Category: Magma

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Strong earthquake swarm in Katla volcano

This morning on 20-October 2025 an strong earthquake swarm started in Katla volcano. Strongest earthquake so far had a magnitude of Mw4,5. It was most likely felt in nearby populated areas. Several earthquakes with magnitude above Mw3,0 also took place. This earthquake swarm is ongoing, but it happens in waves and at the writing of this article there is a quiet period happening.

Red dots showing smaller earthquakes in Katla volcano. Green stars showing stronger activity in Katla volcano caldera.
Earthquake activity in Katla volcano. Copyright of this image belongs to Icelandic Met Office.

At the moment there has not been any signs of magma movement. That might change without warning. There also not been any change in glacier water from Mýrdalsjökull glacier. That only show up after 4 to 8 hours, since it takes time for the glacier water to travel to the glacier rivers from Mýrdalsjökull glacier. If anything more important happens. I’ll post a new update on what is going on.

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Strong earthquake in Hamarinn volcano

Today (18. September 2025) at 00:04 UTC an earthquake with the magnitude of Mw3,6 took place in Hamarinn volcano, that is south of Bárðarbunga volcano.A small aftershock took place soon after the largest earthquake. There are no signs that an eruption is about to happen. Last year this area also had an earthquake, but a bit smaller one.

Green star in Hamarinn volcano, south of Bárðarbunga volcano on Vatnajökull glacier.
Earthquake in Hamarinn volcano. South of Bárðarbunga volcano. Copyright of this image belongs to Icelandic Met Office.

It is difficult to know if any more earthquakes are going to happen in this area. At the moment that is unlikely.

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Strong earthquake in Bárðarbunga volcano on 27-July 2025

On the 27-July 2025 at 23:39 UTC an earthquake with magnitude of Mw5,2 took place in Bárðarbunga volcano. A second earthquake with magnitude of Mw3,1 took place at 23:41 UTC. That second earthquake is embedded into the first earthquake and that makes it impossible to see it in earthquake data without good analyse. The largest earthquake was felt in Akureyri, far north of Bárðarbunga volcano.

Two green stars in Bárðarbunga volcano. The northern green star is the larger earthquake with magnitude of Mw5.2.
The earthquake activity in Bárðarbunga volcano. Copyright of this image belongs to Icelandic Office.

This is normal earthquake activity as Bárðarbunga volcano continues to inflate. This large earthquake happen every few month in Bárðarbunga volcano.

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Update on the eruption in Sundhnúkagígar in Svartsengi volcano at 17th July 2025 at 00:43 UTC

This is a summary update with best information I have at the moment. Some information might be out of date without me knowing about it.

  • The eruption fissure reached 2,5 km when it was at the longest length. It has started to get smaller as the eruption has dropped in intensity over the last few hours.
  • This is the most northern eruption in Svartsengi volcano so far.
  • The lava flow is towards Fagradalsfjall volcano and into Fagradals valley and is now filling up, if it has not done so already.
  • Harmonic tremor looks stable at the writing of this article. This can change quickly and without warning.
  • Early GPS data suggest that deflation of Svartsengi volcano is around 100mm for the last 12 hours where it is most. Depending on the GPS station location in the volcano system.
  • Earthquake activity has stopped or almost stopped in the area.
  • I don’t expect this eruption to last more than few days. However eruptions in this area sometimes continue in one crater at very low volume for a several weeks. At current time its impossible to know if that happens.
  • Fog is currently blocking all view of the eruption. So its impossible for me to know what is happening visually.
  • Gas pollution has been a problem in this eruption and wind direction. This might not improve until the eruption ends.

If there is anything more to report. I’ll post update here about it. I don’t expect there is going to be any need for any future update at the writing of this article.

Updated at 00:59 UTC on 17th of July with missing information.

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Eruption has started in Sundhnúkagígaröðinni in Svartsengi volcano

Today (16-July 2025) at 03:53:31 UTC an eruption started in Svartsengi volcano in Sundhnúkagígaröðinni crater row. This is the most northern part of the eruption area. Far from anything important. The eruption fissure doesn’t look large based on what can be seen on web cameras.

The eruption as seen on the web camera Þorbjörn. The lava strokes are clearly visible and are orange red in colour.
The eruption in Sundhnúkagígaröðinni in Svartsengi volcano. Screenshot from Rúv web camera on YouTube.

It is impossible to know how long this eruption is going to last. It might be few hours and up to few days. If needed. I’ll post updates about the eruption. Normally in this type of eruption that is not required.

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Strongest earthquake in Ljósufjöll volcano system so far

Yesterday (16-June 2025) at 18:05 UTC an earthquake with magnitude of Mw3,7 took place in Ljósufjöll volcano system at the depth of 18 km. It was felt in nearby area that does not have any dense population.

Green star showing the earthquake in the mountain area of Ljósufjöll volcano system in western part of Iceland. Just north of Borgarnes town.
The earthquake activity in Ljósufjöll volcano system. Copyright of this image belongs to Icelandic Met Office.

This earthquake activity continues to happen because of magma inflow into the crust at this location. Since the inflow of magma started at this location, the magma has not moved up into the crust that can be noticed. Resulting in pressure building up at the lower end of the crust in this part of Iceland. The crust in this area is not giving into the pressure from the magma easily and this crust is also old, dense and brittle. Making it much more difficult for any magma to move to the surface.

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Deep earthquake activity continues in Eyjafjallajökull volcano

Deep earthquake activity continues in Eyjafjallajökull volcano. In recent weeks however the earthquake activity has been getting shallower. Going from 29 km depth and up to 24 km depth.

Orange and red dots showing the smaller earthquakes in Eyjafjallajökull volcano. That is located west of Mýrdalsjökull glacier.
Earthquake activity in Eyjafjallajökull volcano. Copyright of this image belongs to Icelandic Met Office.

This activity is far away from any eruption happening again in Eyjafjallajökull volcano. This however is an interesting development. Since this is happening only 15 years after the eruption in Eyjafjallajökull volcano.

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Strong earthquake swarm close to Eldey and Geirfugladrangur island on Reykjanes ridge

Today (24. May 2025) there has been a strong earthquake swarm. Largest earthquake in this swarm so far had a magnitude of Mw5,1. It was felt over a wide area in south Iceland. Over 40 earthquakes with magnitude Mw3,0 or larger have taken place in last few hours.

A lot of green stars and red dots on Reykjanes ridge out in the ocean. This shows the earthquake swarm just off the coast of Iceland.
The earthquake swarm on Reykjanes ridge. Copyright of this image belongs to Icelandic Met Office.

At the writing of this article. The earthquake swarm is ongoing but seems to be slowing down at the writing of this article. Earthquake activity in this area can increase again suddenly. Icelandic Met Office says this earthquake swarm is because of tectonic movement. In my personal view there is a chance magma might be the reason for this earthquake swarm. The exact reason for this earthquake swarm is unclear at the writing of this article. That might change if this earthquake activity increases again.

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Magnitude Mw4,8 to Mw5,3 earthquake in Bárðarbunga volcano

Today (5-May 2025) at 21:14 UTC an earthquake with magnitude of Mw4,8 to Mw5,3 took place in Bárðarbunga volcano. The difference in magnitude is between Icelandic Met Office (Mw4,8), EMSC (Mw5,1) and USGS (Mw5,3). I do not know why this difference is.

Two green stars and red dots showing the earthquake activity in Bárðarbunga volcano in last few hours.
Green stars and red dots show the earthquake activity in Bárðarbunga volcano. Copyright of this image belongs of Icelandic Met Office.

This earthquake activity is because if inflation of Bárðarbunga volcano that has been going on since the eruption ended in Bárðarbunga volcano on 27-February 2015. This type of earthquake activity should be expected every few months in Bárðarbunga volcano.

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Strong earthquakes in Reykjanes volcano

Around 17:00 UTC today (01-April 2025) an earthquake with magnitude of Mw5,3 took place in Reykjanes volcano. This might not be earthquakes because of tension changes in the crust in this area. It is a possibility, but at the moment what is going on is unclear.

A lot of green stars showing large earthquakes in Reykjanes volcano along with all earthquake activity in Svartengi volcano.
Earthquake activity in Reykjanes volcano. Copyright of this image belongs to Icelandic Met Office.

If the earthquake activity in the Reykjanes volcano are not tension earthquakes an eruption might stat out in the ocean. That would be explosive eruption. It is too early to know if that is the case. But next few hours should show if that is the case or not. Earthquake activity is ongoing and the this situation can change quickly and without warning.