Volcano and earthquake activity in Iceland
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.
Earthquake activity happens in this area regularly and there is nothing suggesting that his earthquake activity is because of magma movement in the area.
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.
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.
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.
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.
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.
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.
Yesterday (10-May 2025) at 09:36 UTC an earthquake swarm started in Herðubreið mountain. This earthquake swarm started with a magnitude Mw3,1 earthquake and was followed by a swarm of smaller earthquakes.
This are tectonic earthquakes and there is no sign of magma activity in this area. Earthquake activity is often frequent around Herðubreið, but often with long quiet periods.
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.
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.
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.
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.
This morning around 06:30 a dyke intrusion started in Svartsengi volcano with a strong earthquake swarm. An eruption started at around 09:50 UTC. This eruption is happening only in the area south of the area that erupted on 21. November 2024. A dyke formed in this even and is around 11 km long. This dyke might get longer and is possibly getting longer at the writing of this article.
This situation is still developing and can change quickly. I’ll post update as needed if anything major happens.
During the last few weeks there has been slow increase in deep earthquakes in Eyjafjallajökull volcano. This is unusual because it erupted in the year 2010 and in general only erupts every 290 to 700 years, based on current data into the eruption history of Eyjafjallajökull volcano.
Depth of the earthquakes that have so far happened is around 24 to 26 km of those have been reviewed by Icelandic Met Office. Before the eruption in Eyjafjallajökull volcano in the year 2010 it took around 10 years from start of deep earthquakes until an eruption took place. This might just be deep earthquake activity that might not result in a eruption in next few decades. At the moment this earthquake activity is too small and too few earthquakes to know for sure what is going on.
Today (26-Mars 2025) at 15:06 UTC an earthquake with magnitude of Mw3,2 took place in Krýsuvík-Trölladyngja volcano, just east of Keilir mountain. There has not been a lot of aftershock activity following this earthquake.
This earthquake activity is possibly because of inflation in Svartsengi volcano. Since that results in stress changes along the Reykjanes peninsula, but mostly in the area closest to it. More earthquake activity can happen without warning in this part of Reykjanes peninsula.