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 Some information might be out of date without me knowing about it.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.

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.

Earthquake swarm in South Seismic Zone (SISZ)

This morning (7-July 2025) at 04:38 UTC an earthquake with magnitude of Mw3,4 took place in SISZ, close to a location called Árnes. More then a dozen smaller earthquakes followed the largest earthquake. There are no reports that this earthquake was felt, but its not impossible in the summer houses that are in this area.

Green star showing the largest and yellow dots showing smaller earthquakes.
Green star in the SISZ following the minor earthquake swarm. Copyright of this image belongs to Icelandic Met Office.

I don’t think this earthquake swarm is a sign of a large earthquake happening in SISZ. Since those often happen without much warning. This earthquake swarm has now stopped.

Earthquake swarm in Krýsuvík volcano

Yesterday (18-June 2025) a small earthquake swarm started in Krýsuvík volcano. The largest earthquake had a magnitude of Mw3,4 and was felt in Reykjavík and nearby area.

Green star just west of Kleifarvatn lake in Krýsuvík volcano. A lot of dots show smaller earthquakes in this area.
The earthquake swarm in Krýsuvík volcano. Copyright of this image belongs to Icelandic Met Office.

This earthquake swarm is possibly because of the inflation in Svartsengi volcano. More earthquake activity might happen in this area because of that inflation in next few weeks.

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.

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.

Minor earthquake swarm in Hrómundartindi volcano

During the night of 26-May 2025 at 02:31 UTC an earthquake with magnitude of Mw3,3 took place in Hrómundartindi volcano. This earthquake was felt in Hveragerði town. Few smaller earthquakes followed the largest earthquake.

Green star north-west of Hveragerði town. With few yellow dots showing smaller earthquakes.
The earthquake activity in Hrómundartindur volcano. Copyright of this image belongs to Icelandic Met Office.

Earthquake activity happens in this area regularly and there is nothing suggesting that his earthquake activity is because of magma movement in the area.

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.

Renewed activity in the earthquake swarm east of Grímsey island

Today (14-May 2025) at 05:20 UTC an earthquake with the magnitude of Mw4,9 to Mw5,0 (Icelandic Met Office). EMSC is reporting this earthquake at Mw4,6 (information here). This earthquake was felt in Grímsey and south to Akureyri town.

Many green stars and red dots showing the strong earthquake swarm east of Grímsey island.
The earthquake swarm east of Grímsey island. Copyright of this image belongs to Icelandic Met Office.

This earthquake swarm has been showing signs of happening in waves, with quiet or lower activity between them. What that means is unclear. More strong activity might happen in next few hours or next few weeks. This earthquake swarm might also just stop suddenly, as happens frequently in this area. I am not seeing any signs of magma movement in this area.

Earthquake swarm in Tjörnes Fracture Zone

This morning on 13. May 2025 at 04:02 UTC an magnitude Mw4,7 earthquake took place in Tjörnes Fracture Zone just east of Grímsey island. This earthquake was felt in Grímsey and woke people up there. It was also felt in parts of north Iceland. Total of seven earthquakes with magnitude Mw3,0 or larger have taken place in this area during this earthquake swarm.

Green stars and a lot of red and orange dots showing the earthquake activity east of Grímsey island.
Earthquake swarm east of Grímsey island. Copyright of this image belongs to Icelandic Met Office.

This earthquake swarm is ongoing at the writing of this article. It has been slowing down, there is a chance activity might increase again, but it is difficult to be sure. Often earthquake activity in this area just stops over time period of few days.