Category: Spain

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Overview of activity in Iceland, Spain and Canary Islands

This is a overview of activity in Iceland, Spain and Canary Islands. This is just an short overview. So not all events are included. But it has been quiet during the Christmas holidays.

Iceland

During the 24 to 26 of December there was not a lot of earthquake activity in Iceland. Three small earthquake swarm took place in Katla volcano. In Hengill volcano there was one small earthquake swarm in a location where earthquakes swarms have been taking place for past few weeks. In Katla volcano there was a earthquake swarms inside the caldera. This earthquake swarm are an reminding sign of the activity that is currently taking place in Katla volcano. But this activity took place in north-west part of the caldera. Since Sunday the activity in Katla volcano has again dropped for the time being. But that might change at any time. The largest earthquake that happened was an ML2.3 earthquake. It appeared clearly on my geophone at Heklubyggð.

Stormy weather in Iceland has made it difficult to monitor earthquakes during the past days. This is unlikely to change in next few days. As the path of the winter storms appears to be directly over Iceland at the moment.

Other then this. There was general quiet scene in Iceland during this weekend in Iceland.

Spain

During the weekend Spain had many minor earthquakes. With the largest one going up to ML3.5 in size, based on automatic size estimate. I do not know if anyone of this earthquakes where felt by humans. This earthquake activity is normal for Spain.

Canary Islands

The eruption in El Hierro volcano continued as it has been doing for the past three months. No earthquake appeared on the IGN automatic earthquake list. Harmonic tremor remained the same during the weekend. But yesterday and today there have been reports of new fissures opening. But this does not appears to have changed the harmonic tremor levels on the seismographs on El Hierro Island. This suggests that the currently the eruption remains the same. But I do not know what main eruption vents are open at the moment. They might be at great ocean depth and there eruption signs might not appear on the surface of the ocean.

Other then this it has been quiet in Canary Islands.

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Harmonic tremor continues to drop in El Hierro volcano

It seems that currently the eruption in El Hierro volcano is coming to an end. I do not know if this is an permanent end to the current eruption or just an short break in it. The reports that I have seen so far suggest that the main crater out of the coast of La Restinga has stopped erupting. The current harmonic tremor however suggests that an eruption is still taking place somewhere. But I have no idea where that might be at current time, and so far no clues where that might be. But the lack of earthquakes north of El Hierro Island suggests that an eruption might be taking place there. But that is just speculation.


The harmonic tremor in El Hierro volcano at 20:36 UTC. Copyright of this picture belongs to IGN (Instituto Geográfico Nacional).

Other then this. There is not that much to report from the eruption in El Hierro volcano, or what is left of it at current time. If there are any major changes. I am going to report them soon as I can. But at current time. It does not look like there is isn’t a lot needed to be reported on the eruption in El Hierro volcano.

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Short overview of volcano eruptions in Canary Islands

Here is an short overview of volcano activity in Canary Islands during the past 1000 years. But I do not want to go any more back in time. But this is similar to what I did about Iceland few months ago. For refrence I am using Global Volcanism Program data. I do not have any other data point at the moment. This blog post is going to be updated as more eruptions takes place. This is the same thing that I do with historical overview about volcano eruptions in Iceland.

Year of eruption

Gran Canaria has not had any eruption in past 1000 years.

Fuerteventura has not had any eruption in past 1000 years.

Year ~1060, eruption starts in Tenerife.

Year ~1480 eruption takes place in La Palma.

Year 1492, eruption starts in Tenerife on ~24 August.

Year 1585, May 19. Eruption starts in La Palma. It lasts until 10 August.

Year 1646, eruption starts on 2 October in La Palma. It lasts until 21 December.

Year 1677, eruption starts on November 17 in La Palma. It lasts until 21 January 1678.

Year 1704, eruption starts in Tenerife on 31 December. It last until 27 March in the year 1705.

Year 1706, eruption starts in Tenerife on May 5. It lasts until 13 June.

Year 1712, eruption starts on October 9 in La Palma. It lasts until 3 December.

Year 1730, eruption starts on September 1 in Lanzarote. It lasts until April 16 in the year 1736.

Year 1798, eruption starts in Tenerife on June 9. It lasts until ~14 September.

Year 1824, eruption starts in Lanzarote on July 31. It lasts until 24 October.

Year 1909, eruption starts in Tenerife on November 19. It lasts until November 27. It lasts until November 27.

Year 1949, eruption starts on June 24 in La Palma. It lasts until 30 July.

Year 1971, eruption starts on October 26 in La Palma. It last until November 18.

This blog post is going to be updated regularly.

Blog post updated at 20:55 UTC. Fixed some errors in the text.

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Update on the eruption in El Hierro volcano (13 December, 2011)

Here is a long overdue update on the eruption in El Hierro volcano. But the eruption in El Hierro volcano is now in its third month.

Overall there has not been a lot of change in the eruption that is taking place in El Hierro volcano. But from what I can gather the eruption is taking place in just one vent at the moment. But that is common with this type of eruption. As they start with an fissure, but they end up just one vent erupting and building an cinder cone. Currently the eruption is taking place underwater. But that does not stop it from building an cinder cone. If the eruption continues long enough it is going to form an new island in this location. If that happens, the eruption is going to go from ash making eruption and down to lava eruption. Islands that form in this type of eruptions stand an better chance of lasting more then few months in the ocean. As the eroding powers of the ocean can wipe out a new Island in matter of months if it is just made out of volcanic tuff material.


Current harmonic tremor in El Hierro volcano eruption. The spikes are believed to be explosions taking place in the eruption area. Copyright of this picture belongs to IGN (Instituto Geográfico Nacional).


Steam event taking place in the eruption of El Hierro volcano. This picture is from 4 December, 2011. Copyright of this picture belongs to IGN (Instituto Geográfico Nacional).

There is also an other event that has mostly gone unnoticed by people. But that is the fact that earthquakes have stopped in north part of El Hierro volcano, current rate of earthquakes is close to zero during 24 hour period. This strongly suggests that an eruption has started in north part of El Hierro volcano. I have no idea where it, as there are no signals at the surface of the ocean that give clues to where this eruption might be taking place. But an similar drop in earthquakes took place just after the eruption in south El Hierro volcano started. The depth in north part of El Hierro Island increases sharply and any eruption that is currently taking place on more depth then 1000 meters is going to be hard to impossible to detect properly.

I am going to continue to monitor the eruption in El Hierro volcano. If there are any major changes. I am going to report it soon as I can do so.

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Harmonic tremor in El Hierro volcano drops

There was a change in the eruption in El Hierro volcano last night. The harmonic tremor started to drop of slowly. This drop in harmonic tremor comes several days after a drop in earthquake activity happened. But it might be possible that this drop in earthquake activity in north El Hierro volcano might be because a erupting vent did open up in north El Hierro volcano. But at such depth that the eruption was not noticed on the surface on the ocean. At least that might be the reason. But without any data, this is just a speculation. But at any rate, the earthquake activity in north part of El Hierro volcano has dropped down to almost zero in few days time.


The harmonic tremor yesterday (5 December, 2011). The drop in harmonic tremor can clearly be seen here. Copyright of this picture belongs to IGN (Instituto Geográfico Nacional).


The harmonic tremor today at 08:15 UTC. The harmonic tremor continues to drop during the past few hours. Copyright of this picture belongs to IGN (Instituto Geográfico Nacional).

The harmonic tremor drop is something that has happened before in El Hierro volcano. Just before a new fissure did open up in El Hierro volcano eruption. I am unsure if that is the case now. But it should become clear in about two to three days. But it is also a possibility that this eruption is coming to a end. But it has been erupting now for close to three months now. So this eruption might just ending. But we might have to wait a bit until that is confirmed. But at the moment the harmonic tremor is dropping and that means the eruption is smaller for the moment.

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Activity remains low in Iceland. Eruption continues in El Hierro volcano

At the present time the earthquake activity remains low in Iceland. This goes for both Katla volcano and other areas of Iceland. This is the regular quiet time in Iceland, as it happens sometimes. For the next days, there is a risk of frost-quakes as the ground freezes over in a cold snap.

El Hierro volcano, Canary Islands

The eruption in El Hierro volcano continues as before. New eruption vents have been opening up at random in the south part of El Hierro volcano. Earthquake activity to the north has dropped. While at the same time, the earthquake activity seems to have increased slightly to the west part of El Hierro volcano. I am not sure why that is yet.

In the tremor data. I have been seeing several explosions taking place. But they create a spikes in the tremor plot, that is different then what happens when a earthquake takes place.


The current harmonic tremor from El Hierro volcano. Explosions are the spike activity (30 November, 2011). Some of this however might be sudden increase in eruption activity. Copyright of this picture belongs to IGN (Instituto Geográfico Nacional).

Other then that. The eruption in El Hierro volcano seems to be about the same for the moment as it has been for the past almost two months now. So far it is impossible to know when this eruptions ends. But eruption in La Palma volcano lasted about one month on average. Eruptions in Lanzarote volcano have lasted about three months (last eruption was in the year 1824). Based on this. This might be a eruption that lasts for about 3 to 5 months at the longest in my opinion. But what actually happens is just something that is a wait and see matter.

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Update on the weekend activity

Iceland

This weekend was quiet in Iceland. There was almost nothing going on. There was only one small earthquake swarm in Krýsuvík volcano. But this earthquake swarm was tectonic in nature, not volcanic. The largest earthquake in this earthquake swarm was about ML3.2 in size. Few earthquakes where in Katla volcano, but less this weekend then many others. But it is normal for Katla volcano to be quiet during November to March each year due to snow that is added to the glacier. But that increased the pressure of the glacier on top of the magma chamber (floating balance laws at work here).

Mainland Spain

There was a flurry of earthquakes on Mainland Spain during the weekend. None of this earthquakes where felt, from what I can gather at IGN web site.

Canary Islands, Spain

The eruption at El Hierro volcano continues as it has done for the past almost two months now. The harmonic levels are about the same as it has been, but there seems to be minor intermittent in activity from El Hierro volcano. IGN has setup a picture web site with images that show the activity since this eruption started clearly.

Erik at Eruption blog has good blog post about the magma mixing that appears to be taking place in the eruption in El Hierro volcano.

Other then this. Is is all quiet in Iceland for the moment. But frost-quakes should be expected in the next 48 hours or so in Iceland. As the ground freezes over in a really cold weather.

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Update for the eruption in El Hierro volcano

As the eruption in El Hierro volcano moves closer to the second month. Information on what has been going on has gone bit hard to come by (for me anyway). As people settle with there new reality (erupting volcano). But that does not stop me from reporting on it.

The current status of the eruption is that nothing much has changed since last blog post. But yesterday there where reports of new vents opening up off the south coast of El Hierro volcano. But this is the area where current eruption has been taking place the past month and a half. It remains to be seen if that is going to change or not. But earthquake activity has continued in north part of El Hierro volcano. This earthquake activity seems to be a mixed one. But that means there are both earthquakes due to dike intrusions and local tectonic earthquakes. I now think that this earthquake activity is going to continue all the eruption. I am not sure why a eruption has not started in north part of El Hierro volcano yet. But for the moment it is just earthquakes. The strongest earthquakes in this area can go up to Mb5.0 in size. But I base that on what type of rock makes up the area, along with the thickness of the crust. But that is from 10 km thick.


The earthquake activity for the past 48 hours in El Hierro volcano (picture from 22 November, 2011). Copyright of this picture belongs to IGN (Instituto Geográfico Nacional).


Earthquake activity in El Hierro volcano for the past 4 days. Copyright of this picture belongs to IGN (Instituto Geográfico Nacional).


The earthquake activity from July 2011. This earthquake activity maps out well where the magma lies in the El Hierro volcano. But as the magma expands in the crust, it creates earthquake activity. Copyright of this picture belongs to IGN (Instituto Geográfico Nacional).

The harmonic tremor tells me what is going on in the eruption, when I lack all other visual data on what exactly is going on. But the harmonic tremor increases or drops depending on the strength of the eruption. But that aspect of the eruption is based on how many and how large fissures are open at the time.


The harmonic tremor as it is today (22 November, 2011) at 21:11 UTC. The eruption as can be seen is around the same level as before. But this is not the strongest the harmonic tremor has been. Copyright of this picture belongs to IGN (Instituto Geográfico Nacional).


The harmonic tremor when the eruption was more active then today. This can clearly be seen by how the harmonic tremor is stronger then the scale of the harmonic tremor plot. This happens when a new fissure opens up and its eruption is at the strongest. Copyright of this picture belongs to IGN (Instituto Geográfico Nacional).

The IGN web site on El Hierro volcano eruption can be found here. But it is in Spanish.

I am continuing to monitor this eruption. Even if it is a long term eruption, but that are eruptions that are longer then 1 month. As the for the eruption as a whole, little change has taken place in terms of strenght and location of the eruption. But that might change without warning as before.

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Possibility of a new fissure has opened up in El Hierro volcano eruption

It seems by the harmonic tremor data that a new erupting fissure has opened up somewhere in El Hierro volcano. But given lack of visual observation I do believe that this fissure is at really great depth, and is not leaving any signs on the surface that a new eruption is taking place. Where this new fissure might be is unknown to me at present time. But based on the harmonic tremor data this new eruption seems to be powerful one. It should be expected that new fissures opens up a random while El Hierro volcano is erupting. So far the fissures that have been opening up have been short and out in the ocean. It should also be expect that erupting fissures stop erupting for no reason and with no warning at all. This seems to have happened as I am writing down this blog post.


The harmonic tremor from the eruption in El Hierro volcano yesterday. It can be seen on this harmonic tremor chart that the eruption was powerful all yesterday. Copyright of this picture belongs to IGN (Instituto Geográfico Nacional).


The harmonic tremor around 22:07 UTC. At that time the eruption was in full power as can be seen. Copyright of this picture belongs to IGN (Instituto Geográfico Nacional).


The harmonic tremor at 22:46 UTC. Notice how the drop is sudden when the new eruption fissure stops erupting. What happens is that the magma source that fed the erupting fissure did dry up. Why and how that happens in unknown to me. Copyright of this picture belongs to IGN (Instituto Geográfico Nacional).

This might mean that a new fissure might open up in the next few hours to days. Where that might happen is impossible to know. But as the fissures have been open up so far, it is going to be in a North – south line (about) in El Hierro volcano. What has however become a problem in my opinion is that the magma might have “boiled” the rock and made it soft. So it might not make a earthquakes before a eruption starts in it. This might be the case if the magma has been in the crust for the past 5 weeks. But the only example of that type of event that I know of was in Eyjafjallajökull volcano last year (2010), when a new fissure did open up suddenly and without any earthquakes or warning after 4 weeks of eruption. The reason for that was the same one on what I think might be happening in El Hierro volcano.

From what I can tell, based on data and earthquakes it does not seems that the eruptions in El Hierro volcano are over. As new magma continues to flow in from depth (the mantle). Until that flow stops, El Hierro volcano is going to continue to erupt. However there might be breaks from few hours and up to several weeks between eruptions, in that case no eruption would be taking place. This has its origin in the fact that this is a fissure rift events of shorts, a similar eruption took place in Krafla volcano in Iceland for over a 10 year period. Movement and flash inflation and deflation are also to be expected during this period in El Hierro volcano eruption. As it has many similarities of the eruption in Krafla volcano in Iceland. But it is not exactly the same, just similar. As Krafla volcano is on the inter-plate rift zone. While El Hierro volcano is on a hot spot rift zone, far inside the Africa Plate.

Update on the forum: There have been some technical difficulties with the whois registration. How that works out is not yet clear. I am going to short that issue out before I set-up the forum on the domain. In the case I have to register a new domain name. What happens in this case should be come clear next week I hope.

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Update on the eruption in El Hierro volcano on 9 November, 2011

Short note on comments: This is a short notice on comments. This blog has been getting a spam flood for the past few days. During the past 2 days or so there have been over 300+ spam comments that my spam filter has captured. This makes it ever so hard to find real comments that go into the spam box by accident. If your comment disappears for no reason after it has been posted. Then the spam filter has captured it. Please do not re-post it, as then following comments are just going to go into the spam box too. I have to manually un-check them as spam and approve them. So if you post three comments with the same link, I am going to clear the three comments with the same link. But given the amount of spam that this blog is getting there is always a risk that comment is going to get lost and permanently deleted.

It is also important that if you get “comment is held for moderation” that you do not re-post what you are commenting on. As the comment is going to wait in the moderation until I clear it. I am not always around to check for this, so it might take few hours or more until I approve the comment/s.
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The eruption in El Hierro volcano is ongoing and does not appear to show any signs of ending. However the strength of the eruption has dropped a bit during the past two days. But this was to be expected, since this is a fissure eruption and it has mostly been erupting from the same vents during the past four weeks.

It has become a bit difficult to get accurate information on what is going on El Hierro Island. So I am not going to speculate on that. But from what I can gather it seems that dangerous gas level has been detected on the ground. But the reports that I am reading are bit unclear on this. This has also been mentioned in comments on this blog.


The harmonic tremor from the eruption in El Hierro volcano at 15:23 UTC on 9 November, 2011. Copyright of this picture belongs to IGN.

As can be seen on this tremor plot the harmonic tremor in the eruption is dropping. Explosions that have taken place are also clear on this tremor plot. That might be because the eruption vent is getting smaller, therefor less magma is being push out the erupting vent. Or the currently erupting vent might be closing up. As so often happens with fissure type eruptions. If that happens does not mean that this eruption cycle is over. It just means that the current eruption vent has closed up. New fissures are most likely to open up in coming weeks as the eruption goes on. Where and when it impossible to know for sure.

Earthquake activity continues in north part of El Hierro volcano. This are most likely dike intrusions into the bed rock there. So earthquake activity should be expected to continue north west of the town Frontera. If a dike intrusion manages to find a path to the surface in this area there is going to be a eruption and earthquake activity should drop following that. But until and if that happens there are going to be earthquakes. There is also chance of hydrothermal activity to show up in this area if a dike intrusion gets shallow into the bed rock. But is not go up from the ground and start a eruption. This might also be the reason why some part of El Hierro Island are experiencing high levels of toxic gas for the moment.

I am going to post more on the eruption in El Hierro volcano as I know more what is going on.