Update on the eruption in Fagradalsfjall mountain on 28-May-2021

This is a short update on the eruption in Fagradalsfjall mountain that is currently erupting and is part of Krýsuvík-Trölladyngja volcano system.

  • There have not been any major changes since last update. Minor changes seems to be happening but at the writing of this article, those changes have remained small.
  • Large lava fountain activity has stopped in later part of this week. There is still some lava fountain activity going on but it is minor based on what I’ve seen on the web cameras.
  • Lava is now flowing into Nátthagi. It is expected to reach Suðurstandarvegur road in 20 to 60 days depending on the lava flow into Nátthagi.
  • The western barrier for the lava has stopped the lava flow into Nátthagi at the writing of this article. Bad weather today (28-May-2021) has prevented any observation of the current situation in the eruption area. Its fog and heavy rain in this location currently.
  • Lava reservoir have formed in the lava field. They fill up slowly and then empty them self quickly into the lava field both on surface and with lava tubes that have formed in the lava field. This allows the lava field to expand quickly and without warning into new areas.
  • The lava field is slowly building upwards from the height it has been in recent weeks. Results of this is that soon the walking path to the viewing area on the ridge might soon be blocked by lava going over the area at its lowest points. This might only take few weeks to happen but that depends on how quickly the lava field builds up.

Other then this there has not been a lot of change in the eruption. This phase of the eruption might go on for months. There are clues that this is the first step in the building of a shield volcano or maybe a stratovolcano. What happens is a wait and see on this eruption.


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Earthquake in Brennisteinsfjöll volcano

On 24-May-2021 at 21:36 UTC an earthquake took place in Brennisteinfjöll volcano. The magnitude of this earthquake was Mw3,6 and this earthquake was felt in Reykjavík area.

Green star in the middle of the image of Reykjanes peninsula showing the location of the earthquake that was felt in Reykjavík.
The location of the earthquake in Brennisteinfjöll volcano. Copyright of this image belongs to Icelandic Met Office.

There have been few smaller earthquakes in this area since the largest earthquake, but other than that it has been quiet. This earthquake is believed to have happened because of stress changes on the Reykjanes peninsula because of the eruption in Fagradalsfjall mountain.

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.

Update on the eruption in Fagradalsfjall mountain on 15-May-2021

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

The eruption continues as before but increase in lava output has been detected and is now 70% more according to latest news from Icelandic Met Office and Earth science of University of Iceland. Compared to the start of the eruption on 19-March-2021.

  • The eruption continues in one main crater. It erupts in lava fountain style at the writing of this article. With highest lava fountains reaching the height of 400 to 500 meters. The lava fountains can be seen from Reykjavík and other nearby area.
  • The lava field is about to reach Nátthagi valley and there is now an attempt to stop that from happening. Because of nearby road and fibre optic cable that runs through that area. It is my estimate that attempts to stop the lava flow are going to fail when the lava flow starts going back to Nátthagi valley.
  • The main crater is now 50 to 90 meters high. But his height is always changing because of continued collapse from it inside it and outside it. The process of collapse is slowly growing the crater volume and size.
  • The magma seems to be coming from even deeper part of the mantle compared to with start of the eruption. Based on lava changes in the chemical makeup.
  • There are no signs of the eruption about to be ending soon.

It is difficult to know for sure what happens next in the eruption. Opening up of new craters outside of current line of craters is something that might happen. With the eruption growing in size it is difficult to know for sure what is going to happen next in Fagradalsfjall mountain.

Earthquake activity in Bárðarbunga volcano

Yesterday (12-May-2021) at 15:47 UTC an earthquake with magnitude of Mw3,5. This earthquake was in the normal area of Bárðarbunga volcano caldera. This earthquake activity is connected to inflation of Bárðarbunga volcano that started after the end of Holuhraun eruption in 2015.

Green star in Bárðarbunga volcano caldera and few red dots east of Bárðarbunga volcano showing new deep dyke activity taking place. Image is from 13:20 today (13-May-2021).
Earthquake activity in Bárðarbunga volcano. Copyright of this image belongs to Icelandic Met Office.

There has been a slow drop in earthquake activity during the last few months and it is unclear why that is. Eruptions in Bárðarbunga volcano can be as short apart in time as 18 years or less. The 1996 eruption in Gjálp fissure was from Bárðarbunga volcano, that places the time between eruptions 1996 and 2014 at 18 years.

Earthquake swarm in Krýsuvík volcano

Since last night (night of 3-May-2021) there has been earthquake swarm in Krýsuvík volcano close to Kleifarvatn lake. At the writing of this article this earthquake swarm is ongoing.

Earthquake swarm in Krýsuvík volcano shown by two green stars on top of each other
Earthquake swarm in Krýsuvík volcano. Copyright of this image belongs to Icelandic Met Office.

Largest earthquakes in this swarm had a magnitude of Mw3,2 and there where several other smaller earthquakes that also happened. The earthquake at 03:04 UTC was felt in Reykjavík but I don’t have any reports about the earthquake at 15:49 UTC with same magnitude being felt. It is difficult to know what this earthquake activity means but for now the idea is that this earthquake activity might be connected to stress changes because of the magma dyke connected to the eruption in Fagradalsfjall mountain that is happening within same volcano system.


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I am taking a little vacation between 5 May and until 10 May. Unless something major happens next update won’t be until after 10 May 2021. I am hoping to see the eruption or the area if the eruption is not ongoing next weekend if weather allows for such a trip. I don’t know yet if I can see the eruption, but I hope that I am going to have a chance to see the eruption.