Category: Katla / Mýrdalsjökull

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Katla volcano earthquake last night

Last night there was a earthquake with the size ML2.3 and with the depth of 1.3 km inside the caldera of Katla volcano. This earthquake might well be just part of the normal summer and autumn earthquake activity in Katla volcano. But at the moment it is hard to know for sure the difference at the moment.


Current area of activity in Katla volcano. It is mostly inside the caldera. Copyright of this picture belongs to Icelandic Met Office.


The ML2.3 earthquake in Katla volcano caldera last night. The P and S wave markers are unset. Picture Licence is Creative Commons.


The frequency spectrum of the Katla volcano caldera earthquake. As can be seen this earthquake has a lot of low frequency in it. Picture Licence is Creative Commons.


The Katla volcano caldera earthquake as it was recorded on my Hvammstangi geophone. It is quite unusual to record this small earthquake at this distance. This is filtered at 1Hz. Picture Licence is Creative Commons.


This earthquake here is from Goðabunga this morning. But Goðabunga is part of Katla volcano. But it is yet unknown if it is a volcano system on its own or not. The earthquakes from Goðabunga are different then the earthquakes from Katla volcano caldera, as can clearly been seen on this pictures. Picture Licence is Creative Commons.

Besides this minor earthquake activity. Everything remains quiet in Katla volcano at the moment. When that is going to change is impossible to know.

Blog post updated at 21:10 UTC.

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Earthquake activity in Katla volcano increases again

I was going to write about something else (TFZ and other earthquakes around Iceland in the last few days). But that just has to wait for a little longer.

It seems that Katla volcano earthquakes are increasing again. This increase appears to be similar to the increase in earthquakes before the glacier flood from the 9th to 17th of June and onwards until the glacier flood on 8th and 9th of July. The only difference now is that I am seeing this pattern earlier since I now know what to look for this time around when this is in its early stages.

How this is going to develop now is a wait and see process. But this might take as long time to get interesting as it did in June to July, to the event that ended with the glacier flood from Mýrdalsjökull glacier.


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

It is also worth noticing that the earthquake activity is not as focused as it was in early June and in July. But I am fully expecting that to happen soon. But it remains to be seen if that actually happens or not.

The earthquake activity SSE in the Katla volcano caldera rim is still interesting. I do not know why it is taking place there. But if a eruption would take place at this location. There would be a short glacier flood and some period with volcano ash explosions. But after that it should be lava eruption in that location if it where to last long enough to remove all that water from the crater. But this is all just a speculation and nothing more.

For now. It is just wait and see what happens next.

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Earthquake swarm north of Langjökull glacier and volcano, new hole found in Selfoss town

This is a short update.

Langjökull glacier: Yesterday there was a minor earthquake swarm north of Langjökull glacier and volcano. This area did last time was last year when a good sized earthquake swarm did happen in this area, but last year it did start around this time of year and lasted until November. It remains to be seen if that happens now. So far all the data suggests that this earthquake swarm is just tectonic in nature. It also appears that earthquake swarms in this area start slowly with long breaks between them. So I am expecting more earthquakes there. Unless this has just been a single event with no repeats.

SISZ: On Selfoss town they have just found a new strange hole in the road. The opening of the hole is about 1.5 meter in size. But the depth is about 6 meters (guess?) and area that is hollow under the hole is few hundred meters (guess?) according to the news. It is believed that this did happen because of the SISZ Mb6.3 earthquake that did happen in this area in the year 2008.

Here are news about, with pictures of the hole.

Jarðskjálftahola á Selfossi (Rúv.is, Icelandic, Picture)
Hola myndaðist í jörðinni á Selfossi (Vísir.is, Icelandic, Pictures)

Katla volcano: I think that something might be about to start in Katla volcano. But that is just a speculation that I am doing now. I am far from sure about it. But it should be clear in few hours if something is happening in Katla volcano or not. I base my assessment on rather odd changes in the tremor plot. They are hard to spot, but still there and appears to be growing it seems. But I am going to check and see what happens in few hours time. This might be nothing. But only time is going to tell us that for sure.

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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.