Volcano and earthquake activity in Iceland
I don’t have anything to say about the earthquake that took place (on 29-July-2021 at 06:15 UTC) in Alaska, United States since I don’t know the area geology features. I am going to show the trace of this earthquake as it did appear on my geophone in Iceland.
Since yesterday (24-July-2021) and until today (25-July-2021) there has been rather strong earthquake activity in Katla volcano. The earthquakes are not strong with largest earthquakes having a magnitude of Mw2,6. It is unclear what is going on.
One of the reasons this earthquake activity is happening is that cauldron might be emptying in the Mýrdalsfjökull glacier. That creates a drop in pressure that can start earthquake activity. I don’t know if that is what happened now. If that is what is going on it is going to take the melt water few hours to reach the rivers in Mýrdalssandur sand area. There has not been any change in harmonic tremor activity following this earthquake activity.
Since 22-July-2021 there has been an earthquake activity in Katla volcano. This earthquake activity has been mostly located to the east of the caldera and largest earthquake so far detected had a magnitude of Mw3,0.
There has not been any change in harmonic tremor activity following this earthquake activity. That strongly suggest that this is normal summer earthquake activity for Katla volcano. Earthquake activity is also far too low for it to signal any eruption risk. That might change if earthquake activity changes and grows in size.
Today (21-July-2021) few deep earthquakes took place in Fagradalsfjall mountain that is part of Krýsuvík-Trölladyngja volcano system.
This earthquake activity was not big and the largest magnitude recorded was a magnitude of Mw0,8. Most depth that appeared had a depth of 13,4km.
It is difficult to know what this means. What is possibly happening is that more magma is pushing up in the magma feeding that now exist where the eruption has been happening. If that is happening, it can result in new craters or fissure opening up and start erupting. At the writing of this article this earthquake activity seems to be ongoing, but at slow rate and small earthquakes only so far.
Fog continues to block view to the crater and Fagradalsfjall mountain. But harmonic tremor data shows that the Fagradalsfjall mountain eruption is currently not erupting.
On 24-May-2021 at 21:36 UTC an earthquake took place in Brennisteinfjöll volcano. The magnitude of this earthquake was Mw3,6 and this earthquake was felt in Reykjavík area.
There have been few smaller earthquakes in this area since the largest earthquake, but other than that it has been quiet. This earthquake is believed to have happened because of stress changes on the Reykjanes peninsula because of the eruption in Fagradalsfjall mountain.
Yesterday (12-May-2021) at 15:47 UTC an earthquake with magnitude of Mw3,5. This earthquake was in the normal area of Bárðarbunga volcano caldera. This earthquake activity is connected to inflation of Bárðarbunga volcano that started after the end of Holuhraun eruption in 2015.
There has been a slow drop in earthquake activity during the last few months and it is unclear why that is. Eruptions in Bárðarbunga volcano can be as short apart in time as 18 years or less. The 1996 eruption in Gjálp fissure was from Bárðarbunga volcano, that places the time between eruptions 1996 and 2014 at 18 years.
Since last night (night of 3-May-2021) there has been earthquake swarm in Krýsuvík volcano close to Kleifarvatn lake. At the writing of this article this earthquake swarm is ongoing.
Largest earthquakes in this swarm had a magnitude of Mw3,2 and there where several other smaller earthquakes that also happened. The earthquake at 03:04 UTC was felt in Reykjavík but I don’t have any reports about the earthquake at 15:49 UTC with same magnitude being felt. It is difficult to know what this earthquake activity means but for now the idea is that this earthquake activity might be connected to stress changes because of the magma dyke connected to the eruption in Fagradalsfjall mountain that is happening within same volcano system.
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Vacation
I am taking a little vacation between 5 May and until 10 May. Unless something major happens next update won’t be until after 10 May 2021. I am hoping to see the eruption or the area if the eruption is not ongoing next weekend if weather allows for such a trip. I don’t know yet if I can see the eruption, but I hope that I am going to have a chance to see the eruption.
This is a short update on the eruption in Fagradalsfjall mountain on 30-April-2021.
There has not been any major changes since last update. This are the noticeable changes since last update in the eruption in Krýsuvík-Trölladyngja volcano system.
No other updates have been reported so far. Rúv has installed a new web camera to give better view of the eruption. That camera can be found on YouTube Rúv channel.
Vacation
I am going on a small vacation between 5th May and 10th May. That means next update about the eruption is going to be on 14th May. I don’t know if I can go to the eruption yet as that depends on the weather and the weather is always unstable in Iceland.
Sorry for the late article. I’ve been dealing with technical problems in my mobile phone all day and delayed a lot of things for me.
Yesterday (29-April-2021) an earthquake swarm started in Hengill volcano. This earthquake swarm appears to be tectonic in nature. Largest earthquake in this swarm had a magnitude of Mw3,8 and was felt in Reykjavík.
This earthquake activity looks tectonic in nature and there are no signs that the reason for this earthquake swarm is anything but tectonic stress adjustments for now. I always expect more and stronger earthquakes swarm when cold volcanoes (not erupted for a long time) starts to get warm as was the case before the eruption in Fagradalsfjall mountain when up to 50.000 earthquakes took place from 27th February until 19th March when the eruption started.
During the night of 27-April-2021 an earthquake swarm took place south of Keilir mountain in Krýsuvík-Trölladyngja volcano system. This earthquake activity at this location has been going on for a long time and is interesting. There are no sign that suggest an eruption is about to happen at this location, that is the situation at the writing of this article. Largest earthquake in this swarm had a magnitude of Mw3,2 at the depth of 6,1 km and second largest earthquake had a magnitude of Mw2,8 at the depth of 5,9 km.
It seems that there is a chance there might be changes about to happen in the eruption in Fagradalsfjall mountain. I am going to write about that tomorrow at the earliest, but the article might be delayed of there is a lot going on while I gather information about what is happening.