Update on the eruption in Fagradalsfjall mountain on 21-May-2021

This is a short update on the eruption in Fagradalsfjall mountain on 21-May-2021. This is part of the Krýsuvík-Trölladyngja volcano system.

There has not been a lot of change since last update on the eruption. The eruption has now been going on for two months and few more days. There are no signs of the eruption ending.

  • The lava fountain activity continues as it has been doing for the last month.
  • Output of lava has been increasing and is now around 11m3 compared to 5m3 at the start of the eruption.
  • Lava is now on its way to the ocean by flowing down into Nátthagadalur valley. There is an attempt to try and stop or delay that from happening by pushing up defences and try to hold back the lava field. It is my personal view that this attempt is going to fail, at most it is only going to delay the lava a little bit. Since the lava field also has to get over a hill that is in its path anyway. That is only going to take few days to a week depending on how much lava is being fed into this part of the lava field. That changes all the time with no warning.
  • Most of the lava goes into Meradalir valley where it is for now not putting anything in danger or risking infrastructure.
  • SO2 pollution is starting to show in south Iceland. There was also report of static electric charge build up around the eruption site yesterday (20-May-2021). It didn’t result in a lightning but the risk was in place for a good while.

There are for now no other news of the eruption and it has been quiet in other parts of the Iceland during the last week.

10 Replies to “Update on the eruption in Fagradalsfjall mountain on 21-May-2021”

  1. As of this morning, Saturday May 22, it appears that the lava has breached the earthworks on the right side of the view shown in the Langihryggur RUV.is webcam.

  2. Thanks, Mudpot! Good info and this explains all the police in the parking area. Will they close the area to visitors?

  3. I don’t know local conditions, a google translation of the RUV report is-
    “The eastern dam is broken

    Lava begins to flow over the eastern fortification that was established in Nafnlausadalur and now the lava flows down into Nátthaga.

    This can be seen on the RÚV webcam in the attached photo. The dam probably broke sometime last night and when the light came on it was clear where the lava had flowed over the dam.”

  4. A further report on the RUV website shows a map of the area with the dams and the breach shown. Again from google translation of the RUV story-
    “From the innermost part of Nátthaga to Suðurstrandarvegur, there are about two and a half kilometers in a straight line. It could take the lava a few days to get there.”

  5. In my own opinion, I think it would be wise to use the earthmoving equipment to dig a channel to the sea for the lava, so that the lava might not spread out when it gets to the road, making a roadway permanently impossible. A temporary bridge could perhaps be made across the channel, to keep the fibre optic cable away from the lava.

  6. According to the latest report the lava has breached the western part of the barrier too, but not to a great degree.

  7. Eruption looks to be slowing last couple days. I’m sure the residents of the nearby city of Grindavik would like that to be the case, as lava slowly makes its way toward the ocean. Having the main road cutoff, and fiber optic cables damaged wouldn’t be a very good scenario for them. In the end, if this eruption is a sign of things to come for this region of Iceland, the next few decades could be quite the challenge.

  8. Eruption looks to have weakened a little more as the day has progressed. Went from 1 1/2-2 min eruption every 7 min with rather large output, to 2-3 min every 6-7 min with weaker output. Fountains are smaller, too. The quicker this thing slows, and even stops, the better for Grindavik.

  9. There is some change going on and it is visible on the harmonic tremor charts on Icelandic Met Office website. I don’t know what those changes mean though.

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