Category: Swarm

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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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Earthquake swarm south and east of Grímsey island

Yesterday (12-October-2022) an earthquake swarm started south and east of Grímsey island. This is in the same area as an earthquake swarm took place few weeks ago. Largest earthquakes so far in this swarm had a magnitude of Mw3,5. Larger earthquakes remain a possibility. Largest earthquakes have been felt in nearby populated areas.

Red dots east and south of Grímsey island along with two green stars that show the largest earthquakes. On a blue background and the coastline is fjords and small peninsuals in north-eastern Iceland.
Earthquake activity south of Grímsey island. Copyright of this image belongs to Icelandic Met Office.

This area has frequent earthquakes. This earthquake swarm might grow as sometimes happens. It might also equally just stop, since that is also something that earthquake swarm in this area do.

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Magnitude Mw3,5 earthquake in Krýsuvík-Trölladyngja volcano

Today (12-October-2022) at 14:18 UTC an earthquake with magnitude of Mw3,5 took place in Krýsuvík-Trölladyngja volcano. This earthquake was followed by few smaller aftershocks. This earthquake seems to be happening because of a inflation that is taking place in Fagradalsfjall volcano and this strongly suggests that inflation in Fagradalsfjall volcano is slowly reaching critical levels. There is no eruption expected from Krýsuvík-Trölladyngja volcano as is.

Green star with few red dots just west of Kleifarvatn lake, showing increase in activity in Krýsuvík-Trölladyngja volcano
Earthquake activity in Krýsuvík-Trölladyngja volcano. Copyright of this image belongs to Icelandic Met Office.

This earthquake activity suggests that more stronger earthquake activity is possibly on the way. When it might start is difficult to know for sure. This has been the pattern in recent months. Earthquake activity starts to appears like this and then one day a major earthquake swarm starts. What happens now is a wait and see as before.

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Earthquake activity has started to increase in Fagradalsfjall and Reykjanes volcanoes

Since yesterday (06-October-2022) the earthquake activity has been increasing in the volcanoes Fagradalsfjall and Reykjanes volcanoes. Please note that Global Volcanism Program has updated the informations regarding Fagradalsfjall mountain and now classifies it as its own volcano, this is after a new report and information from Icelandic Met Office. From now on I am going to use that classification when updating on activity in Fagradalsfjall volcano. I’ll not update older articles (too much work), but this also applies to them as such.

This also means that Fagradalsfjall is a new volcano in Iceland.

Earthquake activity in Fagradalsfjall volcano, Krýsuvík-Trölladyngja and Reykjanes volcano. Shown with red, orange and blue dots
Earthquake activity in Fagradalsfjall volcano and Reykjanes volcano along with Krýsuvík-Trölladyngja volcano. Copyright of this image belongs to Icelandic Met Office.

Earthquake activity at start of an eruption cycle in Fagraldsfjall volcano are not large. They grow larger once magma has started to push into the crust, until then the earthquake activity only seems to happens with minor earthquake swarms.

Article updated with new information.

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Strong earthquake swarm on the edge of Reykjanes ridge

This earthquake swarm is around 1330 km away from Reykjavík and in the North Atlantic ocean. What is going on here is unclear, but this is probably an earthquake swarm before an eruption or during an eruption in that area. The ocean depth at this location is between 3 to 4 km so nothing is going to appear on the surface.

Earthquake Zoom - LAT: 50 - 60 ; LON: -44 - 34 ; Red dots and orange dots show the earthquake swarm on the edge of Reykjanes ridge
Earthquake activity on the edge of Reykjanes ridge. Screenshot from EMSC website.

Total of 61 earthquakes have been recorded since 26-September-2022 when this activity started. Largest earthquake so far had a magnitude of Mw5,7 but several earthquakes with magnitude of Mw5,0 appears to have taken place. Because how remote this area is only the largest earthquakes are being recorded. It is possible to monitor the earthquake swarm here on EMSC website.

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Update on the earthquake swarm east of Grímsey island (12-September-2022)

This is a short update on the earthquake swarm that is ongoing east of Grímsey island.

The earthquake swarm that started on 8-September-2022 east of Grímsey island is ongoing. Over 6000 earthquakes have been recorded at the writing of this article. Largest earthquakes in recent days have had a magnitude Mw4,2 and have been felt over a wide area. People living in Grímsey island and tourists in Grímsey island feel this earthquake swarm clearly.

Green stars and red dots in line east of Grímsey island in the ocean. Green star is also close to Húsavík, but that might be an error in recording
Earthquake activity in Tjörnes Fracture Zone. Copyright of this image belongs to Icelandic Met Office.

There are no signs of an eruption is about to start. That might change without warning, but I don’t know likely an eruption is in this location because there’s no good data on possibility of an eruption. There’s also no clear reading from any nearby GPS station. This most likely is just an earthquake swarm. The risk of a magnitude 6 to 7 earthquake in this area remains high and such earthquakes can happen without warning.

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