Category: Þorbjörn

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Ongoing earthquake swarm north of Grindavík town wakes up people

Today (22-May-2022) at 09:53 and 09:57 UTC earthquakes with magnitude of Mw3,5 and Mw3,6 took place north-west of Grindavík town. This earthquake was felt and did wake up people according to the news.

Two green stars north-west of Grindavík town along with a green star north of Grindavík. A lot of orange and red dots around the area showing smaller earthquakes
Earthquake activity close to Grindavík town. Copyright of this image belongs to Icelandic Met Office.

There is no signs that this earthquake activity is slowing down. It does come in waves according to Icelandic Met Office. This means that there are period of high activity with low activity between. Currently, at the writing of this article, there is a low activity period ongoing.

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Increased earthquake activity off the coast of Reykjanestá

Today (20-May-2022) around 18:00 UTC the earthquake activity off the coast of Reykjanestá, that is part of Reykjanes volcano, increased again after few days of little earthquake activity. The earthquake swarm is ongoing and always changing so this article is going to be short because of that.

Green stars out in the ocean where the main earthquake swarm is taking place just off the coastline of Reykjanestá. This is in south-west direction
Earthquake swarm on the Reykjanes ridge, close to Reykjanestá. Copyright of this image belongs to Icelandic Met Office.

Largest earthquake so far had a magnitude of Mw3,8 and the second largest earthquake had a magnitude of Mw3,5. The Mw3,8 earthquake was felt in Grindavík and on nearby towns on Reykjanes peninsula. A Mw3,0 earthquake took place just north of Grindavík and was felt in the town.

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Two strong earthquakes in Reykjanes volcano

Yesterday (31-July-2020) two earthquakes with magnitude Mw3,4 and Mw3,0 took place in Reykjanes volcano. This earthquake activity is part of the inflation that is happening north of Grindavík town in the Reykjanes volcano.


Earthquake activity close to Fagradallsfjall mountain. Copyright of this image belongs to Icelandic Met office.

Earthquake activity in Reykjanes volcano is now mostly continues but it peaks with earthquake activity swarm like this one every few days to weeks. How much earthquake activity depends on how magma inflow is taking place at 3 to 10 km depth. It seems that flow rate is different between hours to days. Since the earthquake activity is continuous in Reykjanes volcano there is a permanent risk of magnitude Mw5,0 to Mw6,0 earthquake in this area.

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Strong earthquake swarm close to Fagradalsfjall (Reykjanes volcano)

Yesterday (19-July-2020) at 23:36 UTC an earthquake with magnitude Mw5,1 took place 0,3 km south-west of a mountain called Fagradalsfjall that is inside Reykjanes volcano. This is the same location that I wrote about in earlier article. At the writing of this article 1340 earthquakes have happened over the last 48 hours. Second largest earthquake took place at 06:23 UTC today (20-July-2020) and had a magnitude Mw5,0. At the writing of this article 26 earthquakes with magnitude above Mw3,0 have taken place. Some rock slides have happened during this earthquake swarm when the largest earthquake took place and more rock slides might happen in this activity.


The earthquake activity on the Reykjanes peninsula in the Reykjanes volcano. A lot of wrong locations are on this map because the SIL network can’t handle all the earthquakes that are happening. Copyright of this image belongs to Icelandic Met Office.


Current earthquake activity on Reykjanes peninsula. Copyright of this image belongs to Icelandic Met Office.

This earthquake activity has been connected to magma injection and inflation in Reykjanes volcano. Currently it is not known if magma has moved into the direction were this earthquake swarm is. At the writing of this article the earthquake swarm has slowed down in activity. How long this slowdown is going to last is difficult to know for sure. There is more risk for strong earthquakes in this area.

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Earthquake swarm in the Reykjanes volcano

Over the last few hours there has been an earthquake swarm close to mountain called Fagradalsfjall in or close to the volcano called Reykjanes. At the writing of this article no earthquake with magnitude over Mw2,0 have happened. That might change without a warning.


The earthquake swarm in the volcano Reykjanes or close to it. Copyright of this image belongs to Icelandic Met Office.

Currently there isn’t anything suggesting that magma is on the move at the writing of this article. This earthquake swarm is something to watch out for since this might increase in size and magnitude over the next few hours. Inflation data from GPS measurements from this area are still unclear. There is also ongoing earthquake swarm north of Grindavík town but it has quieted down in last few hours.

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Two strong earthquakes north of Grindavík town

This morning (18-July-2020) two strong earthquakes that were felt in Grindavík town and Reykjanes area took place this morning at 05:54 UTC and 05:56 UTC in the volcano Reykjanes. Earlier earthquake had a magnitude of Mw3,2 and the second earthquake had a magnitude of Mw4,1. There isn’t a lot to go on by the GPS data that is showing any inflation taking place following this earthquake swarm. The strongest earthquakes were also rather shallow being only at 2,5 km depth.


The earthquake activity north of Grindavík town. Copyright of this image belongs to Icelandic Met Office.

This magma intrusions are a repeated pattern and now strongly suggests that a eruption is going to happen in this volcano. When is impossible to know. What is most likely to happen is that more and stronger earthquake swarm might happen. Current depth of smaller earthquakes in this swarm is now from 8 km to 0,1 km. This appears just to be earthquakes in the rocks at the most shallow depths for now due to pressure changes at more depth from magma. There is a risk of stronger earthquakes in this area because of this dyke intrusions.

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Earthquake swarm in Reykjanes volcano close to Grindavík town

Yesterday (9-July-2020) an earthquake swarm took place north-east of Grindavík town in the Reykjanes volcano. Largest earthquake in this swarm had a magnitude of Mw3,3 and the reason for this earthquake swarm was a magma injection at 4 to 6 km depth into a sill that is forming north-east of Grindavík town, close to what seems to be a old fissure in that area.


The earthquake swarm in the Reykjanes volcano yesterday. Copyright of this image belongs to Icelandic Met Office.

There is a chance that the magma that is pushing this activity might be as shallow as 3 km but currently it is difficult to know for sure but deformation that can be monitored by GPS data is going to give more clear picture in next few days. Currently there doesn’t seems to be enough magma in the higher level of the crust to start and eruption or the magma is blocked by some other unknown factors in the crust.

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Sharp increase in earthquakes in Þorbjörn mountain (Svartsengi/Reykjanes volcano)

Since around 06:00 this morning (13-June-2020) a sharp increase in earthquake activity took place north of Grindavík town. The most dense earthquake swarm was located west of the Blue lagoon with other minor swarms in other nearby areas. The active volcano is Reykjanes and Svartsengi (no Global Volcanism profile). Map can be found here and here (go to Höggunarkort).


The clusters of earthquake activity close to Grindavík town. This map can be found here (Icelandic only). Copyright of this image belongs to Icelandic Met Office.


Current earthquake activity close to Grindavík town. Copyright of this image belongs to Icelandic Met Office.

Largest earthquakes at the writing of this article have a magnitude of Mw3,5 (at 20:27 UTC) but since this earthquake swarm in ongoing that number can change without warning.

There was also considerable noise during the earthquake swarm earlier. Suggesting that something is going on but I do not know what might be for now. The noise results in the blue band thickens during the earthquake swarm.


The termor plot during the earthquake swarm. Copyright of this image belongs to Icelandic Met Office.

Current GPS data (can be viewed here) doesn’t show any major changes at the writing of this article. That might change in next few days.

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Weekend long earthquake swarm in Reykjanes volcano (both of them)

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Over the weekend there has been a earthquake swarm in the Reykjanes volcano. Largest earthquake in this swarm had a magnitude of Mw2,6 on Saturday 06-June-2020 at 01:01 UTC. Other earthquakes have been smaller in magnitude. Around 220 earthquakes have been recorded at the writing of this article.


The earthquake activity in the volcano called Reykjanes and Svartsengi (Þorbjörn). Copyright of this image belongs to Icelandic Met Office.

The reason for this earthquake swarm is inflation that has been increasing in recent days according to GPS data that is not yet corrected or verified. That GPS data can be found here. This inflation increases the risk of larger earthquake in next few days.

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Earthquake swarm north-east of Grindavík town

Today (30-May-2020) at 01:07 UTC an earthquake swarm started north-east of Grindavík town in the volcano of Reykjanes (Svartsengi part). Largest earthquake in this swarm had a magnitude of Mw2,7 and other earthquakes have been smaller in magnitude. This earthquake swarm is currently ongoing and this information is going to get outdated quickly. Current activity doesn’t suggest that an eruption is about to happen.


The earthquake swarm north-east of Grindavík town. Copyright of this image belongs to Icelandic Met Office.

This signals that the inflation in this part of the volcano has started again at earlier speed possibly but this requires a confirmation from GPS data and such confirmation takes a few days. This is information that I don’t have access to because its from satellites that NASA runs to monitor volcanoes. Only Icelandic Met Office and University of Iceland has access to this type of information.