Posted on by Jón Frímann

Glacier flood from Grímsvötn has peaked, harmonic tremors continue

According to news the glacier flood from Grímsvötn has peaked and is already dropping down. So far there has not been any volcano eruption. But harmonic tremor is still ongoing in Grímsfjall volcano and does not show any signs of stopping. But this harmonic tremor appears to be a bit fluctuating for some unknown reason.

Icelandic News. Please use Google translate.

Hlaupið að minnka (Rúv.is)
Vísindamenn í könnunarflugi (Vísir.is – Has video)
Hlaupið hefur náð hámarki (mbl.is – Has video)

85 Replies to “Glacier flood from Grímsvötn has peaked, harmonic tremors continue”

  3. Maybe it has something to do with the release of the water from the lake. I guess only time will tell.

      1. I wouldn’t say tremor was dropping. They’ve changed the time scale, it’s a lot clearer now – have a look:

        http://hraun.vedur.is/ja/vatnajokulsvoktun/grf_trem.gif

        Apart from a couple of brief excursions to higher peaks in the 2-4 Hz band, I’d call that fluctuating but pretty steady – and obviously significantly elevated from earlier in the flood.

  4. I wouldnt be surpised if the tremors subcide quite alot before any activity is seen actually. When the glacial flood has been all released the pressure on top of Grimsfjall will be less and the summit will rise (as seen on GPS) which would mean that there is room for more magma before it suffers critical failure and erupts.

    If this theory is correct I believe that the decrease in tremors is actually the start of an eruptive event which will come in a near future. And that tremors and EQ´s will start up again when the magma reservoir is starting to fill up. And this will continue until….Poof!

    But I may be wrong..Lets see..:)

      2. That one is a good graph.
        That is the one I used in my prediction that we will need another doubling of the 0,5Hz tremors. The baseline value is between 1000 and 2000, the jump was from the 1900 to 3900. If the eruption follows the 2004 pattern we will se a slight and slow fall to around 3000 (+/-250) and then a sudden leap up to between 6000 and 8000 when the eruption starts.
        Look out for when the 0,5-tremors pass 4000, then it is time to take shelter.

        Just an idle extrapolation on my part from old data and the values for the last year.

  5. And just as a abit of extra. If Grimsfjall now did erupt before new year it will be the first time Iceland has had 3 eruptions in one year. 🙂 In recent time that is..I believe that the Skáftar fires were a series of volcanic eruptions but that was in the 1700´s so we wont count that..:)

    1. Daniel, there were only 1 volcano erupting this year in Iceland. Both eruptions, Fimmvorduhals and Eyjafjallajokull, both belong to same volcano, fissure and central crater respectively. Same magma chamber.

      They are even in the same “mountain”. I was hiking there this summer, the distance between the Fimmvorduhals fissure and the major crater is small, about 5 Km. You could easily walk between them.

      1. In 1980 both Hekla and Krafla erupted.
        In 1922 and 1938 both Askja and Grimsvotn erupted.

        So you see sometimes there are two volcanoes erupting in the same year. Ocasionally even two at the same time! There are even cases of 3 volcanoes erupting in same year (e.g 1341)!!

        Between 1721 and 1729, this is only 8 years, 5 volcanoes erupted and some in a powerful destructive way. There were major eruptions of Katla, Krafla (Myvatn) and Oraefajokull, and also eruptions at Kverfjoll and Hekla.

      3. Yes I know but since they are listed as two separate events I thought I would stretch it a bit. 🙂

  6. Well, based on Irpsit’s value of 2600 m³/s the mass loss from the Grímsvötn area is going to be about five times greater than my guestimate.

    This little flailex in language and units is why I didn’t even attempt to fight through Indonesia’s Merapi info. At least with Iceland you have something to work with.

      1. The flow rates of the stream are in cm/sec (?)

        Not so easy to measure the entire cross-sectional flow of a river because the flow rate is different at varying depths and distance from the banks of the river. Hence the discrepancy … 🙂

  7. The harmonic tremor continues to be elevated at Grímsfjall volcano (beyond background noise). It appears to drop a little from time to time but sometimes it rises again from that to previous levels.

  9. Raving, waht they emit if Mercury vapour, Hg0, the zero is a supra index. I measured it in a l ot of volcanoes, and is a good tracer also for geothermal exploration.

    1. I wasn’t aware of mercury emissions from volcanic process. I know that the leeching of naturally occurring mercury is a problem for lakes on the Canadian Shield.

      The mercury danger is much worse when it becomes bound up in organic molecules.

  10. This is interesting. Low period tremor (0.5 – 1Hz) has started to drop while high period tremor has started to rise (2 – 4Hz). This is something that I have not seen before.

    1. Sometimes I’ve seen things like that on webicorders for various non-event happenings (rain, bad signal, loose wire, maybe a generator running nearby…), but assuming things are working correctly, it’s also a sign that all hell is breaking loose.

      Given this: http://twitpic.com/33osbu , I’d say things are probably working correctly……

  13. So what the Met office is that there is a geothermal component to the flood waters?
    As in something from the volcano?

  16. Yesterdays Quake in the Bardarbunga-Askja fissure system was upgraded to M3.3.

    Low-frequency tremor seems to be increasing at GRF, while high-frequencies are decreasing?

  17. Haha!

    Time for the US to go metric anyday soon so it will be easier for you guys?
    But I should probably shut up… since I never get gallons, yards and you whatnots correct… ehrm… 🙂
    But for some reason I am darn good at pints:)

    1. And that was a reply to Lurkings post way up… I will never learn to get my posts right… *sirsighsalot*

    2. The bad part is that in the US, pint’s don’t have the meaning that they used to. Now everybody expects and accepts that a beer is 12 oz.

      Guess I’ll have to mind my P’s and Q’s.

      1. Oh my… I was thinking about the english pint at 57cl.
        But you guys had to invent no less than 2 “almost-pints”… One wet-pint at ca 47cl and the dry-pint at 55cl. And then I haven’t even started on the lack of alcohol in US beer.
        To take it back to Iceland:
        According to Norwegian maritime law no ship was allowed to leave port if the captain couldn’t prove that he had onboard at least 4 cannes (1 canne is 2,62 litres, ie. 12 litres) of mead per day and sailor for the back and fro-trip to Iceland. And the mead was about 7 percent weight alcohol so no wonder the Wikings saw monsters at sea. If the captain skimped on this it was allowed for the crew to beat him to death, without receiving punishment.

    2. depharKrýsuvík is smack bang in the middle of the atlantic ridge and is geothermal hotspot, and as such it is prone for EQs.
      The shallow depth and the linearity of it makes me to give a guess here.
      After the large 2000 earthquake the lake of Kleifarvatn started to loose its water (by now 20 percent) and the quakes are following the western shore of the lake. So my guess is that it is stress-release from the lowered pressure around the lake.
      Remember that it has also been at least 2 large EQ-swarms out in the ocean at the Reykjanes Ridge Zone during the year that probably lubed up the system quite a lot.

  19. Hi Jon and all

    This would also seem to indicate that events at Merapi are off the scale…

    http://www.merapi.bgl.esdm.go.id/aktivitas_merapi.php?page=aktivitas-merapi&subpage=seismisitas

    There was an interesting comment on Eric’s blog about changing plate patterns and Indonesia’s position as some kind of keystone in the arrangement of world plates, but events going on there seem to link to a much deeper hot spot than Iceland’s. Iceland being the point above ground where the plates meet makes it easier to view changes as they happen but, as I assume, is Iceland’s hotspot much closer to the surface?

    1. Except for the dangers due to a lot of people living there it is still a small to midrange eruption.
      But yes it is an interesting point tectonically speaking. Together with Iceland and the Azoric lock it is one of the spots to keap a close eye on. Let’s just hope that Toba keaps dormant…

      2. I have no information about Azores Island. They are not covered by this blog (but comments are ok). If anything happens I am sure that you are going to be first to know by your local news.

  20. A couple of hundred of volcanos ranging from active to pretty much dead via dormant. Home to an ultra large underwater-caldera. Sits on a triplejunction of fracture zone and seems to work as a lock for the mid-atlantic-ridge.
    Pretty much the same as Iceland and Java. Hotspots, fracture zones, intense tectonics and huge amounts of pent up energy.
    But, is it something to worry about? Probably not right now.

  21. Magnitude mb 4.8
    Region NORTHERN MID-ATLANTIC RIDGE
    Date time 2010-11-04 12:29:52.0 UTC
    Location 12.70 N ; 44.96 W
    Depth 200 km
    Distances 1357 km NE Paramaribo (pop 223,757 ; local time 09:29:52.0 2010-11-04)
    1181 km NE Remire-montjoly (pop 19,029 ; local time 09:29:52.0 2010-11-04)

  22. Magnitude mb 5.5
    Region NORTHERN MID-ATLANTIC RIDGE
    Date time 2010-11-04 12:29:37.6 UTC
    Location 12.80 N ; 44.85 W
    Depth 60 km
    Distances 1373 km NE Paramaribo (pop 223,757 ; local time 09:29:37.6 2010-11-04)
    1197 km NE Remire-montjoly (pop 19,029 ; local time 09:29:37.6 2010-11-04)

  23. A mag 3.3 EQ beneath Grimsfjall today.

    Thursday
    04.11.2010 00:35:15 64.414 -17.248 0.1 km 3.3 99.0 1.6 km NE of Grímsfjall

    1. Where do you get this info from? The only EQ I see at this time in this area is a 0.7 according to the Met Office.

      1. Wow..It was at 99.0 confirmed but got downgraded to a Mag 0.7..

        Now it reads:
        Thursday
        04.11.2010 00:35:15 64.414 -17.248 0.1 km 0.7 99.0 1.6 km NE of Grímsfjall

        Ok nothing to see here..Carry on! 🙂

    1. If it is even remotely similar to the 2004 it should soon ramp up again as the “oroí” starts. During that ramping up there should be a short “SWARM” of EQs.
      In the words of my significant other… “Waitso!” (And yes, that is a linguistically correct word)

      3. Yepp, it surely will with all the magma that has intruded into the chamber. 30cm uplift is a lot.

        Nothing happening? In Iceland? Ha:)

        Is it just me getting all these corny captions? What is “hatation rearboy” for a captcha?

  26. Hi Jon
    I did write to Mila to ask about the web-cams but I did not get a reply from them. I have been watching Eyaf today and there were a couple of small whisps this morning but the area of steam or cloud seems a bit larger and steadier and more consistent this afternoon. It could of course just be cloud, perhaps above a warmer area? Otherwise the sky is clear there today so I wonder if it may be that announcing her demise was a bit premature.

    1. Alyson: About two days ago I posted a link to images of Fimmvörduháls where lava was still glowing within the tubes. Some steaming can be expected from the eruption which is gone by now.

    2. I did notice some steam from Eyjafjalljökull main crater (the one that erupted in April). But the weather is decent in that area. But a minor wind however.

      I did use the camera from Heklubyggð too see that.

  27. Thanks Renato
    It is still steaming steadily today, more so than I have noticed in recent weeks.

  28. If that is Eyaf in the distance then I guess it could be. Somehow, I don’t know how, I still have access to the Þórólfsfelli webcam and it is visible on that.

  31. It is clouds. Eyjafjalla is probably one for the history books for now. Until next eruption which may take many many decades.

  32. Hi,

    I just looked at the cam and it looks like steam from the crater. With fresh snow falling on still hot lava it’s no wonder that there is steam over the mountain on a day with not much wind.

  33. Grimsvötn has up until now followed the same pattern as it did before the 2004 eruption.

    As i said in a previous post my theory was that when the glacial flood was depleted the pressure ontop of Grimsfjall would be less and that would result in less tremors since the physical space within the magmachamber would increase (i.e Grim would rise when pressure was released). This would then allow more magma to enter the chamber before it got topped off. When the chamber is full once again the tremors will start to rise again (maybe very fast as in 2004) and a critical failure will occur and Grimsvötn will erupt.

    I still want to see if my theory is plausible so come on Grim..Show us if it´s correct. 🙂

    1. And looking at the graphs at IMO the pattern is VERY much alike..Wouldnt be surprised if the eruption will start within a day.

  34. About the azores question, the volcanoes have had less eruptions than in Iceland, but in past centuries have had some significant eruptions. In Sao Miguel island, there have been some VEI5 eruptions, and calderas about 5m x 5 km wide

  36. Jon, I’m afraid your fears about Merapi may turn into reality. The mountain has roared for hours during the evening and night there, but just a minute ago Sezka told, it is now silent! I have a bad feeling about this…

    2. The problem with mountains like Merapi is that they blow them self up into air on regular basic. This might happen 1000 to 100.000 years or more intervals. It depends on the volcano in question. But for Merapi I am starting to see the signs based on the data that I am currently getting (they are little, but good enough).

      1. What kind of scenario do you think might happen? Something like St. Helens? (Lava dome extrusion and half of the mountain collapse)
        And on which signs do you base your opinion?

      2. I am thinking some type of caldera formation is going to take place. My math suggests that everything in 50 km radius around the mountain is in danger at current time. As I cannot accurately predict when the caldera formation phase starts.

        The next small eruption should take place in 40 to 270 min time or so (according to the math formula that I am working on). But given lack of data, that might be wrong on that.

      3. @Jón Frímann. Do you happen to know how far away the village Selo ( where James Reynolds stayed suring his vist) is from Merapi. Boris mentioned that in an earlier eruption it was coveredwith a thick layer of Bims.
        And another thing, The indonesian people kept saying they have hardly any knowledge about volcanoes, should we maybe tell them to make sure they wear facemask so not to inhale ash? And to try not to inhale sulfuriy smells cause as far as i know SO2 transforms to sulphuric acid when inhaled and thats not really good.

      5. Oh Thanks, so if Merapi should start throwing out Bims Szeska is hopefully out of the danger zone.
        I am not postting on Big Think right now, i really dont want to upset people there or confuse them or delay the helpful informations others are giving there.

  37. Do you know what’s happening? Metro tv is showing images of ambulances arriving to hospitals with injured/dead people… this is geting worse!

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