Category: Katla / Mýrdalsjökull

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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)

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Harmonic tremor drop down. New earthquake happen in Katla volcano caldera

It seems that on many SIL station around Katla volcano that the harmonic tremor has gone mostly down to background levels, on other stations it continues to drop. This are mostly SIL stations that are at the most distance to the source of the area that this minor eruption took place during the night. But at the moment this seems to be over. The main source of the activity appears to be where the eruption took place in the year 1918, or so scientists think at the moment.

According to the news there was an flood wave around 04:00 UTC during the night. When the water meters did show an rise of 5 meters suddenly. Soon after that the bridge over Múlakvísl river was lost in the glacier flood. This did close the main road 1 in this area, that area of the main road is going to remain closed for the next few weeks while they fix the damage done in the flood (build an new bridge).

Even if the harmonic tremor seems to be dropping. This does not seem to be over, as an earthquake activity did resume from around 13:00 UTC in the Katla. Since then the earthquake activity seems to have been building at slow rate.


Tremor plot at 18:23 UTC. The tremor is dropping. It also shows that earthquakes are taking place (spikes the tremor chart). Copyright of this picture belongs to the Icelandic Met Office.


Tremor chart from Goðabunga at 18:24 UTC. Copyright of this picture belongs to the Icelandic Met Office.


Dropping harmonic tremor on Lágu Hvolar. Earthquakes appear as spikes here. Copyright of this picture belongs to Icelandic Met Office.


Dropping tremor and earthquakes as before. Copyright of this picture belongs to Icelandic Met Office.


Earthquakes as they are tonight. The southern part of the caldera is having earthquake swarm, even if it is just an small one. Copyright of this picture belongs to Icelandic Met Office.

I am waiting too see how this develops. Something larger might happen. But nothing else might happen for an while in Katla volcano. The only thing that can be done is too wait and see what happens in Katla volcano.

Icelandic News about the road damage.

Meiri skemmdir en talið var (Rúv.is, Picture, Icelandic)

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Harmonic tremor still high in Katla volcano

Currently harmonic tremor remains high in Katla volcano. But at the moment the harmonic tremor is dropping. Earthquakes have also stopped for the moment. But currently the harmonic tremor is well above the background level for this area. It is still not clear if this was an eruption or just hydrothermal areas clearing it self of extra water. But in the news at Rúv noon they did report that the ice cauldrons that are normally there had deepened over the past few weeks in Mýrdalsjökull glacier.

Update 1: Earthquake activity has stopped for the moment. But I am expecting it to resume soon. As I do not think that this event is over, even if it has just paused for the moment.

Three cauldron have formed in Mýrdalsjökull glacier and large cracks have formed around them. All traffic has been banned on Mýrdalsjökull glacier and the glacier that comes from it.

Here are the current tremor charts from Icelandic Met Office web page.


Harmonic tremor is dropping as can clearly be seen on this picture. Copyright of this picture belongs to Icelandic Met Office.


Harmonic tremor is dropping as can clearly be seen on this picture. Copyright of this picture belongs to Icelandic Met Office.


Harmonic tremor is dropping as can clearly be seen on this picture. Copyright of this picture belongs to Icelandic Met Office.

I am going to post update on Katla volcano later today and earlier if anything major happens.

News with picture of the Mýrdalsjökull glacier. It is covered with dark ash from Eyjafjallajökull volcano eruption last year and volcano ash from the eruption in Grímsfjall volcano 2011.

Miklar sprungur í sigkötlunum (mbl.is, Picture, Icelandic)
Svona lítur jökullinn út (Rúv.is, Icelandic, Picture)
Þrír greinilegir sigkatlar (Vísir.is, Icelandic, Picture)
Brúin rofnaði af í heilu lagi (Vísir.is, Icelandic, Picture)
Óvissa um hlaup eða lítið eldgos (Rúv.is, Icelandic, Pictures)

Blog post updated at 13:13 UTC 9. July 2011.

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Possible small eruption in Katla volcano, small glacier flood followed it

It seems that an small eruption took place in Katla volcano caldera during the night. At the moment it seems to be over. But it is hard to be sure. According to Icelandic news there where three newly formed cauldrons in the Mýrdalsjökull glacier. The eruption is unlikely to break the glacier at current time if it remains small. Newest news reports say that cracks have formed in the glacier around the cauldrons.

Evacuations are currently taking place in Álftaver, Þakgil and any other place that might be danger. People how are close to affected rivers from Mýrdalsjökull are urged to get away from them due to danger of dangerous gases in the glacier water.

The bridge over Múlakvísl is gone, it did vanish the flood water early this morning. According to the news the bridge got flooded around 03:00 UTC last night. This means that Road 1 is closed in this area.

Currently earthquake activity continues in Katla volcano caldera. But the tremor has been dropping for the past few hours after it topped around 03:00 UTC last night.


Earthquakes this morning in Katla volcano. Copyright of this picture belongs to Icelandic Met Office.


Harmonic tremor at 09:16 UTC this morning. Copyright of this picture belongs to Icelandic Met Office.


Harmonic tremor at 09:16 UTC this morning. Copyright of this picture belongs to Icelandic Met Office.

The tremor has dropped, but is not down to background levels yet. This might be small eruption for the moment. But I fear that might change in the next hours to few days. There is also an big risk of new floods from Mýrdalsjökull glacier due to this small eruption, or if new fissures open up at new places.

I am going to post more updates when I know more. At the moment, this is just an small eruption. But as told before. That might change without any warning at all.

News in English.

Possible eruption in Katla (Rúv.is)

News in Icelandic.

Rýma á Þakgil – tugir á svæðinu (Rúv.is)
Mögulegt hlaup í Skálm (Rúv.is)
Ekki stórt gos í Kötlu (Rúv.is)
Sigkatlar benda til að lítið gos sé hafið (Vísir.is)
Sjá sprungur í jöklinum (mbl.is)

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Glacier flood from Múlakvísl has been confirmed

According to the Icelandic news an glacier flood started around midnight in Múlakvísl (link should work, let me know if it doesn’t) glacier river that runs from Mýrdalsjökull glacier. Last time this type of event did happen was in the year 1955, when an minor eruption is believed to have taken place under the Mýrdalsjökull glacier. I do not know if that is the case now. As this might just be hydrothermal water being released due to increased activity in hydrothermal areas that are in Mýrdalsjökull glacier.

Following the flood there is an strong smell of sulphur and there might be dangerous gases in it. At current time the flood appears to be growing and according to the news (written at 01:54 UTC) the bridge was still safe. But there was just 1 meter from the river and up to the floor of the bridge.

Some minor earthquakes have been taking place in the past few hours, they do not appear on the automatic earthquake list on Icelandic Met Office web page. Some of them appear on my Hekla webicorder.

Currently the harmonic tremor is dropping. But that might not mean anything in the long run. So far everything suggests that an eruption has not yet started in Katla volcano. But given the current status that might not last long as it is. The best thing that can be done is to wait and see what happens. But no fear scaremongering please!

Added: When I just finished writing this blog post an new earthquake just started to appear on my geophone at Hekla volcano. IT is from Katla volcano for sure. It was in the ML1.5 to ML2.5 size range it seems. It was an long period earthquake as they have been so far. I think it is from the main caldera, not Goðabunga area.

Icelandic News about the glacier flood.

Hlaup hafið í Múlakvísl (mbl.is, Icelandic)

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Harmonic tremor continue to increase in Katla volcano

When this is written around 00:36 UTC on 9. July 2011 the harmonic tremor levels on SIL stations around Katla volcano have continued to increase. The latest spike in harmonic tremor levels happened after an ML1.5 (automatic size) earthquake that took place at 22:13 UTC. There has been an small earthquake swarm in Katla volcano caldera yesterday. But the largest earthquake in that earthquake swarm had the size ML2.4.

The harmonic levels are getting so strong that they have started to appear on stations around Hekla and on my own geophone, even if it is located almost 60 km away from the source of the harmonic tremor. Currently there is little to suggests that this is slowing down at the moment. But that might yet happen. But it is impossible to know for sure at the moment.

The lack of earthquakes tells me that the magma has not yet reached the surface. When or if that might happen is an good question that I do not have the answer to. But this might take several more hours until something happens in terms of earthquakes or other activity in Katla volcano.


Harmonic tremor can clearly be seen on this SIL station at the end of the tremor chart. This is saved around 00:36 UTC 9. July 2011. Copyright of this picture belongs to Icelandic Met Office.


Harmonic tremor can clearly be seen on this SIL station at the end of the tremor chart. This is saved around 00:36 UTC 9. July 2011. Copyright of this picture belongs to Icelandic Met Office.

As sad before the harmonic tremor can now be seen on SIL stations far away from Katla volcano. But the maximum range so far is around 65 km or so at the moment.

This is the last update for tonight. I am going post an update tomorrow on what has happened during the night. Even just to say people that things have slowed down or gone back to normal. Whatever happens. I am going to post information about it tomorrow when I awake up.

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Harmonic tremor in Katla volcano

At the moment there is an ongoing harmonic tremor going on in Katla volcano. It is just an small one, just above the background level noise floor. This is most likely an small dike intrusion. But nothing in the data from Icelandic Met Office suggests that an eruption has started in Katla volcano at this stage. But that might change without an warning, since this is an volcano after all. This change in harmonic tremor does not seems to be created by an glacier flood of some type. What is interesting is that this harmonic tremor pulse looks like an harmonic tremor pulse detected in the year 1999, just before an small eruption took place in Katla volcano southern caldera rim.

This harmonic tremor is in the high frequency range at the moment. But no change has been seen in the low frequency range at the moment. This is the same thing that did happen in the year 1999. At the moment however it is too early to know what is going to happen in Katla volcano for sure. All that can be done is to watch and wait. This might quiet down, or it might not. Only time is going to tell us what happens next. At the moment the harmonic is falling at fast rate, so this might be over.

Before the harmonic tremor pulse there was an earthquake swarm in Katla volcano caldera. The largest earthquake was ML2.1 and that was an long period event, but that tells me that magma was the source of this earthquakes in Katla volcano caldera. There where two earthquake swarms in the caldera today, but that makes total of three earthquake swarms in the Katla volcano caldera since the beginning of June.


The two earthquake swarms that took place in Katla volcano caldera today. Copyright of this picture belongs to Icelandic Met Office.


The only earthquake that I did record out of this earthquake swarm. This earthquake was ML2.40 with the depth of ~400 meters. This plot is filtered at 1Hz . This picture is released under Creative Common licence. See Licence web page for more detail.


Spectrogram of the ML2.4 earthquake in Katla volcano from this morning. This is filtered from 1Hz. This picture is released under Creative Common licence. See Licence web page for more detail.


Harmonic tremor can clearly be seen at the end of this tremor chart from the Icelandic Met Office. Copyright of this picture belongs to Icelandic Met Office.


Harmonic tremor can be seen at the end of this tremor chart from the Icelandic Met Office, but it is not clear at this SIL station. Copyright of this picture belongs to Icelandic Met Office.


Harmonic tremor can clearly be seen at the end of this tremor chart from the Icelandic Met Office. Copyright of this picture belongs to Icelandic Met Office.


Harmonic tremor can clearly be seen at the end of this tremor chart from the Icelandic Met Office. Copyright of this picture belongs to Icelandic Met Office.


Harmonic tremor can be seen (not clearly) at the end of this tremor chart from the Icelandic Met Office. Copyright of this picture belongs to Icelandic Met Office.


Harmonic tremor can clearly be seen at the end of this tremor chart from the Icelandic Met Office. Copyright of this picture belongs to Icelandic Met Office.

The harmonic tremor is strong enough on many SIL station to go above the background noise level on the SIL stations (wind, ocean waves etc..). But this is not an strong harmonic tremor. They can be stronger.

This does NOT mean an eruption is imminent in Katla volcano. What this does mean that is an magma is on the move inside the Katla volcano. What happens at later time is something that nobody can guess at current time. But it is now time to watch Katla volcano even closer.

It is also important to notice that nobody really knows how Katla volcano behaves before an eruption. We only get those answers after an eruption in Katla volcano. For the moment we can only wait and see what happens in Katla volcano.

I am going to post more updates if anything interesting happens. Also, there seems to have been an Long period earthquake at 22:14 UTC, most likely in Katla volcano. It appeared on my geophone close to Hekla volcano. I am guessing the size of this earthquake is ML2.0+.

Blog post updated at 22:39 UTC. Spectrogram picture added.

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Glacier quakes seen in Mýrdalsjökull glacier and Vatnajökull glacier

It seems that there have been few glacier quakes in Mýrdalsjökull glacier over the past few days. This glacier quakes are created by rain or some other movement in the glacier it self. This glacier quakes normally take place when there is heavy rain, or when the glacier is just moving because of water that is flooding below it. Sometimes glacier quakes also appear to happen around hydrothermal areas, but those might be harder to detect due to distance.

While not on the automatic earthquake list due how poor quality the glacier quakes are. It is still possible to see them on the tremor charts that Icelandic Met Office has on-line.

Glacier quakes seen on tremor chart of Icelandic Met Office. The quakes create an pattern of spikes on the tremor chart, it mixes into the other earthquake activity currently taking place in Katla volcano. Copyright of this picture belongs to Icelandic Met Office.

Same as above. Bust just stronger then on Lágu Hvolar SIL station. Copyright of this picture belongs to Icelandic Met Office.

This glacier quake activity has also been taking place in Vatnajökull glacier. But the force for the glacier earthquakes in Vatnajökull glacier seems to be weather (rain and sun), rather then hydrothermal activity.

Glacier quakes can be seen close the 28th June line on the tremor chart. But most of the activity does not get recorded due to strong wind at the same time. Copyright of this picture belongs to Icelandic Met Office.

Other then this, it is quiet in Iceland. Both in earthquakes and volcanoes.

Update: I did update the history list for eruptions in Iceland to include the last eruption in Grímsfjall volcano.

Blog post updated at 22:36 UTC.