Category: Eruptions

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Special Report: Update 2 on the eruption in El Hierro

This is a special report on the eruption in El Hierro. This is also a good time (as any) to announce that I plan to write about volcanoes in Canary Islands in the future. As I plan on moving to the Canary Islands in about 10 years time (no reason to start late on this). But I have already induced the Canary Islands volcanoes into my personal watch system. But I have my own personal system to watch volcanoes in Iceland and now Canary Islands. However, Canary Islands are not part of my personal emergency system until I move to Canary Islands.

Update to the name of this blog is going to happen soon, but I am not sure when. But I am going to move in a about 10 years time (going to live in Denmark until that happens). Until then, they are going to go into special report group and only major events are going to be blogged about. Please note that this might change if I move earlier to Canary Islands then I now plan.

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The eruption in El Hierro volcano continues today, as it did yesterday. But the strength of the eruption appears to have dropped today from what it was yesterday. But this does not mean that the eruption is over. It just means that the current fissure that is erupting is about to close up, mostly due to the material that it has been ejecting into the ocean floor. That means a new fissure or vents is about to open up somewhere. When and where is impossible to know. But this is the nature of volcanoes that erupt in this manner, but El Hierro is a shield volcano [second link here]. Good examples are Krafla volcano and Vestmannaeyjar Island volcano. Both of those volcanoes are in Iceland.

Today around 14:20 UTC there was a sharp tremor drop in El Hierro. This means that the magma flow dropped in the current eruption fissure. This also means that if the pressure is not enough that fissure is going to stop erupting. Because of this has happened a new fissure or a vent should be expect at any time as I have told before. When and where that might happen is impossible to know, as that outcome depends on where the magma finds its pathways inside the volcano. There might not be any earthquakes before this happens, as the rock is unlikey to be hard enough to make them. Some small earthquakes might happen if the rock layer is hard enough. Today few deep earthquakes have been recorded. This means that new magma is getting into El Hierro volcano from the mantle (where no earthquakes happen). This also means that this eruption might take place for some time now. But it is impossible to know for how long, as there might be a lot of magma flowing up from the mantle it self and up to El Hierro volcano.


The harmonic tremor and the drop in the harmonic tremor today. Copyright of this picture belongs to Instituto Geográfico Nacional.

Many people have been wondering why this eruption has not been seen. The fact is that depth drops quiet fast around El Hierro Island. Around 4 km out the depth is close to 1.5 to 2 km, it is only close to the island that the depth starts to get shallower. At the moment is is hard to say what happens next in this eruption on El Hierro. But more vents should be expect to open up then have already have.

I am going to update this blog post if anything changes in El Hierro volcano eruption.

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Special report: Update on El Hierro volcano eruption

While everything is quiet in Iceland. I am going to continue my coverage of the eruption in El Hierro volcano. Information in English also seems to be lacking for some reason. Please note that I have little understanding of Spanish, so I am just using the data that is available to me on the internet to figure out what is going on.

First I want to say that I am not a expert. I never claim to be one. My knowledge of volcanoes and earthquakes are the result of hard work and studying them on my own (reading research papers and other sources).

It is bit unclear what is going on in El Hierro. But from what I can tell least two things have happened during the past 24 hours. The first thing is that a eruption started at ocean floor around 04:18 UTC yesterday (10 October, 2011). This eruption appears to have been small and was not noticed on the surface of the ocean. Around 06:10 UTC this morning (11 October, 2011) a large movement of magma started to take place inside El Hierro volcano. Where exact break up of this magma is going to take place is unclear at the moment. But it is clear that a eruption is taking place and it is more chance then less that magma is going to find it self a new pathway up to the surface soon. As I do not think that the current eruption vent is keeping up with the current magma that is under El Hierro. But it is worth to notice that El Hierro does not seem to have a magma chamber, like Eyjafjallajökull volcano in Iceland so the eruption size is terminated by the current inflow of magma.

Here is a comparison of harmonic tremor charts from yesterday and today (10 and 11 October, 2011).


The harmonic tremor as it was on 10 October, 2011 at 21:08 UTC. Copyright of this picture belongs to Instituto Geográfico Nacional.


The harmonic tremor as it was on 11 October, 2011 at 20:29 UTC. As clearly can be seen it has grown by a margin or more (I can’t tell for sure) in the last few hours. Copyright of this picture belongs to Instituto Geográfico Nacional.

What is however really interesting is how this eruption is changing fast and without any warning at all. But this is however something that might be expected from a volcano like El Hierro. I see in the news that they are expecting earthquake activity before new vents or fissures open up. That is wrong assessment in my opinion. As new eruption vents and fissures can open without any or much earthquakes activity at all. Earthquake activity before a fissure vents open up depends only on the rock that the magma has to break trough. In many cases it does not have to create any earthquakes before a eruption starts. Good example of this is the eruption in Heimaey Island in the year 1973. Only a small earthquake swarm was detected before a eruption started. All I personally except before a eruption in a new place on El Hierro volcano is a minor earthquake activity. It is also hard to know if that earthquake activity can be detected based on the amount of harmonic tremor taking place at the moment.

Here is my personal assessment on where eruption might take place in El Hierro. Please note that it might be completely wrong. But I base my assessment on the data out there, that assessment might be wrong.


The most chance of the eruption in El Hierro in my personal opinion marked by the two red circles. Copyright of this picture belongs (original) to Instituto Geográfico Nacional.

There have been some deep earthquakes in El Hierro volcano over the past few hours. This deep earthquakes mean that new magma is flowing under El Hierro volcano. This means that the flow is steady (pressure pulse in the magma creates the earthquakes). So this eruption is far from being over it seems. How long it is going to last is a good question that currently nobody has a answer to at the moment.

I am going to update this blog post if I have to or if something new happens in El Hierro.

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Special report: Eruption at El Hierro volcano, Canary Islands

At 04:18 UTC on 10 October, 2011 a eruption did start somewhere close to the El Hierro volcano Island (but inside El Hierro volcano system). So far nothing has been seen to this eruption, so location is uncertain at the moment. At the moment this eruption has only been confirmed by harmonic tremors seen on seismometers on El Hierro island.

From what I can tell, based on the harmonic tremor plots. It seems that the eruption has been growing in size since it started well over 12 hours ago. This suggests that the eruption is growing in size. That also brings up the issue that new fissures might open, both into deeper ocean and on shallower depth and even on land without any warning at all.


The harmonic tremor from El Hierro at 21:08 UTC on 10 October, 2011. Copyright of this picture belongs to Instituto Geográfico Nacional.

A location for the eruption has been suggested, as can be see on this map here.


The speculated eruption in El Hierro. Copyright of this picture belongs to el-mundo.es Thanks to Dr. John v. Kampen for this map via email.

Lack of earthquakes does not mean that magma is not the move and has not reached the surface already. But this however suggests that magma now has a free flow upwards to the surface since sometimes yesterday, when the earthquake activity did drop suddenly from ~100 earthquakes to ~30 earthquakes over the day.


Current earthquake activity in El Hierro. It is my personal opinion that the eruption is around -18.05 and 27.65 to 27.70 (middle of that area, around 450 meter depth). Copyright of this picture belongs to Instituto Geográfico Nacional.


Spectral image of the harmonic tremor. This image clearly shows that the orgin of the harmonic tremor is magma on the move. Not something else. Copyright of this picture belongs to Instituto Geográfico Nacional.

I am going to update this blog post as more is known about the eruption in El Hierro.

Canary Island news about this. With thanks to Dr. John v. Kampen how did send them to me in a email.

Posible erupción al sur de El Hierro (Youtube, Spanish, Video)
¿Emergerá una nueva isla? (Youtube, Spanish, Video)

Blog post updated at 21:49 UTC on 10 October 2011.

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Few right and wrong things about geology in Iceland, part 1

I have seen many speculations on how geology works in Iceland. Some of it is good and based on observation and factual basic. Other however is nothing but speculation and far from anything based on factual evidence on how geology works in Iceland.

Few right and wrong things about volcanism in Iceland

Volcano interaction Status: Limited truth to this

Volcano interaction is something of a debated among scientists. But what is not debated is the interaction between volcanoes that lies far apart. That interaction is none by it’s nature. So while I have been seeing discussion in the comments here that there is some connection between activity between Hengill volcano and Hekla volcano. This is untrue. There is no connection between those volcanoes and never has been. The reason is simple. The volcanoes are far apart. They don’t even share the same magma source. But that is evident by the lava that comes from this two volcanoes. But Hekla volcano has mixed types of eruption sometimes. But Hengill volcano only has Hawaii styles eruptions (if not hit by water) when it erupts, in style with other volcanoes on the Reykjanes ridge rift zone.

The only real life examples of volcano interaction are from Bárðarbunga volcano and Torfajökull volcano. The reason for this interaction is quite simple and logical one. Bárðarbunga fissure swarm cuts right trough Torfajökull volcano. When magma travels south-east in the fissure swarm (it last happened in the 15th century) it can hit the magma inside Torfajökull volcano. When this happens there is a big bang in Torfajökull volcano. As the magma in Torfajökull volcano seems to be colder and more Intermediate (andesitic) [link, Wikipedia] in nature. But in Bárðarbunga volcano the magma is Mafic (basaltic) in nature. When the two magmas mix, it ends with a bang and eruption in both volcanoes. But normally the process that starts this is because there is a ongoing eruption in Bárðarbunga volcano. So when Bárðarbunga volcano. I would worry about that rather then anything else.


See, no connection at all between Hekla and Hengill volcano. Copyright belongs too this picture owner. Owner unknown to me.

Iceland is going to have VEI-8 eruption. Status: Not likely.

All volcanoes can do a VEI-8. But the thing is that they are just not likely to do so. As the size of the eruption is directly connected to the inflow of magma it is getting. In the case of Icelandic volcanoes the inflow just seems to be few magnitude too small to make a VEI-8 eruption. The largest VEI eruption known in Iceland was a VEI-6 eruption that took place in Bárðarbunga volcano in the year 1477 (?).

As for VEI-8 eruption. I am not expecting that type of eruption any time soon in Iceland.

Iceland is one volcano. Status: False.

The simple answer is no. The long answer is. Iceland has many volcanoes, not just one. So the answer is no to this.

Geology in Iceland is well understood. Status: False

Geology in Iceland is understood. But far from being fully understood. As it happens geology science is just starting to now understand what complex progress are taking place in Iceland. A lot have been learned. But a lot more needs to be learned about how geology works in Iceland.

Volcano eruptions comes in active cycles. Status: True

This has been observed by actual data. But volcano activity happens in periods of 80 to 160 years. With a quiet period of 50 to 90 years. But numbers are approximation. During the quiet time there are fewer eruptions and they are smaller (hint: Large eruption can still happen however during the quiet period). Last quiet period started in around the year 1870 and did not end until the year 1983. But that year there was a eruption in Grímsfjall volcano. But then Grímsfjall volcano had not erupted since the year 1954, but that break was 29 years long for Grímsfjall volcano.

This graph here also shows this clearly. But this is volcanism in Iceland during the years 1875 and to the year 1993.


Copyright holder unknown. Copyright of this picture belongs to this owner.

It is impossible to know for sure when the high peak in the current cycle is going to be be. But most geologist are estimating that to be sometimes from the year 2020 and to 2080 or about that. So the years ahead is going to be quite busy in Iceland in the terms of volcano activity.

I am going to write more right and wrongs about Icelandic volcanoes soon. But for now this is good enough.

Sources and other things.

Volcano-tectonic Interaction in the Hengill Region, Iceland during 1993-1998 (pdf)
Volcano geodesy and magma dynamics in Iceland (ScienceDirect)
Interaction between Continental Lithosphere and the Iceland Plume—Sr-Nd-Pb Isotope Geochemistry of Tertiary Basalts, NE Greenland
Tomographic evidence for a narrow whole mantle plume below Iceland (ScienceDirect)
Pdf document on Hengill volcano crustal deformation.
Magma (Wikipedia)
Volcano geodesy and magma dynamics in Iceland (pdf)

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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.

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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.

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All quiet at Katla volcano

Currently everything is quiet in Katla volcano. At the moment the harmonic tremor level have gone back to normal levels. But there appears to be some earthquake activity taking place inside Katla volcano caldera. But most of this earthquakes do not appear on the automatic earthquake list that IMO has. But it might be impossible to actually locate this earthquakes as they might just appear on single or two SIL stations.

The glacier flood is over and the flood water have continued to lower during the day.

It is hard to know for sure what happens next. But the current events started around 17. June when earthquake swarms started to appear on the Katla volcano caldera. This has been developing rather fast since then. I do not expect that to change any time soon. But what I think was harmonic tremor pulses started around 12. June.

For now however all that can be done is to wait and see what happens in Katla volcano. As I do not think that this is over. But we might be in for an few hours or days of an break until something new happens in Katla volcano.

Icelandic News about this.

Einungis brúin eftir (Rúv.is, Icelandic, Picture)
Highway no. 1 disrupted for weeks. (Rúv.is, English, German)

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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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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.