Category: Swarm

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Earthquake activity in Bárðarbunga volcano

Today (20-July-2018) at 06:28 UTC a magnitude 3,4 earthquake was in Bárðarbunga volcano south-east part of the caldera. It was followed by several smaller earthquakes during the day. Earthquake activity is common in Bárðarbunga volcano at the moment, but rate of earthquakes happening continues to drop every 3 – 6 months. When earthquakes happen they are often larger in magnitude.


Earthquake activity in Bárðarbunga volcano, the green star is the magnitude 3,4 earthquake. Copyright of this image belongs to Icelandic Met Office.

There is a risk of larger earthquake in next few hours to 48 hours. If nothing happens after 48 hours there is unlikely going to be a another larger earthquake happening. The magnitude that can be expected is above 4,0.

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Deep earthquake swarm south-east of Bárðarbunga volcano

Since yesterday (18-July-2018) there has been a deep earthquake swarm south-east of Bárðarbunga volcano. Earthquake swarm in this location are common and due to their depth are always the result of magma injection into the crust in this area.


Earthquake activity south-east of Bárðarbunga volcano. Copyright of this image belongs to Icelandic Met Office.

Most depth recorded in this earthquake swarm was 26,3 km and the shallowest was at 13,4 km depth. Error margin might be high in this location due to distance from SIL stations. Smaller earthquakes (magnitude 0,0 – 1,0) are harder to locate and give correct depth. Activity at this location is sometimes followed by a large earthquake in Bárðarbunga volcano (main). That doesn’t always happen. It is not possible to know if that is going to happen now.

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Earthquake swarm deep on the Reykjanes ridge

Yesterday (14-July-2018) and during the night (15-July-2018) an earthquake swarm took place deep on the Reykjanes ridge. This appears to be been a minor earthquake swarm and largest earthquake only had a magnitude of 3,0. This earthquake swarm took place good distance from the SIL network so locations and magnitudes have larger error margins.


Earthquake swarm on the Reykjanes ridge. Copyright of this image belongs to Icelandic Met Office.

This earthquake swarm appears to be over. If any smaller earthquakes are happening in the area were the earthquake swarm took place they are not being detected by the SIL network due to distance. This earthquake swarm can start again without warning.

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Minor earthquake swarm in Katla volcano

During the night of 13-July-2018 a minor earthquake swarm took place in south part of the caldera of Katla volcano.


Earthquake activity in Katla volcano. Copyright of this image belongs to Icelandic Met Office.

Largest earthquake in this minor earthquake swarm was magnitude 2,9 and the second largest earthquake had a magnitude of 1,9. This earthquake swarm is over but new earthquake swarms might start without warning. July often marks the time when earthquake activity starts to increase in Katla volcano.

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Earthquake swarm north of Gjögurtá (Tjörnes Fracture Zone)

At 21:10 UTC a earthquake swarm started in Tjörnes Fracture Zone just north of Gögurtá. Largest earthquake so far had a magnitude of 3,7. Other earthquakes so far have been smaller in magnitude so far. That might change without warning.


The earthquake swarm in TFZ. Green star is the magnitude 3,7 earthquake. Copyright of this image belongs to Icelandic Met Office.

There is some mislocation on the map at the moment due to the automatic location system at Icelandic Met Office website.

Since my geophone at Böðvarshólar is down due to a failed computer and I cannot afford Raspberry shake sensor (weatherproof type) only the largest earthquakes are going to be recorded at Dellukot geophone.

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Ongoing earthquake swarm in Öræfajökull volcano (3-July-2018)

During the last few hours there has been ongoing earthquake swarm in Öræfajökull volcano. This earthquake swarm started around 29-June-2018 in the south side of Öræfajökull volcano. At the moment the earthquake activity seems to be close or directly under Road 1 in Iceland.


The earthquake activity in Öræfajökull volcano on 3-July-2018. Copyright of this image belongs to Icelandic Met Office.

This change in earthquake activity is interesting and is in my view a sign of trouble to come. There are not any older eruption vents in the side of Öræfajökull volcano, but such vents might have been wiped out by glacier over the centuries. There is a good reason to continue to monitor this earthquake activity in Öræfajökull volcano.

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Ongoing earthquake swarm in Öræfajökull volcano (update 29-June-2018)

There is currently ongoing earthquake swarm in Öræfajökull volcano. This earthquake swarm started on 26-June-2018 with the magnitude 3,1 and it has been mostly ongoing since then. All earthquakes are minor in the volcano at the moment. A magnitude 2,1 earthquake happened outside the volcano (but those earthquakes appears to be connected to it) and suggest crustal stresses are changing at the moment at expectational speed (my view).


Earthquake activity in Öræfajökull volcano (red dots). Copyright of this image belongs to Icelandic Met Office.

What also appeared today is a earthquake swarm in the side of Öræfajökull volcano. If this earthquake activity continues it is worrying as it suggests that an eruption might happen in Öræfajökull volcano side and that might be a major issue if a eruption vents opens up in such area. Since this is close to Road 1 and warning time might be limited or close to none in worse case. This type of activity warrants more monitoring in my view.

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Short earthquake swarm on the Reykjanes ridge

Yesterday (28-June-2018) and today (29-June-2018) during the night a short but strong earthquake activity took place on the Reykjanes ridge. Strongest earthquake had a magnitude of 3,2 or 4,1. It is unclear (to me) at the moment what magnitude is correct. Since I did get a signal on Dellukot geophone station that was considerable larger than for magnitude 3,2 earthquake (given distance from the station). Böðvarshólar geophone station remains down due to a broken computer (that I can’t fix).


Green stars show the location of this earthquake activity. Copyright of this image belongs to Icelandic Met Office.

It is unclear at the moment if this earthquake activity is going to continue. At the moment it appears to have stopped, but distance from land makes it impossible to detect smaller earthquakes in this area.

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Update on the earthquake activity in Öræfajökull volcano

This is a update on the earthquake activity in Öræfajökull volcano on 26-June-2018.

Reviewed earthquake magnitude of the largest earthquake that happened at 16:57 UTC in Öræfajökull volcano has placed the magnitude at Mw3,1. Other earthquakes were smaller in magnitude, but strongest earthquake after the main earthquake had a magnitude of 2,1 (at 16:59 UTC).


Earthquake activity in Öræfajökull volcano (green star). Copyright of this image belongs to Icelandic Met Office.

Earthquake activity seems to have quieted down around 20:15 UTC. It might resume without much warning later tonight, tomorrow or days from now. It is not possible to know when the earthquake activity is going to resume. No harmonic tremor was detected following the magnitude 3,1 earthquake. That means this was just volcano-tectonic earthquake due to inflation (assumed) in Öræfajökull volcano.

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Strong earthquake swarm in Öræfajökull volcano [updates pending]

This article is going to be updated later with more details.

A magnitude 3,5 earthquake happened in Öræfajökull volcano at 16:57 UTC. This is a automatic magnitude and is going to be corrected later. A swarm of earthquakes seems to have started in Öræfajökull volcano.


Earthquake swarm in Öræfajökull volcano (green star). Copyright of this image belongs to Icelandic Met Office.

The harmonic tremor images have not yet updated so I don’t know at the moment if any harmonic tremor has started following this earthquake swarm.

This article is going to be updated later with new information.