Day: July 9, 2011

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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.