Category: Swarm

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Strong earthquake swarm in Katla volcano (22-November-2022)

Today (22-November-2022) a strong earthquake swarm started in Katla volcano at 19:55 UTC. Strongest earthquake had a magnitude of Mw4,4. One Mw3,5 earthquake was recorded with several smaller earthquakes. Magnitudes and number of earthquakes are changing. This is an updated text of the earthquake magnitude.

Three green stars in Katla volcano caldera along with few red dots that show smaller earthquakes.
Green stars in Katla volcano showing the locations of the strongest earthquakes. Picture from Icelandic Met Office.

What is going on is unclear at the writing of this article. At the writing of this article I am not seeing any change in harmonic tremor, but that might change without warning. I’ll post updates if anything more happens in Katla volcano.

Added: I added the donate buttons back if people want to support my work. I had to remove them because of a increased fraud risk in October and that might be ongoing risk.

Article updated at 21:16 UTC.
Article updated at 23:06 UTC.

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Earthquake swarm in Kolbeinsey island (north of Grímsey island)

Today (22-November-2022) an earthquake swarm took place in Kolbeinsey island. This is far north of Grímsey island. Largest earthquake had a magnitude of Mw3,1 and total of four of those earthquakes happened. More than dozen smaller earthquakes have happened. Because how far this activity is from Icelandic Met Office SIL network only the largest earthquakes are being measured.

Green stars far north on the map, north of Iceland. This is the location of Kolbeinsey island. There are dots all over Iceland showing smaller earthquakes.
Green stars show the earthquake activity in Kolbeinsey island. Picture from Icelandic Met Office.

What is going on is unclear. This might just be normal tectonic activity for this area. There is only poor monitoring of this area since its out in the ocean and remote.

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Small earthquake swarm in Katla volcano (yesterday 19-November-2022)

Yesterday (19-November-2022) at 21:13 UTC an earthquake swarm started in Katla volcano. This was a small earthquake swarm with just few earthquakes, but it had an earthquake with magnitude of Mw3,2 taking place at 21:13:05. Just before and after this earthquake fewer smaller earthquakes took place.

Green star in Katla volcano caldera. With few smaller red dots that show smaller earthquakes.
Earthquake activity in Katla volcano. Picture from Icelandic Met Office.

Since this earthquake activity stopped, everything has been quiet in Katla volcano.

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Possible dyke intrusion in Fagradalsfjall volcano

Early morning today (10-November-2022) an swarm of earthquakes took place slightly north of the place where the eruption in August 2022 took place in Fagradalsfjall volcano. This possible dyke intrusion was small and only lasted for about 1 hour before it stopped. Depth of the earthquakes was from 5 km to 7 km.

High resolution image of the earthquakes in Skjálfta-Lísa interactive earthquake map from Icelandic Met Office. It shows the dots line up in a fissure like location.
Skjálfta-lísa high resolution map of the earthquake activity. From Icelandic Met Office website.

This activity might give a clue on in what area next eruption is going to take place in Fagradalsfjall mountain. Based on earlier eruption there won’t be any warning before an eruption earthquake swarm starts. In August that eruption started with a minor earthquake swarm, created from a dyke intrusion that was happening. In the hours before an eruption starts there’s going to be a strong earthquake swarm, based on what happened just before the eruption in August. It is interesting if the eruption activity moves north-east, rather than south-west. Why that happens, if it does so, is not something I am clear on why happens.

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Earthquake with magnitude Mw3,2 in Tjörnes Fracture Zone

Today (3-November-2022) at 11:06 UTC an earthquake with magnitude of Mw3,2 took place in Tjörnes Fracture Zone. This earthquake took place a bit of a distance from land. This earthquake seems to be part of an activity that is now happening in Tjörnes Fracture Zone. This seems to be an ongoing earthquake swarm in this area.

Green star out in the ocean south of Grímsey island, this is far from land so this earthquake was possibly not felt. Few red dots around the map showing smaller earthquakes that have also happened.
Earthquake activity in Tjörnes Fracture Zone. Picture from Icelandic Met Office.

It is difficult to know what this earthquake activity means, if it means anything. Its been a while since Tjörnes Fracture Zone had a strong earthquake above Mw6,0 in this area and north of it. Earthquakes in Tjörnes Fracture Zone can go up to Mw7,0 in magnitude, those are rare and happen only after a long time period of quiet it seems.

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Earthquake with magnitude Mw3,2 north of Herðubreið mountain

Today (31-October-2022) at 15:00 UTC an earthquake with magnitude Mw3,2 took place at Herðubreið mountain. This earthquake started a swarm just east of the earthquake swarm that has been going on for more than a week now. Earthquake activity remains high at the writing of this article.

Green star and red dots around Herðubreið mountain. Showing strong earthquake activity in that area.
Earthquake activity around Herðubreið mountain. Picture from Icelandic Met Office.

It is unclear what is going at this area. This looks like a tectonic earthquake activity, but there might be more in this than appears. At the moment, this is just earthquake activity and its unknown if that is going to change.

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Earthquake with magnitude Mw4,0 south east of Grímsey island

During the night of 27-October-2022 an earthquake with magnitude of Mw4,0 took place at 02:13 UTC. This earthquake was followed by few minor earthquakes. This earthquake was also felt in Grímsey island and in Akureyri town.

Green star south east of Grímsey island in the ocean. Where the magnitude Mw4,0 earthquake took place.
Earthquake activity south east of Grímsey island. Picture from Icelandic Met Office.

There’s a good chance of more earthquake activity in this area. Since this seems to connected to or be part of an earthquake swarm that started on 8-September-2022.

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Change in the earthquake activity in close to Herðubreið mountain

Sometime yesterday (24-October-2022) a change happened in the earthquake swarm close to Herðubreið mountain. I am not sure when that change happened and it probably took few hours to happen before I detected it. But the change seems to be that now the earthquake swarm is at two locations and not just one. The second change is that the earthquake swarm is now getting more intense. The earthquakes at the writing of this article are minor, only magnitude Mw0,0 to Mw2,7 at the strongest. Nothing above Mw3,0 so far, but that might change without warning. Depth of this earthquake swarm is around 2 to 3 km at the writing of this article.

Two swarms of red dots show the location of the earthquake swarm east of Askja volcano and south of Herðurbreiðartögl volcano. The earthquake swarm is now west and north of Herðubreið mountain
Earthquake activity close to Herðubreið mountain. Picture from Icelandic Met Office.

What is going to happen next is impossible to know. An eruption in this area has not happened for at least 12.000 years or even longer. I don’t know if stronger earthquake activity is required for this area for an eruption to happen. It already is rather fractured from older earthquake activity and rift activity, that makes it possible for magma to have easier paths to the surface without much earthquake activity. That is at least one idea on the situation in this area. I might be wrong on this, since I don’t have information on the finer details of the crust around Herðubreið mountain.

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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.