Category: Dyke intrusions

Posted on

Earthquake swarm in Brennisteinsfjöll volcano (Bláfjöll mountain)

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.

Posted on

Earthquake activity in western part of Katla volcano

This morning (11. March 2023) at 07:02 UTC an earthquake with magnitude of Mw3,1 took place in western part of Katla volcano. This earthquake happened in Katla volcano caldera rim. The depth was 1,1 km. This was a single earthquake, at the writing of this article.

Green star in the western part of Katla volcano caldera. This is just a one star and one orange dot showing smaller earthquake slightly north of this earthquake.
Earthquake activity in Katla volcano. Copyright of this image belongs to Icelandic Met Office.

Since this earthquake there has not been any new earthquake activity in Katla volcano. I am not sure why that is, but it there’s a chance this earthquake activity might just be over. There has been a lot of frost quakes in last few hours, because of a cold weather happening in Iceland. With freezing going down to -20C in some areas.

Posted on

Earthquake swarm in Katla volcano

Today (9. March 2023) an earthquake swarm started in Katla volcano. This earthquake swarm is ongoing and information in this article can go outdated quickly. Largest earthquakes at the writing of this article have a magnitude of Mw3,3 and Mw3,4. A swarm of smaller earthquakes is ongoing.

Two green stars in Katla volcano askja in Mýrdalsjökull glacier. Along with many red dots that show smaller earthquakes in Katla volcano.
Earthquake activity in Katla volcano. Copyright of this image belongs to Icelandic Met Office.

It is difficult to know for sure what is going on in Katla volcano. But this activity reminds me of what happened few years ago before an small eruption took place in Katla volcano. If that is going to happen now I don’t know. I’ll post information when I know more and if anything more happens in Katla volcano.

Posted on

Earthquake swarm north of Herðubreið mountain

Yesterday (5. March 2023) at 18:00 UTC an earthquake with magnitude Mw3,4 took place north of Herðubreið mountain. This is a small earthquake swarm and is part of an ongoing earthquake swarm in this area that has been going on since October 2022 (or in around that month).

Green star and red dots north of Herðubreið mountain, that is located north-east of Askja volcano. Smaller earthquakes in Askja volcano shown with blue and yellow dots.
Earthquake activity north of Herðubreið mountain. Copyright of this image belongs to Icelandic Met Office.

Depth of this earthquake was only 4,2 km and earthquake activity in this area has been getting shallower with time. If this is magma, then there’s not a lot of it at this depth. Earthquake activity is small compared to the earthquake swarms that happen just before an eruption. It is clear that, if this is magma, it is not pushing its way up the surface at this point in time.

Posted on

The earthquake activity in Skaftafellsfjöll mountain (part under Vatnajökull glacier)

Since May 2011 there has been an earthquake activity in mountain called Saftafellsfjöll. This is slightly north of Öræfajökull volcano and south of Grímsfjall volcano. This earthquake activity is now permanent in this area it seems. Some of it might be glacier quakes, but most of the earthquake activity there is not, because of the depth this earthquake activity is happening at.

Earthquake activity in Skaftafell in Skaftafellsfjöll mountain. Shown as blue, orange and yellow dots on the map of Vatnajökull glacier. Also on this map is earthquake activity in Askja volcano and Herðubreið shown with red dots.
Earthquake activity in Skaftafellsfjöll mountain. Copyright of this image belongs to Icelandic Met Office.
One year worth of earthquake data from Skjalftalísa program on Icelandic Met Office. It shows a clear concentration of earthquakes in Skaftafellsfjöll mountain over this time.
Earthquake activity in Skaftafellsfjöll mountain for 365 days. Picture is from Skjálftalísa on Icelandic Met Office website. Copyright of this image belongs to Icelandic Met Office.

I don’t know for sure what is going on. This earthquake activity clearly shows that something is going on in this part of Vatnajökull glacier. It is my unverified opinion that there is a volcano there. Its not documented and map only show a extinct volcano in this area. This is unlikely to be earthquake activity in extinct volcano, its not impossible, what makes this unlikely is that this earthquake activity happens regularly and has been going on since May 2011. There is ice quake activity in this same area, but some of this earthquake activity is both deep and being located in areas with no glacier. If those are not measuring errors or something like that (I find that unlikely in many cases). I don’t think there’s going to be an eruption in this area, at least not for a long time if it ever happens. This earthquake activity might have been going on for a lot longer then from May 2011.

– This is not an registered or confirmed volcano in this area. Unless there’s an eruption, it might be a long time until a confirmation happens.

Posted on

Earthquake swarm close to Geirfugladrangur on Reykjanes ridge

Today (21. February 2023) an earthquake swarm started close to Geirfugladrangur on Reykjanes ridge. This is possibly in another volcano than Reykjanes volcano that is just east of this location, this is because of distance and its unlikely that Reykjanes volcano extends this far south. It has no other name than Geirfugladrangur. Largest earthquake in this swarm had a magnitude of Mw3,1 and this earthquake swarm is ongoing and stronger earthquakes are a possibility.

Earthquake swarm on the Reykjanes ridge, marked by orange and green star were the largest earthquake took place. A lot of yellow dots close to Reykjanestá area.
Earthquake swarm on Reykjanes ridge. Copyright of this image belongs to Icelandic Met Office.

This earthquake pattern seems to indicate that a magma dyke intrusion is taking place. This area of the Reykjanes ridge last erupted in 16th to 18th century and has been quiet since.

Posted on

Strong earthquake swarm in Reykjanes volcano on Reykjanes ridge / Reykjanes peninsula

This earthquake swarm is ongoing at the writing of this article and information can change without warning. The largest earthquake recorded by automatic magnitude of Mw3,7 at the writing of this article. Around 30 to 40 earthquakes have happened so far, but that number might change quickly. This earthquake activity has some signs that it might be happening because of magma intrusion in the area, out in the ocean but signals are not clear.

Three green stars and red dots on the left down side on the map of Reykjanes peninsula, the earthquake activity is happening out in the ocean on the Reykjanes ridge.
The current earthquake activity on Reykjanes ridge. Copyright of this image belongs to Icelandic Met Office.

This earthquake activity is in the volcano Reykjanes, that volcano goes into the ocean and is on dry land. Making possible future eruptions both explosive and flowing magma at the same time. To date, Reykjanes volcano only has had earthquake swarms and no eruption. When that is going to change is impossible to know.