Volcano and earthquake activity in Iceland
Yesterday (19-November-2022) at 21:13 UTC an earthquake swarm started in Katla volcano. This was a small earthquake swarm with just few earthquakes, but it had an earthquake with magnitude of Mw3,2 taking place at 21:13:05. Just before and after this earthquake fewer smaller earthquakes took place.
Since this earthquake activity stopped, everything has been quiet in Katla volcano.
This started on Monday (14-November-2022) with an earthquake of magnitude Mw2,0 at 25,6km depth. This depth is as deep as the crust goes in this location of Iceland. This earthquake activity has been followed by two micro-earthquakes of magnitude of Mw0,5 and Mw0,6 at 11,5 km depth.
There are no clear or obvious signs that Hekla volcano is about to do anything. But this deep earthquake activity suggests magma movements at depth or pressure changes maybe. This is clearly not a big activity and at the writing of this article I don’t expect anything to happen.
Early morning today (10-November-2022) an swarm of earthquakes took place slightly north of the place where the eruption in August 2022 took place in Fagradalsfjall volcano. This possible dyke intrusion was small and only lasted for about 1 hour before it stopped. Depth of the earthquakes was from 5 km to 7 km.
This activity might give a clue on in what area next eruption is going to take place in Fagradalsfjall mountain. Based on earlier eruption there won’t be any warning before an eruption earthquake swarm starts. In August that eruption started with a minor earthquake swarm, created from a dyke intrusion that was happening. In the hours before an eruption starts there’s going to be a strong earthquake swarm, based on what happened just before the eruption in August. It is interesting if the eruption activity moves north-east, rather than south-west. Why that happens, if it does so, is not something I am clear on why happens.
Sometime yesterday (24-October-2022) a change happened in the earthquake swarm close to Herðubreið mountain. I am not sure when that change happened and it probably took few hours to happen before I detected it. But the change seems to be that now the earthquake swarm is at two locations and not just one. The second change is that the earthquake swarm is now getting more intense. The earthquakes at the writing of this article are minor, only magnitude Mw0,0 to Mw2,7 at the strongest. Nothing above Mw3,0 so far, but that might change without warning. Depth of this earthquake swarm is around 2 to 3 km at the writing of this article.
What is going to happen next is impossible to know. An eruption in this area has not happened for at least 12.000 years or even longer. I don’t know if stronger earthquake activity is required for this area for an eruption to happen. It already is rather fractured from older earthquake activity and rift activity, that makes it possible for magma to have easier paths to the surface without much earthquake activity. That is at least one idea on the situation in this area. I might be wrong on this, since I don’t have information on the finer details of the crust around Herðubreið mountain.
This earthquake activity is ongoing at the writing of this article.
I normally don’t write article this late unless I think it is important.
This earthquake activity in Katla volcano seems to be at that nature that it is worth writing a short article about it this late. At 00:46 UTC an earthquake with magnitude of Mw3,6 (this is early reviewed earthquake magnitude, it might change when reviewed later tomorrow at Icelandic Met Office). Few smaller earthquakes have happened following this earthquake. Currently the earthquake activity is slow and it is possible that nothing more might happen.
I don’t know if this is a sign of an eruption that is going to happen or if this is just an earthquake activity that happens regularly in Katla volcano. There are now 104 years since last major eruption in Katla volcano and the situation is unclear on what is going on. If anything more happens I am going to write an update tomorrow. There’s a good chance nothing more might happen, but it is worth keeping a watch out for this if anything changes suddenly.
This morning on 23-October-2022 an earthquake swarm took place in west part of Fagradalsfjall volcano. Largest earthquake in this swarm so far had a magnitude of Mw3,0.
This earthquake activity is the result of magma pushing up into the crust at around 5 km depth. This is not a large dyke intrusion and possibly won’t result in a eruption, unless there’s a sharp increase in earthquake activity and that has happened (the August 2022 eruption started this way). This is currently a situation that requires monitoring for changes. If anything is going to happen is impossible to know.
During the night of 23-October-2022 an earthquake swarm started north of Herðubreið mountain. This looks like a tectonic earthquake swarm, rather then a magma related activity. At the writing of this article, over 500 earthquakes have been recorded.
Largest earthquake at the writing of this article had a magnitude Mw4,0 and one magnitude Mw3,1 earthquake took place. Second largest earthquake had a magnitude of Mw3,3. This earthquake swarm is ongoing at the writing of this article and there’s still a risk of larger earthquakes happening north of Herðubreið mountain. The largest earthquake was felt in Akureyri according to news reports.
A fissure has opened up in south part of Grímsfjall volcano without erupting at this moment. Pictures show that there’s a lot of hydrothermal activity in this fissure. I can see by the Facebook post (link below) that this is a new fissure in a location that it didn’t exist before. Based on recent history, this strongly suggests that this is the area where next eruption is going to happen in Grímsfjall volcano. When and how big such eruption is going to be is impossible to know. This fissure is located around Lat: 64° 24′ 13,476″ N Lon: 17° 13′ 57,282″ W. It possibly is growing and has made holes in the glacier large enough to swallow large cars.
The Facebook post with pictures can be found here. But you might need a Facebook account to view the pictures. I can’t add them here because of copyright.
Today (21-October-2022) an earthquake swarm took place in Brennisteinsfjöll volcano. Largest earthquake had a magnitude of Mw3,0 at 10:23 UTC. This earthquake swarm is possibly over, it is however difficult to be sure.
This is probably just a tectonic earthquake activity. But it is worth noting that volcano activity as has been seen in Fagradalsfjall volcano (Iceland newest volcano) is going to move east on Reykjanes peninsula. How fast and how long that change is going to happen is not known because of lack of data and written records from 700 to 900 years ago are incomplete and vague on details at best.
This evening on 16-October-2022 an strong earthquake swarm started close to Geirfugladrangur and Eldeyjarboða on the Reykjanes ridge. At the writing of this article the strongest earthquake had a magnitude of Mw4,4 but that might change without warning.
It is difficult to know how this earthquake swarm is going to evolve but there are clues in this activity that this might be a large earthquake swarm. However, activity in this area is also known to just stop without warning.