Earthquake activity south of Keilir mountain

During the night of 27-April-2021 an earthquake swarm took place south of Keilir mountain in Krýsuvík-Trölladyngja volcano system. This earthquake activity at this location has been going on for a long time and is interesting. There are no sign that suggest an eruption is about to happen at this location, that is the situation at the writing of this article. Largest earthquake in this swarm had a magnitude of Mw3,2 at the depth of 6,1 km and second largest earthquake had a magnitude of Mw2,8 at the depth of 5,9 km.

Earthquake activity south of Keilir mountain shown by a green star on the map of Reykjanes peninusla
Earthquake activity on the Reykjanes peninsula. Copyright of this image belongs to Icelandic Met Office.

It seems that there is a chance there might be changes about to happen in the eruption in Fagradalsfjall mountain. I am going to write about that tomorrow at the earliest, but the article might be delayed of there is a lot going on while I gather information about what is happening.

Update on the eruption in Fagradalsfjall mountain on 26-April-2021

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

There are no major changes reported during the last few days. But there have been minor changes in last few days. Here the latest changes that have been reported.

  • The oldest craters have stopped erupting. One of the crater has changed into a lava lake for now while the other is possible also a lava lake even if it is not visible. A lot of gas (smoke) comes from the more south crater in the crater row 1.
  • There are three to four craters that continue to erupt. There seems to have been a tiny increase in the eruption today (26-April-2021). This can be explained by how few craters are currently erupting.
  • No new craters have opened up in last few days. This is correct at the writing of this article.
  • Harmonic tremor seems to be decreasing. It is unclear why that is since the eruption is currently ongoing.

There are no other reports about the eruption. I am not sure when next update is going to happen but it is going to be soon as possible if anything changes in the eruption.

Update on the eruption in Fagradalsfjalli mountain on 23-April-2021

This is a short update on the eruption in Fagradalsfjall mountain on 23-April-2021 for the last week. Information is provided with best effort. The volcano that is erupting is Krýsuvík-Trölladyngja volcano system.

No major changes have been seen this week in the eruption. Here are the highlights.

  • According to last chemical analyse of the lava. The magma that is coming up is getting more primitive and from deeper part of the mantle. This increased the chance that the eruption is going to go on for months to years. Details can be found here on Twitter or here on Facebook.
  • Thickness of the lava is in most places just 16 meters. In Geldingadalur valley the thickness is at most 50 meters and getting thicker as the eruption continues and the valley slowly fills up. The lava doesn’t flow far and so it piles up next to the erupting craters.
  • At the writing of this article it seems that crater 1 is slowing down or shutting down. There seems to be some activity but it is low and mostly just gas is blowing out.
  • Craters continue to collapse as the eruption goes on. This happens at random and results in flood of lava happening.
  • The most active area now is the craters that opened on 7th of April and other time after that.

Other than this the eruption continues to be stable and the flow of lava is around 5m2/second according to last report I did read in the news.

Update on the eruption in Fagradalsfjall mountain on 19-April-2021

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

  • The crater that started erupting on 5-April-2021 has stopped erupting. I am unclear when it stopped erupting but that must have happened sometimes in last few days.
  • Smaller vents have opened up but none of them have been able to create any major eruption crater. Most of those have also stopped erupting and been buried by fresh lava from others craters when they stopped erupting.
  • Earthquake activity has been appearing along the dyke in last few hours. I am unclear what that means at the writing of this article.
  • New fissures with steam or hot air have been reported south of current eruption. I am unclear where they are located. There don’t appear to be any new fissures north of the crater that has stopped erupting at the writing of this article.
  • Crater 1 has now started to smoke a lot. While the second vent continues to erupt a smaller eruption. I am unclear on why one of the vent is smoking as it has been doing for the last few days.
  • The eruption is now 1 month old today. The eruption started on 19-March-2021.
  • Amount of lava being erupted has increased since the start of the eruption according to latest reports.

I don’t have any more reports today but that might change without warning. If that happens. I am going to write an article soon as I can.

Update on the eruption in Fagradalsfjall mountain on 16-April-2021

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

There has not been any major change since last update. In this week four new craters started erupting and I write an article about that earlier in this week for more details.

  • It was reported today (16-April-2021) that lava has now started to flow outside of Geldingadalir and to the east. This lava is now flowing over a walking path that people used to get close to the eruption. Getting close to the eruption might not be possible any more. There is also a chance that lava is going to is going to flow to the south of the craters more than it already has done.
  • Swarm of small earthquakes took place north-east in Fagradalsfjall mountain early morning around 06:00 UTC. Largest of those earthquakes had a magnitude of Mw2,8.
  • There is no sign of the eruption ending.
  • There continues to be a high risk of new vents opening up and start erupting without warning.

There are no more reports this week outside of what I did write about what was happening earlier in the week. If anything major happens I am going to post an update soon as possible.

Stronger harmonic tremor reported in Fagradalsfjall mountain eruption

Yesterday (15-April-2021) it was reported (late) that harmonic tremor seems to have been increasing in the eruption since midnight. This normally happens if new craters have opened up. The weather is really bad at the eruption site currently so viewing the eruption with any web camera is difficult if not impossible. Rúv web cameras failed last night because of the weather that has been seeing wind peaks up to 41 meter/second with heavy rain. Current weather forecast is that the weather is not going to start improving until late today (Friday 16-April-2021). The increased tremor might be weather but weather is in general easy to filter out and doesn’t affect the lower bands (0.5 – 1Hz) that much as it does higher bands (2 – 4hz). What is happening won’t be clear until the weather starts getting better.

Information about the volcano Krýsuvík.

News and web cameras that might work

Órói auk­ist en aðstæður óljós­ar (mbl.is, Icelandic)
Gosið í Geld­inga­döl­um í beinni (web camera, mbl.is) – The fog cover sometimes breaks a little on this web camera.

Update on Fagradalsfjall mountain eruption on 9-April-2021

This is a short article about the eruption in Fagradalsfjall mountain that is part of Krýsuvík-Trölladyngja volcano system.

This week has been busy and please read the older articles about what happened earlier in this week.

  • Lava output is now 50% more according to University of Iceland measurements compared to start of the eruption (19-March-2021). Gas output is also more then in start of the eruption. It has resulted in problems depending on wind direction.
  • There is a high risk that an eruption might start south of Geldingadalir valley eruption. There is also a high risk that new eruption is going to start north of the 5-April-2021 eruption.
  • There is no change in inflation in the area. It has slowed down but remains the same.
  • There continues to be low level earthquake activity along the dyke from Keili to Fagradalsfjall mountain.

Any change that is going to happen without warning and might not happen without any earthquake or little earthquake activity.

Next update is going to be on 16-April-2021 unless something major happens. This eruption is always changing and this weekend and next week might get interesting. If anything happens I am going to write new article soon as possible.

Update at 22:43 UTC

Icelandic Met Office released this map and press release (in Icelandic only) about the risk new fissures can open up both north and south the the current craters that are erupting. This page is updated regularly so if you are looking at this later than 9 to 10 April 2021 you might have to look for this information.

Map showing marked area that goes little south and north of the current erupting fissures in Fagradalsfjall. That area has been marked as dangerous by Icelandic Met Office. The map also shows the lava fields in purple.
The new area that has a risk of new fissures opening up without warning. Copyright of this image belongs to Icelandic Met Office.

The map shows the area that is now at risk of new fissures opening up without warning.

Update 10-April-2021 at 15:20 UTC

Around 03:14 UTC on 10-April-2021 fissure number 4 did open up between fissure number 2 (5-April-2021) and fissure number 3. The eruption from this crater doesn’t seem to be large but it did happen under a new lava that had flowed over that same area few days before from fissure 2. In fissure/crater 1 the amount of erupting lava did drop a little just before the new eruption.

I am noticing that it seems new fissures are opening up more frequently then before. This seems to have changed after opening up of fissure 3.

Timeline of fissure openings so far.

1st fissure 19-March-2021
2nd fissure opened 5-April-2021
3rd fissure opened 7-April-2021
4th fissure opened 10-April-2021

Time period between new fissures opening up currently seems to be 3 to 4 days. I suspect that this is going to change soon and it is possible that new fissure that opens up might get larger as the eruption goes on. There seems to be phase in this eruption that is happening in Fagradalsfjall mountain. I am not perfectly sure what that phase is now since I’ve never seen this before and I don’t have any data on this type of eruption behaviour from other volcanoes outside of Iceland. That I know of.

Video of the eruption fissure 4 opening up.

Nátt­úr­an er óút­reikn­an­leg og ófyr­ir­sjá­an­leg (mbl.is)


Article updated at 22:48 UTC.

Article updated at 15:39 UTC on 10-April-2021.
Article updated at 15:54 UTC on 10-April-2021.

Update on Fagradalsfjall mountain eruption on 8-April-2021

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

Last 24 hours have been busy in the eruption. Here are highlights of what has happened best to my knowledge.

  • New fissure opened up and started erupting between the Geldingadalir eruption, second day of Easter eruption and the new eruption fissure is between the two.
  • The lava fields have now merged and are now one large lava field from Geldingadalir down to Meradalir valleys.
  • The eruption continues at the same slow rate as before even with several new vents erupting.
  • Morgunblaðið lost their first web camera to the lava flow (news can be found here in Icelandic). Icelandic Met Office had hardware close to the new lava flow. I don’t know if that hardware was saved from the lava flow but it was planned attempt to do so before it was lost to the lava.
  • The fissures might merge at future point and start erupting at one large fissure eruption. It is impossible to know if that is going to happen or when that might happen.
  • There has not been any deflation detected in the GPS data after the eruption started. That GPS data can be viewed here.
  • New fissures have been detected north of the crater that started erupting on 5-April-2021. Those fissure might start erupting without warning.
  • There is a risk of the eruption also going south-west and opening up fissures there. That has not yet happened but the possibility remains as a high risk possibility.

The situation is difficult to predict and new fissures can open up without warning. If nothing major happens then next update is going to be Friday 9-April-2021 on the eruption.

Update on the eruption in Fagradalsfjall mountain on 6-April-2021 (2nd update)

This is a short update and second update for 6-April-2021 for Fagradalsfjall mountain that is part of Krýsuvík-Trölladyngju volcano system.

  • During the night a new fissure was discovered between the new eruption and the old eruption. The fissure is about 150 meters long and there is hot air coming up from it.
  • There are reports of a new fissure north of the new eruption and land has been sinking down at that location. No other changes have been reported at the writing of this article.
  • The lava going down into Meradalir valley slows down once it is there because it cools down quickly once it is there. There is a lava river going down in the Meradalir valley and that lava is moving quickly.
  • It is now estimated that this is a start of a long volcano activity period on Reykjanes peninsula that is going to last for centuries with breaks of 10 to 20 years between active periods of 30 to 50 years.

The situation is currently changes often during the day and the night and the risk of a new eruptions starting without any warning is now extremely high.

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New fissure opens up north-east of current eruption in Geldingadalir valley

This is a short article.

New fissure started to open up at around 11:37 UTC on 5-April-2021 when a magnitude Mw1,5 earthquake (most likely) took place in Fagradalsfjall mountain. The new fissure is expanding and but I am now estimating that the current length of the new fissure is 1,2 km based on Rúv News web camera view. The new fissure is north-east of the earlier eruption in Geldingadalir valley any.

Small eruption fissure that is forming north-east of earlier eruption
The new fissure opening up. Copyright of this image belongs to Rúv. From Rúv web camera.

I’ll post update about this later today when I know more.

Update at 16:29 UTC

The larger fissure is around 300 meters long according to reports. Part of it seems to be under its own lava flow based on what I am seeing on new videos of the fissure. The second fissure is about 10 to 30 meters long. There is also a one single eruption vent in the area just outside of the fissure areas. The lava flow is going into Meradalir below the new fissures. It might soon go into a what seems to be a lake or a dried up lake in that valley that is a lot larger and deeper than Geldingadalir valley that is now full of lava. The eruption in the original craters continues but at lot less energy levels than before. This might only be temporary change but it is impossible to know for sure what is going to happen.

Drone video of the new fissure from Morgunblaðið

Nýtt dróna­mynd­skeið af sprung­unni (mbl.is)

Next update is going to be again in few hours as this situation develops.

Pictures are from Department of Civil Protection and Emergency Management.

Two eruption fissures erupting lava from a the ground and the lava is orange in colour. Lava river goes down hill and into a valley
The eruption from a helicopter as seen today. Picture is from Department of Civil Protection and Emergency Management. Free to use.
River of lava flowing downhill into a valley called Meradalir
The lava river into Meradalir valley. Picture is from Department of Civil Protection and Emergency Management. The pictures is free to use.

Article updated at 16:36 UTC.