Volcano and earthquake activity in Iceland
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
Today (9. March 2023) an earthquake swarm started in Katla volcano. This earthquake swarm is ongoing and information in this article can go outdated quickly. Largest earthquakes at the writing of this article have a magnitude of Mw3,3 and Mw3,4. A swarm of smaller earthquakes is ongoing.
It is difficult to know for sure what is going on in Katla volcano. But this activity reminds me of what happened few years ago before an small eruption took place in Katla volcano. If that is going to happen now I don’t know. I’ll post information when I know more and if anything more happens in Katla volcano.
Yesterday (5. March 2023) at 18:00 UTC an earthquake with magnitude Mw3,4 took place north of Herðubreið mountain. This is a small earthquake swarm and is part of an ongoing earthquake swarm in this area that has been going on since October 2022 (or in around that month).
Depth of this earthquake was only 4,2 km and earthquake activity in this area has been getting shallower with time. If this is magma, then there’s not a lot of it at this depth. Earthquake activity is small compared to the earthquake swarms that happen just before an eruption. It is clear that, if this is magma, it is not pushing its way up the surface at this point in time.
Since May 2011 there has been an earthquake activity in mountain called Saftafellsfjöll. This is slightly north of Öræfajökull volcano and south of Grímsfjall volcano. This earthquake activity is now permanent in this area it seems. Some of it might be glacier quakes, but most of the earthquake activity there is not, because of the depth this earthquake activity is happening at.
I don’t know for sure what is going on. This earthquake activity clearly shows that something is going on in this part of Vatnajökull glacier. It is my unverified opinion that there is a volcano there. Its not documented and map only show a extinct volcano in this area. This is unlikely to be earthquake activity in extinct volcano, its not impossible, what makes this unlikely is that this earthquake activity happens regularly and has been going on since May 2011. There is ice quake activity in this same area, but some of this earthquake activity is both deep and being located in areas with no glacier. If those are not measuring errors or something like that (I find that unlikely in many cases). I don’t think there’s going to be an eruption in this area, at least not for a long time if it ever happens. This earthquake activity might have been going on for a lot longer then from May 2011.
– This is not an registered or confirmed volcano in this area. Unless there’s an eruption, it might be a long time until a confirmation happens.