Posted on by Jón Frímann

Small glacier flood from Grímsfjall volcano caldera

Today (11-May-2015) a glacier flood started from Grísmfjall volcano caldera. This is not a dangerous glacier flood due to its small size. There is however a danger from sulphur gases and other gases that dissolve when the pressure is dropped on the water. If people get too close to the Gígukvísl glacier river where the flood comes from Vatnajökull glacier they risk a damage to there eyes and lungs due to burning effects from the gases in the air.

grf.svd.11.05.2015.at.20.47.utc
Increased harmonic tremor from Grímsfjall volcano. Copyright of this image belongs to Icelandic Met Office.

There is now a increased harmonic tremor from Grímsfjall volcano. It is not clear why that is, it is either the glacier flood or hydrothermal vents boiling at the bottom of the lake due to the sudden pressure release on them. There is nothing suggesting that an eruption is going to follow this glacier flood from Grímsfjall volcano. Last glacier flood took place in 2014.

Icelandic News

Lítið hlaup í Gígjukvísl (Rúv.is, Icelandic)

31 Replies to “Small glacier flood from Grímsfjall volcano caldera”

  1. Just being an amateur. You say “There is nothing suggesting that an eruption is going to follow this glacier flood from Grímsfjall volcano. Last glacier flood took place in 2014.”. If it is not an eruption what is it than that heats the ice to create a flood from this vulcano. And as widely known there were some vulcano activity last year from the vulcano next door.

    1. Hi Jonas!
      You don’t need an eruption under the glacier to cause ice melting and floods.
      It’s enough heat available to do that only when magma is moving closer to the surface (always under the ice cap), but does not break through it.
      To this moment, the flood is caused by that, called hydrothermal vents.
      But we can’t rule out that some magma will find it’s way. Why we know it hasn’t yet? The tremor signal is too small for an eruption under the ice.

    1. I’m (confused amateur) thinking that a flood that’s been building up for a time and then gets released should be indicated by a drop – not an increase – in the tremor plots?

      2. For me (also bloody amateur), it seems the water has been melted continiously and was released right away. No wall or crater or damm stopped it while streaming downwards. IMHO there existed an (more or less) open path under the ice for the water to escape before.
        The smoothly rising water level at Gikjukvisl’s gauge can be taken as a result for that. (Could be..) 😉

      3. The question is the if the rising tremor is due to water flow and steam thing in contact with heat or magma movement and tension?

      4. If the tremors were caused by water flowing, the flood should obviously be bigger by now, (and getting bigger) since the graph is still crawling upwards.

        If they are boiling vents, then the boiling is also still increasing by the hour.

        Most probably, this is just going to go back to normal soon, but as long as the tremors rise I’m monitoring it anyway in lack of other, bigger stuff going on. 🙂

      5. It is bigger now. We will se if the tremors becomes lower when the flood is smaler.

  4. There are two new webcams around Holuhraun.

    First is a cam with view to the south on the river Jökulsa a Fjöllum. On the right the new lavafield is visible. Name is JökulsaS.
    I don’t know where it is located exactly. South of Vaðalda, I would say.

    Second is named FlæðurS. Looking south, too.
    I have no further information on that.

    http://brunnur.vedur.is/myndir/webcam/2015/05/12/
    (Change date manually)

    Maybe someone can help out.

  5. According to a graph that I watch showing the buildup in pressure in the caldera it is to early for an eruption. 1,400+ days since May 2011. It shall take a few more years.

    1. I’m sure you recall indications shortly after Holuhraun started that something else might be brewing in this locality. Grimsfjall is in the right zone for the southern route you predicted for pressure build up after the vent closed. Even the IMO warned that something else may occur without or with little warning.

      Whilst I wont be holding my breath, it certainly would not surprise me.

  7. The tremor has accelerated much during the night and at the same time the conductivety of the water had gone up a lot.

    1. It is the “high” frequencies tha goes up and those under 1 Hz even goes down a little. More shaking than rocking.

      1. It seems that in the past hours the low freq. has gone up too significantly. Could be a small eruption of some sort.

    1. Google translate: “Increased turmoil in the seismometer on Grímsfjall station suggests that race from Grimsvotn is at its peak.”

  11. I just realized that the glacier flood is a part of how Grimsjall works. I posted at vc as well. Flooding occurs, earthquakes gradually pick up after each flood gradually increase. The process repeats itself several times over the years. So whether an eruption occurs not I guess this is how the volcano behaves. It is all interesting.

  12. As predicted: After the flood peaked the tremor peaked. This was a boiling streaming phenomena.

    1. Not really normal. The bigger ‘slosh’/peak from May 13 is over, but the tremor situation is now back to how it looked about a week ago – 2-4Hz tremors were already pretty elevated by then – and seems to increase with similar rate. The streadily increasing tremors had been going on since around May 2.

      from May 9. And yes, image belongs to IMO.
      http://i.imgur.com/EcEbkVg.gif

      1. Sorry, I was obviously too hasty there. The tremor keeps dropping, not picking up again. It looked different then.

      2. This why we should listen to the Icelandic geologists. They work with these things every day. You would expect some knowledge and skills. They predicted this and it happened.

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