Volcano and earthquake activity in Iceland
Today (16. December 2022) at 21:44 UTC an earthquake with magnitude of Mw3,1 took place in Katla volcano. This seems to be a single earthquake at the writing of this article.
This earthquake activity seems to be normal and there is nothing to suggests that more is going to happen in Katla volcano at this time.
The police and Icelandic Met Office have now advised people not to go to Mýrdalsjökull glacier. This is after the earthquake swarm earlier today. According to Icelandic Met Office this earthquake swarm is similar to what happened before the minor eruption in Katla volcano in July 2011 that resulted in a glacier flood down Mýrdalssand and destroyed the bridge over the glacier river in that area. All trips to see ice caves in Mýrdalsjökull glacier have been temporarily forbidden by the Icelandic Police.
In July 2011 it took around 24 hours from the start of the earthquake activity then until something happened. If that is going to be case now I don’t know. That this activity is similar to July 2011 eruption is worrying. The eruption in July 2011 was minor and didn’t break the glacier, but it resulted in damage in that area from the glacier flood.
Largest earthquakes now have the magnitude of Mw3,8 and Mw3,0 (few of them). Other earthquakes have been smaller in magnitude but that might change without warning.
Today (31-July-2021) at 12:53 UTC an earthquake with magnitude of Mw3,3 took place in Katla volcano. A swarm of smaller earthquakes continued after the largest earthquake, this earthquake activity seems to be ongoing at the writing of this article.
Summer earthquake activity in Katla volcano is common and that makes it less clear what is going on in Katla volcano at the writing of this article. There is now a chance of more earthquake activity in Katla volcano.
Yesterday (29-July-2021) there was an earthquake activity in Katla volcano. Two strongest earthquakes had the magnitude of Mw3,2 at 19:20 and 19:22 UTC. Third largest earthquake at 19:28 UTC had a magnitude of Mw2,8.
It is unclear if this earthquake activity is just summer activity or part of a larger activity. At this time I am not expecting an eruption since the earthquake activity is currently too low for such event to about to take place. There are going to be thousands of earthquakes in Katla volcano before an large eruption. Until that happens. I do not worry about this activity.
Today (28-July-2021) at 12:36 UTC an earthquake with magnitude of Mw3,1 took place in Katla volcano caldera. Few smaller earthquakes have followed the largest earthquake.
This looks like a normal summer earthquake activity in Katla volcano. If that changes is impossible to know. There is no change in harmonic tremor on SIL stations around Katla volcano.
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.