Eruption at Reykjanes

/ 19/03/2021

The long-awaited eruption has started, and has been confirmed by IMO. Just after 9pm the first light became visible on the cameras. At 21:40 official confirmation came. IMO has decided that the eruption began at 20:45. The location is not entirely clear yet, but the most recent earthquakes would indicate it is pretty much where expected, just south of the peak of Fagradalsfjall. There was no seismic signal, but in hindsight the near-surface M3.1 this afternoon was the straw that broke the camel’s back.
This solves the question whether this event was tectonic or magmatic. This is the first eruption in Reykjanes since about 1200 AD, and is likely the start of a longer period (centuries) of new activity on the peninsula. The current eruption may or may not last long. We do not know very much about how volcanics on the peninsula works. But eruptions here are likely to produce of order 0.1 km3 of lava, enough perhaps to reach the ocean and cause inconvenience, but not do major damage.

The fact that there were no earthquakes announcing the eruption suggests that the magma was already very close to the surface. A filled conduit is silent. The earthquakes come from breaking the conduit open, and tremor from filling it up. There was almost no tremor either (a15-min low frequency burst before the eruption was reported, only noted in hindsight), so magma may already have been ready since a few days. It was just waiting for the weekend.

The red glow suggests fountaining but we are waiting for further reports. We will add news here as it appears. We actually rely mostly on you!

And as a final point, when we announced the 1-year postponement of the eruption last year (April 1), we had no idea how close we were to reality.

A direct view of the rift is from the following webcam. It was at first pointing in the wrong direction but not has a great view of the eruption

https://www.ruv.is/frett/2021/03/20/beint-vefstreymi-fra-borgarfjalli-ad-eldstodvunum

Another suitable webcam is https://www.ipcamlive.com/60401b8d3413c
Also see
https://www.visir.is/g/20212080986d/oroasvaedid-i-beinni-utsendingu

Road cameras are at http://www.road.is/travel-info/web-cams/south-west-iceland

Image provided to us by Judge Matthews and reproduced by permission

The eruption is confirmed to be in the Geldingaladir. A 500-meter fissure is reported with 4-6 small fountains. In this location the lava will be confined and does not appear to endanger infrastructure. It is a perfect small eruption. The valley is enclosed, and if the the eruption lasts long enough to fill up the valley (less likely) it would flow into another valley and go north away from any people. (It seems more likely that the eruption will stop well before but may erupt in a new location.) For a detailed map, we recommend http://kortasja.lmi.is/mapview/?application=kortasja


www.facebook.com/Vedurstofan/photos/a.431284043605831/3930732966994237/

Keep posted! And keep posting.


https://www.ruv.is/frett/2021/03/20/beint-vefstreymi-fra-eldstodvunum

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558 thoughts on “Eruption at Reykjanes”

  4. This lava is quite fluid

    But not at all as fluid as pahoehoe lavas are in Trölladyngja at Bardarbunga

  5. I make the eruption rate as around 15 m3/s over the first 24 hours, That is most the estimated volume of the lava flow and should be within a factor of 2 of the actual number.

    • How long will this eruption last?
      The magma supply is not enormous in Reykjanes

      • If most eruptions in this area are around 0.2-0.3 km3, they probably involve at least 2 km3 of magma most of which stays underground. At the current rate it will take a few years to do this, so my guess is

      • This little eruption last many years?

        Or perhaps its many small episodes with a a year or three between them

  6. There’s quite clearly a flow going on to the right behind the main cone, would be nice with a view that showed that side.

  8. Nice to see a view of the events! This morning all i saw was fog no matter wat webcam i checked. offtopic: reading the comments on the mobile page is really hard 🙁

      • it is for comments, but not for the article than its lot of scrolling. this site is not really optimized for mobile it seems.

        • Correct. We are a small team! Some simple solutions have been suggested which I don’t recall. But holding the phone sideways seems to be the easiest.

        • Most mobile browsers have a Desktop Site feature. Which loads the website as if on a PC.

          Its not perfect, but it does solve a lot of the issues on mobile.

    • So it was these guys who went up close to the cone 🙂

      The lava is definitely erupting as pahoehoe, it is probably turning into a’a later because the eruption rate is too high not because of anything to do with the composition of the lava.

      Google earth has also finally loaded the vent area of Holuhraun properly too and most of the lava around it is also pahoehoe, it looked dark in the videos but that was lighting not surface texture. Maybe the lava in Iceland isnt as shiny as lava in Hawaii, so the difference between pahoehoe and a’a surface isnt obvious from colour.

      • Near Trölladyngja at Bardarbunga you can find very smooth and fluid thin pahoehoe with very fine thin ropes .. suggesting very low viscosity

    • You’ll need to get more popcorn for tomorrow! We’ll keep the lava warm for you

    • I watched it part of the night. For a while the output was enormous and the progress of the lava field was swift.

    • Thank you. Is it just me or did the magma flow start increasing yesterday afternoon?

    • Thank you for those time lapses. I was able to catch up on everything I missed as I slept on the other end of the planet.

  15. I worry a lot about the people on the webcam. Aren’t they in danger of being closed in by the lava streams on each side? Not to mention the danger of being so close to the gushes 🙁

  17. Oh by the way, when the lines on the seismograph (like FAF right now) are thicker than usually, is that the weather or some sort of tremor? 🙂

  18. Where can I find the GPS/Land deformation data?

    On a side note, I have learned quite a bit about volcanoes and earthquakes from you all. My knowledge has been increased from a the back of a postage stamp to the back of an envelope.

    Thanks.

  19. There are quite a few people on the other side of the cone, suggesting to me that the view (at least for the moment) is more interesting on that side. Obviously there could be people out of frame on this side as well…

    • Sorry, should have checked better, this image is at least 20 hours old. So slightly out off date.

      • Thanks, I thought so, it still shows the progression though. I think the reason the people are on the slopes opposite, isn’t so much it’s more interesting, but they can’t get to the valley floor any more.

      • It also gives an idea of the height of the peak above the valley, which can then be used to estimate the cone height. The peak is 35-40 metres above the valley floor, so if you take off 10 metres-worth of lave height, perhaps 30 metres still showing, the coen is approximately half of that, so about 12-15 metres tall.

    • So it is a depression rather than a river valley?

      If yes, it may explain why the rock was weak enough for lava to get through.

  23. Valley 10-20 days to fill

    Given the lava flow in Geldingadalur as it is now, it would take 10-20 days to fill the valley with lava. Subsequently, the lava presumably slides away from the slope, likely south of the mountain towards Niger, and then Ísólfsskáli.

    This is the assessment of Magnús Tuma Guðmundsson, professor of geophysics, based on calculations published by Jóhann Helgason on social media.

    “If the eruption continues for so long, it eventually comes up very much lava. There is little flow but it remains to be seen how long this lasts,” said Magnus Tumi in a conversation with mbl.is.

    Probably searching south
    The lava flow is expected to be up to 5-10 cubic meters per second. In John’s opinion, the volume of the valley is about 6.8 million cubic meters. If it goes ahead, the valley will fill it in 10-20 days.

    As stated in John’s post, the flow will likely look to the southwest of Nigeria if the valley fills up. Then it remains to be filled with lows before it can proceed towards the Isle of Man, which is the first structure that can occur in its path.

    Given the current corridor, however, it should be several weeks until real concerns about damage to structures need to be made.
    …
    https://www.mbl.is/frettir/innlent/2021/03/21/dalurinn_10_20_daga_ad_fyllast/

    • That would be dramatic. A lava flow from Iceland to Nigeria by way of the Isle of Man. Could perhaps, just perhaps, google’s translation be less than perfect? Hard to believe, I know.

      • Interesting cruise along side the lava flow – what was that about wanting a bridge between Scotland and Ireland, we might just manage it

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