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.

Ongoing earthquake swarm close to Keilir mountain

The earthquake swarm with Keilir mountain continues today (2-October-2021) and largest earthquake at the writing of this article had a magnitude of Mw4,2. This might change without warning.

Green stars on Reykjanes peninsula close to the mountain Keilir. Shows where the current activity is.
The earthquake activity close to Keilir mountain. Copyright of this image belongs to Icelandic Met Office.

Based on what I am seeing it is my view that magma is the reason why this earthquake activity is happening. The magma seems trapped, based on the earthquake activity and that is interesting. This suggest that the feeder channel, that possibly started at this location has closed up and that is the reason why the eruption in Fagradalsfjall mountain stopped. At least that is the working idea, if it is true I don’t know.

Department of Civil Protection and Emergency Management and Icelandic Met Office has warned people against going to Keilir mountain because of risk of volcano eruption or large earthquakes.

It is unclear at the writing of this article if there are changes to hydrothermal activity close to Keilir mountain. There have been reports about it, but they remain unconfirmed at the writing of this article.

There is now a risk of an earthquake with magnitude of Mw6,0 in the area of Keilir mountain. The earthquake activity shows a pattern of high and low activity every few hours. Why this happens is not well understood at the writing of this article.

Earthquake activity in Katla volcano

Today (14-August-2021) an earthquake with magnitude Mw3,1 took place in Katla volcano. Other earthquakes where smaller in magnitude.

Green star in the Katla volcano caldera along with dots showing smaller earthquakes that are spread in the caldera. Showing location of smaller earthquakes that have happened in last few days.
Earthquake activity in Katla volcano. Copyright of this image belongs to Icelandic Met Office.

This earthquake activity appears to be normal late summer activity in Katla volcano. There was a minor increase in conductivity in nearby glacier rivers in last few days, that suggests that cauldrons have been emptying their water this summer. This is normal and happens almost every summer due to glacier melt.

Earthquake activity on the Reykjanes ridge

Yesterday (11-August-2021) there was a earthquake swarm on Reykjanes ridge. This earthquake swarm was not felt because of distance from the coastline.

Few green stars in the far left corner of the Reykjanes ridge along with few red dots. Image is from 11-August-2021
Earthquake activity on Reykjanes ridge. Copyright of this image belongs to Icelandic Met Office.

Largest earthquake in this swarm had a magnitude of mb4,4 according to EMSC. Information about this earthquake can be found here. The distance from the SIL network made it difficult to know when this earthquake swarm started and stopped.

It is unclear if this part of the activity period that Reykjanes peninsula and Reykjanes ridge is now entering and is going to last for few centuries.


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