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Earthquake swarm in Tjörnes Fracture Zone

Today (18 October, 2011) at 08:53 UTC a earthquake swarm started in TFZ. So far this earthquake swarm is small in nature, only about dozen earthquakes so far. But the largest earthquakes have been with the size of ML3.6 according to IMO automatic earthquake detection system (called SIL). There is a good chance that this earthquake swarm is going to continue for the next few hours. But it is hard to know that for sure at the moment.


The area with the earthquake activity in Tjörnes Fracture Zone (TFZ). Copyright of this picture belongs to Iceland Met Office.

There are no volcanoes in the area where this earthquake swarm is taking place.

Blog post was updated at 11:58 UTC on 18 October, 2011

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Short note on Hengill volcano man-made earthquake swarm

This is a short note on the Hengill volcano man-made earthquake swarm.

The earthquake swarms that have been taking place in Hengill volcano are man made due to Orkuveita Reykjavíkur pumping down water at the depth of 2500 meters or more (down to 4000 meters from what I have read). It is clear that Orkuveita Reykjavíkur (short name OR) does not have any option but to continue this water pumping, as it is mandated that they do so in there operation permit. They have been doing this for some time now. But when they started using new drilling holes to pump down water the earthquake swarms started to happen. The people at OR claim that it is unlike that this earthquake swarms are going to grow in size and magnitude. I do not agree with that assessment.

It is my view that increased water pumping into the bedrock is going to increase earthquake activity. This has been agreed on by geologist that are not connected to OR or the government. But the largest earthquake that this area can make is Mw 6.0 in size according to a estimate on this area. So far, the largest earthquakes have been up to ML 4.0 in size so far. A jump in magnitude from ML3.5 size that was in earlier pumping was done.

There is also risk of pollution of the groundwater from heavy metals in the hot water (lead, zinc, copper and others). But this risk also seems to have been underestimated. As they claim that pumping down the water below the 800 meters groundwater line does not affect the groundwater. But it seems that no studies (that I know) have been done to confirm this.

News on Rúv about this.

Aukin dæling mun auka skjálftavirkni (Rúv.is, Icelandic)

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Special report: Update 4 on the eruption in El Hierro, Canary Islands, Spain

Short note on comments: During the eruption in El Hierro there has been a lot of comments on this blog. Over the past 4 days (or so) there have been about ~1500 comments. If your comments is held for moderation, the blog says so. Do not try to repost your comment if that is the case. As the second comment is just going to be held in moderation as the earlier one. It takes me a little while to approve the comment and to make it appear. If your comments disappears and cannot be seen, the spam filter has eaten it. It also takes me a while to check the spam filter and restore comments that have gone there. Please do not just post comment with nothing but links, that increases the risk that the comment is going to be eaten by the spam filter.
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Short note: Please note that I am not a expert in the field of volcanism, volcanoes and earthquakes. I never claim to be one. Regardless if I am asked or not. I am a man with interest in this field. I read a lot of books and studies on volcanoes and earthquakes. But that does not make me a expert in this field. If you want to speak with a expert, go and find one. Because I am not it.

Now. About the eruption in El Hierro volcano in Canary Islands. This is going to be a short blog post about the eruption.

From what I can tell and the information that I have seen. At least two more vents have opened up on the from what I can gather on the pictures and the reports from Canary Islands. So far all the new vents are under the ocean and at depth of no less then 150 meters. So seeing them directly is quite hard for the moment. There are continues deep earthquakes under El Hierro volcano, but that suggests that new magma is flowing into El Hierro volcano.

During the weekend floating magma bombs where (or some type of magma, I do not have the exact word for it in English at the moment) floating on the ocean. But this means that at least one of the vents that started erupting in the beginning is getting close to break the surface of the ocean. If the eruption continues in that vent for a little while longer. If it gets above the surface of the ocean, it is going to form a island and a lava eruption is going to start once the ocean cannot get any more into the crater.


The harmonic tremor of the eruption in El Hierro volcano today (16 October, 2011) at 22:35 UTC. Copyright of this picture belongs to Instituto Geográfico Nacional.

There is a risk of new fissures in El Hierro opening up without warning. From what I am estimating, the area that this can happen has expanded about ~5 km or so from my original estimate that I made in few blog posts ago. The risk of new fissure opening up on land is going to remain high while this eruption is taking place. But this might well be a period of eruption activity for El Hierro. It is impossible to know for how long it is going to last, it could be weeks or it could be months and up to years of activity.

I am going to post more information on El Hierro when I know more tomorrow. I am also going to write about the earthquake activity in Hengill volcano tomorrow if I have time to do so.

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Special report: Update 3 on El Hierro eruption in Canary Islands, Spain

I am going to fully integrate Canary Islands into my watch volcano monitoring system in the beginning of next month, but Canary Island won’t be part of my emergency system until I move to Canary Island (that is because of technical reasons mostly). When that happens, blog post regarding earthquake and volcano activity won’t be a special report. Just a normal blog post as with Icelandic volcanoes. I am doing this as I plan on moving to Canary Islands in about 10 years time (+- maybe few years depending on how my plans work out). A name change on this blog is planned in the beginning of the year 2012. But it takes a while for me to think up a new name for this blog.
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The eruption in El Hierro volcano continues at the same phase as before. With little change so far. Currently the eruption seems to be in two vents, as it did when it started on Monday. There have been unconfirmed reports of new vents opening up closer to the coastline. But given lack of direct evidence that should be there. I do not believe that a new vents have opened up closer to the coastline so far.

Deep earthquake continue in El Hierro volcano. But that means a new magma is coming in from the mantle and is flowing upwards into the volcano. For long as deep earthquakes are being recorded the eruption is going to continue. It is impossible to know for how long this inflow of magma from the mantle is going to continue. But this means that the eruption is going to continue for time being. With the risk that new vents might open up at any time on and around El Hierro volcano. This inflow of new magma has also been confirmed by GPS measurements on El Hierro volcano (the island). But since the eruption did start, no major change has been seen on the GPS real time data.


The harmonic tremor in El Hierro volcano yesterday. Copyright of this picture belongs to Instituto Geográfico Nacional.


The harmonic tremor in El Hierro volcano today (until 21:20 UTC about). As can be seen by comparing the pictures between today and yesterday. Not much has changed since yesterday in terms or harmonic tremor. Copyright of this picture belongs to Instituto Geográfico Nacional.

If a eruption vents open up on a land. The following eruption is going to be lava only. No volcano ash and no explosions as El Hierro is a shield volcano like the one on Hawaii and that means only lava eruptions. If a eruption vents opens up on the shallow coastline, there are going to be explosions for as long the ocean water can get into the crater. The moment it closes up the explosions stop and lava eruptions starts.

Please note that I am on slow internet connection (3G). So I am not going to post anything if the internet connection is really slow, as sometimes seems to happen. I am going to try and solve this issue by using my 3G phone and connect that way. At least I am going to try and see what happens.

Blog post updated at 03:20 UTC on the 15 October, 2011.

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Earthquake swarm in Askja volcano and Katla volcano

During the night there was a earthquake swarm in Askja volcano and in Katla volcano. The earthquake swarm in Katla volcano might be ongoing, but it is hard to know that for sure at the moment.

The earthquake swarm in Askja volcano are signs that volcano is preparing for a eruption period. But it seems like that magma has been starting to collecting in Askja volcano last year (in March of 2010). This progress also seems to be moving along faster then I did expect last year. But the earthquake swarm that took place during night was because if a possible dike intrusion from Askja volcano that got into the crust inside Askja volcano fissure swarm. So far the pressure of the magma is not high enough to start a eruption and I am unsure how long this progress needs to continue before Askja volcano is ready for a eruption. The largest earthquake that happened during the night was ML3.4 and on around 1 km depth according to the news on Rúv.


The earthquake area in Askja volcano. It is outside the main Askja volcano, but inside Askja volcano fissure swarm, the star marks the location of the ML3.2 earthquake (automatic size). Copyright of this picture belongs to Iceland Met Office.

Earthquake activity continues in Katla volcano as before. Most of the earthquakes are as before just small ones. Currently the earthquakes do not appear to be from dike intrusion as happened last week (5 October, 2011) with the earthquakes that where up to ML3.9 in size (checked data). After this large earthquake swarm activity dropped considerably. But it has been picking up again slowly during the week. But earthquake observation has been difficult due to frequent storms during the past two weeks that have been passing over Iceland. This storms have had wind up to 30m/s and wind gusts up to 56m/s (recorded).


The earthquake swarm in Katla volcano caldera. This area was active this summer when there was a minor eruption in Katla volcano. Copyright of this picture belongs to Iceland Met Office.

For the moment it is hard to know what happens next in Katla volcano or in Askja volcano. But it is clear that Askja volcano is preparing for a eruption (along with Kverkfjöll volcano). It is clear that Katla volcano is continuing to prepare for a eruption. But it is impossible to know when and how big that eruption might be. Until a eruption takes place, more dike intrusions with following earthquake swarms should be expected in Katla volcano.

Note: I am going to write more on El Hierro volcano (Canary Islands, Spain) later today. When I know more on what is going on in that volcano. But information gathering takes a little time when it is in a language that I do not properly understand yet.

News on this from Rúv.is.

Jarðskjálfti við Lokatind (Rúv.is, Icelandic)

Blog post updated at 14:23 UTC on 11 October, 2011

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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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Two geophones ordered

Yesterday I did order two new geophones to expand my geophone network. I am not yet sure when they are going to be up and running. But that is going to happen soon (hopefully) after they arrive in Iceland.

I want to thank everyone how did support this effort so that I was able to buy this two new geophones. All that is left now is to get a computer for the geophone station that is going to be close to Katla volcano.

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Tremor pulses in Hamarinn volcano (most likely)

During the past two weeks there have been tremor pulses in Hamarinn volcano (is claimed to be part of Bárðarbunga volcano system), at least most likely that volcano. But it might also be a volcano that I call Skrokkalda Volcano (other name might be Hágöngur volcano) (it has no entry on GVP web page, I do not know why). But given recent history I find it unlikely to be the case.

This harmonic tremors might be due to dike intrusions. I find it unlikely to be from a man made lake called Hágöngulón that is in this area. The harmonic tremor pulses look like sharp spikes on the tremor plot on the Skrokkalda SIL station.


Harmonic tremor spikes from Hamarinn volcano. Copyright of this picture belongs to Iceland Met Office.

This pattern of harmonic tremor spikes was seen all last year and all of the year 2009 from what I can remember. I do not have tremor charts from that period. But however this suggests that more magma has now started to flow into Hamarinn volcano. But there was a small volcano eruption (it seems so, given the flood that took place in July) in Hamarinn volcano last summer (summer 2011). What happens next is a good question.

This process of inflow of magma seems to without earthquakes, or close to it. I do not know why that is and I have no ideas that explain it.