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.
It has just been reported that (today 14. April 2023) that there is now a high levels of Hydrogen sulfide (H2S) close to Múlakvísl glacier river that comes from Mýrdalsjökull glacier, that is on top of Katla volcano. Tourists have been asked to be careful in the area. Currently the conductivity in Múlakvísl is not high, but according to Icelandic Met Office that is expected to change in next few hours.
Earthquake activity in Katla volcano at the moment is at normal background levels, that might change without warning if there is anything more happening with this sudden increase in gas levels. The gas levels changed early morning on 13. April 2023 according to Icelandic Met Office website.
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.
Today (19. March 2023) at 14:59 UTC an earthquake with magnitude of Mw3,1 took place in Bárðarbunga volcano. This is normal earthquake activity and shows the inflation that is happening in Bárðarbunga volcano is ongoing after the end of the eruption in 2015.
This type of earthquake activity happens once to twice a month with a earthquake close to magnitude five happening every three to four months. This earthquake activity is getting lower with time, it is likely that it is going to take few more years until it completely stops.
Since end of February 2023 there have been slowly growing signs in form of a small earthquake activity in Fagradalsfjall volcano and nearby area. It is impossible to know when next eruption starts in Fagradalsfjall volcano, but last time the quiet time was around 10 months. If it is going to be shorter or longer now is impossible to know.
Currently the earthquake activity is minor, but that can change quickly and without much warning. At the writing of this article, its been 6 months and 24 days since the eruption in Meradalir valley ended. I don’t know if this is going to happen the same was as it did before last eruption. Since there’s a lot of magma at depth of 5 to 10 km now and that changes how everything functions and behaves in the crust.
Yesterday (14. March 2023) at 20:43 UTC an magnitude Mw3,0 earthquake took place in Askja volcano. This is just one of smaller earthquakes in Askja volcano. There have been almost no earthquake activity following the inflation in Askja volcano in recent months. Suggesting to me (this is my personal opinion) that this inflation is not going to result in a eruption. Deflation might start in few months or years time, if it starts at all. Why this happens the way it does is unknown to me.
It is my personal view that earthquake activity in Askja volcano is going remain low and even vanish for a time. I don’t think anything is going to happen this time around. I am however known to get this wrong, because nobody can be sure what happens next 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.