Posted on by Jón Frímann

Uncertainty level declared for Grímsfjall volcano

Icelandic civil protection (Almannavarnir) have declared a uncertainty level over Grímsfjall volcano due to glacier flood coming from them. This level is the lowest level of warning that Almannavarnir have in case when there is a risk of dangerous events taking place.

At current time no eruption has started in Grímsfjall volcano. Note that this volcano is often called Grímsvötn in Iceland. But it is the same location with two names.

Almannavarnir announcement. Please use Google Translate.

Óvissustig vegna Grímsvatna (Icelandic)

Icelandic news. Please use Google Translate.

Almannavarnir lýsa yfir óvissustigi (Rúv.is)
Óvissustig vegna Grímsvatna (mbl.is)

Text updated at 19:47 UTC on the 1st of November 2010.

183 Replies to “Uncertainty level declared for Grímsfjall volcano”

    1. I better take that nap (that I need) before everything starts in Grímsfjall.

      Before the eruption there is going to be a earthquake swarm in the Grímsfjall. A single earthquake doesn’t say a lot.

      1. How long do you guestimate the swarms will ensue before the eruption?

        I want plenty of time to short UAL after it pops on 11/3 from the elections and the fed printing more money…Just Kidding

  2. Hi everybody from Teide volcano, in Canary Islands. Jón, i agree abour the quake swarm to appear before an eruption and i think a degassing event can melt the ice. I mean, maybe we are not heading to another eruption, but an intense degassing process could lead the ice cap to melt faster than usual. Moreover if we agree that the degassing process, usually CO2 and some sulphur species, is driven by water vapor, and heat. Maybe a different point of view…trying to spot some light into this issue….

    Cheers!!

  3. A earthquake swarm before a eruption starts in Grímsfjöll is normally about one to two hours before it starts.

    Currently it is now just wait and see what happens in Grímsfjöll.

  4. tremor seems to be on the rise in the last days up there. Should be the glacier flood itself?

      1. Didn’t the 2004 eruption start immediately after a Jökulhlaup
        took place at the Grimsvötn?

    1. Water has been collecting in Grímsvötn since 2004. When the last flood took place from Grímsvötn. So this is not created by sudden magma activity or by eruption at current time.

      1. i would like to see the isostatic bounce if the water goes out fast from the caldera….could trigger an eruption for sure.

    2. Luis: Boa noite. This is also what I am wondering: if flooding couldn’t be caused by magma even before an eruption takes place.
      BTW Onde você mora? Nos Açores? Abraço!

  10. I’m missing something. If the flood is occurring for it’s own reason, why the certainty of an eruption to shortly follow?

    1. This is just my impression: Just due to the fact, that Grimsvötn tends to behave like this. Is this justified? Well… That big amount of melt water does not exist without a significant heat source. And, it does not really matter in my amateur opinion that much for how long it took to melt it, as the amount of heat needed in this case (under a permanent glacier) points to volcanic origin anyway. So, there certainly is a reason to be cautious!

    2. Since the Grimsfjall lake is conatined by walls of ice it might have been a critical failure in the containment which has released a large amount of water.

      However, looking at the lastest inflation, EQ´s, tremors rising in a sharper curve and the magma reservoir which is under alot of pressure (commented by a geophycisist in Iceland) I would say that a volcanic explanation would be alot more likely than just a coincidence.

      But I think we dont have to wait long until we get to see what is happening.

    3. The area under the glacier is geothermally active. This melts the glacier and fill the Grimsvötn lake. At some point every few years this lake is so full, that the icebarrier which holds the water breaks and releases the water. This is what happened now and happened as well in 2004.
      When there is enough magma close to the surface and the volcano is almost ready to erupt, this release of pressure from above can trigger the eruption. Thats how it happened in 2004 and probably now.

    2. There currently is a strong wind in (south-)west of Iceland, that might be the cause? However this seems different than any other time I’ve seen a storm passing.

    3. Other stations around Katla show familiar wind signatures, but the HVO is a bit peculiar. Harmonic tremor? Jon?

      1. Im a bit curious also but there are some strong winds in the neighbouring areas. Maybe strong gusts of wind?

        1-2 Hz seems to be “wider” than usual and the 0.5-1Hz does not seem to be affected by whatever is making these charts behave like they do.

      2. Can someone explain what measuring these charts are showing? And what’s the difference between the green, red and blue?

      3. The charts show seismic activity or movements in the ground. The different colours record within different Hertz. Red is 0.5-1Hz, Green is 1-2Hz and blue is 2-4Hz. As i understand it the hertz measure the frequency of the tremors in cycles per second. So if the green rises it means it is more “noice”..And if it gets wider it means that the tremor is larger (horizontal/vertical movement)…The actual scale on the charts are however unknown to me…Maybe they are just a baseline scale (whatever number) to see if the tremors deviate.

        If Im wrong I look forward to a correction so that I might learn ab it more aswell. 🙂

      4. And please note that the weather in Iceland are often harsh. This also shows up on these monitoring station and very clearly so detecting volcanic or harmonic tremors is very difficult. Thats why we are happy to have Jón here who has more knowledge of these signals. 🙂

  15. Well not that the eruption itself is imminent but that there is an increase in likelyhood of an eruption. I know the difference is very small but still. It can be significant. 🙂

    And for the record after watching the EQ´s, deformation at the GPS stations and now these past two days events I would be surprised if an erution DIDNT occur in a foreseeable future.

    1. Im just happy that it is in a remote location so hopefully noone will get hurt. And predictions from icelandic geologists say that the eruption itself will be minor so an airtraffic shutdown doesnt seem likely. But as we all know volcanoes can not be predicted per se so we will have to wait and see..Hope for a good show with lots of stunning new images. 🙂

      1. The only damage so far is a high-tension powerline. One of the posts has been knocked down by an iceblock, cutting of the town of Kirkjubaejarklaustur of the power line.

    2. In the year 2004 it took five days from the start of the glacier flood until the eruption started. So I am expecting something similar to that time frame now.

      But the failed eruption in March 2010 might have changed things inside Grímsfjall volcano. But I don’t think that is going to stop a eruption from taking place. But I am expecting a larger eruption then took place in the year 2004.

      1. Yes, it is the new earthquakes. There depth is different or from 3 km to 2 km. Normally Grímsfjall volcano is quiet in the earthquake side of thing. Like Hekla for a example. But unlike Hekla it appears that there might be a slightly longer pre-earthquakes happening before it starts to erupt.

        This small earthquakes are a signal that magma is getting unstable inside Grímsfjall volcano. But when it starts erupting is a good question.

    1. And they look to concentrate at depth of 1 km. This is getting very interesting!

      1. These quakes has been going on since forever and doesnt mean anything in particular. If Katla were to erupt I suspect you would se glacial flooding and alot of earth quakes. Similar to what happened at Eyjafjallajökull. On march 4th for example there were more than 2000 earthquakes beneath that volcano.

        So these 10´ish earthquakes probably just means that the icecap is setting abit or just that the fracture is creaking abit.

    1. Could you explain this? Do you mean that the increase in tremor is not only related to the drainage of the subglacial lake?

      1. Part of the tremor is due to the glacier flood. But part of it is due to noise from Grímsfjall volcano.

        But I am still waiting for earthquakes swarm that signals a start of a eruption in Grímsfjall volcano.

      2. …if things go like they used to go before.

        Another option is a more violent eruption with shorter warning time and a bigger explosion. It all depends how solid/strong the rock on top of the volcano is nowadays.

    1. You are reading the tremor plot correct. The 1-2Hz and 2-4Hz bands have been rising far more then I would think happens due the glacier flood.

      But until the earthquakes starts I am unclear on why the harmonic tremors are increasing.

    1. Aha ok..So the stars are EQ´s larger than mag 3.0. the timeline has to be answered by Lurking but it seems to be a quite long timespan..maybe from Eyjafjallajökulls eruption or so.

    2. Sorry.. no, the stars represent the most recent quakes. (last day or so) The rest are historical back to about 10/1/10.

      There is no magnitude data in that plot.

      It was not intended as a definitive plot, just an illustrative one.

      1. Gah I thought I was interpreting it correctly..Ok I will reboot and rethink your plot …;)

    3. The issue comes from trying to make the recent ones stand out from the others. No matter what symbol I used it got muddied… the stars worked the best.

      In a nutshell, nothing odd is going on at Katla… well, nothing really odd. There was a lot of what appeared to be dike/sill activity, and so far, this just seems to be a continuation of that.

      The only real odd-ball is that 15 km deep one to the south. But it’s just a solitary quake.

  30. What plot are you referring to? The tremor plot or earthquake plot?

    On both the timespan is indicated on the bottom axis written by date. And the EQ´s are colour coded according to how old they are.

  31. Daniel_swe says:
    November 2, 2010 at 19:29

    This comment can be ignored. I answered too fast on a previous post. 🙂

  32. One thing that is interesting though regarding the activity of Grimsfjall is that it has been exactly 6 years, to the day since it erupted last.

    In 2004 it started erupting on November 2nd. So lets see…a few hours left (icelandic time) and we will see if it is a very accurate volcano or not. 🙂

    2. Hecla erupted nicely every 10 years for 40 years, with the next anniversary in February 2010. So last year I picked that Hecla would be the next VEI3 on Erik’s blog.

      February 2010 Hecla does nothing at all. Instead Eyjaf erupts 40 km to the south. Humpf, all I can say is volcanos are like cats.

  34. In the year 2004 it took about five days from the start of the glacier flood from Grímsvötnum until the eruption started. So this might take a few more days before a eruption starts.

    Or not… we will see.

  35. But still..Grimsfjall seems to quite regular.

    1998 in december
    2004 in november
    2010 (in november?)

    6 years between each eruptive phase..Give or take a week or two.

    1. Just counting the last few of course. Earlier eruptions has been more irregular as any volcano is unpredictable but still, quite a coincidence. 🙂

  36. Tremors keep increasing. Windspeeds are quite low at the moment 4-8m/s according to IMO.

    1. It is highly likely that you are seeing water in the tremor graph. The key thing to watch for is a change in the spectral response.

      I don’t have a fingerprint of what magma itself would look like… 1 hz increase? Dunno. Jón w0uld have a better idea of that.

      My gut feel is that the lower freqs would be more indicative of magma movement. (lower freqs also travel further)

  38. I checked the hydrology map on IMO but the river (Gígjukvísl) doesnt appear on that page.

    It would be interesting to match the increase in waterflow against the tremor chart. I think the tremors would increase more than the waterflow. The reason I think that is both water and seismic “noise” shows up on that chart. So if the tremors increase more in comparison to the flow and continues to do so…Well..Boom..:)

      3. Password and Username are also given in Icelandic if you don’t use google translate.

      5. That’s a start… many thanks.

        Of note is that the temperature of the water has gone up about 5°C over 14 hours.

      6. @ Lurking

        Where do you see an increase in the water temperature? When I look at the water temp data from Gígja they are pretty steady at ~0 degree C.

        The water flow and conductivity increased nicely, but due to the presence of ice (i.e. melting glacier) the temperature stayed steady at ~0 degree C.

      8. @ Lurking

        The red curve is actually the air temperature. The water temperature is the blue curve at the bottom of the plot and that one isn’t moving much at all…

    2. Okay… I’m struggling here.

      Could one of you fine denizens of Iceland please post the name of the river that I’m looking for in Icelandic spelling/nomenclature? Transliteration to English would be appreciated, but isn’t really needed. I’m trying to find the river data on the linked site.

      At least it’s not in Navaho.

      1. Which river do you mean? The one with the flood? Thats the Gígja.
        If your are looking for it on the vmkerfi site, which was mentioned above, go to Suðausturland on the left side and then choose: Gígja; V159

    1. Well, I think the district is Austurland, and here are the available rivers/stations:

      Fjarðará í Seyðisfirði
      Hrafnkela; V288
      Jökulsa á Dal, Brú; V164
      Jökulsá á Dal, Hjarðarhagi; V110
      Jökulsá á Fjöllum, Grímsstaðir; V102
      Jökulsá á Fjöllum, Upptyppingar; V289
      Jökulsá í Fljótsdal, Hóll; V109
      Kelduá, Víðivellir
      Kreppa, Lónshnjúkur; V233
      Lagarfljót, Lagarfell; V007
      Reykjará; V366
      Upptyppingar, veðurstöð; S4020

    1. @ Lurking

      Neat plot, as usual.

      Can’t wait to see what will happen next. The seismicity has been unusually quite the last few hours. I guess the next set of earthquakes might trigger the long awaited eruption (speculation!)…..

  41. @Lurking – I was a bit too slow – just found the right page but you beat me to the info – good deal.

  45. While we wait the water level keeps rising in the Gígja, and so is the conductivity. The jökulhlaup from Grímsvötn is still going strong, draining more and more water, relieving more and more weight from the crater….

    1. This would be harmonic tremor pulse I believe. So there is definitely magma on the move now. It remains to be seen if that is going to result in a eruption or not.

  48. Hello all, I’m delighted about what I can learn from an experienced team like you here! Thanks a lot!
    One question beside: Here the three webcams by the bridge over the said river. Updated once per hour. One looks west, one looks east and the middle one “down the road” (Giggle Transl.)
    Now, as the road is going roughly E/W, might it be looking away fron the road, towards the sea?

    http://www.vegagerdin.is/umferd-og-faerd/vefmyndavelar/lomagnupur/

    And the other question is, what is on the west-looking cam the yellow sheen behind the cliffs? It was not there yesterday, if I remember right, maybe there were low clouds.. The moon? but has not been moving last two hours. Reykjavik lights? A nearer village, Kirkjubaer…? But so late at night? I just wonder.

    1. There is one camera, that looks west, the last one. And to the west there should be no light, there is just the sander, a open sand plain.

  49. A big tremor pulse jump is taking place on Grímsfjall SIL sensor. This tremor pulse is growing fast at this moment. I am expecting earthquakes to start soon if the magma starts to push up to the surface.

  50. @GMK

    Thanks for the info link, but I got confused by the layout change and may have inadvertently changed your settings while trying to get back to a familiar layout.

    I have gone into my browser and cleared all the cookies for the applicable site. What ever changes you make in your layout should no longer be interfered with by my browser.

    If you saw no change at that site, then my issue was probably just me driving my browser haphazardly barely avoiding trees. No sweat, it was just a cookie. If you did see an affect, my apologies. Like I said, I was confused by the layout change.

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