Category: Monitoring

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Changes in Grímsfjall volcano

Few days ago changes started to happen in Grímsfjall volcano. It is hard to describe this changes. But they appears to be changes in harmonic tremor levels in Grímsfjall volcano. But they appears to be above background levels and the reason why that is a bit unclear at the moment, but I do not think that this is ice movement as I did think it was first. As this has been lasting for too long. Following this has been a slow increase in earthquakes in and around Grímsfjall volcano. This earthquakes don’t appear on the automatic SIL system, even if they are up to ML2.0 in size. This suggest that there origin is from magma movements, not tectonics one (tectonics earthquakes also happen there).

So far nothing suggest that a eruption is immanent. But that can change without any warning. As Grímsfjall volcano is known to start a eruption with no warning at all.


Harmonic tremor levels in Grímsfjall volcano on 30th March 2011. Picture is from around 17:30 UTC. Copyright of this picture belongs to Icelandic Met Office. The picture is from there web site.


Earthquakes in Grímsfjall volcano on 30th March 2011. Picture is from 17:30 UTC. Copyright of this picture belongs to Icelandic Met Office. The picture is from there web site.

All that can be done for now is to wait and see what happens. But my opinion is that something is up in Grímsfjall volcano. But what that is remains unclear at the moment.

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There might be a volcano eruption in less then a one year time in Báðarbunga volcano (Kistufell field)

I do not know if this is Icelandic media sensationalism or just a simple misquote in the news article. But according to Morgunblaðið (mbl.is) in a interview with the geologist named Sigurlaugar Hjaltadóttir (works at Icelandic Met Office) she sad that there is more risk of a eruption in north-west side of Vatnajökull glacier due to the high earthquake activity in the area. But while the earthquakes continue to be at great depth, there is a less chance of a eruption in the area.

But she might be referring to is that a earthquake activity in the area might be increasing because of Grímsfjall volcano and Bárðarbunga volcano interaction. But it remains be seen if that is the case or not here. It is however clear that only time is going to tell us if there is going to be a eruption in this area soon or not.

The news in Icelandic. Please use Google Translate or something similar to understand.

Gæti gosið innan árs (mbl.is)

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Minor earthquakes where seen after the large earthquakes in Grímsfjall volcano

Following the two large earthquakes (ML3.5 and ML4.2) there was a swarm of small earthquakes in that area. The earthquakes where seen on Grímsfjall SIL station, but do not appear to have been strong enough to be recorded on other SIL stations around Vatnajökull glacier. This appears to have lasted until around 13:00 UTC on 13th of January 2011. But after that it did quiet down.


Plot is from IMO web site.

Icelandic Met Office tremor plot that shows the two large earthquakes and following minor earthquakes. This area in Grímsfjall volcano has been quiet since the two earthquakes took place few days ago.

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Earthquake detection and winter storms

In the last two days there have been a strong winter storm going over Iceland. The wind has been coming from the north with snow and cold weather. But this has also been followed by a strong wind all over Iceland and this strong wind has been preventing the SIL network from detecting micro-earthquakes in Iceland. Because of that it appears that Iceland has been unusually quiet on Iceland Met Office maps. This might not necessary be the case in reality. But due to a lot of wind noise the SIL network is unable to detect the smallest earthquakes that happen in Iceland. Some stronger earthquakes might appear on the SIL network if they take place.

So the quiet time in Iceland is down to weather, not something else. As the weather improves we should start to see micro-earthquakes again on Icelandic Met Office maps. It is always a good idea to check the weather forecast in Iceland if there is a sudden drop in earthquakes in Iceland.

Note 1: There are sometimes times however in Iceland when there is nothing wrong with the weather and yet still no earthquakes. What is going on there is simple, there are no earthquakes taking place in Iceland. This happens sometimes. But this is a rare, but it does sometime happen.

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New SIL seismometers around Eyjafjallajökull volcano and Mýrdalsjökull (Katla)

The seismometers that British Geological Survey did pay for to be installed around Eyjafjallajökull volcano and Mýrdalsjökull (Katla volcano) have been integrated into the Icelandic Met Office SIL Seismometer Network. They have at least been marked into the Icelandic Met Office earthquake web page.


Image is from Icelandic Met Office. Copyright of this picture belongs to them.

The new stations are marked with a triangles on the map. The older SIL stations can be found at Icelandic Met Office tremor web page. Currently the new SIL stations are not on Icelandic Met Office Tremor web page yet.

What this means for earthquake recording in this area is that Icelandic Met Office is now able to detect smaller earthquakes. Location of earthquakes is also going to improve a great deal, so automatic location of earthquakes is going to improve a great deal in this area. This means that more earthquakes are going to be visible on Icelandic Met Office maps then before.

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Last activity update before Christmas and Christmas stuff

Here is the last activity update before Christmas starts. As I did expect a deep earthquakes have started again under Eyjafjallajökull volcano. So far the main depth is about 10 to 15 km. So far nothing indicates a immanent eruption in Eyjafjallajökull volcano. But it is wise to keep watch on the deep earthquakes that have started to re-appear under Eyjafjallajökull volcano.

But Eyjafjallajökull volcano is not the only volcano making earthquakes. There are also earthquakes taking place in Grímsfjall volcano and in Esjufjöll volcano. The continues earthquake swarm in Krísuvík volcano. But this is the same that has been going on in previous weeks in that area.

There has also been some minor earthquake activity in Grímsfjall volcano. A signal that Grímsfjall volcano is getting ready for a eruption in the year 2011 maybe.

Non-volcanic earthquakes

There has been a lot of earthquakes in the Tjörnes Fracture Zone (TFZ). But the largest earthquakes in the last 24 hours did get the size ML3,0 according to the automatic SIL system that Icelandic Met Office runs. The size might be subject to a review later on.

But other then this it has been quiet in Iceland earthquake wise and volcano wise. But when the most frost was going on over Iceland there was a lot frost earthquakes taking place. But those events are false earthquakes and are due the fact that freezing water appears to crack the ground, sometimes with considerable force. The frost needed for this to happen has to be below -10C far as I understand.

Christmas stuff

I am going to take my Christmas break from 12:00 UTC on the 24th of December (2010) until the 27th of December (2010). While this break is on comments might be held longer in the moderation queue then normally. If anything major happens, I am going to post information about it when I can in this time. But unlike us humans nature doesn’t care about our days off. But I am hoping for a quiet Christmas in Iceland like everywhere else.

There is going to be special Christmas blog post tomorrow for all those Christmas greetings.

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Warning level around Eyjafjallajökull volcano lowered down to uncertainty level

In a press release by Almannavarnir (Iceland Civil Protection) it is announced the lowering of the warning level around Eyjafjallajökull from danger area down to uncertainty level. There are also some travel restriction lifted that have been in place around Eyjafjallajökull volcano. The current warning level is the lowest warning level that Almannavarnir has.

The Press release by Almannavarnir in Icelandic. Use Google Translate at own risk.

Lækkun á almannavarnastigi frá neyðarstigi niður á óvissustig vegna eldgossins í Eyjafjallajökli (almannavarnir.is)

Icelandic News about this.

Almannavarnastig lækkað í óvissustig (mbl.is)
Almannavarnir lækka viðbúnaðarstig (Rúv.is)
Almannavarnastig vegna Eyjafjallajökuls lækkað (Vísir.is)

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British Geological Survey costs the set-up of six seismometers around Eyjafjallajökull and Katla

According to Rúv it appears that British Geological Survey did pay for the set-up of six seismometers around Eyjafjallajökull and Katla volcanoes. This seismometers are able to detect lower frequencies better then current seismometers around Eyjafjallajökull and Katla. This type of sensors are normally called broadband seismometers and have frequency range down to 0.001Hz and up to 60Hz. I do not know how far the sensors that BSG did cost. But I am going to assume that they go down a bit farther then IMO sensors in the area. According to Rúv the sensors are already up and where on-line earlier this year.

They are located at following location.
Mælifellssandi not far from Slysaöldu, Rjúpnafell east of Mýrdalsjökul, two are located both sides of Eyjafjallajökull on Ásólfsskálaheiði at south and Smjörgili at north not far from Gígjökli glacier. Fifth sensor is going to be set-up in Pétursey in Mýrdal. The location of the six sensors has not been decided yet.

The cost of this project is about 100.000 pound according to Rúv.

The reason for this is that authorities in UK (and Europe) want to get more warning if there is a big eruption in Katla volcano. Mostly to prevent the air chaos that took place when Eyjafjallajökull erupted earlier this year.

Five sensors where in the area before. The sensor net is going to be really sensitive when the new sensors go on-line at IMO headquarters in Reykjavík. But more sensors give more accurate location of earthquakes, both in depth and location.

The news from Rúv in Icelandic. Use Google Translate at own risk.

Bretar setja upp jarðskjálftamæla (Rúv.is)