Earthquake swarm in Hengill volcano

Sorry for the late article. I’ve been dealing with technical problems in my mobile phone all day and delayed a lot of things for me.

Yesterday (29-April-2021) an earthquake swarm started in Hengill volcano. This earthquake swarm appears to be tectonic in nature. Largest earthquake in this swarm had a magnitude of Mw3,8 and was felt in Reykjavík.

Far left on image is a green star that shows the earthquake activity in Hengill volcano
Earthquake swarm in Hengill volcano. Copyright of this image belongs to Icelandic Met Office.

This earthquake activity looks tectonic in nature and there are no signs that the reason for this earthquake swarm is anything but tectonic stress adjustments for now. I always expect more and stronger earthquakes swarm when cold volcanoes (not erupted for a long time) starts to get warm as was the case before the eruption in Fagradalsfjall mountain when up to 50.000 earthquakes took place from 27th February until 19th March when the eruption started.

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.

Earthquake swarm in Krýsuvík volcano (currently erupting in Fagradalsfjall mountain)

Yesterday (24-April-2021) an earthquake swarm took place in Krýsuvík volcano close to Kleifarvatn lake. The largest earthquake had a magnitude of Mw3,1 and the second largest earthquake had a magnitude of Mw3,0. Both earthquakes where felt in Reykjavík area and other nearby areas. This activity is closer to Reykjavík then earlier earthquake swarms.

Earthquake activity close to Kleifarvatn lake east of the eruption in Fagradalsfjall mountain
The earthquake swarm close to Kleifarvatn lake. Copyright of this image belongs to Icelandic Met Office.

This earthquake activity is not connected to the eruption in Fagradalsfjall mountain. That however doesn’t rule out that magma might be the reason why this earthquake activity is happening. Currently the earthquake activity is too low for this to be a start of a second eruption. It is impossible to know if this is going to develop into anything more serious at the writing of this article. There needs to be a lot more earthquake activity in this location before an eruption starts, even if an eruption might not start with a lot of earthquake activity as was seen when the eruption in Fagradalsfjall mountain started. This is based on assumptions that might be wrong but only time is going to show what happens in this area.

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.

Strong earthquake in Reykjanes volcano 5 km north of Grindavík town

Yesterday (20-April-2021) at 23:05 UTC an earthquake with magnitude Mw4,1 took place and was felt over a wide area and in Reykjavík. At 21:20 UTC and earthquake with magnitude of Mw3,1 took place and at 23:29 UTC an earthquake with magnitude of Mw3,2 took place. Earthquake activity has continued today with smaller earthquakes and several earthquakes with magnitude above Mw2,0.

Green star on the Reykjanes peninsula not far from Grindavík town
Earthquake activity in Reykjanes volcano not far from Grindavík town.

This earthquake took place in the volcano Reykjanes based on location on the map. The map is slight unclear on the location of the Reykjanes volcano and what volcano is exactly there but this is based on best possible assumption that I can do. More earthquake activity in this area or close to it is a high possibility.

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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.

More earthquakes far north of Kolbeinsey island

This morning (15-April-2021) more earthquakes where recorded far north of Kolbeinsey island. This activity is probably outside of Kolbeinsey ridge but I don’t know the name for this part of the north Atlantic ride. Largest earthquake took place at 09:29 UTC and had a magnitude of mb4,4 according to EMSC. Information about the earthquake can be found here.

Green stars out in the ocean where strong earthquake activity is happening
Earthquake activity far north of Kolbeinsey island. Copyright of this image belongs to Icelandic Met Office.

It is not possible to know what is going on at this location. It is extremely remote and under 2 to 4 km deep ocean. If anything more happens at this location it is only going to be detected by seismometers.