Volcano and earthquake activity in Iceland
Yesterday (29. August 2023) at 23:49 an earthquake with magnitude of Mw3,7 took place in Katla volcano. This earthquake was felt on nearby camping sites and farms according to a news report. Few smaller earthquakes took place following the largest earthquake.
Nothing more happened following this earthquake, as has been the case for the last few earthquake swarms in Katla volcano. More earthquake activity can start in Katla volcano without warning.
During the night of 26. August 2023 an dyke intrusion started in Brennisteinsfjöll volcano. This was in the form of many small earthquakes, most of them did not reach magnitude Mw1,0. What gives this away as an dyke intrusion is the fact the deepest earthquake in this swarm had a depth of 21,1 km. There was interestingly, a lot of surface earthquakes. I am not sure on why that is.
There’s no risk of eruption at the moment from Brennisteinsfjöll volcano. Earthquake activity is too low and this process is clearly not far along now for an eruption too happen. That might change without much warning at some point.
Yesterday (13. August 2023) an large earthquake swarm took place close to Geirfugladrangur (small rock island, population birds) on the Reykjanes ridge. The largest earthquake had a magnitude of Mw4,5 and was felt to Akranes town and possibly in other nearby towns on Reykjanes peninsula. There where not many reports about this earthquake being felt. Something above 400 earthquakes took place during the most active phase of this earthquake swarm.
This earthquake swarm seems to be ongoing. It is at the moment, at much slower rate than before. There are clues that suggest this might have been a earthquake activity connected to magma movements in this area. Its difficult to be sure, because this area is under the ocean and measuring what is going on gets more difficult as future away from land activity happens. Eruption at this distance is going to appear on the Icelandic Met Office SIL network.
Yesterday (12. August 2023) an small earthquake swarm took place in Hofsjökull volcano. Largest earthquake had a magnitude of Mw3,0 and the second largest earthquake had a magnitude of Mw2,5. The area is remote and there are no reports of this earthquakes being felt.
According to Morgunblaðið news there where report of smelling gas after this earthquake activity. There is a risk of gas pockets around Hofsjökull volcano, probably mostly to the north in the area closest to the earthquake area.
I don’t have any other information about Hofsjökull volcano. Because it last erupted more than 12.000 years ago. At most there might have been smaller eruptions that resulted in lava flows sometimes in the last 12.000 years. I don’t expect an eruption now, this earthquake activity might signal a long term change in Hofsjökull volcano. How long that is going to be is anyone guess. It might be in the next 100 to 500 years or maybe never. Hofsjökull volcano is on its own rift zone that is slowly dying off. Along with Kerlingafjöll volcano to the south of Hofsjökull volcano. This are the only two (?) active volcanoes on this old dying rift zone (its around 5 to 10 million years old).
Today (30. July 2023) an earthquake swarm took place in Torfajökull volcano. This volcano is located north of Katla volcano (Mýrdalsjökull glacier). This area has had regular earthquake swarms over the year. Why is not clear. There is no clear signal of magma movement in this area. Torfajökull erupts highly Felsic magma that’s mostly explosive and some type of magma that can flow as a lava flow (maybe in later stage of an eruption, I don’t know for sure).
The largest earthquake in this swarm had a magnitude of Mw3,2. It was felt in nearby tourist areas and caused few rock slides. Icelandic Met Office is still warning against rock slides because of this earthquakes close to the earthquake swarm location. There is a ongoing risk of more stronger earthquakes in this area of the volcano at the writing of this article.
Yesterday (28. July 2023) at 23:42 UTC and 23:55 UTC two earthquakes with magnitude of Mw3,2 and Mw3,6 took place in Bárðarbunga volcano. EMSC is reporting the earthquake at 23:55 as Mw4,7 and that information can be found here.
There where few smaller earthquakes following this larger earthquakes. This is normal inflation activity in Bárðarbunga volcano and this is going to continue for next 30 to 70 years (based on earlier history).
Yesterday (23. July 2023) at 23:17 UTC an earthquake with magnitude of Mw3,5 took place in Katla volcano. This earthquake was felt to Hvolsvellir town in south Iceland.
No other earthquake or activity took place following this earthquake. Katla volcano remains quiet at the writing of this article.
Since 14. July 2023 there has been a minor earthquake swarm close to Skjaldbreið lava shield just south of Presthnjúkur volcano. Largest earthquake took place yesterday (20. July 2023), with a magnitude of Mw3,0.
This is tectonic earthquake swarm and its just normal activity. Its not connected to eruption in Fagradalsfjall mountain, because its outside of that area influence. This earthquake swarm is ongoing at the writing of this article.
This article is short. The eruption is mostly stable at the writing of this article but the situation can change quickly without warning.
It is impossible to know how long this eruption is going to last. Since dyke intrusions are poor magma containers this eruption might be a short one if there isn’t a constant supply of fresh magma from the deep mantle. Its too early to know if that is the case here. I have also noticed that once the eruption ends in any area, that area is not going to erupt again. When the eruption ends, it ends forever and that makes this a single eruption activity or crater rows. This area might be Monogenetic volcanic field (Wikipedia).
Since this type of eruptions are mostly uneventful and just continue. I plan on only posting updates when there are some news or changes to the eruption happen.
Update at 17:41 UTC
ISOR is reporting that their station called FAF (Fagradalsfjall) has to be moved because the lava is flowing directly at it. They are going to find a new location for this station. This report can be seen here on Facebook in Icelandic.
This is a short update because events are changing quickly.
I’ll post new update soon as I have any new information or if anything changes. Experience has shown that this type of eruptions are rather uneventful for a longer time periods. I’ll adjust my updates in accordance with that.