Category: Swarm

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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.

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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.

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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.

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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.

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Eruption in Svartsengi volcano, Sundhnúkagígar crater row

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.

A lot of red dots on Reykjanes peninsula because of the eruption in Svartsengi volcano, in Sundhnúkagígar crater row.
Earthquake swarm because of dyke intrusion and eruption in Svartsengi volcano. Copyright of this image belongs to Icelandic Met Office.
A view of the earthquake swarm. Showing the sharp increase of the earthquake around 06:30 UTC.
How the earthquake progressed today in Svartsengi volcano. Copyright of this image belongs to Icelandic Met Office.
Picture showing the eruption south of the defense barrier. Abandoned greenhouse next to the defense barrier. Picture from Rúv web camera.
The lava flow from Rúv web camera on YouTube. Screenshot from Rúv web camera.

This situation is still developing and can change quickly. I’ll post update as needed if anything major happens.

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Earthquake in Krýsuvík-Trölladyngja volcano east of Keilir mountain

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.

Green star just north of lake Kleifarvatn and east of mount Keilir. The map has a lot of smaller dots showing earthquake activity in other areas of Reykjanes peninsula.
The earthquake activity on Reykjanes peninsula. Copyright of this image belongs to Icelandic Met Office.

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.

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Earthquake swarm in Reykjanes volcano

Today (12-March 2025) at 14:29 UTC an earthquake swarm started in Reykjanes volcano. The largest earthquake had a magnitude of Mw3,8. At the writing of this article. This earthquake swarm seems to be ongoing.

Red dots and green stars on Reykjanes peninsula at the edge where it goes out into the ocean. Dots all over Reykjanes showing other earthquake activity.
Earthquake swarm on Reykjanes peninsula in Reykjanes volcano. Copyright of this image belongs to Icelandic Met Office.

This doesn’t look like an magma related earthquake swarm. This seems to be a fracture earthquake and might be connected to stress changes in the crust because of the high inflation in Svartsengi volcano, that is not far away from this location. The earthquake swarm is at a low now, but might increase again with stronger earthquakes without warning. If needed, I’ll post an update on what is happening.

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Strong earthquake swarm in Bárðarbunga volcano

This evening on 22-February 2025 at 21:04 UTC an earthquake with magnitude of Mw5,2 took place in Bárðarbunga volcano. This has been followed by several smaller earthquakes and this earthquake swarm seems to be ongoing.

Green stars and red dots in Bárðarbunga volcano that is located to the west part of this image, not far from the center in Vatnajökull glacier. Other parts of this image show other volcanoes with limited earthquake activity.
Earthquake activity in Bárðarbunga volcano. Copyright of this image belongs to Icelandic Met Office.

This earthquake activity is possibly magma trying to find a path to the surface. If it is going to be successful now is another story. It is possible for the magma to fail this. It is difficult to know how this is going to evolve and progress in Bárðarbunga volcano. However, it is clear that for now, no eruption is imminent.

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Small earthquake swarm in Brennisteinsfjöll volcano

Today (24-January 2025) at 06:06 UTC an earthquake with the magnitude of Mw3,0 took place in Brennisteinsfjöll volcano. This doesn’t seem to have connected to magma movement in this area or volcano. This looks like more like a tension related earthquake. It was probably not related to inflation in Svartsengi volcano.

Green star in Brennisteinsfjöll volcano, that is located on the south and eastern side of Reykjanes peninsula. Few dots next to the green star showing the largest earthquake.
Green star in Brennisteinsfjöll volcano. Copyright of this image belongs to Icelandic Met Office.

There is a risk of stronger earthquakes in this area. Currently there are no signs that this connected to magma movement in this area.