More earthquake activity in Katla volcano

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.

Earthquake activity in Katla volcano at 18:50 UTC this image shows three green stars, two of the stars are earthquakes from 29-July activity. New green star is from the earthquake today (31-July)
Earthquake activity in Katla volcano. Copyright of this image belongs to Icelandic Met Office.

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.

Earthquake activity in Katla volcano yesterday (29-July-2021)

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.

Cluster of smaller earthquakes in blue and red colours inside Katla volcano caldera. Two green stars on the north-east side of the caldera show the largest earthquakes.
Earthquake activity in Katla volcano. Copyright of this image belongs to Icelandic Met Office.

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.

More earthquake activity in Katla volcano

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.

Green star in north-east part of the Katla volcano caldera where the magnitude 3,1 earthquake took place. One red dot in the same location shows a new earthquake that has happened there.
Earthquake activity in Katla volcano. Copyright of this image belongs to Icelandic Met Office.

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.

More earthquake activity in 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.

Earthquake activity in Katla volcano caldera. A lot of yellow dots showing the locations of the earthquakes from south to north and then turn to east direction.
Earthquake activity in Katla volcano. Copyright of this image belongs to Icelandic Met Office.

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.

Earthquake activity in Katla volcano

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.

Earthquake activity to the east of Katla volcano caldera shown on the image by ring line. A second smaller cluster of earthquakes is the west and little bit inside the caldera of Katla.
Earthquake activity in Katla volcano. Copyright of this image belongs to Icelandic Met Office.

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.