Posted on by Jón Frímann

Harmonic tremor still high in Katla volcano

Currently harmonic tremor remains high in Katla volcano. But at the moment the harmonic tremor is dropping. Earthquakes have also stopped for the moment. But currently the harmonic tremor is well above the background level for this area. It is still not clear if this was an eruption or just hydrothermal areas clearing it self of extra water. But in the news at Rúv noon they did report that the ice cauldrons that are normally there had deepened over the past few weeks in Mýrdalsjökull glacier.

Update 1: Earthquake activity has stopped for the moment. But I am expecting it to resume soon. As I do not think that this event is over, even if it has just paused for the moment.

Three cauldron have formed in Mýrdalsjökull glacier and large cracks have formed around them. All traffic has been banned on Mýrdalsjökull glacier and the glacier that comes from it.

Here are the current tremor charts from Icelandic Met Office web page.


Harmonic tremor is dropping as can clearly be seen on this picture. Copyright of this picture belongs to Icelandic Met Office.


Harmonic tremor is dropping as can clearly be seen on this picture. Copyright of this picture belongs to Icelandic Met Office.


Harmonic tremor is dropping as can clearly be seen on this picture. Copyright of this picture belongs to Icelandic Met Office.

I am going to post update on Katla volcano later today and earlier if anything major happens.

News with picture of the Mýrdalsjökull glacier. It is covered with dark ash from Eyjafjallajökull volcano eruption last year and volcano ash from the eruption in Grímsfjall volcano 2011.

Miklar sprungur í sigkötlunum (mbl.is, Picture, Icelandic)
Svona lítur jökullinn út (Rúv.is, Icelandic, Picture)
Þrír greinilegir sigkatlar (Vísir.is, Icelandic, Picture)
Brúin rofnaði af í heilu lagi (Vísir.is, Icelandic, Picture)
Óvissa um hlaup eða lítið eldgos (Rúv.is, Icelandic, Pictures)

Blog post updated at 13:13 UTC 9. July 2011.

56 Replies to “Harmonic tremor still high in Katla volcano”

  1. Update 1: Earthquake activity has stopped for the moment. But I am expecting it to resume soon. As I do not think that this event is over, even if it has just paused for the moment.

    So Jon, what are you expecting that is going to happen, if you think the event has just paused for the moment?

    1. I am not yet sure what to expect. But my idea on how to figure out volcanoes tells me that this should resume in about ~4 to 8 hours. Hard to be sure on that however.

      But I think that Katla volcano is heading for an full eruption soon. But when is the good question.

      1. If this happens again, (as you said that you expect it to happen) would it then be a sure sighn that it has started an full eruption or could it mean something else?

  2. Now there are two small quakes. One at 13.05h, which also shows up on the IMO page and another one approximately at 13.35h, which is only visible on Jóns helicorder.

  3. Like major earthquake, before it happen there is a period of time silence.

    I guess the Katla will erupt within 48 hours.

    This eruption also will accompany with a major earthquake (> Mw 7.0) at some other place in the world.

      2. Sorry, but what is a troll? Is my english so bad that I dont know what that means… 😀

      3. David: A troll is a sort of elf or gnome. A monster that scares people’s nightmares. This is from Norsk mythology.
        But we use here to call those who say a 7.0 EQ is going to happen when it won’t.

      4. Yep… a troll. The problem here is that “troll” also figures into some of the names of the geologic features in Iceland.

        Another way to look at them is as yet another scaremonger poking at you with a stick.

        Keep your objectivity and ignore the idiots.

    2. This makes one wonder if Peter Pan is also correct about Katla…..

      A major earthquake struck off the northeastern coast of Japan Sunday, prompting tsunami advisories for several coastal regions, the Japan Meteorological Agency (JMA) said.

      The U.S. Geological Survey said the earthquake struck at 10:57 a.m. at the epicenter, about 130 miles east of Sendai.

      The earthquake was more than 20 miles deep and had a magnitude of 7.0, the USGS said.

      The JMA measured the magnitude of the quake at 7.1.

      http://edition.cnn.com/2011/WORLD/asiapcf/07/09/japan.earthquake/index.html

  5. July 9, 2011 – ICELAND – A glacial flood, probably, from the volcano Katla in Mýrdalsjökull has disrupted the Ring Road (highway no.1), by the river Múlakvísl on Mýrdalssandur in south Iceland, tearing the bridge across Múlakvísl. The road is closed between Höfdabrekka, east of Vík, and the river Skálm, near Álftaver. The flood is thought be the result of a small eruption underneath the icecap of Mýrdalsjökull, probably in the Katla crater, ruv.is reports. “At least this is not a large eruption, the Katla eruption people have been waiting for,“ geophysicist Freysteinn Sigmundsson told ruv.is “If it is a volcanic eruption, it is a small event and possibly only geothermal water.” The Civil Protection Department has issued a warning to people in the area, to beware of sulphurate smell near the river, as it might be poisonous sulphurate gas. The mountain route Fjallabaksleid nyrdri is open for 4X4 vehicles only, and is the only open road in the area. The Álftaver area is being evacuated and preparation for evacuating the camping area in Thakgil. In the past few days, people had actually been speculating about an eruption in Hekla, a different volcano in south Iceland. –Icelandic Review
    http://theextinctionprotocol.wordpress.com/2011/07/09/small-eruption-confirmed-under-icelands-katla-volcano/#comment-12499

    1. Why you don’t link the original source (icelandreview.com) rather than link to a shitty 2012 website?

  10. I still see long periods at Jón’s geophone. Could those be from hlaups?

    1. Thank you Jón.
      What a mess!
      Think it’s only a small eruption…

    2. No. It is just the wind that is picking up in the area. It sometimes does so during the afternoon in Iceland when the wind comes in from the main land out to the ocean or the other way around in some places.

  13. Is there a possibilty of a full scale eruption of katla in the near future? ( by that I mean in the next few weeks)

  15. Tremor has reached background levels again.
    http://hraun.vedur.is/ja/Katla/god_trem.gif

    My guess; a nice burst of hydrothermal heath, maybe a phreatic explosion, nothing more. If this is a precursor to an eruption later on this year, who knows, for that my guess would be as good as any.

  16. Zakos, anything is possible. But as I read the entrails right now, this appears to be a repeat of the kind of small suspected eruption we saw in 1999.

    Could we have a major eruption soon? Yes. But there’s nothing to indicate one is on the cards.

    This is my opinion and worth what you paid for it 🙂

    Mike

  18. It appears that a relevant number of small earthquakes occurred in the last the last 3-4 hours on the southeast area of the Katla caldera have been located and added to the official (QCed on the vedur.is website) lists.

  19. Is the small earthquake swarm at Myrdalsjokull also a result of the wind, like the noise on Jon’s Hekla helicorder?

  22. It can mean a lot of things david, lets see what jon thinks when he gets back.

  23. Could this potentially mean a bigger eruption is on the way? Or is it too early to tell?

    1. I was referring to the Godabunga tremor chart (which is smoothed) vs earthquakes for the Myrdalsjokull area:

      http://i.imgur.com/Afayn.png

      From the Godabunga tremor chart, it indeed looks like tremor has decreased. What we see now on other charts I think is intermittent activity due to earthquakes, not really tremors themselves, although probably Jon’s comments will be more accurate on this.

  27. After the 1918 eruption Katla had 2 more in the 20th century they were the same as this up to now, just dints in the ice VE1 probbably, not enough to melt the ice through to the sky. But did the 1918 start with just dints? They could have appeared long before the 1918 as the volcano activity grew. In them days people didn’t just drive up and have a look.

    I hope the press don’t interpret Jon gone swimming to – Oh my God it must be hot in Iceland, run to the hills.

    1. Lol – it’s OK the British press are too busy picking over the bones of the News of the World at the moment.

  29. See two cars drive past the Katla webcam today, never seen one before.

    1. they have been around for a hundred years or so, i’m surprised you have never seen a car before…

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