Eruption in Grímsvötn appears to be over (hopefully correct this time around)

It appears that the eruption in Grímsvötn / Grímsfjall volcano is over or is about to end, but authorities in Iceland might not declare the eruption over until after next weekend. No ash plume has been observed for over 24 hours now from Grímsfjall volcano. Harmonic tremor pulses are still taking place in Grímsfjall volcano and it is still dangerous to get close to the eruption site. As explosion still take place in the eruption area and that makes going there dangerous. It is not only the area where the water is that is having explosions. There are also gas and explosions taking place in the crater rims and nearby area. According to news today Icelandic Met Office did stop recoding the eruption in Grímsfjall volcano around 07:00 UTC this morning (28. May 2011). But harmonic tremor pluses might still be taking place in Grímsfjall volcano. But the SIL stations around Grímsfjall volcano have now started to record background noise again, including the SIL station at Grímsfjall volcano.

Earthquake activity has continued at similar levels as before the eruption took place. I am not sure why that is. But this might indicate that Grímsfjall volcano has already started to prepare it’s next eruption. But when that might happen is a question that only time is going to answer. The main earthquake activity is currently taking place NW of Grímsfjall volcano, and SW of Grímsfjall volcano.

According to automatic GPS data it appears that Grímsfjall volcano has started to inflate again. This inflation appears to be rather rapid at current moment. But it appears to be close to 1mm/day inflation to the south and east. This means that new magma has already started to flow into Grímsfjall volcano magma chamber and magma system from greater depth. So far Grímsfjall volcano has not started to inflate upwards and it might be an while until that happens, as there might be enough space for the magma to move into inside Grímsfjall volcano.

Measurements of the volcano tephra that did fall, along with measurement of the volcano ash that did fall have recorded the depth up to 170 cm in some areas of Vatnajökull glacier even at distance of 8 km from the eruption site. This is going to create problem in the summer when it is dry and the wind blows this volcano ash around Iceland. But mostly in the areas that where closest to the main ash fall areas.

Update 1: According to news on Vísir.is the Icelandic Coast Guard did see an plume with the hight of 1,5 km yesterday. This plume was however mostly made out of steam rather then volcano ash. The news about this can be found here, along with an picture of the plume. Here is an second news of this steam plume that was seen yesterday.

Update 2: According to news on Rúv there is small harmonic tremor being recorded. But most of the time, no harmonic tremors are being detected from Grímsfjall volcano. The Rúv news can be found here (Icelandic, Picture). It also has an new picture of the eruption crater. But this picture was taken around 10:00 UTC today (28. May 2011).

Icelandic News about this. Use Google translate on this for an risky translation.

Eldgosið mælist ekki lengur á jarðskjálftamælum (Vísir.is, Icelandic)
Enginn gosmökkur í dag (From 27. May 2011, Rúv.is, Icelandic)

Blog post updated at 19:11 UTC.
Blog post updated at 20:15 UTC.

Explosions are still taking place in Grímsvötn crater

While the activity has almost stopped in Grímsfjall volcano, but there are still explosions taking place in Grímsvötn lake where the eruption took place due to magma going up, explosions take place all over the fissure at random times. That makes travelling to this area really dangerous thing to do. Ash fall is still taking place in Grímsfjall volcano when explosions take place. But the ash fall is limited to the local area in Grímsfjall volcano. Because of this, the official word is that the eruption is not yet over. Even if it just an small eruption at the moment. So far there is no data that suggests that new magma is currently flowing into Grímsfjall volcano. This is according to news in Icelandic media.

An new caldera (correct word?) has formed in the glacier close to the eruption site. But that suggests that a lot of heat is below in the glacier and is creating strong melt where this taking place. This is according to news on Rúv. But they don’t say where this glacier melt is taking place. But it can be assumed that this formation is somewhere close to the current eruption site. But when I know more about this location. I am going to update this post when I can.

Harmonic tremors pulses are still being detected from Grímsfjall volcano up to 200 km away from the volcano. Why they are still taking place while there is no eruption taking place is unknown to me. It is important to notice that currently the harmonic tremor is slowly dropping for now. But it might increase again without any warning. For now there is no way to know what this tremor means for Grímsfjall volcano.

Automatic GPS data from Icelandic Met Office tells an interesting story. According to this data (it might not be 100% accurate due to nature of GPS) Grímsfjall volcano has moved close to 320mm to the west, close to 350mm to the north, it has also lowered down about 250mm. This is major movement in Grímfjall volcano. To compare it with something, Eyjafjallajökull volcano only inflated about 60mm before it did erupt. This is many times more deflation that took place in Grímsfjall volcano then in Eyjafjallajökull volcano for example.

Earthquakes are still taking place SE and SSE of Grímsfjall volcano. There is no volcano at this location. So I am assuming that this are tectonic earthquakes taking place due to stress changes in the crust around Grímsfjall volcano. All earthquakes so far have been small but with the depth from 15 and up to 5 km.

Extra: According to new news (while I was writing this blog post). The Civil Emergency Authority in Iceland has lowered the alert level from danger level to alert level. News about that can be read here (Icelandic, mbl.is)

Icelandic News about this. Google Translate in an maze. It might work or maybe not.

Enn sprengivirkni í Grímsvötnum (Rúv.is, Icelandic)
Jarðeðlisfræðingur: Orðum ofaukið að gosinu sé lokið (Vísir.is, Icelandic)

The eruption in Grímsvötn / Grímsfjall volcano most likely not over

Here is a interesting paradox. While the eruption it self has currently stopped in Grímsfjall volcano. The tremor chart around Grímsfjall volcano is still acting like there is a eruption ongoing. I do not know why this is like this. But because of that I don’t think that geologist that monitor Grímsvötn eruption in Iceland are not ready to call off this eruption at current time. At least that is what the news did say at 12:20 UTC on Rúv.

They are also issuing warning to people not going to close to the volcano. As explosions due happen and they can throw up rocks that weight up to 1 ton. If anyone gets hit by that rock, that person does not have to worry about what happens next. The save distance for viewing the crater is estimated to be 2 km or more.

I have no idea what happens next. But I am guessing that this eruption might resume soon and without an any warning at all.

The tremor plot at 15:00 UTC. Pictures are from Icelandic Met Office.

This pattern of tremor is interesting. I am yet unsure what it means. But my guess is that this eruption is not over. Even if it has just stopped for now. I normally consider eruption over when the tremor has gone back into background noise (wind, ice, ocean etc..). That has not yet happened with Grímsfjall volcano eruption at this moment.

Update 1: Here is an tremor plot that Icelandic Met Office has released. The article where this picture is from Icelandic Met Office can be read here, it is in english.


Click on the picture for full size. I must point out that this picture is big. Copyright of this picture belongs to Icelandic Met Office.

Blog post updated at 20:46 UTC.

Less powerful eruption in Grímsvötn / Grímsfjall volcano

It has been reported in the news that the eruption in Grímsfjall volcano (also known as Grímsvötn) is getting less powerful as the time passes. This is perfectly normal for an eruption in Grímsfjall volcano.

This can also be seen on tremor plots around Grímsfjall volcano. They clearly show the eruption getting less powerful over time. It has also been reported in the news that the material that is being erupted is now estimated to be 100 tons/second at the moment. But just yesterday it was 1000 tons/second and up to 2000 tons/second. The eruption is currently stable, even if it smaller then it was in the first few days. It is also not certain if this eruption is going to turn into lava eruption. As there seems to be enough water to continue ash phase of the eruption for the next few days.

Grímsfjall SIL station. It clearly shows the eruption getting less powerful over time.

Kálfafell SIL station. It shows the same pattern as Grímsfjall SIL station. Copyright of both pictures belongs to Icelandic Met Office.

In the news it has also been suggested that there might be less or no influx of new magma from great depth. But I do not know for sure if that is just speculation or not.

The ash plume has only got up to 3 to 5 km according to news reports. This means that has dropped a good distance in the last 24 hours. But yesterday it did reach up to 5 to 9 km. So ash is not spreading far away as it did earlier in this eruption. What is creating flight disruption in Europe and over Iceland is the volcano ash that was ejected in the first few days of the eruption. It has also been an big problem in Iceland is the volcano ash that is getting air blown on the ground. The ground is dry so the volcano ash moves easily because of that. Update 1: It has also been reported that the ash that did was ejected on the first day of Grímsvötn eruption was like all the ash ejected in the Eyjafjallajökull volcano eruption in the year 2010. They also say that this eruption was about the size of normal Katla eruption in there own estimate. News about this can be found here (Icelandic, picture)

Scientists did go today up to Vatnajökull glacier in an attempt to get close the eruption site. Flight over the Grísmfjall volcano is also taking place in an attempt to see the eruption site and take measurements of the eruption.

Update 2: There has been an minor spike in the tremor plot in the last hour or so. I do not know why that is. But this suggest that the eruption is growing in power again.

Icelandic News about it. Use Google Translate if you want some funny reporting.

Dregur úr gosvirkni (Rúv.is, Icelandic)
Dregið hefur úr eldsgosinu – umtalsvert minni gosefnaframleiðsla (Vísir.is, Icelandic)
Dregur úr gjóskuframleiðslu (mbl.is, Icelandic)

Please note that information here might get outdated really fast and with no warning at all!

Post updated at 17:57 UTC.

General overview of Grímsvötn eruption on 23. May 2011 at 20:33 UTC

This is a general overview of Grímsvötn eruption on 23. May 2011 at 20:33 UTC.

Ash cloud: The ash cloud is still going strong. It is however a bit lower then in first few days. Measurements of the ash plume now says that it is between 5 to 9 km. Because of that it does not appear on the radar at IMO. The ash cloud has now been detected all over Iceland, except for the most western part of Iceland (Westfjod). In the areas closest to the main ash cloud the visibility is from 1 meter and up to 500 meters when it is at it’s best. Ash fall is expected to last for the next few days, or until the crater does not get any water into it to make the ash. The ash cloud is expected to reach Scotland tonight (Rúv, Icelandic). BBC News about cancelled flights due the ash cloud. Farmers live stock has started to die due to the ash cloud. It is unknown how the wild life is doing while the ash cloud covers part of south Iceland. Current output of the Grímsfjall volcano is about 1000 to 2000 tons of ash pr second. It was around 10,000 tons of ash pr second during the first days of the eruption.

Rúv News, Öskufall næstu daga (Icelandic, Rúv.is)

Eruption: Even if the ash cloud is lower now. It appears that the eruption is still going strong. In the evening news at Rúv it was reported that there was a chance the magma that powers this eruption might be from a great depth (more then 20 km). Tremor graphs that are online show and suggest that the eruption is still at full power. The reason why they are at lower noise level is most likely due to fewer explosion in the eruption, as less water is in the crater. When water no longer goes into the crater it turns into lava eruption. There is also an speculation that new fissures might open up in this eruption where there is more glacier cover (evening news on Rúv). But that would mean flash glacier flood and new ash cloud when the eruption would break the glacier covering it. But so far this has not happened and is nothing but a speculation. It would mean earthquake activity when the magma would break the crust, as happened when the eruption did start on 21. May 2011.

GPS data: According to report from IMO and University of Iceland the deflation now has been 50 cm to northwest and has subsided 25 cm. According to the report this about 60% larger then after the eruptions in the year 1998 and in the year 2004.

Web cameras: Grímsvötn Míla web cam is now up and running. It should be possible to see the eruption when an ash cloud is not in the way. But so far that has been the case.

Please note that information here might get outdated really fast and with no warning at all!

Updated at 20:42 UTC.

Few harmonic tremor charts of Grímsvötn eruption

Here are few harmonic tremor charts from the Grímsfjall volcano / Grímsvatn eruption. It can clearly be seen where the eruption looses strength for an few hours. It is also clear when the eruption starts to regain it’s eruption strength again.

The volcanic tremor is best seen on 0.5 – 1Hz band, alongside 1 – 5Hz bands.


Grímsfjall volcano / Grímsvötn SIL station.


Skrokkalda SIL station.


Kalfafell SIL station.


Fagurhólsmýri SIL station.


Kreppurhaun SIL station.


Askja volcano SIL station.

All pictures are from Icelandic Met Office web page. Copyright of this pictures belongs to them.

Grímsfjall/Grímsvötn volcano eruption update at 21:54 UTC

This is a minor update to the Grímsfjall volcano / Grímsvötn eruption.

Process of the eruption: The harmonic tremor on the SIL stations around Grímsvötn is increasing again after it did drop a little bit down earlier today. Following this the ash plume has again appeared on radar images from Icelandic Met Office. Currently however the ash plume is just around 10 km high. According to the news, the eruption is made out of basalt. But that is a common eruption type for Grímsvötn. The ash cloud is formed when hot magma gets into contact with ice and water and explodes on contact. This eruption is now expected to many times larger then the eruption in Eyjafjallajökull volcano last year.

Ash cloud: The ash cloud does now covers most of Iceland, except the northern part of west Iceland (for the moment) and east Iceland (for the moment) but that is expected to change in the next 24 to 48 hours. Ash has been reported in most town in Iceland. That includes Reykjavík, Akureyri, Selfoss (heavy ash cloud) and more. According to web cameras there is heavy ash fall close to Hekla volcano from Grímsfjall volcano (web camera pointed towards Hekla is here, Eyjafjallajökull is here). Due the ash cloud all flight to and from Iceland has been grounded until this ash clouds goes away.

Earthquakes: Few earthquakes are recorded. But only two earthquakes have been recorded around Grímsfjall volcano and close to in the past few hours. But that does not mean that they are not happening. But they might simply be lost in the harmonic tremors from the eruption.

Other: Nothing at the moment.

Please note that information here might get outdated really fast and with no warning at all!

Grímsfjall/Grímsvötn volcano eruption update at 16:02 UTC

Here is the second update today of the Grímsfjall volcano. But it is also known as Grímsvötn.

Process of the eruption: The eruption has not changed a lot since this morning. But its power has dropped a little bit since it started yesterday. But there also seems to be the case that this eruption increases on regular basis. But it is impossible to know for how long that eruption pattern is going to continue in Grímsfjall volcano. Early estimates of this eruption (reported by the news in Iceland) is that this eruption is about 10 times bigger then the eruption in Eyjafjallajökull volcano. But that is a early estimate and is a subject to a change. But in general there is nothing to suggest that this eruption is slowing down, even if it does not have the same power as it did in the first few hours of eruption.

Ash cloud: The ash cloud has dropped a little from it’s high of 20 km. Current measurements place the hight of the ash cloud around 15 to 18 km high up. Reports say that the lowest point was around 10 km, before the ash cloud did get higher again. Update 1: There have been recorded over 15,000 lightnings in this eruption alone. But they where recording 2198 lightning in 1 hour since the eruption started. News about it can be found here (Icelandic, picture). Update 2: The ash cloud is now from 10 to 20 km high. But it depends on the power of the eruption. But that seems to change over time and does not remain a constant.

Earthquakes: So far, most of earthquake activity in Grímsfjall volcano has stopped. But that suggest that the magma now has a clear path to the surface. There has been some earthquake activity in Hamarinn volcano. But it is unclear if that is connected to the eruption in Grímsfjall volcano.

Other: It is dangerous to go into the ash cloud. The government has closed off part of road one due the ash cloud. People how find them self in the ash cloud should find a shelter soon as possible, or of they are inside a house they should remain there. Reports are of communication problems where the ash clouds goes over due to static charge in it. This interferes with GSM, 3G phones, radios and tv receptions. In worst cases people can not expect a reception of any radio signal where the ash cloud is most dense.

Sorry for lack of links. I do not have the time to post them into this blog post.

Please note that information here might get outdated really fast and with no warning at all!

Updated at 16:17 UTC.
Updated at 16:26 UTC

Grímsvötn/Grímsfjall volcano eruption update at 08:52 UTC

This is a short update on Grímsfjall volcano/ Grímsvötn eruption. This is short update because a lot of details in this eruption are still unclear at this moment.

Process of the eruption: The eruption in Grímsvötn is still growing strong. Icelandic Met Office SIL sensors show a uneven process in the eruption. But they also show that the eruption has dropped a little bit in power since it originally started in yesterday. That is normal for a eruption in Grímsfjall volcano. It starts strong and then slowly drops in power over time. But what is unusual for this eruption is the uneven process that is taking place (seen with SIL data) in the eruption. What that means is unclear. It is more unclear what it means to the eruption. While it is unclear at the moment. It appears that the eruption is taking place a little south of the eruption in the year 2004. But that is unconfirmed, as ash cloud to the ground blocks the view the eruption site.

Ash cloud: The ash plume is reported to have reached 20 km high yesterday. From as I can gather that has not changed. This ash plume appears be made from two to three ash cloud columns. With the strongest one getting the highest. A lot of lightning is taking place in the ash cloud. Due to the ash cloud, all flight from and to Iceland has been cancelled until further notice (don’t ask question about that here, ask your airliner for information about this closure). The ash did start to fall in populated areas few hours after the eruption did start in Grímsvötn. The ash is described as fine, but more crude (bigger particles) then the ash from Eyjafjallajökull volcano eruption in the year 2010. The ash cloud is moving west in higher layers of the atmosphere over Iceland. While it moving south in the lower layers of the atmosphere as the wind is from north in Iceland at the moment.

Earthquakes: After the magma has found it’s way to the surface. All earthquake activity did stop in Grímsfjall volcano. This is normal. But what is unusual is that there have been few earthquake swarm after that in Grímsfjall volcano. I do not know what it means or why this is happening. But this is interesting development.

Other: The earliest estimation on the size of the Grímsfjall volcano eruption 2011 is that this looks like it is a bigger eruption then in Eyjafjallajökull volcano eruption in the year 2010. But that is closer to speculation based on visual observation of the eruption. But it is clear that this eruption is bigger then the year 2004 eruption in Grímsfjall volcano.

A new video has been relased of the eruption. It is from yesterday when the eruption was starting.

Update 1: They now say that this is the largest eruption in Grímsvötn / Grímsfjall volcano in the last 100 years. Rúv news about this, Stærsta gos í Grímsvötnum í 100 ár (Icelandic).

Please note that information here might get outdated really fast and with no warning at all!

Update at 09:24 UTC.

Ash cloud confirmed from Grímsfjall volcano

A eruption ash cloud has been confirmed from Grímsfjall volcano. I do not know how high it currently is. But Icelandic news is reporting that the cloud is rising fast and high (estimated 3000 – 4000 meters and rising). Explosions have been seen from good distance.

Update 1: They estimate that there are 10 to 12 hours until the glacier flood appears from this eruption. The ash cloud can be tracked with lighting map here.

News about this.

Strókur rís hátt yfir Grímsvötnum (Rúv.is, picture)
Tíu til tólf klukkutímar í hlaup (Rúv.is, new picture)
Allir viðbragðsaðilar komnir af stað vegna gossins (Vísir.is, Picture)
Mjög öflug gosstöð (mbl.is, New picture)

Updated at 19:41 UTC.
Updated at 19:53 UTC.
Updated 20:21 UTC.