Earthquake swarm in Brennisteinsfjöll volcano (Bláfjöll mountain)

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Earlier this week, an swarm of earthquakes started in south of Brennisteinsfjöll volcano, also known as Bláfjöll mountain. This earthquake swarm started on a west to east fault north of a lake called Hlíðarvatn. This earthquake swarm has only been minor earthquakes, with magnitudes in the range of Mw0,0 and up to Mw2,3 but at the writing of this article, nothing above that magnitude. Over the week this earthquake swarm has evolved into a single area that seems to be circular, based on current earthquake activity. This strongly suggests that magma is the reason why this earthquake swarm is happening.

Red dots in south of Brennisteinsfjöll volcano. Showing the earthquake activity in that volcano. Red dots are also visible in Hengill volcano in a unrelated earthquake swarm.
Earthquake activity in Breinnisteinsfjöll volcano. Copyright of this image belongs to Icelandic Met Office.
Dots in different sized showing the earthquake swarm in Brennisteinsfjöll volcano. This is a image from Skjálfta-lísa website from Icelandic Met Office.
Earthquake as they appear on Skjálfta Lísa website from Icelandic Met Office. Screenshot from Icelandic Met Office website Skjálfta Lísa.
Google Earth image of the area where this earthquake swarm is taking place. It shows the road, the Hlíðarvatn lake and other feature in the landscape. Including a old lava flow the west of the current earthquake swarm. The landscape also seems to show older craters at this location, but those are weathered down to almost nothing.
Google Earth image of the area where the earthquake swarm is taking place. Picture is from Google Earth.

At the writing of this article, the earthquake activity is too small to start an eruption. Since this area is cold and the crust is too hard for the magma to flow freely inside it. Current depth of the earthquakes is around 5 to 7 km at the writing of this article and has not changed a lot during the week. While the Skjálfta Lísa image does not show this, it is possible that the earthquake activity has started to spread more east, compared to earlier in the week when this activity started. This earthquake actiivty might stop, as often happens in the early stages of a new eruption cycle in a volcano.

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Earthquake swarm in Reykjanes volcano and deep earthquake activity in Brennisteinsfjöll volcano

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Today (10-December-2020) at 00:08 an earthquake with the magnitude of Mw3,5 took place in the volcano Reykjanes. This earthquake was felt in nearby area. Since then there has been a minor earthquake swarm going on in the area of Reykjanestá.


Green star shows the earthquake activity in Reykjanes volcano. Copyright of this image belongs to Icelandic Met Office.

Brennisteinsfjöll volcano

Today (10-December-2020) an deep earthquake swarm took place in Brennisteinsfjöll volcano. All earthquakes that took place where small in magnitude but depth was from around 5km to 12 km depth. It is not known at the writing of this article if this suggests an magma movement inside Brennisteinsfjöll volcano.


Orange dots to east of Krýsuvík volcano show the activity in Brennisteinsfjöll volcano. Copyright of this image belongs to Icelandic Met Office.

I am expecting more earthquake activity in Brennisteinsfjöll volcano in next few months. It is going to take few weeks to months to see if anything more is going on there.

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Earthquake swarm on Reykjanes peninsula – Bláfjöll area

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Today on 24-November-2018 a magnitude 3,3 earthquake took place in Bláfjöll area. Second largest earthquake in this swarm had a magnitude of 2,9. Other earthquakes have been smaller in magnitude.


Earthquake activity in Bláfjöll area. Copyright of this image belongs to Icelandic Met Office.

The larger earthquake was felt in Reykjavík area according to news reports. The earthquake swarm appears to be ongoing.

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