Category: Magma

Posted on

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.

Posted on

Overview of Hamarinn volcano current activity

Here is a short overview of the Hamarinn volcano activity this summer. From what I can gather in the current data this is most likely not over. During the past few days there have been at least suspected two minor eruption in Hamarinn volcano. But it hard to confirm it due to glacier that is covering this area.

This all starts on 12. July 2011 at 07:30 UTC with this event here.


The tremor spike on 12. July 2011 at 07:49 UTC. Copyright of this picture belongs to Icelandic Met Office.

When the clock is around 19:10 UTC the same day the tremor chart looks like this.


The tremor spikes are now three on 12. July 2011 at 19:09 UTC. Copyright of this picture belongs to Icelandic Met Office.

On the 13. July 2011 the tremor plot looks like this. But at that time the glacier flood had started and broken from the Vatnajökull glacier.


The tremor chart at 13. July 2011 at 01:10 UTC. Copyright of this picture belongs to Icelandic Met Office.


The tremor chart at 13. July 2011 at 12:59 UTC. Copyright of this picture belongs to Icelandic Met Office.

Then there was a short period of break when nothing interesting happened in Hamarinn volcano. That break did last until 16. July 2011 when a new, but smaller spike did appear on Skrokkalda SIL station.


The tremor at 16. July 2011 at 15:22 UTC. It is not fully clear what did happen at this time. But this was most likely a earthquake in Hamarinn volcano. But that is yet unconfirmed at this time. Copyright of this picture belongs to Icelandic Met Office.

Then there is a new break that lasts until 1. August when a earthquakes happens deep under Bárðarbunga volcano. But the deepest earthquake had the depth of 25.2 km. But it is also important to notice this earthquake that took place on 13. July 2011 and it is from Hamarinn volcano.


The earthquake from Hamarinn volcano. This picture is released under Creative Commons licence. Please see licence web page for more details.

On the 3. August 2011 around 02:00 UTC a new harmonic tremor spike starts to be visible on Skrokkalda SIL station.


The tremor plot at 01:55 UTC on 3. August 2011. Copyright of this picture belongs to Icelandic Met Office.

This day two minor harmonic tremor happens. A change in Skaftá glacier river is noticed. That is higher conductivity and slightly more water. It was announced in the news that a Skaftá glacier river flood was about to start from the eastern glacier cauldron that is formed above the Hamarinn volcano. Today however that does not seem to be the case. As no glacier flood has taken place so far.

Today (5. August 2011) there was a new harmonic tremor spike on Skrokkalda SIL station. It did follow the same pattern as before. It started and lasted for about 20 to 60 minutes or about that long.


The tremor chart 5. August 2011 at 17:38 UTC. Copyright of this image belongs to Icelandic Met Office.

So far today only one harmonic tremor has been detected. But given the past experience that is unlikely to hold for a long time now. But it is impossible to know when a new event starts or how big it is going to be.

The original event on 12. July 2011 did create new cauldron in the glacier. This map from Icelandic Met Office shows the location of those new cauldrons. But it has been marked with a star on the map. The coloured dots are earthquakes in this area over the past few years.


Map of the area that is currently active in Hamarinn volcano. Copyright of this image belongs to Icelandic Met Office.

Given the current data I am expect a full scale eruption in this area soon. When is hard to know for sure. But until that happens there are going to be more smaller eruptions in this area. I do not know why there is a lack of earthquakes following this events. I cannot explain it. But because of that this can only be seen after it has started on the tremor charts.

Posted on

Sharp rise in harmonic tremor on Skrokkalda and Grímsfjall SIL station (among others)

There is a sharp rise in harmonic tremor on the Skrokkalda and Grímsfjall SIL station. I do not know yet what volcano is responsible for it. But the Hamarinn volcano is a suspect at the moment.

Current tremor plot.


The tremor spike is at the end of this tremor plot. Copyright of this picture belongs to Icelandic Met Office.


The tremor spike is at the end of this tremor plot. Copyright of this picture belongs to Icelandic Met Office.

I am going to post more information about what is going on when I know more. This blog post might get updated soon if needed.

Posted on

Grímsfjall volcano inflates after the large May 2011 eruption

It can be sad that Grímsfjall volcano did not waste any time starting to prepare for next eruption after the large May 2011 eruption. But that eruption was the largest one in at least 140 years or so. This large eruption did mean that there was a large deflation that took place during the eruption. Where the most deflation was around 250mm down, and around 300mm north, and around 350mm east.

Since then Grímsfjall volcano has however been inflating at interestingly high speed. Currently the GPS data shows that it has reached around 250mm east, north and 200mm up since the eruption. But the magma chamber is going to expand horizontal before it expands upwards (think of this in 3D). So it is going to be a while until a inflation upwards is going to be seen.

The GPS data is clear on this as can bee seen here.


Current inflation at 27. July 2011. Copyright of this picture belongs to Icelandic Met Office.

It is hard to know when Grímsfjall volcano is going to erupt next after this big eruption. But it might take few years until we see a new eruption in Grímsfjall volcano.

Posted on

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)

Posted on

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.

Posted on

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.

Posted on

Small harmonic tremor spike from Hamarinn volcano

There seems to be a small harmonic tremor spike taking place in Hamarinn volcano (Bárðarbunga volcano) at the moment. This tremor spike is not strong at the moment. This tremor spike appears to have been pre-seeded by few long period earthquakes (not all of the earthquakes seen on Skrokkalda are from Hamarinn volcano, few are from Katla volcano), but that suggests that magma is on the move in Hamarinn volcano. But this would the second harmonic tremor in a time period of 48 hours it seems.


The harmonic tremor spikes can be seen at the end of this tremor plot. Copyright of this picture belongs to Icelandic Met Office.

Currently it is impossible to know what happens in Hamarinn volcano. As it’s pre-eruption behaviour is rather unknown. But if there is a eruption in this area I am expecting a lot of earthquakes, with size well over ML3.0.

Blog post updated at 16:20 UTC.

Posted on

Possible minor eruption in Hamarinn volcano yesterday. Update on Katla volcano

There appears to be more in this new hydrothermal activity in Hamarinn volcano then at first sight. It seems that this actually might have a eruption in Hamarinn volcano (Bárðarbunga volcano). If this event is confirmed, this is the first eruption in Hamarinn volcano since the year 1910.

This also mean that there is a chance of more activity in this area in coming weeks or months. But when it might happen is impossible to know.


The new cauldrons are marked with a “X” on this map. Copyright of this picture belongs to Icelandic Met Office.

This eruption was really small and did just last for few hours. But it was able to melt a lot of ice and create rather large glacier flood from Vatnajökull glacier. If the activity resumes in this area this is going to repeat it self in terms of glacier flood.

Icelandic News about this event.

Innskot af kviku (Rúv.is, Icelandic)
Eldgos gæti hafa brotist upp við Hamarinn (Vísir.is, Icelandic, Pictures)
Fundu nýjan sigketil (mbl.is, Icelandic, Pictures)

Sigketill við Lokahrygg (Icelandic Met Office, Icelandic, Pictures)

Update on Katla volcano

Here is a short update on Katla volcano. There have been repeated short burst of harmonic tremors taking place inside the Katla volcano caldera. This harmonic tremor spikes have been small and they are hard to see on the harmonic tremor graph that Icelandic Met Office has on-line. Other then this it has been quiet so far in Katla volcano.

Posted on

New hydrothermal area found in Vatnajökull glacier

After the glacier flood that took place last night and today the source of this flood has finally been found. According to the news the source of this flood is a new hydrothermal area inside the Bárðarbunga fissure swarm. But this new hydrothermal area is located in Hamarinn volcano (also known lokahryggur or Loki-fögrufjöll), sadly the news does not say exactly where it is located. Just that it located in western Vatnajökull glacier. This flood did go down the river Sveðju and into the Hágöngulón lake (human made lake) that did swallow it whole according to the news. The overflow after the dam lake was full did go into an even larger natural lake, that did not feel any effects of this glacier flood.

In terms of size this glacier flood was larger then the glacier flood in Mýrdalsjökull glacier last week. But that was only about 2000 m3/sec, but this was somewhere around 2200 m3/sec. But this are the numbers that I have seen in the news. But this are not confirmed numbers and might be subject to change on later date.

Other then this activity. It has been rather quiet in Iceland in terms of earthquake and volcano activity.

Icelandic news about this.

Áður óþekkt jarðhitasvæði fundið (Rúv.is, Icelandic)
Virkjunarlónin gleyptu gríðarstóra flóðbylgjuna (Vísir.is, Icelandic)

Órói við Lokahrygg í Vatnajökli (Icelandic Met Office, Icelandic, Pictures)