Strong earthquake swarm in Katla volcano

This morning there was a strong earthquake swarm in Katla volcano. At the writing of this article the largest earthquake had a magnitude of Mw4,8 and the second largest earthquake had a magnitude of Mw4,7, the third largest earthquake had a magnitude of Mw4,5. This earthquakes where felt in nearby farms and towns close to Katla volcano. Currently, a lot of smaller earthquakes have happened in Katla volcano.

Red dots and green stars in Katla volcano caldera showing the main earthquake activity.
Earthquake activity in Katla volcano. Copyright of this image belongs to Icelandic Met Office.

There are no changes in harmonic tremor levels at the writing of this article. That makes an eruption unlikely to happen now. That might change later without warning. The air aviation code has been moved to yellow and can be viewed here.

I’ll write a new article if something more happens.

Earthquake swarm north of Grindavík town, next to Blue Lagoon

This morning (25. April 2023) an earthquake swarm started north of Grindavík town, next to the Blue Lagoon. This earthquake swarm is ongoing at the writing of this article. If this is going to result in a eruption is impossible to know. The magma has reached the depth of 2 km and that is not good news if this continues to intensify. Large earthquakes do not need to happen before an eruption starts under the correct conditions in the curst and there has been a lot of dyke activity in Reykjanes volcano in last 3 years. Without that activity resulting in a eruption.

Red dots north of Grindavík town and next to the Blue lagoon on the map (the lagoon doesn't appear on the map). Time on map 25. Apr. 14:00.
Earthquake activity north of Grindavík town. Copyright of this image belongs to Icelandic Met Office.

Eruption at this location would be bad, because of the tourist infrastructure next to this location that is the Blue Lagoon. Only thing that can be done now is to monitor the situation and see if it changes from what is currently happening.

It is possible to view the earthquake swarm in high resolution on Skjálfta-Lísa and other private websites that have similar maps.

Earthquake swarm in Grímsfjall volcano

Today (23. April 2023) at 15:!5 UTC an earthquake swarm took place in Grímsfjall volcano. Largest earthquake in this swarm had a magnitude of Mw3,3. Few other smaller earthquakes also took place.

Green star and red dots under it in Grímsfjall volcano. Also in this image is the earlier earthquake in Bárðarbunga volcano, shown with a green star.
Earthquake activity in Grímsfjall volcano. Copyright of this image belongs to Icelandic Met Office.

There are no signs that Grímsfjall volcano is about erupt following this earthquake swarm. That might change without warning, but seems unlikely to happen at the moment. More earthquakes might happen in next few hours.

Earthquake swarm west of Grímsey island

Today (18. April 2023) at 07:59 UTC an earthquake swarm started west of Grímsey island. The distance is around 36 km west of Grímsey island. Largest earthquake in this swarm had a magnitude of Mw4,2 and was felt in Siglufjörður and Akureyri towns.

Green star, red dots and orange dots west of Grímsey island. This shows the earthquake activity in this area. Dots also across north eastern Iceland as smaller earthquakes also happen there. Time on map is 18. apr. 23. 14:05 (Icelandic time).
Earthquake swarm west of Grímsey island. Copyright of this image belongs to Icelandic Met Office.

At the writing of this article, this earthquake swarm is ongoing and there’s a risk of stronger earthquakes in this area. This area last had a major earthquake swarm in June 2020. With largest earthquake in that swarm having a magnitude of Mw5,8.

Small earthquake swarm in south part of Brennisteinsfjöll volcano

Today (13. April 2023) there has been a small earthquake swarm in south part of Brennisteinfjöll volcano. This location had an earthquake swarm few weeks ago at this same location. It also was small in magnitude. Depth of this earthquake swarm has now decreased from 7 km to around 3 km. At least that is what it seems, based on the current earthquake data.

Red dots in south of Brennisteinsfjöll volcano showing the minor earthquake activity now taking place in this volcano. Nearby volcano also have minor earthquake activity, shown in orange to red dots.
Earthquake activity in Brennisteinsfjöll volcano. Copyright of this image belongs to Icelandic Met Office.

This earthquake activity shows a sign of magma movement. It is my opinion that the magma is now pushing it self trough the crust at this location. That can take a while, up to several weeks before an eruption starts. I did see something similar happen before the Bárðarbunga volcano eruption in 2014. That process took good three months before the eruption and was marked by small earthquake swarm like this one. How long this is going to take is impossible to know, because what type of crust is at this location is not well understood (outside of types of rock it is made out of at the first top layers). This is in my view an earthquake activity that needs to be monitored, because of possible eruption risk at this location. This is directly north of a small lake south of the earthquake swarm. If an eruption happens and the lava flows into the lake, that might create a lot of problems.

This earthquake swarm can be viewed here in more details. The website is Skjálfta-Lísa and is only in Icelandic.

Earthquake swarm 43 km west of Grímsey island

A minor earthquake swarm took place around 43 km west of Grímsey island. The largest earthquakes in this swarm where not felt because of distance from populated areas. This earthquake swarm took place on a north end of a rift valley that is at this location and goes all the way to Akureyri and little south of Akureyri town. Where it ends is unclear.

Green stars far west of Grímsey island on the map from Icelandic Met Office with the time at 23:00 UTC on 5. April 2023. This earthquake swarm is far north of Akureyri town.
Earthquake swarm on Tjörnes Fracture Zone. Copyright of this image belongs to Icelandic Met Office.

Largest earthquake in this small earthquake swarm had a magnitude of Mw3,5. This area had a large earthquake swarm in June 2020 with the largest earthquake in that swarm reaching magnitude of Mw5,8 that was felt over a large area in north Iceland. Large earthquake swarms happen in this rift valley regularly. I am not sure how often it does happen. More earthquakes in this area might be possible without any warning. Distance from land makes it difficult to record earthquakes at this location if they are small in magnitude.

Earthquake swarm in Fremrinámar volcano

An earthquake swarm in a volcano called Fremrinámar today (30. March 2023). This is the first time I’ve seen an earthquake swarm in this volcano. All earthquakes where small in magnitude and the magnitude range was from Mw0,1 to Mw1,0. Depth was 5,8 km to 9,1 km.

Fremrinámar volcano is located on this image south of Krafla volcano, located close to Mývatn lake in eastern north Iceland. Few orange dots are on the map showing the earthquake activity.
Fremrinámar is located south of Krafla volcano. Copyright of this image belongs to Icelandic Met Office.

This is the first time I’ve seen an earthquake activity in this volcano. I’ve been monitoring earthquake activity for close to 30 years at the writing of this article. Last eruption in Fremrinámar volcano took place around 3200 years ago (1200 BCE according to Global Volcanism Program). There is a second (and I assume newly discovered) volcano north of Fremrinámar volcano and south of Krafla volcano called Heiðarsporðar. That volcano last erupted around 2200 years ago. This earthquake activity doesn’t seems to be in that volcano, but this map on Icelandic Met Office website is not fully up to date it seems. Based on the volcano website Catalogue of Icelandic Volcanoes. This earthquake activity is only mentioned here now, because I’ve never seen an earthquake swarm in this volcano before.

Earthquake swarm in Brennisteinsfjöll volcano (Bláfjöll mountain)

Earlier this week, an swarm of earthquakes started in south of Brennisteinsfjöll volcano, also known as Bláfjöll mountain. This earthquake swarm started on a west to east fault north of a lake called Hlíðarvatn. This earthquake swarm has only been minor earthquakes, with magnitudes in the range of Mw0,0 and up to Mw2,3 but at the writing of this article, nothing above that magnitude. Over the week this earthquake swarm has evolved into a single area that seems to be circular, based on current earthquake activity. This strongly suggests that magma is the reason why this earthquake swarm is happening.

Red dots in south of Brennisteinsfjöll volcano. Showing the earthquake activity in that volcano. Red dots are also visible in Hengill volcano in a unrelated earthquake swarm.
Earthquake activity in Breinnisteinsfjöll volcano. Copyright of this image belongs to Icelandic Met Office.
Dots in different sized showing the earthquake swarm in Brennisteinsfjöll volcano. This is a image from Skjálfta-lísa website from Icelandic Met Office.
Earthquake as they appear on Skjálfta Lísa website from Icelandic Met Office. Screenshot from Icelandic Met Office website Skjálfta Lísa.
Google Earth image of the area where this earthquake swarm is taking place. It shows the road, the Hlíðarvatn lake and other feature in the landscape. Including a old lava flow the west of the current earthquake swarm. The landscape also seems to show older craters at this location, but those are weathered down to almost nothing.
Google Earth image of the area where the earthquake swarm is taking place. Picture is from Google Earth.

At the writing of this article, the earthquake activity is too small to start an eruption. Since this area is cold and the crust is too hard for the magma to flow freely inside it. Current depth of the earthquakes is around 5 to 7 km at the writing of this article and has not changed a lot during the week. While the Skjálfta Lísa image does not show this, it is possible that the earthquake activity has started to spread more east, compared to earlier in the week when this activity started. This earthquake actiivty might stop, as often happens in the early stages of a new eruption cycle in a volcano.

Earthquake activity in western part of Katla volcano

This morning (11. March 2023) at 07:02 UTC an earthquake with magnitude of Mw3,1 took place in western part of Katla volcano. This earthquake happened in Katla volcano caldera rim. The depth was 1,1 km. This was a single earthquake, at the writing of this article.

Green star in the western part of Katla volcano caldera. This is just a one star and one orange dot showing smaller earthquake slightly north of this earthquake.
Earthquake activity in Katla volcano. Copyright of this image belongs to Icelandic Met Office.

Since this earthquake there has not been any new earthquake activity in Katla volcano. I am not sure why that is, but it there’s a chance this earthquake activity might just be over. There has been a lot of frost quakes in last few hours, because of a cold weather happening in Iceland. With freezing going down to -20C in some areas.

Earthquake swarm east of Grímsey island in Tjörnes Fracture Zone

Yesterday (9. March 2023) and today (10. March 2023) an earthquake swarm has been east of Grímsey island. Largest earthquake in this swarm had a magnitude of Mw3,8. There have been around 40 to 60 earthquakes in this swarm. Making this earthquake swarm rather small, compared to many other earthquake swarm that have been at this same location.

Green star east of Grímsey island, in a circle that shows a submarine volcano at the same area. Red dots are in the same area showing smaller earthquakes.
Earthquake activity east of Grímsey island. Copyright of this image belongs to Icelandic Met Office.

This earthquake swarm seems to be ongoing at of the writing of this article. It is impossible to know for sure if an stronger earthquake is going to happen in this area.