Posted on by Jón Frímann

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.

597 Replies to “Special report: Update on El Hierro volcano eruption”

  1. Very well said!
    Diana I am always looking forward to your commends. Much appreciated.

  2. We dont know where the tremor is coming from. The sole station is ‘CHIE’ and thats east of Restinga almost halfway to Valverde, west of the village Isora.
    Map (of sorts) here:
    http://www.ign.es/ign/headwide/visorsismologiaEstaciones.do

    Unlike with Ejyaf where the volcano was surrounded with seismometers we cant compare tremor magnitudes to get a rough idea of location. So to my mind CHIE could be picking up tremors from the region of EQ focus between Sabinosa and Fontera, its not much further away than Restinga.
    The assumption that the tremor comes from subsea Restinga was based upon the shallow EQs there coinciding with tremor rising. But we cannot be certain that is a valid conclusion. Lets hope the authorities have access to more tremor stations than we do.

    1. No, we have tremoring on EGOM-station, but my favourite is EHIG (plus 2 more, but with less signal strength).
      There is enough station to pinpoint it fairly well.
      I could do it within about 100 x 100 metres if I had the raw data acces for the station network.
      I need 4 stations for depth with the same certainty.

      4. No need- got them.
        La Palma and Gomera are roughly 100 and 85 km away – You can use them to determine the difference between Restinga and Sabinosa? They are almost on same arc from Gomera within a km or so. So La Palma signal is crucial- but its 100km away and difference is around 11km between Restinga and Sabinosa.
        I did not know tremor locating could be made that accurate over such distances ( translation: I dont believe it).

      5. What are you talking about?

        Distance is one factor, yes, but the important thing is the degrees they are separated from each other individually.
        Have you ever done triangulating?

        With a 3 hydrophones placed with just kilometres in between you can locate a ship hundreds of kilometres away with a high accuracy.
        Sorry Peter, this used to be my job to build those things. I know exactly what can and cannot be done.

        Thing is sensitivity… How good is the equipment. But at such low frequencies, and over so long time, even crap equipment will get good enough data.

      6. depends on how well you know the average velocity structure between islands, I suspect it is well calibrated by now … lot more difficult to get depth, i think, due to very heavy noisy(read volcanic-seismic activity ) environment … but this is years away from my uni days ….

      7. @Carl

        Isn’t earthquake location done with triangulating?
        Why can’t you decide the location of the tremoring the same way? Sorry for the ignorance

      8. You can easily do that if you have acess to the raw-data, and if the tremoring is spotiform.
        In this case the tremoring is not localized, so there is not at singular spot to identify.

  3. Not being a ‘soft sediment oceanographer’, but could the gas bubbles be organic decomposition products from recent sediments released where the ocean floor has been disturbed by eq’s? A bit like walking near peat bogs!

    1. I have no idea of the detailes composition of the sediments there, but like to think that do strengthen my feeling there’s no actual eruption taking place.

    2. Something killed the fish!
      It must have been fast and sudden, or the fish would have moved away if the water temperature or chemical composition changed slowly.
      I would have thought an ongoing “eruption” would be seen by bubbles and discolouration.
      Would there be smokers (geothermal vents ) near the coast as in the submarine caldera of Kolumbo ? A sudden pulse of heat and gasses could have happened as pressure below increased.
      I too feel that somehow the eruption proper has not started. The deformation seems to still be increasing.
      http://www.ign.es/ign/resources/volcanologia/html/deformacion.html

      1. Anaerobic gases from sediments? I seem to remember Papua/NG tribes stir the bottom of ponds/streams to release gas and go fishing!

  4. http://www.ign.es/ign/head/volcaSenalesDiasAnterioresHora.do?nombreFichero=EGOM_2011-10-12_08-09&estacion=EGOM&Anio=2011&Mes=10&Dia=12&tipo=2&hora=06-07

    http://www.ign.es/ign/head/volcaSenalesDiasAnterioresHora.do?nombreFichero=CHIE_2011-10-12_08-09&estacion=CHIE&Anio=2011&Mes=10&Dia=12&tipo=2&hora=06-07

    http://www.ign.es/ign/head/volcaSenalesDiasAnterioresHora.do?nombreFichero=EHIG_2011-10-12_08-09&estacion=EHIG&Anio=2011&Mes=10&Dia=12&tipo=2&hora=06-07

    comparition … aprox 20sec difference between same event I suppose.
    Egom Ehig pretty equal in latence

  6. the colour on my monitor has gone crazy – pink now looks yucky grey blue and red looks black. not good when trying to look at tremor charts and earthquake maps

  7. Carl at 9:28
    Not only that they take time sitting on the throne, but then they are proud of their output. So Mr Hierro doesn’t want to be ashamed in front of his mates, it’s normal that he prepares well before he sets “it” free.

  8. I’ve noticed with the earthquakes that have been happening since 10th october, that they start off deep and then get slightly shallower over the next couple, then deep again, and shallower, then deep again.

    It’s like the magma is trying different routes to the top, then getting stuck and trying another one.

      2. Clipping again since after 10am but back to a more or less solid line (if you can call it that) after 12pm. Is this the magma getting ‘blocked’ and then exploring other routes? Presumably (and it’s never good to presume or assume) due to the many channels/caves once a way is blocked the other conduits mean that not enough pressure is building to force a way out, until of course all routes are filled/blocked or weak spot allows pressure to be relieved.

        This corresponds with some fluctuation in the waveforms (‘Onda’ on the chart – excuse me if I have these the wrong way round).

        Is it just me or is this (the yellow) moving slowly into the 6HZ+ frequency – which was mentioned before as a sign to watch for (I think it was GeoLoco or Renato). I am only reporting what I see on the charts and as a novice I could be talking utter rubbish.

  10. Doppler shift difference between Las Palmas and El Hierro.
    I whipped up a quick result. Bare with me that I am doing this on visual, and not on raw data, so it is inexact.
    Base assumption, the magma is moving from the supposed eruption site ca. 5 km outside the coast.
    First of all, the speed is “high”. About 4km per hour. So it should allready be there since a long time ago. My guess is that it is filling something up right now, but I cannot say where.
    It is travelling in a direction that is pointing towards the station on El Hierro. It is between 0 degrees to 15 degrees west. That is good as it gets.
    So, either on a straight line from the quake star on the picture towards CHIE, up to 15 degrees towards the west.
    That is as good as it gets.

    1. Hello Carl, could you break that down into words that a simpleton such as myself could understand.

      Dopplershift – that’s the pitch of sirens changing as they drive past.

      And assuming it’s the source of the tremor driving past that you’re talking about – and that it’s not changing pitch much ? but it is getting ‘redder’ so is that the ‘pitch’ rising? (or is that not what you were looking at?)

      I understand that a thing coming toward you changes its sound profile in a different manner depending on the direction it is coming toward you at.

      But due to my ignorance I can’t understand the info you’re giving out.
      Could you please spell it out slightly – cheers.

      2. @ Edward Lane
        Lets take a guess. He’s using the psd data in the La Palma tremor plot here:
        http://www.ign.es/ign/head/volcaSenalesAnterioresDia.do?nombreFichero=EHIG_2011-10-12&ver=s&estacion=EHIG&Anio=2011&Mes=10&Dia=12&tipo=2

        and comparing it with that for Hierro:
        http://www.ign.es/ign/head/volcaSenalesAnterioresDia.do?nombreFichero=CHIE_2011-10-12&ver=s&estacion=CHIE&Anio=2011&Mes=10&Dia=12&tipo=2

        The Hierro data is relatively deficient in the higher frequencies ( towards the top end of the psd curve). That would he claims be due to the Doppler effect shifting the frequency distribution if the source was moving towards the detector at CHIE but not towards EHIG.
        But If we look at the Gomera data (EGOM) it does not look much different from La Palma yet Gomera is almost aligned with the direction of the claimed Doppler shift at CHIE.
        Its very clever. But I’m not sure I believe it.

      3. NO that’s the wrong way round – Doppler from magma motion from the star towards CHIE would increase the contribution of higher frequencies at CHIE compared with La Palma
        Now I’m puzzled too.
        Carl?

      4. ………unless the magma is moving the opposite direction – east to west – when we would perhaps expect higher frequencies at CHIE to shift lower by Doppler.

      5. Not doppler shift of magma movement, but of the different seismic wave types “seen” from the perspective of the measuring equipment. Ed: The geophone is you, the seismic wave is the horn of the car passing by…

      8. attenuation is frequency dependant, higher frequencies decay (in amplitude) faster, if there were more high frequencies at La Palma than than CHIE, we would have to throw away the last 100+ years of seismology as bogus … at 100 km (whatever) attenuation would be significant , even at 10 Hz.

        although i agree that EGOM looks like it has more high frequencies, i would guess that the general (Harmonic) seismo-volcanic noise and plot scaling going on at CHIE is the culprit

        my 2c worth …

  11. @ Carl
    Leaving Mount non-Doom seamount and getting away from lava-torial (or lava-tree) matters and returning to Middle Earth – I can’t find any decent location/s for the Lokatindur fissures to which you have referred. Please!!

    1. Alan C Try this map.
      http://atlas.lmi.is/kortasja_en/

      In the search enter Lokatindur

      Choose the second name and it will be highlighted in Yellow on the map
      Moving out from the close up you will see it is on the NW flank of the Askja volcano.
      I believe this is the one that more likely may be grumbling.
      The other is too far East.

    1. Your are looking at an hourly chart – signal only from last hour. Click on the button with the arrow pointing upwards to get the daily chart and the “usual” PSD profile.

      2. What I mean is that I think that on this hourly chart the PSD plot does not take into consideration all data until the hour is finished (I think, because I’ve noticed this weirdness before), so that’s why tyou get the weird thing.

        You can also go back to previous hour (use arrow buttons) and you’ll get the correct PSD.

      4. I had no arrows on mine until today – then they appeared on the right of the screen – think it might have been a browser issue. 🙂

    2. nvm. It was strange due to lack of data on the page. Starting to look better now. 😉

  14. Hi Jon, I am hearing on the news about a ‘Bulge’ that has formed on the island. Have you heard about this and if so what are your thoughts on this if you don’t mind, is it a concern? Many thanks. 🙂

    1. I remember at Eyjaf that the EQS stopped almost completely and the tremor started a few days before Fimvorduhals erupted.
      The calm before the storm? On other hand Eyjaf has a magma chamber so seismicity could well follow a totally different pattern?

      1. Eyja did not have a normal magma-reservoir, it had a sil-system of horizontal dykes. Think a tubinged maze and you would be right.
        El hierro is a fissure volcano that seems to be sitting dead center on a tripple-junction. So I guess that Hengill or Bardarbunga is a better example. It seems to have magma-reservoir from what we can see on Lurkings plots. But the main magmatic feeding during an eruption is probably from the hotspot.
        But, how the magma-reservoir looks like nobody knows. The knowledge of how Eyja looks like came during and after the eruption. I think this eruption will give a lot of answers about the innards of El Hierro too, but not with as good detailing since the Spaniards have been negligent in building up a good monitoring system.
        I hope they have the brains to install new equipment post haste now, but I do not think they will… Mañana…

  16. For what it’s worth, my amateur translation of this article:
    http://www.elmundo.es/elmundo/2011/10/11/ciencia/1318358011.html
    I can’t help but feel that this is just so very “fluffy” in style and does not really give any precise information. Anyway, here it is and then I’d better go do some work today.

    The Seismic Network shows that “we are about to witness birth of a volcano”

    The director of the National Seismic Network, Emilio Carreno, said that the submarine events of El Hierro announce a possible “birth of a volcano”, an extraordinary opportunity for the sicence from which the only alternative is to learn.

    “This is is an experience to gain from. We do not know much about patterns of magmatic behaviour and while primarilt ensuring that the situation is under control with respect to population safety, this is a very good opportunity for scientists,” said the expert. “What we could be about to see – as I said – it the birth of a volcano, if that actually happens.”

    Carreno explaine that the process is being monitored since the beginning with the most advanced monitoring equipment for identification of movement of Earth’s crust, which in a zone of the island as El Hierro, is thinnest and most brittle, with the average width of 15km.

    The expert of IGN clarified that the phenomenon is caused by constant movement of magma over which the Earth crust is settling, while at the same time resisting the dynamic pressure of the incandescent mass and the movement energy originating in conduction or heat transfer.

    The approach of magma towards the coast at La Restinga, south of El Hierro, could result in an explosive eruption if it reaches the surface at less than 200m depth under the sea. However this does not mean that there is a danger to population if appropriate measure are taken, according to an investigator of CSIC at the Institue of Earth Sciences and the secertary general of the International Volcanology Associatoin, Joan Marti.

    AROUND 10000 EARTHQUAKES

    The abotu 10000 earthquakes registered during the last 3 months at El Hierro were a preamble to this new seismic activity, which however is totally different and is measured in a different way.

    The “volcanic tremor”, explained the spokeman, is a signal registered on seismographs, showing the ascending movement of magma in low frequencies. “As in a pipe”, said he, to compare the behaviour of this incadescent mass located in the interior of the Earth.

    The previous shakings (earthquakes) however, were typical manifestations of crustal activity, still caused by the magma, but moving in a manner of “hot gelatine”, where the tremor indicated a change in direction movement and predicted a rutpure, depending on the strength and the velocity.

    This is how a volcano is born, said Carreno, even though in this case, since the phenomenon is located underwater, “it will be very difficult to ascertain how and when it occurs. We have to be guided by the instruments,” and it is not clear how the process will end.

    A POSSIBLE FISSURE

    Last Saturday’s earthquake of high magnitude, 4.3 on Richter scale, could have cause a fissure to open through which the eruption started, he added cautiously, althought he confirmed that there are indications, such as increase of water temperature and dead fish floating on surface which could be considered confirmative indicators. Under the sea, however, “this type of eruptions are subdued.”

    Information that IGN collects is published on a web page as soon as it is confirmed. “We do not hide anything”, ensured Carreno about his work, which is supported by hundreds of volunteers from entire Spain who enter their earthquake experience on the web, and to whom he gives thanks.

    Volunteers describe very well their observations and this helps us to compare wiht our instrumental information and determine preventive measures, said he.

    “Everything we know about earthquakes and telluric movement is information aimed for mitigating effects of phenomena that we can not predict, nor contain, nor control,” he added.

    In La Restinga, at the El Hierro, 547 inhabitants are closely following the development of the geological phenomenon just five km off the coast and 1000m under the sea.

      1. Ursula,
        Many thanks – so an undersea eruption off Restinga its going to be….enjoy the show, its a novelty – official!
        But Fimmvorduhals turned out to be a flanking sideshow.

        The deformation between Sabinosa and Fontera occurred above the initial burst of thousands of EQs, which progressed downwards. They offer no explanation for that, and the ‘bulge’ is still there.

        I must say I’d have more confidence if there were some Icelandic names behind these pronouncements! Eruptions are not quite so novel to them.

    2. Volunteers from entire Spain…
      Carl and Lurking an spanish? 🙂
      Just kidding, of course there are tons of spanish mates out there.

    3. “althought he confirmed that there are indications, such as increase of water temperature and dead fish floating on surface which could be considered confirmative indicators”

      So, there is no dead fish… and no raised water-temperature.

  18. Just saw the press conference on RTVC of the Cabildo of El Hierro. A few things I picked up:
    -Uncertainty – still no idea where a possible eruption is taking place (Mrs Blanco, Instituto Geografico said there’s deflation, so something has to be coming out).
    -The possibility for people of La Restinga to go back to their house in a surveyed manner, just to get clothes, medication, pets etc.
    -They also spoke about the possibility to let fishermen get their boat and moor in one of the other harbours.
    -The possibility to get a boat with a underwater robot to do an submarine survey, there is such a boat in Galicia but they need the fiber-optic infrastructure (where they talking about the Nautilus?? I think they said the Spanish geographic institute has a boat theirself??)

  19. In a press conference now the government are saying that they might send out a boat with a robot to get data from underwater. Better late than never… 😉 They also said that there are no changes, and urge the residents of the island to remain calm.
    (source: canarias7.es)

  21. Whilst this is going on in Hierro it is nice to see Harmonic tremmor picking up again near Katla, although quakes have virtually stopped.
    Keeping us on our toes.
    With all the official misinformation, can anyone give an update on what they think has occurred and what has not occurred at Hierro.
    We have reports on here via gps stations of 30mm inflation, we have reports from so called officials saying under water eruption. We have knowledgable people on here saying possible just gas release.
    Can someone clarify the situation as believed to be current by users on here.
    Do you believe this is eruption thats taken place.
    Do you expect eruption to still be waiting.
    Is there inflation or deflation?
    Why are supposedly official sources giving such contrasting, misleading and vague information, personally i would have more respect for an official who says ” we are unsure at this time” than make a wild guess and pertraying it as a fact.
    I am learning to trust you guys and gals on here more than the so called experts on this particular geological incident

    2. We are getting now more storms over south iceland than in the summer (actually there is one, too), so at any time, when there are no quakes showing up, check the wind first. The small quakes get lost in the noise that the storms cause.

    3. Don’t forget the decision about what / how to communicate is left to the same kind of people that lead whole nations to be bankrupt… 🙂
      No comment about what is going on from my side. I have my own view on things that differs “in some points” from the official’s, but I’m not having enough background info and time to “treat” it and predend anything firmly.
      They have data and specialists enough, we’ll just see what comes. Anyway nobody is to blame. What we see and dare to guess out of it would just have been impossible some years ago… Still nobody has “the recipe” to say things with absolute accuracy. Nevertheless I find their communication particularly mediocre.

    4. Richard Feynman said it best:
      “Science is the belief in the ignorance of experts.”

    1. Translation of the article in Publico:

      “We are losing valuable data because we do not have a scientific vessel there ”
      Experts criticize that no ship has been sent to study what is happening under Mar de Calmaa
      Javier Salas Madrid 12/10/2011 13:21 Updated: 12/10/2011 13:29
      During the afternoon and Monday night nobody could say for sure whether there was an eruption under the waters of Mar de Calmas. This situation could have been solved, according to several experts consulted in the area, if some of the research vessels that Spain has at their disposal, was sent there. On Tuesday, at the closing time of this newspaper, they had just flown over the area with helicopters and samples were taken at the surface of water on board a rescue ship, methods far from the technological sophistication needed to know what happens to more than 900 meters deep. The Canary Islands government did not request help from Madrid to mobilize that ship for emergencies, that falls under the Ministry of Development, until Monday.
      However, some experts lament that the important Spanish scientific potential for investigations at sea was not mobilized immediately, since for days one counted with the possibility that the earthquake triggered an underwater eruption. “We are losing valuable information, irreplaceable data,” laments Professor of Geology at the University of Las Palmas, Francisco José Pérez Torrado, who misses a research vessel in the Canaries.
      The Spanish Institute of Oceanography has the necessary material to investigate what is happening south of El Hierro. So says its director, Eduardo Balguerías, who yesterday confirmed this newspaper that no one has called them yet. “We have no request for information or request to perform an intervention. But we can provide what they demand from us as required,” he says.

      At the Canary Islands, the ship Professor Ignacio Lozano is present, a ship that would fit “perfectly” to the needs of a mission like this. The director of the Oceanographic Centre of Canary, Maria Angeles Rodriguez confirmed that the emergency committee that holds the reins in the El Hierro crisis called the material available to this organisation”taylor made”, but yesterday no one had asked anything. Yesterday afternoon, however, sources of the committee assured this newspaper that they were preparing the “red tape” to request a scientific vessel that will help them to detail what happens.
      The best way to find out what happens in the calm would send there a remote control submarine called Liropus 2000, which was acquired last year and costed a half million euros and has cameras and sensors that transmit information in real time. But the ship is in the throes of tuning in Cantabria, alongside the ship that carries the Ramon Margalef. “The problem is that you can not move one of these vessels just in case, as they have a detailed agenda for two years in advance. In addition, one of such boats supposes a daily expenditure of about $ 10,000,” said Balguerías.
      The last ubmarine volcanic eruption of importance occurred in April this year at Axial Volcano, off the coast of Oregon. This eruption was not discovered until July, when researchers dipped a camera up there , giving them the smoking gun they needed.

      PS — the Liropus 2000 can be found here: http://translate.googleusercontent.com/translate_c?act=url&hl=en&ie=UTF8&prev=_t&rurl=translate.google.com&sl=auto&tl=en&twu=1&u=http://www.ba.ieo.es/es/presentacion/equipamiento/equipamiento-cientifico/664-liropus-2000-el-nuevo-rov-del-ieo&usg=ALkJrhgfCKQdowJroHCzqxrTuLTlKfqTow

  23. Yeah just noticed all stations are showing same increase, not just ones around Katla. That plus gale warnings should have been a bit of a give away. I expected one frequency to rise due to weather not all 3. Still learning about quakes and Volcanos

  24. 3-4Hz on the spectrogram is starting to show increase in activity since mid day yesterday or so. Why is this? Might this be the “sound” of degassing as it has a higher frequency. I.e higher pitch? Or has magma found new more open conduits which alows it to move at a higher speed?

    1. The tremor on the top chart would seem to support the “open conduit” theory since it is decreasing slightly (less resistance/vibrations).

  25. yes, Skr and Sly charts was watching the increase in all 3 frequencies and thought it was harmonic tremor, but been pointed out its wind causing it.

  26. The Icelandic Coastguard plane TF-Sif is in the Mediterranian working for the EU on some border control project.

    She was designed and built specially for volcano research and has all kinds of tools for that, like a radar that can take thermal images.
    http://www.lhg.is/starfsemi/adgerdasvid/eftirlitsflugvelTFSIF/

    I bet she can find the under sea eruption that took place, and supply thermal images of the area and add to the information scientist have to work with.
    Its just a matter of asking the EU to lend it for a couple of days.

    1. You should email IGN with that information. I bet they have no idea of that possibility.

      1. The agency TF-SIF works for is Frontex and Frontex has its command center in Madrid.

      2. That assumes we are talking joined up government.
        If the plane is also Madrid-based it should have been diverted to the task yesterday.
        Flying time? 1200miles: 4 hours??

      3. TF-SIF flew from Reykjavik to Senegal and landed there August 30th, so i guess she is based in Senegal.
        Im not sure how far that is in flying time.

        The command center is in Madrid, but the plane is in Africa.

      4. Sif will be in the area until the end of this month, then she returnes to Iceland.

        I aggree, Someone should mention this possibility to the IGN. probably no me though.
        My Spanish is not very good and i am just a amateur in respect to volcanos, not even a good one 🙂

      5. Fonix,
        I’ve emailed them with your information. I’m an amateur too, on all of geology, but had a career in science research so have good idea of just how compartmentalised things can get.
        Peter

      7. Excellent 🙂
        SIF has equippment to mesure air pollution like gas, and all kinds of stuff that may be of use.

  27. In answer to
    Pyro: Are you referring to the tremor-plots?

    yes, Skr and Sly charts was watching the increase in all 3 frequencies and thought it was harmonic tremor, but been pointed out its wind causing it.
    Just so it does not confuse as few posts between by time i typed it.

    1. Ok, thanks for replying.

      The weather really looks horrendous at Iceland today ref. Katla cam… Brr!

    1. System saturated, less possibility to react to pressure build up – next step after reaching a certain energy level might be surface cracking… ???

    1. Before the graph started clipping, one could see that a constriction in the graph often was followed by increasing tremors. But that will of course not go on for ever.

      2. Lovely post earlier Diana. It is a really lovely community on this site and collectively something far greater than the sum of parts seems to be emerging. Enjoy reading your posts too. We all bring something even though we may not realise it. There is a saying that everything that we are we owe to someone else and this blog really reminds me of it.

        And speaking of which as I have a sort of marketing background (amongst a few other things – I am a Jack of many trades) I was wondering if there are others with similar experience/contacts and if we can work together to help Jon. There must be companies we can badger (contact politely) who would be happy to ‘sponsor’ Jon’s work. This could be donating equipment or even promoting. Whilst I can’t add to the understanding in the way Carl/Lurking (amongst many others) do, we can help in other ways to his invaluable work. Many hands make light work.

        I am quite good when it comes to wording for companies so would be glad to give my tu’pence worth (2 cents) but I am useless at sales (I am best at wording/presentation). Maybe we could do a collaborative template asking letter for Jon (which we would of course ask for his approval first) which we can translate. I am sure a few companies would be happy to have their name on a helicorder page for a small donation? An idea to ponder at least.

  32. Noticed that at Vatnajökull quakes are doubled for past days. A few ghosts in the system. This and the Katla errors (the 3> that keep popping only to get downgraded) shows why slow and cautious is the best approach.

    Wednesday
    12.10.2011 08:46:59 65.197 -17.051 1.1 km 2.1 47.49 10.9 km WNW of Lokatindur
    Wednesday
    12.10.2011 08:46:59 65.208 -16.934 0.2 km 2.2 99.0 8.0 km NNW of Lokatindur
    Tuesday
    11.10.2011 22:59:59 64.653 -16.720 8.7 km 2.1 99.0 5.1 km WNW of Kverkfjöll
    Tuesday
    11.10.2011 22:59:58 64.452 -16.449 18.5 km 2.2 37.91 22.1 km SSE of Kverkfjöll

  33. About “open conduits”

    The description of the “Cueva de Don Justo” made me think differently about the rock of the island El Hierro and its surroundings. The author of http://myelhierro.com/en/cuevadonjusto.php (sorry for reposting but is seems so important) describes the caves as a “real labyrinth”. “The corridors, created as a result of prolonged volcano eruption, often crosses and intersects. In some places there are even eight parallel arranged tunnels. The whole underground passage has a total length of 6315 metres, what makes it the longest on El Hierro, the third longest on the Canary Islands….”

    This sounds like a “sponge” structure to me, which maybe also is present under the seafloor. If the floor is broken by quakes, gases could easily enter the water of the sea. This vents could be very far away from the magma, because the “tunnels” are so long and the pressure so high. Gases could spread widely before they enter the seawater.

    So I start believing in the “open conduits” theory. This would explain a lot, including the sudden death of fish and the trembling ground in La Restinga. At least to an amateur like me.

    3. Yes I crawled into that system in ’64. AFAIK it was the result of a down-hill flow of lava at the surface Bit of sqeeze in places where roof had drooped down, although we could stand up in the tunnels. But too small to be a consideration I think compared with the scale of an eruption. But I gather served as a valuable refuge for anti-Franco forces.

      1. Are these ‘caves’ being confused with lava tubes, where lava flows for considerable distances from the vent – fissure or central – within tubes insulated from the air by thick layer/s of congealed lava and escapes to form a conventional flow where the tube ends?

      2. Yes they are lava tubes- stalactities of solidified lava hang from roof. Ouch. Nice and cool down there……nowadays.

      6. “Those are Lava Tubes.
        They have absolutely nothing to do with degasing.”

        If there is an open connection between the magma and the already existing tube, the pressure will force gases through the tube. Anything wrong with this idea?
        Imagine the tube has a weak part or has been broken and has an open connection to air or to seawater.

        I suppose gases as well as magma can spread fast and widely through these tubes!

        BTW a good link from Stefan: http://en.wikipedia.org/wiki/Lava_tube

        It also says something about the width of the tubes (or “caves”):

        “Lava tubes can be up to 14–15 metres (46–49 ft) wide, though are often narrower, and run anywhere from 1–15 metres (3 ft 3 in–49 ft 3 in) below the surface. Lava tubes can also be extremely long; one tube from the Mauna Loa 1859 flow enters the ocean about 50 kilometers (31 mi) from its eruption point, and the Cueva del Viento – Sobrado system on Teide, Tenerife island, is over 18 kilometers (11 mi) long, due to extensive braided maze areas at the upper zones of the system.”

      1. Look like good lava tubes even with the lava-drip stalactites- corker of a sculptural tree too!

  35. Planes, submersibles …..locating the focus of an eruption 900m deep in the sea can’t be that diffcult surely? Small boat ( preferably fast) plus aquaphone ( or waterfproofed microphone)- just drive around measuring decibels.
    Then triangulate.
    That and a nose for sulphur?

    1. Would work well. Low-teck is often good tech 🙂
      Best would be to have 2 directional underwater microphones, then you could in one or 2 attempts (depending on location) pin point it. It would also give a sound file that could be interpreted. Eruptions and de-gassing have distinctly different audio components.

  36. Current Volcanic Islands (AVCAN)
    The tremor signal pops are suffering, as explained yesterday, which unclogs the basis of new earthquakes. We already knew that according to their signal amplitude appears to be related with the force of the eruption. If you look closely at the sign, it seems that we have other less obvious changes since although it seems that something decreases in intensity, if we look at the spectrogram, can … see other changes …

    Frequencies of 1-3Hz are increasing
    The 1 Hz are stable.
    Frequencies <0.5Hz are newspaper intensity.

    According to bibliobrafia, the components that decrease and increase 0.5Hz to 3Hz major may be due to the entry into pre-eruptive phases.

    http://www.uclm.es/profesorado/egcardenas/SISMICIDAD_VOLCANICA [1]. pdf

    Be that as it will have to be aware that no clogging much, because the answer will trigger an earthquake at the moment are small and as the literature says, paraece you progress to the surface (Henry). Ver mais

  37. OK so sea water does not attenuate sound well – we’d have to drive our fast boat too far away to see decibels drop off.
    So use directional aquaphone?
    Any acoustic wizards here?

    1. Yes, I am an acoustic moroon. I after all built the current hydrophone system used on subs in the more westernish world..

      You need two boats, two hydrophones (directional microphones for underwater use basically) two GPS:es and ham radio. Plus two idiots with wristwatches and some recording equipment and you have it.

      You can do it with electrical tape, two ordinary microphones, plastic bags, and home made parabolas. Low tech is good enough here since the frequencies are so low.

      A normal rock-band have the equipment to do it really…

  38. I’d say the observed fluctuations are the start of what could be the last pre-eruptional phase. At least in regards of the main eruption – precision meant to be nice to those convicted that there’s already something “serious” going on at a subaquatic level…

    2. Just saw that, and right after a line of yellow all up and down the spectrum as if there was a quake.

    3. From AVCAN’s facebook page:
      Atencion… Parece que el flujo de lava se ha taponado… el tremor ha bajado de repente… ¿tendremos sismos fuerte de disparo?, habra que estar muy pendientes, ya que si lo hace, hay que ver donde es….(Enrique)

      Attention… Seems that the flow of lava is plugged (?)… the tremor has suddenly decreased… Do we have strong quakes of shots (?)? Stay very attentive (tuned), whatever it is, we have to see what it is… (Enrique)

  42. So, the clogging makes the tremor appear diminished.
    What is actually taking place is that there are changes in frequencies, i.e, the earthquakes we were looking for.
    We are on the verge of an eruption.

      2. No. The magma that was erupting has stopped because it closed the crater it was erupting trough. This regularly happens in eruptions like this and it is a dangerous events. As now the magma has to find a new path to the surface.

        Some earthquakes might now happen following this as has been mentioned here before. The earthquakes would happen just before the new fissure opens up or a new vent that is going to erupt.

  45. They have adjusted the sensitivity of CHIE – there’s no change at EHIG or EGOM.

      1. Five-fold reduction in recorded amplitude at CHIE – to stop it clipping.
        No such reduction at the others.

    2. I disagree — look at the spectrum for EHIG and you will see that the red line at appx 1hz dips down in frequency at around 14:30, the same time as the shift at CHIE.

    3. Yes, there is also a decrease at CCAM (Tenerife), EGOM (Gomera), EHIG (La Palma) and EOSO (Gran Canaria). Maybe from this decrease a triangulation could be performed to calculate the location of the tremor.

    4. I don’t think so, the frequency scale on y axis on the spectral chart is still the same. I think there were a few strong earthquakes at about 14:30, check this for the per minute view of 14-15h:
      http://www.02.ign.es/ign/head/volcaSenalesDiasAnterioresHora.do?nombreFichero=CHIE_2011-10-12_14-15&estacion=CHIE&Anio=2011&Mes=10&Dia=12&tipo=2&hora=14-15

      And then the tremor receeded strongly. You can see the same pattern in EGOM:
      http://www.02.ign.es/ign/head/volcaSenalesDiasAnterioresHora.do?nombreFichero=EGOM_2011-10-12_14-15&estacion=EGOM&Anio=2011&Mes=10&Dia=12&tipo=2&hora=14-15

      Also confirmed by AVCAN message that I translated above.

      So now what, next thing it goes boom?

  46. Actualidad Volcánica de Canarias (AVCAN)
    The tremor sign is being clogged up, as we have explained yesterday. We already knew that. According to the amplitude of the signal, it seems that we have less evident changes and, although they seem to be diminishing in intensity, if we take a closer look at the spectrogram, we see other changes…
    Frequencies between 1-3Hz increasing
    Those of 1Hz are stable.
    Those <0.5Hz are loosing intensity.
    According to the bibliography, what decreases the 0.5Hz components and increases those larger than 3Hz may be due to the entrance in pre-eruptive phases.

    1. In other words, magma cannot flow anymore, because there is no longer where to go. We should expect a larger quake in the next hours.
      And maybe, then, we’ll finally know where this is heading to.
      So I guess.

  48. On other hand the one second resolution data do show a convincing reduction in activity.
    Apologies all.

  49. you might be right/wrong , hard to say without amplitude/energy units being displayed meaningfully

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