Posted on by Jón Frímann

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.

529 Replies to “Special report: Eruption at El Hierro volcano, Canary Islands”

      1. Sorry, VEI is not what I meant to say, I meant this is very hug!
        (just been reading on VEI index and getting confused)

    1. forgot to mention that it’s a live Q&A and you can submit questions. Giggle translate as ever amusing 🙂

  5. teideano teideano
    @eruptionsblog some reports of felt tremor by some….ok, really prelimianr and needs confirmation, but if felt, then we have a problem.
    há 8 minutos Can anyone explain this?

    1. Still fits the scenario with filling of the reservoir and gaining pressure. Just wonder when the shallow eq will appear and if there’s a long phase of them until the magma finds its way up (and I still keep thinking it will use old pathways and erupt quite close of if not on the island).
      Whole volume still isn’t full, pressure not high enough to break through, but at this pace (ups and downs, but trend is upwards and rahter “dynamic”) we’ll get a firework in some hours/days.
      Gas emmissions don’t radically change the main process that is going on.
      If I was a local I would gently start packing my bag. No need to panic yet, but when I see the decision and communication skills the authorities have shown yesterday, I might have lost some trust in them when it’s about watching over my life. El Hierro isn’t a so bad volcano, and it shows its intentions. It would be unacceptable if we lost human lifes in this context. Really hope they don’t underestimate what’s cooking there, even if it isn’t Yellowstone… After reading the island-chef that already saw himself re-open the tunnel because of the benefic effects of the underwater-fart that opened some fish the doors to nirvana…

    2. I don’t think so. When we’ll see a lot of orange / red filling the line at 7 to 8 Hz, then we’ll have to seriously wait for the “boom”.
      From in 9 hours on (12/00 CET) ’til saturday, but probably sooner than later in that time span. Still no element that makes me calculate my guesstrapolation again.

    1. Influx of magma in the shallower part of the chamber, pressure build up, now near enough to the surface to become felt. First “real” work on the pathways from the reservoir to the surface starting? Hmmm… Really, really interesting developpment.

  14. Off Topic, but I wonder if German terrorists know something we don’t…

    “A previously unknown left-wing group, calling itself the Hekla Reception Committee, said it planted the devices…

    “Police said they were not familiar with Hekla, which is also the name of an Icelandic volcano.”

    http://www.bbc.co.uk/news/world-europe-15255047

    1. Probably just using the name Hekla because Hekla was considered in the Middle Ages as the gateway to Hell.

    2. Or because it’s the spider in “Biene Maya”… Or was ist Tekla? Don’t exactly remember. I’d call a terrorist group Willy or Flip.
      Joke for the german TV watchers only, I guess.

  15. The spectrogram isnt that just a measuring tool of what noise is beeing made?

    You have the constant rumbling from the harmonic tremors around 1-2 Hz which dies down when you get to a higher frequency. The yellow area with “spikes” would be explosions or earthquakes which would be fracturing rock or something similar.

    1. So basically the more red/orange/yellow shown would mean higher noise and the frequencyrange could help identify the source. The red area (harmonic) seems to be quite the same while the orange/yellow has been increasing abit.

    2. I understand it the same way. Energy that get’s free by “small” things like fractionning. Will look very different when the bottle is open.

    3. It is really impressive to see also the first ( about 2 Hz) and second (about 3 Hz) harmonics of the main 1 Hz signal. This only means that the conduits are fully open (i.e. more like open pipes with no obstacles) for the magma to flow. And, the pressure build-up will be very very strong… If we see earthquakes, it is due to magma seeking a path to the surface.

    2. Video of constant shaking on El Hierro.. so that pretty much confirms the low rumble/shake reported on twitter

    1. Indeed. And if you look at both the spectrogram chart and this tremorchart you can clearly see that the graphs are beeing saturated. I.e the “noise” is higher than the scale and gets cut.

      But that we can determine that the tremors are actually larger than what is shown on the charts.

      1. So the next step here is a sold colored area.

        If you all allow i’d like to repeat one question: Does this tremor chart indicates that the existing (?) eruption underneath the sea becomes stronger? Or is this an indication, that somethings moving up (based on the EQs during the last day, headding to the islands mainland)? If the second option applies, i guess we will see new swarm with very shallow depth due to the last blockade: The surface. Correct?

      2. I wait for the latter, as I still believe this underwater degassing is of secondary interest.

  19. I think that the magma has reached the upper layers just as Geoloco said. Now it will start looking for pathways to the surface and if it cant find any it will create some. I wouldnt be surprised if we will see an increase in shallow quakes now that the pressure is starting to build.

    1. I’d say that from the moment when these shallow quakes stard, we can begin to see patterns and speculate if the old pathways can be an interesting option for the magma to take, or if we have a new “channeling” to the surface that takes place, or in what way we go completely on the creation of a fat fissure…

  21. From AVCAN FaceBook page (Spanish text & Giggle version in English):

    3 hours ago:
    Nueva situación: si bien el sismograma de CHIE es completamente ilegible, el espectrograma está presentando señales de microseísmos, (líneas amarillas verticales), que acompañan al importante tremor y que pueden ser atribuíbles a la fragmentación del subsuelo, (ya sea submarino o terrestre), el magma se mueve y fractura. No sabemos si están siendo localizados o son localizables estos eventos por el ruido de fondo y la relación S/N (señal/ruido), pero les recomendamos que estén atentos a la información que se pueda facilitar por parte de las autoridades (JR).

    New situation: While CHIE seismogram is completely illegible, the spectrogram is showing signs of microseismicity (vertical yellow lines), accompanying the major tremor and may be attributable to the fragmentation of the subsurface (either submarine or terrestrial) the magma moves and fracture. We do not know if they are being located or locating these events are background noise and the S / N (signal / noise), but we recommend that you be attentive to information that can be facilitated by the authorities (JR).

    10 min ago:
    URGENTE
    14:17 Ante la evolución del fenómeno sísmico que afecta a la Isla de El Hierro, y como medida preventiva, se está procediendo al desplazamiento de la población de La Restinga al punto de encuentro establecido en el plan de protección civil ubicado en el campo de fútbol, teniendo en cuenta la posibilidad de que la migración del foco eruptivo se acerque a la costa, informa el Gobierno de Canarias en un comunicado.
    (de CANARIAS7)

    URGENT
    14:17 In the evolution of the earthquake that affected the island of El Hierro, and as a preventive measure are being taken to the displacement of the population of La Restinga to the meeting point set in the civil protection plan in the field located football, taking into account the possibility that the migration of eruptive focus approaches the coast, to the Government of the Canaries in a statement.
    (from Canarias7)

    So Lurking was right about the “point”, they seem to start evacuating La Restinga now…

      2. Thanks!
        No chance to get on the site right now. Must be too many interested in reading it…

      5. So far this says that the government has asked the population of La Restinga to move to the football field (courtesy of Google).

        As the football field is also not too far from Lurking’s predicted eruptions site, I would hope that this is just a meeting point prior to leaving the area.

  22. teideano teideano
    @eruptionsblog Evacuation under way in El Hierro, evacuation under way in El Hierro. Magma migration should be inland.
    há 1 minuto

  23. Brief update from El Mundo. Translation by Google:

    “The authorities have asked little more than five hundred inhabitants of La Restinga on the island of El Hierro, who come to the meeting under Volcanic Risk Plan for the possibility of another eruption occurs closer to the underwater coast.

    This has been reported to the Coordinating Center Efe Emergency and Security in the Canaries.

    Before this appeal, the residents of this seaside town, the southernmost of the island should be moved to the soccer field of the locality to follow the instructions of the authorities.

    La Restinga (547 inhabitants) is the closest to the submarine eruption occurred yesterday in El Hierro, located five kilometers from the coast and about 1,000 meters deep.”

    http://www.elmundo.es/elmundo/2011/10/11/espana/1318339342.html

    Reply

  24. Good idea to get everyone out there. Anyone an idea how big of an eruption we can expect?

  25. The spectrogram would then actually support the idea that the eruption has not yet started. It starts to get noisier by the minute and that would indicate that the source of the noise is getting closer to the actual instruments right? And they are most probably landbased.

    Give it a day or two and I think there will be an eruption on dry land.

    Caveat. Wildly speculating without any sort of scientific or factual backing here. 😉

    1. But possible. The submarine eruption may only have been the pre-eruption emission of gases. Jon’s early forecast of 27.65 to 27.70N and 18.02W is well on land.

    2. I’m afraid the scientists working on the island now enter a fase where they themselves have to guess and estimate because their tools can no longer properly read what is happening, the spectral graph is flatlining.

      http://www.01.ign.es/ign/head/volcaSenalesAnterioresDia.do?nombreFichero=CHIE_2011-10-11&ver=s&estacion=CHIE&Anio=2011&Mes=10&Dia=11&tipo=2

      The tremor drowns out the eartquake signals. Very hard to measure their size and origin, is what I gather from reading on several platforms & Facebook pages, There seems to be very little additional material on the island to help measure what the source is of the quakes that are happening right now. Two scientists from one of the other islands have hired a boat and came over on their own expenses to set up a provisonal station in a house in La Restinga to try get more data on the sources of quakes and tremor. I suppose they will evacuate too.

      ALARM LEVEL ON EL HIERRO WAS JUST RAISED TO RED
      http://www.diariodeavisos.com/2011/10/11/actualidad/el-gobierno-de-canarias-evacua-la-restinga

  26. I also think it has not yet started. It would be really really weird that a body of magma can move through kilometers of non-ductile crust (which has not experienced any kind of eruption for at least 200 years) while producing only a small dozen of earthquakes! I’m expecting the tremor to pick up first. This might be just gas release combined with subsurface magma movements.

    1. When magma breaks the rock it does not have to create large earthquakes. As rock that is under less pressure breaks more easily. Before the eruption at Heimaey Island in Iceland there where few to none earthquakes just before the eruption started. That volcano also had around 3000 year break before the eruption cycle around the years 1960 to 1973.

      It might well be that a small vent did open under the ocean. But what might have happened there is that it did closed up. Such thing happens all the time in eruptions. That also explains the increased tremor activity seen on seismometers on El Hierro.

      So a new magma is mostly on its way up now. But where it is going come up is unclear. I think that the location is going to be close to the coastline. But it might also be inland. It is hard to know for sure at this moment.

  28. Jón Frímann Jónsson Given the current tremor. People should expect a new vents to open up. This might be closer to the vents that are already open and erupting. But the current harmonic tremor suggest that the flow of magma up is greater then the output of the vent that is currently in place (even if not observed). Please note that this is based on my own estimate and might not work out like in a actual events.
    há 22 minutos ·

  30. this is interesting-
    11/10/2011 12:08 – Vulcanologists have officially reported that there has been an underwater eruption at 600m depth, 5 kilometers south of La Restinga on El Hierro. This happened at 04:00 yesterday morning (Monday, 10th October 2011). As the volcanic activity continues, they have not ruled out a further eruption closer to the coast of the island. While magma is flowing from the aperture, it is minimal due to the pressure of the water.

    minial flow due to the pressure of the water????

    its from this site
    http://www.canariesnews.com/2011/09/28/el-hierro-earthquakes-update/

    1. 600 meters is only about 5.9 MPa. From where this is coming from that pressure is piecemeal to overcome.

      Whoever made that statement needs to have their head adjusted… with a wrench.

  31. I have a long day of driving to do. But I do want to bring to peoples attention (again) that whatever this is, is pushing up through the 200 to 545 thousand year old El Julan slide debris field.

    My interpretation is that the path will not be as hard to establish due to the chaotic nature of that. Another possible interpretation is that this debris field has had 200+ thousand years to congeal as a mass with the disordered structure of concrete. So establishing a path may be difficult. You can read it either way.

    In my UNTRAINED opinion, it will likely skirt the boundary region between the broken debris field and the unbroken scarp face… and when it reaches a weak enough areas, will pop to the ocean floor or surface.

    For now… I drive.

    If any residents of El Hierro read this, stay safe and don’t do anything stupid… like going on a diving expedition to snap a photo. (that just proves that Presidents are full on morons no matter what the nationality is)

    3. OR as another completely untrained amateur guess: they must have had a submersible down to view what is occuring underwater and are seeing that the magma volume is low in proportion to the tremor aka all this noise cannot be attrributed to the observed eruption and belongs to a seperate process occuring elsewhere… i.e the eruptive magma pressure at the eruption site is too low to account for the tremoring observed.

      Perhaps GeoLoco’s suggestion that this is pressure build up associated with filling of a magma chamber and perhaps movement elsewhere nearer to land.

      Either way, something is occuring to suggest that the earlier laid back approach due to a belief that a full eruption was occurring beneath the sea was misplaced, and that the evidence is sufficient to persuade (reluctant) local officials to call both an evaculation and raise the alert level.

      I hope all persons advised to evacuate do so, with due haste, and that all stay safe during whatever occurs next.

      1. Apologies for the typos. Must remember to check what I type before posting. Fingers and brain do not always co-ordinate properly at the speed that I type.

  32. Evacuation in El Hierro. The reaction of the inhabitants of La Restinga to the eviction of the Canarian Government has been mixed. While dozens of people still lying in the sun on the jetty, others have taken the car and turned away in a hurry. @ bernardomarin is there.

  33. A few questions from a novice:

    What scale of a possible eruption are we talking about here? Eÿafjellajökulish or St. Helenish?

    Approximately how big is the magma reservoir? Do we know if it will be a “red” or “grey” outburst?

    1. Sure not of St. Helen’s type.
      Now it all depends on the amount of water that comes in contact with magma at shallower depths.

      2. Depends on how you define reservoir.

        If you assume that everywhere that the grouped quake clusters were at as it filled in a dike structure to the north is part of the reservoir. Pretty damned big. But that was in a rough cylinder a couple of kilometers wide and 5 or so kilometers long.

        My assumption is that in that structure… maybe 0.5 to 1% is eruptible. Its been a while since I did the calculation, but it came out somewhere on the order of 0.5 km³ of material. That’s about half of St Helens in my worst case scenario.

        But I’m not a geologist and my numbers and assumptions can be pretty far off.

      1. Does it have a facebook-account? If not, how will it get the info? Nothing’s easy with new technologies…

      2. GeoLoco:
        I have just found out that you need a FB account for the site.
        Why don’t you join the Tuff team group at Facebook, for Eruptions / Jón Frimmann’s bloggers?

      3. Tuff team? I missed that. But interested, if I don’t have to sell my soul and family… 🙂

  37. I don’t think I would be staying on El Hierro just now, I would probably rent the house out to some volcano watchers and get off the island. I would probably advertise the property on here.

    I wish all inhabitants of El Hierro the best of luck and hope the final outcome from this eruption is beneficial rather than destructive.

  38. Coming home to this…..
    Amazing to watch.
    What strikes me is the totally different attitude of the government here and for example Indonesia.
    It seems so me that something more mayor as a small underwatereruption is underway. And I sure hope the people will be moved farther away as that footballfield :-/

    1. es decir el tremor está en un constante 4.0 y mayor?
      Does that say tremor is at a contant 4.0 and above?

  40. Darn – just realised that Lurking going for a country drive means no nice plots for a while. I was hoping we’d be getting a direction calculated by El Lurkster, from the harmonics picked up at the Gomera station. I didn’t understand how he was going to do that, but he seemed to suggest he could (at Eruptions). Oh well maybe later – and even after the eruption it might be interesting to see if it was on/off target.

    2. It would require finding the portion of two traces in the station data that had a really good match and then finding an angle that would produce those arrival times.

      Not having an algorithm or gear that could do it for me was gonna be a pain… but the concept is simple. The difficult part is finding two distinct features that match on both traces AND have pretty good precision in the time stamps. Even at that is was gonna still be a rough guess.

  41. @#$ couldn’t get out the door without doing a plot.

    This is a REPRESENTATIVE profile if the area south of La Restinga taken from a slice through the terrain data. It’s not the actual terrain, but shows about what it’s like.

    You can infer old scarp faces from the profile. My guess is that the magma will travel to the surface along one of these boundaries.

    http://i56.tinypic.com/v2tvyp.png

      1. But this yours last sketch left me even more concerned: if this is a submarine vent, there’s a crack right beneath the newer scarp face with a lot of “loose” terrain in front an upon it.
        Or did I get it all wrong?

      4. Well, I’m getting “looser” with age. Dunno if it applies for terrains…
        Go get your ride!
        And Lurk, many thanks, pal!

      5. Thanks for diagram. That’s quite a mass of material on that slope.

        Should it give way I would have thought there could be a Tsunami risk.

        Has anyone examined the Tsunami risk from this activity?
        I would have thought the West African coast could be at risk, if such an event happened.

    2. @ Lurking: Thank you so much!! We really love you here 😉
      (take care while driving – keep your thought on the road and not on plots….)

    3. What kind of a hot bitch can you be? 🙂
      Iiiiiihaaaaaa! Good to be among f…ing geeks/nerds/volcanoholics like you guys!

    4. Kinda hard to plot anyway Lurk; too bad we don’t have a station set up for you to listen to… From high tech to low tech (ham.) Voice mail too fussy while driving.

    1. As I understand it, the yellow vertical lines in the multi-colour section below are indicative of possible earthquakes.

  43. Don’t know if this info has been posted yet?
    16:05-The president of the Cabildo El Hierro, Alpidio Armas, is on the football field with neighboring La Restinga. He says there is a real risk of eruption on the ground.

  44. So, these quakes at Torfajokull… Does this mean that it is possibly waking up? Or this Hekla, or nothing at all?

    Or… as an EXTREME long-shot, could this be somewhere with no previous eruptions… *Shoots himself with embarrassment* 😀

    2. Decreasing, well, still going strong any way. Maybe it´s just not increasing any more. We’ll see in a while. Any one else feeling very apprehensive and excited about this? 🙂 You’ll have to admit it is fun to watch for the development!

      1. I am very concerned about the local residents. They really should be thinking about getting people off El Hierro.

        The eruption could happen anywhere, any time on or near El Hierro & the size is not yet known.

      2. Oops, I’m sorry, I didn´t think. Of course it´s not fun for people close to the eruption area. I meant us nerds/volcano followers who like to look on plots and are following the build-ups for months and years before something happen, and now this uncanny event!

    3. That’s a bad sign, if the tremor decreases abruptly. It can only mean magma met an obstacle, and an earthquake when it breaks.

  47. http://canariasimporta.blogspot.com/p/al-minuto-sismos-el-hierro.html

    16:17-Current Volcanic Islands (AVCAN) The tremor signal is awesome, bestial, huge, wild, extreme, I run out of adjectives, and a tremor like that is not normal, from 38 hours in asset falls in the range of a few tremors, only 5-10% of them reach that status so long.

    16:07-The intense heat prevailing in La Restinga requires paying attention to some displaced people to the football field, especially the elderly.

    16:05-The president of the Cabildo El Hierro, Alpidio Armas, is on the football field with neighboring La Restinga. He says there is a real risk of eruption on the ground.

    1. “16:07-The intense heat prevailing in La Restinga requires paying attention to some displaced people to the football field, especially the elderly.”

      This scares me, because due to weather forecast it should only be about 26 degrees Celsius there. Could the heat come from beneath?

      I would like to tell people to go away, don’t wait for the presidents desicion…

      1. Yes. There is a small link between unusually warm or calm weather and seismic activity. I became aware of it when earthquake watching in California. 4 degrees warmer than expected may be a symptom of activity below the island.

      2. October being very warm in several european countries,
        I spent a lovely weekend at the beach (in Portugal).
        Not related with volcanic activity.

    2. If it was me, I would be looking at evacuating the whole island, until we knew what was going on, not hanging around on a footbal field near where one of the possible eruption sites.

      3. But what I really meant concerning the heat is that magma might have come so close to the surface that it heats the surronding. They talk about “intense heat prevailing”, that is certainly much more than some 4 degrees warmer than it was.

      4. The football field is just a meeting point to people who dont own their own vehicles or/and dont have place to go and need state assistance.

    1. Thanks luisport – to think we were puzzling over the little bit of tremor at 0600 yesterday !!

    2. This is very awesome and horrible at the same time. I hope that people stay safe there. I’d take the next plane to any destination… A cousin of a friend of mine lives there with her family – I really do hope she took the plane…

  49. Currently the whole of Canaries is experiencing warmer than usual conditions Tenerife is up to 35C this afternoon for example. Currently there are hot winds blowing from Africa – The warm conditions are definitely not related to the Volcanic activity.

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