Category: Earthquakes

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Earthquake activity in Katla volcano (24-October-2022)

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.

Green star in south part of the Katla volcano caldera. Few red dots around it showing smaller earthquakes.
Earthquake activity in Katla volcano. Picture from Icelandic Met Office.

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.

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Earthquake swarm in west part of Fagradalsfjall volcano

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.

Green star just west of main Fagradalsfjall volcano. Few blue, yellow and red dots on the map showing earthquakes in other nearby volcanoes
Earthquake activity west of Fagradalsfjall volcano. Picture from Icelandic Met Office.

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.

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Earthquake swarm north of Herðubreið mountain

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.

Earthquake swarm north of Herðubreið mountain, a lot of red dots and green stars on the map. Located east of Askja volcano and south of Herðubreiðartögl volcano
Earthquake activity north of Herðubreið mountain. Picture is from Icelandic Met Office.

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.

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Fissure opens up in south Grímsfjall volcano (no eruption)

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.

Grímsfjall volcano with few brown sand on Google Earth image. With triangle in the center to mark its location. Location marker in yellow in the right side of the image not far from the brown patches on the image.
The location of the fissure. Picture from Google Earth program.

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.

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Earthquake swarm in Brennisteinsfjöll volcano

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.

Red dots in Brennisteinsfjöll volcano on Reykjanes peninsula, located just south of Reykjavík city and east of Kleifarvatn lake. A lot of yellow and orange dots on the map in few volcanoes showing smaller earthquake activity
Earthquake activity in Brennisteinsfjöll volcano and other nearby volcanoes. Picture is from Icelandic Met Office.

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.

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Earthquake swarm north of Grímsey island

Today (19-October-2022) at 10:26 UTC an earthquake with magnitude of Mw3,8 took place and at 11:58 UTC an earthquake with magnitude of Mw3,3 took place at the same location. I don’t know if any of the larger earthquakes where felt. A swarm of smaller earthquakes took place and that activity is ongoing when this article is written.

Two green stars north of Grímsey island in Tjörnes Fracture Zone. This is out in the ocean far from land and populated areas.
Earthquake activity north of Grímsey island. Picture is from Icelandic Met Office.

This earthquake activity probably is continuation of an large earthquake swarm that started in that area in September. I don’t know if this is going to result in more stronger earthquakes, but that is a possibility.

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Strong earthquake swarm on Reykjanes ridge close to Geirfugladrangur and Eldeyjarboða

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.

Red dots and green stars on the Reykjanes ridge out on the ocean. Reykjanes peninsula on the left side of the image
Earthquake activity close to Geirfugladrangur and Eldeyjarboða on the Reykjanes ridge. Image from Icelandic Met Office.

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.

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People advised not go to Mýrdalsjökull glacier

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.

Two green stars and few red dots in Katla volcano caldera on the east side of the volcano under Mýrdalsjökull glacier
Earthquake activity in Katla volcano. Copyright of this image belongs to Icelandic Met Office.

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.

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Earthquake swarm in Katla volcano

Today (16-October-2022) an earthquake swarm started in Katla volcano in Mýrdalsjökull glacier. Largest earthquake at the writing of this article had a magnitude of Mw3,8. I don’t know if it was felt in nearby towns and farms. Second largest earthquake had a magnitude of Mw3,0.

Green star and red dots in Katla volcano caldera that is covered with Mýrdalsjökull glacier.
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 and the situation can change quickly. This might be a normal earthquake swarm and nothing more might happen. This type of earthquake swarm is not uncommon and I am not sure what is required for an eruption to start in Katla volcano.

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Something is going on in Grímsfjall volcano

This is a tricky thing to write about. Because nothing has started on the surface and might not start on the surface. It seems that something is going on in Grímsfjall volcano. Since the glacier flood is almost over or has finished the harmonic tremor level should have started dropping, it has not done so and I am not sure why that is. This might be boiling of the hydrothermal systems in Grímsfjall volcano when the pressure on the suddenly drops. Currently the harmonic tremor doesn’t look like it has reached eruption levels, that might change without warning.

Rising harmonic tremor, with a high top from storm noise on the 10/10. Colours are blue, green and purple that is barley visible at the end of the line.
Harmonic tremor in Grímsfjall volcano. Copyright of this image belongs to Icelandic Met Office.
One red dot in Grímsfjall volcano in middle of Vatnajökull glacier shown by white area on the map
Earthquake activity in Grímsfjall volcano. This is almost no earthquake activity. Copyright of this image belongs to Icelandic Met Office.

It is difficult to know what is going on. Since there seems to have been a change in Grímsfjall volcano after the big eruption in May 2011. What that change is I don’t know. It seems to have slowed down Grímsfjall volcano eruption rate from what it was, its been 11 years since last eruption. It might continue if no eruption starts now following the small glacier flood that just ended.