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.

Earthquake swarm in Herðubreið mountain

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.

Green star and few orange dots showing the earthquakes in Herðubreið mountain. The green star shows the largest earthquake.
Earthquake activity in Herðubreið mountain. Copyright of this image belongs to Icelandic Met Office.

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.

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.