers here. Best! Renato Rio

      3. @Mots Fo: But there are, indeed, poetry-lovers, so, feel free to post some more of your acquis. 🙂

      4. Thanks All for the kind responses………..
        i didn’t think that type of information had any credibility to it and that it turned up here kind of through me for a loop. i was just trying to ‘clear the air’ so to speak………. asking for assurance that most here didn’t follow this line of thought. Thank You for Your kind responses. i don’t mind leaving myth at the door at all…………. rather relieved to do it….
        Hoping You will find this note, Jon.
        Best!motsfo

  22. Jón: Hraun station is again on the rise, and many others are showing again a slight ascent. Don’t you think?

  23. BTW Þórólfsfell cam is showing an interesting view with lights and clouds playing a beautiful pattern.

  25. @Jack I’ve been watching the same trend…very interesting but very quiet today.

  26. Jon, do the icelandic seismologists/volcanologists monitor the floor positions of the fissure systems with GPS?

  27. The tremors are visible even near the western edge of Vatnajökull (see stations Skrokkalda, Kálfafell and Fagurhólsmýri the last one being strongest). In the west, the whole Reykjanes peninsula shows the same behavior, except Vogar, which looks very interesting… This is very large area! If it is volcanic,, something BIG is cooking. I suspect, it must be related to weather…

  28. @Jack: The only thing is, that the weather in South-Iceland is pretty quiet. No storm or rain happening for the first time in a few days.

  29. @Jack @ Finland, The GPS stations monitor all the most active volcanoes in Iceland. It is hard to monitor the fissure system them self as there is no magma in them until the erupt.

    This high frequency noise on the SIL stations continues, yet no earthquakes. I am a bit surprised that there has not been any earthquakes at the moment.

  30. My logic on monitoring the fissure systems goes like this: Iceland sits on the Atlantic ridge, so there must be slow widening on those fissures aligning with the ridge. The widening process may be slow, but it might be easier to see via the floor dropping lower,
    (if there is no magmatic filling from below). If widening is truly seen, but no floors dropping, magma must fill the fissure from below. Of course this does not hlod, if the fissure has a steady rocky floor. Any thoughts on this?

  32. @Jack: Makes sense to me. That could well explain the simultaneous eq’s and tremors along the fissure system. But this is a layman’s opinion.

  33. I think this relates to Katla. Because the stations on the south and east side of Myrdalsjökull (Skogar, LáguHvolar) show more rise than that on the west side of Eyjafjallajökull (Midmork). Also, most earthquakes are occuring on the western flank of Katla, around Godaland. However, this area shows no inflation, so I think we are still a little away from the eruption (if it were to occur on this side). Or are there any stations to measure inflation at other points of Myrdalsjökull?

  34. However the rise of tremor at Grindavik (very far away from Katla or Eyjafjallajokull) seems very strange. Maybe a large magma movement under Katla could increase tremor far from the volcano, and cause tremor along the SW Reykjanes ridge.

      1. I have seen this kind of signal (fast rise, slow decay) 1-2 times before (after the Eyja eruption) on stations near Katla. However, on those occasions I did not check the other stations farther away.

  35. First of all… this is all occurring on the Mid Atlantic Ridge. In the last month or so, there have been a few M5.0 or so quakes on the far south end of the Reykjanes ridge, as well as a few popping off down on the Azores and other FZ’s in between.

    We (meaning you guys and me) have noted that the quakes from the Reykjanes area to the Hekla/Katla/Eyj area tend to track deeper as you get further from the Reykjanes area… this appears to follow the bottom contour of the crust block but is not as deep as the Moho. roughly midpoint. The deeper you go the hotter it gets… at depth the rock is effectively plastic and the amount of stress that you need to generate a quake goes up. We aren’t getting many quakes.. if any at all. But we do have that odd tremor pattern.

    My guess is that if magma is on the move, it is making it’s way down from the Reykjanes area very very deep, following the weaknesses that connect the MAR proper (up at Reykjanes) with this spur that then reconnects with the MAR up at Bardabunga.

    Caveat: I am not a botanist. I have very little experience with flowering plants.

    (I am also low on coffee)

  37. Lurking @, what you say and image in the link below:

    The isotopic composition intermediate Icelandic basalts suggests a dilution of the plume by the asthenosphere, which reflects the position of Iceland at the base of the ridge. This dilution increases gradually along the Reykjanes Ridge.
    http://planet-terre.ens-lyon.fr/planetterre/XML/db/planetterre/metadata/LOM-islande.xml
    A short tour of Iceland with volcanoes we do not know. Click on the blue links to visit to Iceland
    http://www.regeafaitunbeauvoyage.fr/geologie.html

    1. i couldn’t get the first site to open for me………… the second was wonderful………..
      Great photography!
      Thanks for the links………. i’ll try again tomorrow
      Best!motsfo

  38. Shérine: Merci beaucoup par l’article. Little by little I’m trying to catch up with those methods and getting a better view of the whole picture. The second one is meant for me: simple, many images, and no “couche D” to get confused at. 🙂

  39. Has anyone checked the river data – temperature and level – to see if this tremor may be associated with water rather than magma?

  41. Did you guys know that there is actually a volcanic vent between Katla and Eyja? And that’s exactly where that long stream of quakes has been occurring recently, on Katla’s west flank, between the two. I keep wondering if something might be ready to blow there, or if the quakes could be due to magma intrusion there near this vent.

    But according to tomography, this area between Katla and Eyja is supposed to be an aseismic, 15 km high velocity (hard mass) area where no magma is likely to be present. I have a thread going over at ATS about the potential for Katla to erupt:
    http://www.abovetopsecret.com/forum/thread615281/pg1

    1. Well it was where it all started!
      Fimmvörduhals (the fissure you refer to) is located between Myrdalsjökull and Eyjafjallajökull and had a small(er) fissure event which was widely covered in media prior to the Eyjafjalla eruption. And a small correction to your post on ATS..Katla is not the english name for Myrdalsjökull. Myrdalsjökull is the name of the glacier and Katla is the name of the volcano beneath it.

  42. Have been watching things for a while here. There certainly seems to be an intrusion of magma occurring in all major volcanic zones. We are certainly due an earthquake of 4M+ it remains to be seen whether this will trigger an eruption. It does seem quite likely at this point in time. As an earlier post pointed out this is a VERY complex system of faults and fissures so it is difficult to say where an event might occur. Barðarbungu is every bit as big as Katla and is connected to a greater reservoir of magma, it is however not so explosive and is further away from Reykjavik. The environmental impact from this one could be equally as big (if not bigger) than the threat posed by Katla

  43. I am wondering how much warning one might expect from Katla that there is a pending eruption. Could one expect it to be similiar to EJ’s pattern (which I have to try to remember the frequency and timelines – I’ll see if I can find that).

  44. OTTAWA, Sept. 13 (UPI) — Canadian scientists say the country’s government is trying to muzzle them, controlling what they say and who they talk to.

    Scientists with Natural Resources Canada say they were told this spring they would need “pre-approval” from the office of Minister of Natural Resources Christian Paradis to speak with national and international journalists, Postmedia News reported.

    Documents show the rules apply not only to contentious issues but benign subjects, such as floods that occurred 13,000 years ago, Postmedia said.
    (they are not supposed to inform the public about any earth changes)

  45. Apparently we had an earthquake of 4.8M in Hellisheiðarvirkjun,http://www.vedur.is/skjalftar-og-eldgos/jardskjalftar#view=table it is only ten minutes away from my home. Nothing was felt here and it does not show up on other sites?. I did state in my last post a quake of 4+ was expected soon. This area is not thought to be a risk for eruption but there has been some constant activity over the past months so who knows?, I could have an eruption on my doorstep. Hope not, we just cleaned the car.

  46. @iceboundalien The only reason for the quake was the fact that you cleaned the car. I won’t clean my car here in Chicago for fear of attracting huge storms. Just kidding lol hopefully your doorstep will be fine…

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