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.

Earthquake swarm north of Herðubreið mountain

Today (17. February 2023) at 09:26 UTC an earthquake with magnitude of Mw3,5 took place around 4 km north of Herðubreið mountain. This earthquake seems to have started an earthquake swarm in that area. It is unclear if this earthquake activity is connected to inflation that is taking place in Askja volcano.

Green star north of Herðubreið mountain. This is east of Askja volcano. Few dots of smaller earthquakes also in Askja volcano.
Earthquake activity in Herðubreið mountain. Copyright of this image belongs to Icelandic Met Office.

There has been increase in earthquake activity at this location in Herðubreið mountain, but why is unclear.

Earthquake with magnitude Mw3,2 north of Herðubreið mountain

Today (31-October-2022) at 15:00 UTC an earthquake with magnitude Mw3,2 took place at Herðubreið mountain. This earthquake started a swarm just east of the earthquake swarm that has been going on for more than a week now. Earthquake activity remains high at the writing of this article.

Green star and red dots around Herðubreið mountain. Showing strong earthquake activity in that area.
Earthquake activity around Herðubreið mountain. Picture from Icelandic Met Office.

It is unclear what is going at this area. This looks like a tectonic earthquake activity, but there might be more in this than appears. At the moment, this is just earthquake activity and its unknown if that is going to change.

Change in the earthquake activity in close to Herðubreið mountain

Sometime yesterday (24-October-2022) a change happened in the earthquake swarm close to Herðubreið mountain. I am not sure when that change happened and it probably took few hours to happen before I detected it. But the change seems to be that now the earthquake swarm is at two locations and not just one. The second change is that the earthquake swarm is now getting more intense. The earthquakes at the writing of this article are minor, only magnitude Mw0,0 to Mw2,7 at the strongest. Nothing above Mw3,0 so far, but that might change without warning. Depth of this earthquake swarm is around 2 to 3 km at the writing of this article.

Two swarms of red dots show the location of the earthquake swarm east of Askja volcano and south of Herðurbreiðartögl volcano. The earthquake swarm is now west and north of Herðubreið mountain
Earthquake activity close to Herðubreið mountain. Picture from Icelandic Met Office.

What is going to happen next is impossible to know. An eruption in this area has not happened for at least 12.000 years or even longer. I don’t know if stronger earthquake activity is required for this area for an eruption to happen. It already is rather fractured from older earthquake activity and rift activity, that makes it possible for magma to have easier paths to the surface without much earthquake activity. That is at least one idea on the situation in this area. I might be wrong on this, since I don’t have information on the finer details of the crust around Herðubreið mountain.

Earthquake swarm north of Herðubreið mountain

During the night of 23-October-2022 an earthquake swarm started north of Herðubreið mountain. This looks like a tectonic earthquake swarm, rather then a magma related activity. At the writing of this article, over 500 earthquakes have been recorded.

Earthquake swarm north of Herðubreið mountain, a lot of red dots and green stars on the map. Located east of Askja volcano and south of Herðubreiðartögl volcano
Earthquake activity north of Herðubreið mountain. Picture is from Icelandic Met Office.

Largest earthquake at the writing of this article had a magnitude Mw4,0 and one magnitude Mw3,1 earthquake took place. Second largest earthquake had a magnitude of Mw3,3. This earthquake swarm is ongoing at the writing of this article and there’s still a risk of larger earthquakes happening north of Herðubreið mountain. The largest earthquake was felt in Akureyri according to news reports.

Earthquake swarm close to Herðubreið

Since yesterday (18-December-2018) there has been a earthquake swarm close to Herðubreið (Wikipedia). Largest earthquake in this swarm had a magnitude of 2,7. The earthquake swarm is currently ongoing and there is a risk of larger earthquake happening in this area.


Earthquake swarm in Herðubreið area (red dots). Copyright of this image belongs to Icelandic Met Office.

Over 140 earthquakes have been recorded so far and since this earthquake swarm is currently ongoing that number is going to change. This earthquake swarm appears to be only tectonic in nature. There is no sign of magma movement in the crust on nearby SIL stations.

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Two earthquake swarms in Iceland today (02-June-2017)

Today (02-June-2017) there have been two earthquake swarms taking place in Iceland. Both are minor in terms of magnitude, the second earthquake swarm is now getting close to 60 – 80 earthquakes at the moment.

Western Icelandic Seismic Zone

This earthquake swarm is taking place on the edge of the slow moving Western Icelandic Seismic Zone (as I call it). This is a earthquake active zone between Langjökull, Snæfellsnes and Vestfjörð up to Táknafjörður village. It sometimes has earthquakes with magnitude up to 5.5.


The earthquake swarm in western Iceland. I don’t think anyone of this earthquakes did go above magnitude 2,0. Copyright of this image belongs to Icelandic Met Office.

Herðubreið – Herðubreiðartögl

Also today there has been a earthquake swarm in Herðubreið and Herðubreiðartöglum. This is a common earthquake swarm. Far as I know none of the earthquakes that have happened so far have reached magnitude 2,0 at the moment. As this earthquake swarm is currently ongoing it is impossible to know for sure what happens next.


The earthquake swarm in Herðubreið and Herðubreiðartöglum (to the north-east of Bárðarbunga volcano). Copyright of this image belongs to Icelandic Met Office.

What is known is that magma has been migrating in this direction, but at this moment there is nothing suggesting that this magma has found a path to the surface and it remains at ~15 km depth. Earthquake swarms in this area normally last up to two weeks at the most.

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Earthquake swarm close to Herðubreið

All of last week there has been a minor earthquake swarm close to Herðubreið volcano crater. Yesterday (17-March-2017) the earthquake swarm increased from several earthquakes an hour and up to around several dozen earthquakes an hour. Largest earthquake so far had the magnitude of 2,9 but earlier report suggested it had a magnitude of 3,3 it was then downgraded. Since midnight (18-March-2017) around 200 earthquakes have happened. Currently the earthquake swarm is ongoing and this article might get outdated quickly.


The earthquake swarm close to Herðbreið volcano crater (red dots). Copyright of this image belongs to Icelandic Met Office.

I don’t expect an eruption in this area, since currently there isn’t anything suggesting that magma might be responsible for this activity. This part of Iceland is also outside all major volcano areas, but it might possibly leak magma for some unknown reason. Last eruption in this area took place during the last glacier period in Iceland, when exactly is something I don’t know, but it ended 11.700 years ago. Eruption in this area would also create a larger earthquake activity then is currently happening, due the fact the crust in this area is cold and would require a magma to break it before it reached the surface.

This article is going to be updated if needed.

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Overview of week 41 activity in Iceland

Week 41 in Iceland was rather quiet, compared to last two weeks in Iceland. Here is a overview over the highlight in the earthquake activity in Iceland.

South Iceland Seismic Zone (SISZ)

Constant earthquake activity has been in SISZ over the week and it has been ongoing for the past weeks, none of the earthquakes have been large, with almost all of them being less then magnitude 1,0. Largest earthquake in this swarm had the magnitude of 2,5.

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The earthquake activity on SISZ. Copyright of this image belongs to Iceland Met Office.

Bárðarbunga volcano

For most part earthquake activity in Bárðarbunga volcano was normal this week, with regular earthquake swarms taking place in the usual places. The most interesting earthquake this week took place under Trölladyngju, it was only magnitude 0,7, but it was on depth of 26,2 km.

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Earthquake activity in Bárðarbunga volcano. Copyright of this image belongs to Iceland Met Office.

Herðubreið

Earthquake swarm has been taking place all week in Herðubreið. Earthquake swarms are common in this area and often have magnitude 3,0 earthquakes or larger. The earthquake swarm is ongoing when this is written.

151011_1815
Earthquake activity in Herðubreið/Herðubreiðarfjöll area (north of Askja volcano). Copyright of this image belongs to Iceland Met Office.

Reykjanes ridge

A magnitude 3,4 earthquake took place deep on the Reykjanes ridge this week. The earthquake was not felt and there might have been more than one earthquake. My geophone in Heklubyggð shows more than one earthquake one hour after the magnitude 3,4 earthquake happens.

151008_2040
Earthquake activity on the Reykjanes ridge. Copyright of this image belongs to Iceland Met Office.

A magnitude 3,0 earthquake also took place around 200 km off the coast of Reykjanes peninsula (around 153 km south of Eldeyjarboða). That earthquake location was poor due to the distance from the SIL network.

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Strange sounds heard from Herðubreið

Yesterday (6-August-2014) strange sounds were heard from Herðubreið (Wikpedia link). It is unclear what is creating this sounds, it was first thought that a avalanche had taken place, that however doesn’t seems to be the case. Some have suggested a land-slide or rock-slide might have taken place. That has not been confirmed at the time of writing of this article. What might have happened, if anything did happen in Herðubreið is currently unknown and might remains so for a while longer.

Icelandic news about this

Snjóflóð féll í Herðubreið í gær (Vísir.is)
Óútskýrðar drunur frá Herðubreið (Vísir.is)