Category: Katla / Mýrdalsjökull

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Two SIL stations have failed during winter on Mýrdalsjökull glacier

During a rather harsh winter in Iceland. Two SIL stations have failed on top of Mýrdalsjökull glacier. This are the SIL stations Austmannsbunga and Etnu glacier (local name). The reason for the failure is ice that loaded on to the mast the SIL stations. Making it fall down on the ground. Therefor making the SIL stations lost contact with Icelandic Meteorological Office and University of Iceland. University of Iceland and Icelandic Meteorological Office plan a trip soon to this area of Mýrdalsjökull glacier too fix this SIL stations that are broken. But the weather has too improve first in Iceland before that can happen.

I also suspect this is the problem with the SIL stations on Vatnajökull glacier. That SIL station just has the term “vot“.

Icelandic news about this weather related failure

Skjálftamælir á Mýrdalsjökli óvirkur (Rúv.is)

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Interesting earthquake swarm in Katla volcano

There is a interesting earthquake activity taking place in south part of Katla volcano south caldera rim. This activity has been ongoing since in July 2011 after the minor eruption that year. The most logical reason for this earthquake activity is that in this location is a magma dike on the move. If that is actually the case is impossible to know for now. But this activity remains interesting for many reasons.

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Earthquake activity in south Katla volcano caldera rim. This earthquakes are all small earthquakes. Copyright of this image belongs to Icelandic Meteorological Office.

This earthquakes are small. Most of them are on the magnitude range of 0.0 to 0.5. There depth is around 1 km up to 0.1 km (around 100 meters). So whatever is creating this earthquake activity is already shallow up in the crust. I do not know if there is going to be a eruption in this area. That is just a wait and see as always with volcanoes. But it is my estimate that (based on older data) this might mean there is more activity going to take place in Katla volcano soon. But that might fail. Since volcanoes are by nature unpredictable. So there are no assurances about what is going to happen next in Katla volcano.

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Comparison of volcano eruptions

When there is nothing going on in Iceland. It is good to prepare for the future by checking out what has happened in the past. Here is a comparison of harmonic tremor data from few past eruptions. I only have limited set of data to work with here.

Grímsfjall volcano eruptions 2004 and 2011

Harmonic tremor indicates how strong the eruption is when it is happening. This is clearly visible on the harmonic tremor plots from the Grímsfjall volcano eruptions in the year 2004 and compared to the eruption in Grímsfjall volcano eruption in the year 2011.


Harmonic tremor in Grímsfjall volcano eruption in the year 2004. Copyright of this image belongs to Icelandic Meteorological Office.

This harmonic tremor plot is from the early start of the eruption. It clearly shows when the eruption starts and how it progressed during it’s first few hours.


Here is the volcano eruption start in Grímsfjall volcano on 23. May 2011. This is the start of the eruption. It clearly shows the difference from the eruption that took place in the year 2004. Both is that starts sharper. But is also a lot more powerful then the eruption in the year 2004. Copyright of this image belongs to Icelandic Meteorological Office.

Eyjafjallajökull volcano and Katla volcano

Sometimes it is useful to compare two eruptions of two different volcanoes. This is useful when you really don’t have anything else to compare with.


Harmonic tremor in Eyjafjallajökull volcano eruption back in the year 2010. This is from the second phase of the eruption. But I seems to have misplaced or not saved harmonic tremor data from the first phase of the eruption (at least I cannot find them for the moment). Copyright of this image belongs to Icelandic Meteorological Office.


Harmonic tremor connected to a minor eruption in Katla volcano in July 2011. This eruption was minor. But created a flood that took out a bridge. Copyright of this image belongs to Icelandic Meteorological Office.


Diffrent SIL stations from the same minor eruption in Katla volcano in July 2011. This clearly shows that this minor eruption in Katla volcano was possibly larger then eruption in Eyjafjallajökull volcano year earlier (2010). But it did not manage to break the ice of Mýrdalsjökull glacier. Copyright of this image belongs to Icelandic Meteorological Office.

Past data show and are useful to learn what happens in a volcano. For this reason I now save important information on what is happening in a volcano. So I can compare it with future activity when it takes place.

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Earthquake swarm in Katla volcano caldera

Yesterday (14.12.2012) from 20:50 UTC until 22:52 UTC there was an minor earthquake swarm in Katla volcano caldera. The largest earthquake in this swarm was a magnitude 2,2 earthquake. With the depth of 0,1 km. So it was a shallow earthquake. This is not uncommon for this part of Katla volcano. This earthquake activity has its origin in hydrothermal activity or changes in hydrothermal systems in this area of Katla volcano caldera.


Earthquake swarm in Katla volcano. This area has had earthquakes swarms before. Copyright of this image belongs to Icelandic Meteorological Office.

I do not expect anything special to result from this earthquake swarm. Since it is highly unlikely that Katla volcano is going to erupt in December. It is also a when it comes to earthquakes. Katla volcano has a lot of them during the year and earthquake swarm as this one should be expected to happen every once in a while.

Blog post updated at 10:42 UTC on 15.12.2012.

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Earthquake swarm in TFZ continues, little earthquake activity in Katla voclano, new earthquake activity in Askja volcano

Here is a short update on activity in Iceland for the past few days.

Tjörnes Fracture Zone

Earthquake activity continues in Tjörnes Fracture Zone. But this earthquake activity has been ongoing since 20 October, 2012. Every once in a while a magnitude 3.0 earthquake takes place, or larger. The risk of large earthquake taking place in this area remains. General alert for this area is also in effect because of this danger of large earthquake taking place in this area.


The earthquake activity in TFZ. Copyright of this image belongs to Icelandic Meteorological Office.

Katla volcano

Winter has come. At least when it comes to earthquake activity in Katla volcano. But little to none earthquake activity is now taking place in Katla volcano. Earthquake activity is now well below background level. It can be expected that current status is going to remain in Katla volcano until next summer.


Earthquake activity in Katla volcano for the past few days. Nothing important is taking place in Katla volcano as this image clearly shows. Copyright of this image belongs to Icelandic Meteorological Office.

Askja volcano

While Katla volcano is getting quiet. It seems that Askja volcano is getting slightly more active. But earthquake activity in Askja volcano during the past few weeks suggests a minor magma intrusion (dike intrusion) might have taken place. But none of the earthquakes that took place where above magnitude 2.0 in size.


Earthquakes in Askja volcano during the past few days. Copyright of this image belongs to Icelandic Meteorological Office.

I do not think this earthquake activity in Askja volcano means it is getting close for an eruption. Since there are no signs in that direction at the moment. But this earthquake activity is interesting. What ever it means in the short term for Askja volcano. It is also common that volcanoes have earthquake activity without anything happening at all following such earthquake activity.

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Magnitude 3.1 earthquake in Katla volcano this morning

Today at 08:26 UTC this morning a magnitude 3.1 earthquake took place in Katla volcano. There was minor pre-earthquake activity before the magnitude 3.1 earthquake took place, the depth of this earthquake was around 100 meters (0.1 km). There was also some minor aftershock activity following this earthquake. No change in harmonic tremor took place following this earthquake. So there is a good chance this was just part of normal autumn activity in Katla volcano. This earthquake activity did appear clearly on my geophone network. It can be viewed here on my geophone network web page.


The earthquake as it did appear on my geophone station in Skeiðflöt. This image is released under Creative Commons licence. See CC licence page for more details.


The earthquake as it did appear on my geophone station in Heklubyggð. This image is released under Creative Commons licence. See CC licence page for more details.


The location of the earthquake in Katla volcano. Copyright of this image belongs to Icelandic Meteorological Office.

More earthquakes like this should be expected in Katla volcano. But it is impossible to know if there is going to be an eruption in Katla volcano any time soon. But so far everything is quiet in Katla volcano. Besides occasional earthquake swarm that is taking place in Katla volcano.

Icelandic news about this earthquake activity

Jarðskjálfti í Kötlu – 3,2 að stærð (Rúv.is)
3,2 stiga skjálfti í Kötlu (mbl.is)
Snarpur skjálfti í Kötlu (Vísir.is)

Blog post updated at 19:34 UTC on 03.10.2012
Blog post updated at 05:45 UTC on 04.10.2012

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Katla volcano eruption in the year 1918

Last large eruption in Katla volcano was in the year 1918. Cameras where a bit hard to find during this time and it took long time to take pictures of eruptions in those days. There are few pictures that exist today of the eruption in the year 1918 and the aftermath that did follow it.

Here are the only pictures of the eruption taking place in Katla volcano during the year 1918.


The ash cloud from Katla volcano during the eruption in the year 1918.Author of this picture is unknown. Picture is assumed in public domain due to age (94 years ago). Death of author is unknown to me. Corrections welcomed.


Ice bergs from the glacier flood that did follow the eruption in Katla volcano during the year 1918. Author of this picture is unknown. Picture is assumed in public domain due to age (94 years ago). Death of author is unknown to me. Corrections welcomed.


Painting showing the ash cloud of the Katla volcano eruption in the year 1918. I sadly do not know how did paint this picture or it’s copyright status. Corrections welcomed.

Based on this pictures. This is what we should expect from Katla volcano in the next big eruption. I do not know when that might be. It might be a long wait.

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Minor earthquake swarm in Katla volcano

Normal autumn activity appears to be starting in Katla volcano. This earthquake activity is not something to be alarmed about. But worth keeping an eye on anyway.


The earthquake activity in Katla volcano during the past 48 hour period. Copyright of this image belongs to Icelandic Meteorological Office.

This is just normal autumn activity. As such it is not dangerous and does not mean anything. More earthquakes might happen in next few days to weeks.

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Earthquakes in Tindafjallajökull volcano

One of the most quiet volcanoes in Iceland had earthquake swarm today (17.09.2012). I am not aware of any major earthquake activity in Tindafjallajökull volcano during the past 20 years. I am not sure that if there has been any earthquake activity in Tindafjallajökull volcano during this time. One off-earthquake might have happened once in a while. As they do with every volcano in Iceland from time to time. It is unclear why this earthquake swarm took place. But this might be due to stress changes in the area. Rather then anything volcanic taking place in Tindafjallajökull volcano.


Activity in Tindafjallajökull volcano. Copyright of this image belongs to Icelandic Meteorological Office.

The largest earthquake in this swarm had the magnitude of 1.1. The depth of this earthquake swarm was from 10.7 km and up to 3.1 km. This earthquake swarm appears to be over by now.

Katla volcano

The image above also shows earthquake activity in Katla volcano. This earthquake activity is well below what did happen in May to end of July this summer (2012) in Katla volcano. Currently the activity in Katla volcano is low and has been so for many weeks now. I am not expecting that change without some increase in smaller earthquakes first. For the moment, everything is quiet in Katla volcano.

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Katla volcano geology and features

Here is a short blog post about the geology and the features of Katla volcano. This article is based on science and my knowledge of Katla volcano. It might not be error free and up to date. But I do my best in that regards. But as I cannot afford to buy published or subscribe to web pages that publish science articles about volcanoes in Iceland. I do my best with what I can get for free online (that is often some amount of articles). So my information might be outdated, or might have been replaced by new research that I might not know about. But I use peer-reviewed articles when they are available to me.

Evolution of Katla volcano

Katla volcano is an caldera volcano. It formed in the classic way the caldera forms. The formation of Katla volcano took place around before Holocene, but the data that is available in sediments around Katla volcano only go far as ~8400 years. So it is unknown when Katla volcano formed. Instead of water. Katla caldera has glacier that is from 300 to 740 meters thick where it is thickest. For comparison, Hofsjökull volcano glacier is around 650 meters thick where it is thickest (from what I have read, newer studies might have changed that assessment). The exact age of Katla volcano is currently unknown, but it has been suggested that it is of Pleistocene age (2.6 ma to 11,700 years). The shape and form of Katla volcano during this time period is also unknown today. It is also believed that Eyjafjallajökull volcano is considerable older then Katla volcano. But Eyjafjallajökull volcano is among Iceland oldest volcanoes. Being around 750000 years old according to studies into it.

Katla magma chamber and activity

Katla magma chamber goes trough evolutionary changes every 4000 to 6000 years according to estimates and data gathered by scientists. In the past 12000 years, since last ice age it has gone trough that process twice. But this means current set of magma pluming inside Katla volcano is not going to last for more then few thousands of years at best. I do not know exactly what this changes in Katla volcano pluming mean in terms of eruption. But I find it most likely to be nothing in real terms. It has been noted with study into geological past of Katla volcano that it experiences period of high and low activity. Katla volcano has high and low in it’s eruption activity. Based on data from the past 12.000 years. Currently Katla volcano is having a low period activity. That means fewer eruptions with long quiet time between them. As has been the pattern for the past 1100 years or so. This is according to survey data on activity in Katla volcano for that time period. I do not know if changes in Katla volcano magma chamber influences this low and high period of volcano activity in Katla volcano.

Katla lava

Katla volcano erupts basalt lava normally. On extremely rare occasions Katla volcano erupts magma that is andesite in nature. But that is really rare occurrence in nature. I expect next eruption in Katla volcano to be basalt in nature. But no lava is going to flow due the glacier that is on top of Katla volcano. But that is going to create an ash cloud that is not so different from Grímsfjall volcano ash cloud seen in the May 2011 eruption. As the magma in the two volcanoes are mostly basalt in nature. But that maks for darker but also more large ash particle (less small ash particles). So the ash cloud is not going to create the same problem as Eyjafjallajökull volcano ash cloud did in the year 2010.

Reference articles

Katla volcano, Iceland: magma composition, dynamics and eruption frequency as recorded by Holocene tephra layers (2007)
Bergrún Arna Óladóttir & Olgeir Sigmarsson & Gudrun Larsen & Thor Thordarson