Grímsvötn/Grímsfjall volcano eruption update at 08:52 UTC

This is a short update on Grímsfjall volcano/ Grímsvötn eruption. This is short update because a lot of details in this eruption are still unclear at this moment.

Process of the eruption: The eruption in Grímsvötn is still growing strong. Icelandic Met Office SIL sensors show a uneven process in the eruption. But they also show that the eruption has dropped a little bit in power since it originally started in yesterday. That is normal for a eruption in Grímsfjall volcano. It starts strong and then slowly drops in power over time. But what is unusual for this eruption is the uneven process that is taking place (seen with SIL data) in the eruption. What that means is unclear. It is more unclear what it means to the eruption. While it is unclear at the moment. It appears that the eruption is taking place a little south of the eruption in the year 2004. But that is unconfirmed, as ash cloud to the ground blocks the view the eruption site.

Ash cloud: The ash plume is reported to have reached 20 km high yesterday. From as I can gather that has not changed. This ash plume appears be made from two to three ash cloud columns. With the strongest one getting the highest. A lot of lightning is taking place in the ash cloud. Due to the ash cloud, all flight from and to Iceland has been cancelled until further notice (don’t ask question about that here, ask your airliner for information about this closure). The ash did start to fall in populated areas few hours after the eruption did start in Grímsvötn. The ash is described as fine, but more crude (bigger particles) then the ash from Eyjafjallajökull volcano eruption in the year 2010. The ash cloud is moving west in higher layers of the atmosphere over Iceland. While it moving south in the lower layers of the atmosphere as the wind is from north in Iceland at the moment.

Earthquakes: After the magma has found it’s way to the surface. All earthquake activity did stop in Grímsfjall volcano. This is normal. But what is unusual is that there have been few earthquake swarm after that in Grímsfjall volcano. I do not know what it means or why this is happening. But this is interesting development.

Other: The earliest estimation on the size of the Grímsfjall volcano eruption 2011 is that this looks like it is a bigger eruption then in Eyjafjallajökull volcano eruption in the year 2010. But that is closer to speculation based on visual observation of the eruption. But it is clear that this eruption is bigger then the year 2004 eruption in Grímsfjall volcano.

A new video has been relased of the eruption. It is from yesterday when the eruption was starting.

Update 1: They now say that this is the largest eruption in Grímsvötn / Grímsfjall volcano in the last 100 years. Rúv news about this, Stærsta gos í Grímsvötnum í 100 ár (Icelandic).

Please note that information here might get outdated really fast and with no warning at all!

Update at 09:24 UTC.

Ash cloud confirmed from Grímsfjall volcano

A eruption ash cloud has been confirmed from Grímsfjall volcano. I do not know how high it currently is. But Icelandic news is reporting that the cloud is rising fast and high (estimated 3000 – 4000 meters and rising). Explosions have been seen from good distance.

Update 1: They estimate that there are 10 to 12 hours until the glacier flood appears from this eruption. The ash cloud can be tracked with lighting map here.

News about this.

Strókur rís hátt yfir Grímsvötnum (Rúv.is, picture)
Tíu til tólf klukkutímar í hlaup (Rúv.is, new picture)
Allir viðbragðsaðilar komnir af stað vegna gossins (Vísir.is, Picture)
Mjög öflug gosstöð (mbl.is, New picture)

Updated at 19:41 UTC.
Updated at 19:53 UTC.
Updated 20:21 UTC.

Earthquake swarm close to Geirfuglasker on Reykjanes Ridge

Today at 15:08 UTC a earthquake swarm did start close to Geirfuglaskeri on Reykjanes Ridge. This earthquake swarm has so far been small, with the largest earthquake having the automatic size ML2.4 with the depth of 10 km.

So far this earthquake swarm has remained small. But it is unclear if this earthquake swarm is going to continue. But there was a break in this earthquake swarm from 16:12 UTC too 18:55 UTC. But I did think that this earthquake swarm was over, until it did start again.

It is impossible to know if this earthquake swarm is over or not.

Deep earthquake in Herðurbreiðarfjöll volcano (Askja volcano fissure swarm)

Today at 06:57 UTC in Iceland there was a ML0.2 earthquake east of Herðurbreiðarfjöll volcano. While the size of this earthquake is really small. It is the depth that is interesting in this case. The depth of this earthquake was at 25,7 km depth. This is a interesting depth given the increase in earthquake activity in Askja volcano.

According to my geological map (a rather new one) the mountain named Herðubreiðarfjöll is a volcano that is inside Askja volcano fissure swarm. A common thing that happens in Iceland. This area has many active fault lines and has erupted in modern time. But I do not know when this volcano last erupted, as there are no information on Herðurbreiðarfjöll volcano activity in the GVP database and I have not found anything useful on the internet about this volcano.

Earthquake activity continues in Askja volcano. But at slower rate then before. Other then this, it is quiet in Iceland as it has been for the past few weeks.

Earthquake in Askja volcano last night

Here is a picture of a earthquake that took place in Askja volcano last night. This earthquake was bearly visable on my geophone close to Hekla volcano. From this data it is clear that the earthquakes are created by magma movements inside Askja volcano. But the earthquake swarm is taking place on the edge of Askja volcano main system. It is not happening outside as it might appear.

It is also worth pointing out that not all of Askja volcano earthquakes might appear on the automatic SIL system. But most of them should do so. As Askja volcano is remote and in a unpopulated area there should not be any damage from a eruption. The only damage might happen if there is a eruption in Askja caldera lake due to ash cloud that might form.


Askja volcano earthquake. This is low pass filtered at 1Hz. This image is released under Creative Commons License, see top link for more information. Click on this picture for full resolution.

This earthquake has magma signature from the looks of the earthquake signal. But due to distance it is hard to be sure on that.

When this is written a tremor pulse appears to be starting in Askja volcano. But this might also be a swarm of micro earthquakes taking place in Askja volcano without the earthquakes appearing on the automatic SIL system. At this point it is hard to know for sure, as this activity is new.


Locations of the earthquakes in relations to the Askja volcano system. As can be seen on this map from Icelandic Met Office, the earthquakes are clearly inside Askja volcano. Even if they are not at the main caldera. Picture is from Icelandic Met Office web site. Copyright of this picture belongs to Icelandic Met Office.

Blog post updated at 16:37 UTC on 5 May 2011. Picture is added.

More information on the Askja volcano earthquakes

The earthquake activity in Askja volcano continues to evolve at rather fast phase. A lot faster phase then I did originally expect. Far as I can tell from the Icelandic Met Office SIL data (tremor plots). The earthquakes that are now taking place in north Askja volcano appear to be mostly magma related earthquakes. The strongest earthquake so far did happen today and had the size ML2.5 with the depth of 0.1 km. The deepest earthquake so far took also place today and had the depth of 19,6 km. It had the size ML1.4.

However earthquakes with the depth of 22 km has been recorded close to Herðubreiðartögl. Few days ago a tornillo earthquakes (most likely the case now. But yet unconfirmed from my point of view) started too appear in Askja volcano. But that means that magma is on the move in Askja volcano. Currently this might also be the case with the earthquake activity east of Askja volcano. But at this moment it is a bit more unclear what the activity east of Askja volcano means. But it is also possible that magma is also pushing east from Askja volcano. But so far earthquake activity east of Askja volcano has been different then from the earthquake activity north of Askja volcano. But it has not been focuesed on a single spot like the earthquake activity in north part of Askja volcano system.

It is unclear at this moment how this is going to evolve in the long term. But no reports of increased hydrothermal activity have so far appeared in the news. Currently the activity is rather low, so a eruption is not yet imminent in Askja volcano. But that might change without any warning at all at any time.


Current Askja volcano earthquake activity. Click on this picture for full resolution. Picture is from Icelandic Met Office web site. Copyright of this picture belongs too them.

Due to distance. I do not record any small earthquakes from Askja volcano. But they need to be larger then ML3.0 to appear on my geophone network.

Overview of the Askja volcano earthquakes

This is just a short overview of the Askja volcano earthquakes that have been taking place over the past few weeks. I do not at this have a good picture of what is happening in Askja volcano.

In Week 15 earthquake activity started north of Askja volcano. This activity have been growing since then, with considerable difference between Week 16 and Week 17. Currently the earthquake activity is ongoing. It is not clear if this earthquake activity has slowed down or not. Many of the earthquakes that are taking place north of Askja volcano are shallow. But most of the earthquakes are happening on a depth from 1 km and up to 0.0 km. I am currently unclear on why the activity is so shallows as seems to be the case.

A second set of earthquakes have also been taking place in Askja volcano system. But this earthquakes are taking place east of main Askja volcano. But Askja volcano fissure system goes east and then north from the main volcano. It also goes several km south of main Askja volcano. But that area has not seen any activity so far. While the activity east of Askja volcano is not clustered as it is north of it. It is showing many of the same signs as the earthquakes north of Askja volcano. They are shallows with most of the earthquakes taking place in less then 1 km depth. As before I am not sure why the earthquakes are taking place on less then 1 km depth. But one idea for both the earthquakes north and east of Askja volcano is that there is magma pushing up the bedrock north and east of Askja volcano. But does not at this time have the power to break up trough the crust and start a eruption. Only one deep earthquake has so far been recored, it was on a 22,8 km depth. The location of this earthquake was not far from Herðubreiðartöglum mountains.

Due to lack of GPS data it is hard to see any deflation or deformation in Askja volcano. But it has been known since last year (2010) that Askja volcano has started to prepare for a eruption. But it remains unclear how long it is until Askja volcano is fully ready for a eruption. Last eruptions that took place in Askja volcano where in the years 1961, 1938, 1926, 1924, 1923. More on Askja volcano eruption history here (GVP web page).

Hekla volcano earthquake last night

Last night at 21:39 UTC there was a ML0.7 earthquake in Hekla volcano. Depth of this earthquake was 1.3 km. It is unclear if this earthquake is a pre-event before a eruption starts. But few years ago there was a earthquke in Hekla volcano. But no eruption did happen that time around.


Hekla earthquake. Click on the picture too see it in full resolution. This picture is released under Creative Common License, see top link for more information.

This is a picture of the earthquake. The distance was 16.8 km from my geophone to the location of the earthquake. My geophone is close to Hekla volcano and because of that it is really sensitive to any activity that takes place in Hekla volcano (given good weather).

About the earthquakes north of Askja volcano

The earthquakes that are now taking place north of Askja volcano are interesting for many reasons. One of the biggest reason why this earthquakes are interesting is the fact how shallow they are. But it is also interesting on how small the area the earthquakes are taking place on.

This earthquake activity did start in Week 15 with one earthquake. In Week 16 the activity had grown up to few earthquakes. In Week 17 (current) the activity has continued to grow in this area. This activity currently stands out in the earthquake activity around Askja volcano.

While it is common for Icelandic volcanoes to erupt from a central vent. It is also common for Icelandic volcanoes too erupt from fissures (like Fimmvörðuháls Eruption 2010). One of the clues to this type of eruption close to a central volcano is a earthquake activity. It is my opinion that this earthquake activity qualifies as pre-activity for a fissure eruption in the area of Askja volcano. But if anything happens soon is a different question and it is impossible to predict for now. It is however sure that before such eruption the earthquake activity in this area needs to increase a lot more from the current levels of earthquake activity that are being seen today.

Currently no eruption is immanent in Askja volcano.