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.