Update on Katla volcano activity

This is an update on Katla volcano activity. The largest earthquakes in the earthquake swarm during the night had a magnitude of Mw4,4. There where total of eight earthquake with magnitude above Mw3,0 in this earthquake swarm and in total of 58 earthquakes in total according to Icelandic Met Office website. This earthquake activity is ongoing even if currently there are no earthquakes taking place (at the writing of this article).

This earthquake activity was clearly felt in Þórsmörk area and was resulting in people loosing sleep.

Green stars and yellow dots in Katla volcano caldera on the Icelandic Met Office map. Time on map is 30. June, 23, time is 11:15 Icelandic Time.
Earthquake swarm activity in Katla volcano. Copyright of this image belongs to Icelandic Met Office.

According to news reports on mbl.is there has now been increase in conductivity in Múlakvísl glacier river. This seems to be directly connected to the earthquake swarm activity that took place during the night. There is also more water in the Múlakvísl glacier river, if that is connected is unclear, because of rain in Iceland in recent days, there is general more water in rivers. Harmonic tremor has not started to change. That can happen without warning at any time.

Icelandic News

Rafleiðni fer stígandi í Múlakvísl eftir skjálfta (mbl.is)
Önnur skjálftahrina í Mýrdalsjökli (ruv.is)

Strong earthquake swarm in Katla volcano

During the night of 30. June 2023 an earthquake swarm started in Katla volcano. At the writing of this article the largest verified earthquake had a magnitude of Mw3,3.

Green star and red dots in Katla volcano caldera.
Ongoing earthquake activity in Katla volcano. Copyright of this image belongs to Icelandic Met Office.

This earthquake swarm is ongoing at the writing of this article. Currently an eruption has not started, if that is going to change is something that just has to show it self in next few hours if this earthquake activity continues to increase. All that can be done for now is to monitor this situation.

Magma detected deep under Reykjanes peninsula

According to a news on Rúv News there has been detection of magma at considerable depth on Reykjanes peninsula. This magma is actively trying to reach the surface, but has not been successful for now. This has resulted in a lot of dyke intrusions on the Reykjanes peninsula in recent months. Earthquake activity seems to follow each inflation period on the Reykjanes peninsula according to the news.

The magma in the deep crust and in the mantle is going to increase in volume until it can break up the surface. How long that is going to take is something I don’t know. Next eruption cycle is going to start with a large earthquake, just like the last one. Based on all current data that I have.

Rúv news in Icelandic

Jarðskjálftavirkni aukist síðustu daga og vikur (Rúv.is)

Earthquake in Þórðarhyrna volcano

Today (29. June 2023) at 07:48 UTC an earthquake with magnitude of Mw3,1 took place in Þórðarhyrna volcano. This was just one earthquake and a minor Mw1,3 earthquake happened at 08:17 UTC and since then its been quiet. Þórðarhyrna volcano is inside Grímsfjall volcano fissure swarm but is an independent volcano in this setting. Sometimes Þórðarhyrna and Grímsfjall erupt at the same time.

Green star in south part of Þórðarhyrna volcano. Not many other earthquakes on the map. Time on map is 29. June, 23, time 13:20 Icelandic time.
Green star in Þórðarhyrna volcano. Copyright of this image belongs to Icelandic Met Office.

Last eruption in Þórðarhyrna volcano took place around late 1890 or early 1900. I am not sure what year exactly, because eruption often attributed to Þórðarhyrna volcano took place in Grímsfjall volcano and sometimes the reverse happened. Last eruption took place around 120 to 140-ish years ago.

Earthquake swarm in Krýsuvík-Trölladyngja volcano (Kleifarvatn lake)

Today (28. June 2023) an earthquake swarm took place in Krýsuvík-Trölladyngja volcano in Kleifarvatn lake. Largest earthquake had a magnitude of Mw3,2 at 09:21 UTC and was felt in Reykjavík area and other nearby towns.

Green star and red dots in Kleifarvatn lake in Krýsuvík-Trölladyngja volcano. There are red dots and orange dots in nearby Fagradalsfjall volcano.
Earthquake activity in Krýsuvík-Trölladyngja volcano. Copyright of this image belongs to Icelandic Met Office.

Its unclear what is going on at this location. Most likely explanation for this activity is stress changes because of inflation in nearby Fagradalsfjall volcano. At the moment, I don’t think there is going to be an eruption in Krýsuvík-Trölladyngja volcano. This earthquake swarm looks like its ongoing at the writing of this article.

Earthquake swarm in Hofsjökull volcano

Today (28. June 2023) an earthquake swarm started in Hofsjökull volcano. At the writing of this article it seems to be over, but I am uncertain if that’s the case. This was not a large earthquake swarm, with just around eight earthquakes happening. All where below Mw3,0 magnitude in size.

Red dots in western part of Hofsjökull volcano caldera. Time on map is 28. June. 23, 09:30 Icelandic time.
Earthquake activity in Hofsjökull volcano. Copyright of this image belongs to Icelandic Met Office.

Largest earthquake in this swarm had a magnitude of Mw2,6. While other earthquakes where smaller in magnitude. I am not sure what is happening in Hofsjökull volcano. There have not been any eruptions in Hofsjökull volcano in the last 8000 to 12000 years. There might not have been any eruption in Hofsjökull volcano for more than 12000 years, how much longer is information I do not have.

Earthquake with magnitude of Mw3,6 in Katla volcano

Today (27. June 2023) at 07:42 UTC an earthquake with magnitude of Mw3,6 took place in Katla volcano. This earthquake was part of a earthquake swarm that had started few moments earlier. There is no change in harmonic tremor at the writing of this article and earthquake activity has slowed down again. This earthquake was felt in nearby areas.

Green star and red dots in Katla volcano caldera, along with older earthquakes from yesterday shown as blue and yellow dots. Time on map is 27. june. 23, 09:20 (Icelandic time).
Earthquake activity in Katla volcano caldera. Copyright of this image belongs to Icelandic Met Office.

This earthquake activity seems to happen in active time periods with quiet period between them, when there are few to no earthquake activity. This activity is ongoing at the writing of this article.

Renewed earthquake activity in Katla volcano

Today (26. June 2023) the earthquake activity in Katla volcano increased again for few hours. Largest earthquake this time had a magnitude of Mw2,5. This earthquake activity has slowed down again. This earthquake activity is ongoing, even if there is no activity at the writing of this article.

A lot of orange dots and blue dots showing earthquake activity in Katla volcano caldera. Time on image is 26. June. 23, 19:55 Icelandic time.
Earthquake activity in Katla volcano. Copyright of this image belongs to Icelandic Met Office.

Its is still unclear what is going on in Katla volcano. There was no change in harmonic tremor following this earthquake activity. Showing that magma did not move in any obvious way when this earthquake activity took place.

Earthquake swarm in Reykjanes volcano

Today (26. June 2023) an earthquake swarm took place in Reykjanes volcano. This earthquake swarm is in a location in Reykjanes volcano that has been having repeated earthquake activity over the last few months. This strongly suggest that at this location there’s an active dyke that might erupt in the future.

Earthquake swarm out in the ocean close to Reykjanestá in the Reykjanes volcano. A lot of red dots piled on top of each other. Blue to orange dots located elsewhere on the Reykjanes peninsula. Time on map 26. June. 23. 16:05 (Icelandic Time).
Earthquake swarm in Reykjanes volcano. Copyright of this image belongs to Icelandic Met Office.

Largest earthquake in this swarm at the writing of this article had a magnitude of Mw3,0. Other earthquakes have been smaller in magnitude. I am unclear on how many earthquakes have happened in Reykjanes volcano at the writing of this article. This earthquake swarm is ongoing at the writing of this article.

Earthquake swarm in Katla volcano

Today (24. June 2023) an earthquake swarm started in Katla volcano. Largest earthquakes had magnitude of Mw3,8 and Mw3,3. Other earthquakes have been smaller. This earthquake swarm is ongoing but has slowed down since this morning.

Two green stars in Katla volcano caldera along with blue and red dots that show this earthquake activity. It is spread over some area in the caldera. Time on image is 24. june 23, 13:45.
Earthquake activity in Katla volcano. Copyright of this image belongs to Icelandic Met Office.

At the writing of this article there is no clear sign that an eruption is about to happen. That might change without a warning. This earthquake activity might stop and nothing more is going to happen until next time. That is what has been going on for the last few months and years.