Category: Katla / Mýrdalsjökull

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Earthquake swarm and minor harmonic tremor in Katla volcano

There has been a minor earthquake swarm in Katla volcano today. This earthquake swarm started around 09:00 UTC and lasted with breaks until 14:39 UTC. The largest earthquake in this swarm was ML1.7 with the depth of 3.5 km. Following this earthquake swarm there was a small harmonic tremor spike seen on few SIL stations around Katla volcano. It is unknown at this time if there has been a small glacier flood taking place. But if that is the case, it should be known in the next few hours if that is the case or not.


The earthquake swarm in Katla volcano caldera. Copyright of this picture belongs to Icelandic Met Office.


The harmonic tremor spike can be seen on this SIL station. It is located close to the end of tremor plot. Copyright of this picture belongs to Icelandic Met Office.


The harmonic tremor spike can be seen on this SIL station. It is located close to the end of tremor plot. Copyright of this picture belongs to Icelandic Met Office.

This harmonic tremor is small, but larger then last harmonic tremor that took place in this are about one week ago (far as I can remember). Currently there is nothing that suggests that eruption is imminent. This is just earthquake activity in the same place as it has been for the past five or so weeks.

Sorry for the short blog post. I have gone sick with some cold. No advice needed on how to get rid of it. That is going to take few days on it’s own.

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Currently all is quiet in Iceland

At the moment it is rather quiet in Iceland in earthquakes and volcanoes. When that might change is impossible to say. But in the last few days there have been minor earthquake swarms on the Reykjanes Ridge. It is not related to volcanism, but rather tectonic movement along the rift zone.

There is continued minor earthquake swarm activity in Katla volcano. But it has quieted down from about two weeks ago. For the moment, the glacier floods seems to have stopped.

Other then this minor earthquake activity, everything is quiet in Iceland.

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Small glacier flood from Mýrdalsjökull glacier (Katla volcano)

During the night (and when I had unstable power) there was a small glacier flood from Mýrdalsjökull volcano. Some minor harmonic tremor change was detected following this glacier flood. This even was small one, many times smaller then what did happen on the 8 to 9 July 2011. Due to security concerns the Civil Emergency Authority did close the main road in Iceland for this area. Since they never know how big the flood can actually be. The main road was closed for about one hour. This glacier flood was detected around midnight 20 to 21 July 2011.

This flood is actually so small it is hard to see it on the harmonic tremor plot from the SIL stations around Katla volcano.


Tremor plot from 07:50 UTC this morning. It is hard to see the harmonic tremor from this minor glacier flood. Copyright of this image belongs to Icelandic Met Office.


Tremor plot from 07:50 UTC this morning. It is hard to see the harmonic tremor from this minor glacier flood. Copyright of this image belongs to Icelandic Met Office.


Tremor plot from 07:50 UTC this morning. It is hard to see the harmonic tremor from this minor glacier flood. Copyright of this image belongs to Icelandic Met Office.

What happens next is impossible to know for now. But it seems that activity continues to be high in Katla volcano. All that can be done is to wait and see what happens. But I am going to continue to monitor the changes in Katla volcano as best that I can do until I finish my summer job (29. July).

Icelandic News about this.

Aukin leiðni í Múlakvísl og órói í Mýrdalsjökli (Vísir.is, Icelandic)
Náið fylgst með Mýrdalsjökli (mbl.is, Icelandic)
Hringvegurinn opinn á ný (Rúv.is, Icelandic)
Breytingar í Múlakvísl (Rúv.is, Icelandic)

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Interesting earthquake activity in Katla volcano

Sometimes there is a strange earthquake activity in volcanoes. I do think that this qualifies as one of that cases. But there has been odd and what appears to be grown earthquake activity in SE part of the caldera rim in Katla volcano.


The earthquake activity is the earthquake spot the SE in Katla volcano, out side the caldera. Copyright of this picture belongs to Icelandic Met Office.

From what I can gather this activity started in Week 27 or about that time. Since then it appears to have been growing in number of earthquakes. I do not know yet if there have been any changes in the area, like hydrothermal activity.


Week 27. One earthquake can be seen in this area. Copyright of this picture belongs to Icelandic Met Office.


Week 28. More earthquakes in the same area. Clear sign that the activity is growing. Copyright of this picture belongs to Icelandic Met Office.


Weeek 29 (crurrent week) . Even more earthquakes at the same location. Copyright of this picture belongs to Icelandic Met Office.

While I do not yet what is going on there. This is something that might be interesting to watch and see what happens. Because small amount of magma might just have found a new pathway up the surface in this area. Even if it does not erupt, this might create new hydrothermal area if this is in fact magma. But given that this is in a volcano and really dense earthquake swarm. It is my guess that it is the case.

Power outage: Due to some maintenance work on the local power grid where I live I lost all power from 01:00 until about 06:20 UTC this morning. But that means that this blog post is late by several hours and my geophone webicorders have been off-line at the same time. Sadly I cannot afford few UPS like this one to keep my system up and running when the power goes out. As I need at least four of them at home and one with each webicorder computer (at location).

I am going to post update on what did happen during the night around 09:00 08:00 UTC. When I know more and after some more sleep.

Blog post updated at 07:29 UTC on 21. July 2011.

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New cauldrons forms in Mýrdalsjökull glacier (Katla volcano)

According to the news here in Iceland there have been a formation of at least three new cauldrons in Mýrdalsjökull glacier, where they have not been before in the glacier. But this means that the hydrothermal areas under the glacier are growing in size due to new magma pushing up into the crust and warming it up.

This has been revealed after a daily checking of the status on the glacier. But the current cauldrons that formed on the 8 and 9th July have also deepened according to the same news. A lot of deep cracks are also forming in Mýrdalsjökull glacier. Making the south part of the glacier extremely dangerous at current moment.

There is also risk of minor glacier flood from water collecting under the glacier (both really small and slightly larger ones). But water might be collecting in ice-caves under the glacier and break free without any warning at all. The Civil Emergency Authority in Iceland warn against travelling in this area on Mýrdalsjökull glacier.

The reason why this is happening is the fact that hydrothermal activity is increasing under Mýrdalsjökull glacier in Katla volcano. But this is a clear sign that Katla volcano is warming up to a eruption. When that might happen is still a question with no answers.

Currently there is no good way to know what happens in regards to possible glacier floods due to this increased hydrothermal activity in Katla volcano. But floods are expected to take place without any warning now in this area.

Icelandic News with pictures of the cauldrons.

Þrýstingur fellur í sigkötlunum (Rúv.is, Picture)
Ferðamenn koma ekki nálægt sigkötlum (Vísir.is, Icelandic, Picture)
Ferðamenn aka ofan í ketil sem er að springa (Vísir.is, Icelandic, Picture)
Ástæða til að vakta svæðið (mbl.is, Icelandic, Picture)
Sigkatlasvæðið er varasamt (mbl.is, Icelandic)
Sigkatlasvæðið stækkað (mbl.is, Icelandic, Picture)

Blog post updated at 00:51 UTC 20. July 2011.

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Small earthquake swarm in Katla volcano caldera

At the moment there appears to be a small earthquake swarm in Katla volcano. Currently this is just a earthquake swarm. All the tremor plots are normal and show no signs of harmonic tremors and magma on the move. The largest earthquake in this earthquake swarm in inside Katla volcano caldera was a ML1.3 with the depth of 1.7 km according to reviewed data from Icelandic Met Office.


The earthquake swarm in Katla voclano. It is deep inside Katla volcano caldera as can clearly be seen. Copyright of this picture belongs in Icelandic Met Office.


The ML1.3 earthquake as I did record it on my Heklubyggð geophone. Given the shape and how low period this earthquake is. I would say that it was created by magma pushing upwards in the crust inside Katla volcano caldera. This picture is released under Creative Commons licence, see the licence web page for more details.

At the moment (when this is written) it seems that this earthquake swarm is over. For the moment anyway. But it hard to know for sure if it resumes or something else starts in Katla volcano.

Update 1: A earthquake with the magnitude ML3.8 did happen in Katla volcano caldera at 02:02 UTC. Following this earthquake there have been many aftershocks. It is not yet clear if this means that Katla volcano is starting a eruption or not. But that should be clear in few hours if that is the case or not.


The ML3.8 earthquake that happened at 02:02 UTC. This is by the automatic SIL system, so it’s size can change. This picture is released under Creative Commons licence, see the licence web page for more details.


The location of the ML3.8 earthquake in Katla volcano caldera and the following aftershocks. Copyright of this picture belongs to Icelandic Met Office.

Blog post updated at 02:26 UTC on 18. July 2011.
Blog post updated at 02:40 UTC on 18. July 2011.

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New harmonic tremor detected in Katla volcano

Earlier today there was an minor harmonic tremor in Katla volcano. It’s source was inside the Katla volcano caldera as before, it is impossible to know the exact location of the source this harmonic tremor spike. But earthquakes around that same time might give a clue about it’s origin.


Harmonic tremor can be found close the end of this tremor chart. It is peaks from the background noise that is currently taking place in Katla volcano on this SIL station. Copyright of this picture belongs to Icelandic Met Office.


Harmonic tremor can be found close the end of this tremor chart. It is peaks from the background noise, it small but it can be found. Copyright of this picture belongs to Icelandic Met Office.


Current earthquake activity in Katla volcano caldera. Copyright of this picture belongs to Icelandic Met Office.

This harmonic tremor spike was small compared to the one on 8 – 9. July 2011. But this means that this area continues to be highly active and dangerous in my opinion. While there currently is an little pause ongoing in this area. I do not think that current events are over. When they end and how I don’t have any idea. But I am guessing that this is going to end in an full eruption of Katla volcano. When that might happen is something I don’t have any idea about.

For the moment. The only thing that can be done is to wait and see what happens in Katla volcano.

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Update on Katla volcano at 22:25 UTC

Here is an short update on Katla volcano.

There has not been a lot of earthquake activity in Katla volcano during the past few hours. The harmonic tremors are back to normal. But show increased noise from the glacier due the formation of the cauldron in it.

Here is an picture of the current travel ban area. The red lines mark the travel ban area on Mýrdalsjökull glacier. Picture is from Civil Emergency Authority in Iceland.

Other then this it is quiet in Katla volcano. But it important to notice that it is impossible to know for how long this quiet time is going to last given the pattern of activity over the past few weeks in Katla volcano.

Next update on Katla volcano is going to be when it needs to be posted.

Icelandic News about this.

Minnka hættusvæðið á jöklinum (Rúv.is, Icelandic)

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Overview of current events in Katla volcano and current status

Here is an overview of the current events in Katla volcano. This is the short version, as I have not had the time to go over all the data collected so far.

12 June: On this day I did notice the first harmonic tremor spikes. This tremor spike was small and only noticed on few SIL stations around Mýrdalsjökull volcano. No earthquake activity was detected following this event. At least no earthquake activity that was unusual in my opinion.

17 to 18 June: The first earthquake swarm took place on this day that I connect to the current events. This earthquake swarm was special and different from the normal earthquakes that I see in Mýrdalsjökull volcano caldera. It was how dense this earthquake swarm was. There was no or little harmonic tremor following this earthquake swarm.

21 June: New harmonic tremor spike took place in Katla volcano on this day. It was a bit stronger then the first one. But lot smaller then what did happen this weekend.

28 June: What appears as an glacier earthquakes did appear on this day. Along with normal earthquake activity inside the Katla volcano caldera.

After this the events of July 8 start, it did end on the 9 July after what is most likely an minor eruption inside the Katla volcano caldera. This event is over it seems and Katla volcano has once again paused. But that has happened repeatedly over the past few weeks. The time between stops is different and it is impossible to know when the current pause ends. It is also impossible to know what happens next time activity picks up in Katla volcano caldera. Currently the earthquake activity continues in the Katla volcano caldera, but there are few earthquakes happening now then earlier this weekend.

For now all that can be done is to wait and see what happens.

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All quiet at Katla volcano

Currently everything is quiet in Katla volcano. At the moment the harmonic tremor level have gone back to normal levels. But there appears to be some earthquake activity taking place inside Katla volcano caldera. But most of this earthquakes do not appear on the automatic earthquake list that IMO has. But it might be impossible to actually locate this earthquakes as they might just appear on single or two SIL stations.

The glacier flood is over and the flood water have continued to lower during the day.

It is hard to know for sure what happens next. But the current events started around 17. June when earthquake swarms started to appear on the Katla volcano caldera. This has been developing rather fast since then. I do not expect that to change any time soon. But what I think was harmonic tremor pulses started around 12. June.

For now however all that can be done is to wait and see what happens in Katla volcano. As I do not think that this is over. But we might be in for an few hours or days of an break until something new happens in Katla volcano.

Icelandic News about this.

Einungis brúin eftir (Rúv.is, Icelandic, Picture)
Highway no. 1 disrupted for weeks. (Rúv.is, English, German)