Posted on by Jón Frímann

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.

252 Replies to “Possibility of a new fissure has opened up in El Hierro volcano eruption”

  1. re IGN GPS:

    someone posted a link to a new detailed GPS plot from IGN for ElHierro. The plots includes North,East and Vertical components separately … I stupidly didn’t bookmark them .. Can somebody repost them, SVP ?

  2. ESMC

    2011-11-20 14:31:12.4 32.23 N 19.98 W 10 mb 5.0 M. MADEIRA ISLANDS, PORTUGAL REGION MAD
    2011-11-20 14:31:10.0 32.03 N 20.43 W 82 ML 4.1 M MADEIRA ISLANDS, PORTUGAL REGION IMP

    1. 2011-11-20 15:35 37,38 -15,89 10 2,5 Madeira-Tore — —
      2011-11-20 14:31 32,24 -20,56 10 4,0 Madeira Islands, Portugal Regi — —
      Only find this in Portuguese meteo site…

    1. Fascinating isn’t it! I don’t think the two pictures are connected in any way though but that could be the reason the Ramon Margalef was in those two areas anyway as the land areas are no doubt being studied by other means.

  4. It seems that Katla turns around and falls asleep. Now we just need that Hekla has a bad night and move, most of all for keeping us busy.

    1. Hope it was a good week end. Look forward to the next post when you have had time to do one.

  8. Just found on avcan.org’s facebook site: http://www.facebook.com/pages/Actualidad-Volc%C3%A1nica-de-Canarias-AVCAN/163883668446#!/permalink.php?story_fbid=292383360795063&id=134042953295772

    “URGENTE: Miembros de la Unidad de Helicópteros de la Guardica Civil, que actualmente colabora con INVOLCAN en la vigilancia de la erupción en el Sur de La Restinga han localizado una nueva boca eruptiva en el mar. Más datos en los próximos minutos.
    URGENT: Members of the helicopter unit of the Civil Guardica, currently working with INVOLCAN in the monitoring of the eruption in the South of La Restinga have located a new eruptive mouth on the sea. More data in the next few minutes. (Translated by Bing)”

  9. Just going back to Iceland, I was wondering what’s going on at Svartakot?
    http://hraun.vedur.is/ja/oroi/sva.gif
    There’s obviously been a bit of a malfunction (or adjustment), but is the spikiness since it came back online genuine? It resembles some of the signal at Krokottuvotn and Vatnsfell, but Svartakot is normally extremely quiet. Could they have turned up the gain, or is this just a mechanical failure?

    1. Just looks windy to me. I get the impression any eruption runs and hides when I go and look.

  11. Tvc afirma la apertura de una nueva boca en la Restinga, ya está 100 por 100 confirmado?

    TCF says the opening of a new mouth at la Restinga, is now 100 per cent confirmed? (Translated by Bing)

  12. THE SCIENTIFIC WORK OF GROUP OF THE PEVOLCA MAINTAINS THE ANTICIPATION OF AN EXPECTED MAXIMUM MAGNITUDE IN THE ISLAND OF 4.6

    21-11-2011… 14: 32 – Ministry of economy, finance and security

    Changes in the signal of tremor may be associated to a collapse of the wall of the volcanic edifice or a change in the rate of emission

    The scientific working group of the Plan of Civil protection by volcanic risk (PEVOLCA) has confirmed this morning that in El Hierro stands a seismicity with an expected maximum magnitude of 4.6, taking into account “the analysis of the seismic catalogue of the last twenty days”.

    In any case, the number of earthquakes has decreased in recent days, as well as their frequency, producing a meaningful record in the early hours of Saturday to Sunday “with a magnitude 3.7 movement”.

    Scientists confirm that the seismicity occurs in same alignment NNW-SSE, at the end of border, but always at a depth of between 15 and 27 kilometres. The evolution of the eruptive process, therefore, “remains stable, but leaves open the scenario of a possible eruption in the North, which is not, in any case, of imminent.”

    On the deformation, follows the same pattern of stability than in previous days with regard to horizontal displacement observed in GPS stations. With respect to the vertical displacement GPS in the Gulf stations mostly point towards a slight elevation, while the rest notes a slight collapse.

    For its part, the tremor signal experienced a significant change last Thursday, to diminish its intensity sharply, to recover again on Saturday. This phenomenon may be associated “to a collapse of the wall of the volcanic edifice that has formed in the Restinga or a change in the rate of emission”. These data may be confirmed by the research vessel ‘Ramón Margalef’ when you perform the next bathymetry.

    The direction of the Special Plan of Civil protection and emergency care by volcanic risk in the autonomous community of Canary Islands # PEVOLCA # reiterates that in the current position of the volcanic light red to La Restinga and yellow for the rest of the island, the population of the island must focus its attention on the messages offered by the competent authorities to which the Scientific Committee assists. Public administrations have devices and means to deal with a modification of the current situation with the communication, at the appropriate time, of precise instructions to the population.

    1. But not always at a depth of 15 to 27 metres in the 20 days to yesterday evening:

      5 EQs depth up to and including 10km (of which 3 had blank depths)
      59 EQs depth 11km to 14km

    2. Judith hon… post the link to these things when you can. I can translate it better than Gollum Giggle.

      Thanks.

  13. A few more reccent 2D plots. On these I have shown EQs pre Bob in red and Bob onwards in blue. Note that IGN seem to have recorded EQs out of sequence around the time Bob erupted so the eruption time is not 100% clear (assuming that an EQ occurred as Bob erupted). I have taken early morning on 10/10 as being pre eruption and later as being post the start of the eruption.

    overview: http://oi44.tinypic.com/14c9zib.jpg
    analysis of daily ranges: http://oi44.tinypic.com/8x8rx4.jpg

      2. Thank you. I was only out by three quakes, which fortunately do not make too much difference to my plots but it may be worth noting that there were only 2 quakes >3 preceding Bob:

        1104077 09-Oct-11 14:35:00 27.6353 -18.0193 13 3.6 SW EL PINAR.IHI
        1104096 09-Oct-11 16:43:38 27.6215 -18.0105 16 3.1 SW EL PINAR.IHI

        and that ~47 smaller quakes occured after these before Bob erupted.

  14. Looks like its all political why Avcan had to retract their statement about the new mouth.

    Copied from Avcan

    just incorporated, and on the news of the new eruptive mouth on the sea in the area of la Restinga, should verify and confirm, it seems that it has been bubbling, but it is a fact that has to be confirmed by the PEVOLCA to not pass about Tenerife in 2004, in which each one says one thingwhich at the moment seems to be that it has been withdrawn.

    So at the moment is cannot confirm that there appeared a new eruptive focus in the area of La Restinga. “In the next few hours there will be a reconnaissance flight by helicopter of GES and a group of scientists.” this is the statement sent by the Working Group of the PEVOLCA to the media. In how much you know more do it to get (Henry)

    Which had bug, this was the warning (for confirm and check)…

    “Urgent: members of the helicopter unit of the Civil Guardica, currently working with INVOLCAN in the monitoring of the eruption in the South of La Restinga have located a new eruptive mouth on the sea.” “More data in the next few minutes.”

    And so, it published the Provincia.es (for confirm and verify)…

  15. Copied From Avcan

    Please, Antonio, they have to remember that we are to do other things besides this forum and to know that it has happened, rogariamos a little patience, still we don’t know very well that is what has happened, it seems that you have to channel the information through the PEVOLCA, to avoid the media mess that happened in Tenerife in 2004, so in terms of know something it will know (Henry).

    1. What that says is that until you are killed by a tsunami, quake or hot ash you are not officially dead until PEVOLCA says so.

  16. Current Volcanic Islands (AVCAN)
    Do you just realize what I just did? I shared from my private wall a post that put “test”. After I deleted on my wall and be able to verify that also disappeared here. That’s what happened. The involcan published a post and we share but disappeared when they eliminated him. I wanted to tell you that we have felt very bad. We thought we deserved more confidence but some seemed very demanding post and you accuse us without us knew why. I think we deserve the benefit of the doubt. That said, I could not shut up, apologies to everyone for the inconvenience (Fernando)
    (giggle translation)

  17. Lurking

    May I ask if earthquakes did not cause this new vent what did?

    Someone on another site has posted this vent is nearer and parallel to the coast and this does not look good.

    Do you agree?

    1. The island of El Hierro sits atop of Jurassic era sediments.

      Back when the Atlantic ocean was initially opening up, it went through a stage of development not too different than the current Rift Valley of Africa. As the crust thinned from being drawn apart, it lowered in elevation and formed a basin which then collected sediment from normal erosion in the area. As the sediment thickened, it began compressing at it’s lower extents… eventually becoming shale.

      Later, when the Canary hotspot poked a few holes in it and made the islands, it did so on top of this sedimentary basement.

      Shale, though a rock, is not extremely strong. It has a pretty low tolerance to stress and can easily slide/ooze. Unlike the Central US, the shale under El Hierro has remained under a rather large blanket of water ever since the Atlantic has covered the area. This allows the pore pressure to remain quite high, and assists in lubricating any movement.

      As the volcanoes developed, some of the sedimentary material, mainly the shale, has been able to undergo metamorphosis due to the hight pressure and heat. Given the pressures involved, the likely products range from slate to phyllite and schist, with phyllite being the most likely product given the depths.

      Phyllite has a bending strength of about 48.6 MPa and is in an environment of 400 to 500 MPa. Essentially that means that when pushed, it will ooze. Everything else in the strata is going to be least resistive since Phyllite is the most advanced product that is likely, and the hardest and densest.

      Quakes will only occur if the dynamic load that is placed on the material exceeds it’s ability to bend or deform to comply with the stress.

      And, that’s about the best explanation I can give you… other than the very real possibility that the entirety of the island is made up of old tubes and pathways from previous activity, and it probably doesn’t need a lot of new fracturing to find a path to the surface (subsea for now).

      1. And that shale holds a lot of hydrocarbons in it. It creates gas that spreads the strata pretty easily so it just adds to Lurks argument.

      2. Also add to the equation, that the rock will be more ductile (so will bend more easily) with the heat from magma and also heat generated by the swarms of EQs that we have seen.

    2. I gather (I am not a volcanologist) that the vent was blocked (probably collapsed – possibly generating a noticable earthquake??), and then this new vent is the tube (a bit further back) opening up under the pressure that blockage causes, but that the action of sediment ‘rupture’ doesn’t seem to be preceded or accompanied by many earthquakes – however the sound of magma/gas flowing through the vent and erupting underwater is what I gather is making the larger harmonic tremor.

      At least that’s my take on what has been said on the various blogs in the last while 🙂

  18. Maybe I am going to be unpolite, but I am a little bit with so much discussion around El Hierro eruption. After all, this is not only a non-Icelandic eruption, but it is a minor eruption and mostly under water.

    In lack of other interesting events, this event is at most uninteresting to me. All of you, please forgine me, but I get bored to see so many posts and comments on this tiny underwater eruption.

    But I can understand why, since nothing else volcanically is going on in Iceland or around the world.

    1. I meant, “but I am a little bit bored”. But no wish to start any discussion because of this 🙂

    2. Irpsit-But this is the post on El Hierro and Katla is fairly quiet. This one has a lot of potential for human kills such as the islanders. Katla will go eventually and with a loud lead in to the main noise.

      This one is fairly silent because of the type it is. It could enter the tube system under the island and exploit it literally within minutes. Thats not boring I dont think… At least to me.

      It isnt a minor eruption underwater. No its an eruption field of about 3-5 football fields which is about the same as the mouth on St. Helens. It has multiple vents in that area right now and no one is sure whether its the main show or not.

      Kind of crazy when you think about it.. .Most of the quakes are to the NW and the eruptive activity is about 40 miles SE. So, what is really happening there could affect the lives of everyone on this planet or nearly so. A flank failure and we get a tsunami, an eruption into the tube system or the tunnel and you are going to need a bunch of new Spaniards because it could happen very quickly.

      Certainly not ho-hum to most of us.

    3. If I have understood it correctly, this El Hierro eruption is very similar to those occurring in Icelandic coast from time to time. So, it’s better to learn with El Hierro, how these subaquatic shallow-water eruptions behave…

  19. But I can understand why, since nothing else volcanically is going on in Iceland or around the world.

    Popocatepetl is on ‘yellow alert’ status at the moment, Hawaii had a 3.9 quake yesterday on the main island, and Etna is continuing her paroxysm events every couple of weeks. Granted there’s not much in the way of msm activity going on but you never know whats around the corner, especially given Hekla can erupt with little or no warning at all.

    2. Judith… restate that to be totally clear. The sea being sucked backwards would indicate a tsunami. The Restinga harbor is 50 feet deep… I cant see anything other than water but agreed, the camera has been focused to high resolution in a single area.

      1. The sea can appear to be sucked backwards by phenonema other than tsunamis. Sounds more like eddies from local currents generated by the eruption or a retreating tide.

    3. I had the same impression of ocean flowing out from the shore when watching the cam at a time this afternoon, but thought it was an optical illusion due to the light and wave pattern.

  21. 21/11/2011 @ 17:47 – Canarian government confirm that there is a second underwater eruption taking place off the south of La Restinga.

    21/11/2011 @ 15:02 – As reported by INVOLCAN (volcanological Institute of the Canary Islands), members of the Guardia Civil Helicopter Unit, which are currently working with Involcan on the monitoring of the eruption in the South of La Restinga, have found what could be a new underwater eruption. Apparently, this new emission zone is located east of the other two eruptive and a light eruptive bubble similar to that observed in the early stages of the eruption has been noticed in this new area. In the next few hours there will be a reconnaissance flight by helicopter from the GES and a group of scientists. Meanwhile, scientists have found a slight rise in ground deformation. Yesterday the National Geographic Institute (IGN) recorded 24 earthquakes at a depth of between 15 and 27 km, and four of them were felt by the population. The movement of greater magnitude, 3.7 on the Richter scale, occurred at 03.15 and was located 2 miles off the coast of Frontera at a depth of 21 km and was felt mainly in the town of Tigaday. In total, from July 17th, 2011 over 11.700 events have been logged.

    1. I wish they would get their story straight.

      First theres something, then someone gets blasted for saying it since it’s not happening and not official, yet shows up in the cams.

      Now it’s real, or not, but could be, but, but….

      *sigh, freaking cluster@#$

  22. Jon/M Kruger

    I was watching the webcam for at least 30 minutes in daylight and there was a lot of churning in the sea near the port then the sea started to have ripples they were a darker colour than the sea and they were being pulled backwards.

    Even in the calm area in port where the boat is moored the ripples were darker and going backwards.

    This went on for a good 20 mins.

    It was about the same time the 3.3 quake happened at 1805.

    2. Hey, I believe you. This thing as I said is not following the rules in most any manner. I get this mental picture of El Hierro being a huge iron composite sticking up through the sea floor. Its dangerous to say the least if for no other reason than the size of previous volcanoes that were there.

      Might get to see one rising from the sea floor yet again.

    3. If you see it happening, collapse your screen so you dont lose it and open this up or Eruptions and post it.

      There are lots of eyes on this thing right now and its not very good what we are seeing. If Lurks ooze theory is right then the whole island could be moving. I wonder if anyone has done a zero point line on the thing from a fixed GPS to determine if it is moving off to the NE.

      1. What on earth (no pun intended) could possibly move the island? Do you mean like tremors or what?

      2. The Island of El Hierro is not moving as you think of it. There is movement. But it might be counted in meters in certain areas. But in others there is no movement.

        This is how fissure eruption episodes work. For the Island of El Hierro, the movement is going to be minor. For the Island as a whole it moves several mm over thousands of years. So do not expect a change in location any time soon. In about 10 million years the location is going to be different. But that is how the Canary Island system seems to work.

    1. Well I guess that proves that I thought I saw something. Luis, very good.

      Try to speed it up on the download though. Its easier to watch hours that way and you can slow it down and speed it up as needed.

  24. Dont think the sea going backwards was anything to do with the tide.

    Today Monday, 21th of November of 2011, the sun rose in Puerto de la Estaca (El Hierro) at 7:38 h and sunset was at 18:17 h. The moon rose in the east (96º) at 3:21 h and set in the west (261º) at 15:17 h.

    In the high tide and low tide chart, we can see that the first low tide was at 3:09 h and the next low tide at 15:43 h. The first high tide was at 9:24 h and the next high tide will be at 22:01 h.

  27. I don’t know enough about volcanoes to have an informed enough idea about what is going to happen with El Hierro. Eyaf started small and picturesque, then grew steadily and mostly from a distance. Merapi was shocking in the scale of the impact on the local population – and in the organisation of the military when they were trying to evacuate people from cold lahars and pyroclastic flows. The logistics of moving a lot of people in rapidly escalating risk was difficult to comprehend, given the scale of the erution.

    El Hierro is different. It is very steep, and yet seems to have been bigger in the past. It has ‘bites’ taken out of it, and trying to envisage what was there before, and how it might relate to what is there now, is a challenge. The promonteries appear to be growing with extensions of lava from vents below the water level. Lava tubes are hollow, and so would seem to be gas tubes.

    I cannot currently find the paper that suggested El Golfo sheared before the main eruption 250,000 years ago, but if that is a precedent, then how might it relate to what is happening now? There are under-sea vents on the ends of all 3 points of the island, mostly degassing, with occasional magma bombs. The hot magma originates from a hot spot far below the island, yet the quaking is located along a rift.

    It exerts a fascination because it is not fully understood. It may go on like this for years or it may do something we don’t yet have the understanding to predict.

    1. Yes I noticed, there were 3 quakes at 4.8 an 2 at 4.4
      Iceland usually has a volley of small tectonic quakes, not long after such quakes on the ridge, if I remember correctly.

  31. Strain:

    The translation of the GPS hubs (x, y, z ) at the ground surface is reflection of the movements at depth. One could estimate a straight line strain based on some amount of spreading at depth. The funny problem is that you are looking at a basement composed of lava tubes and chambers. See the dive videos for el Heirro. So it would seem that a great deal of deflection must take place at depth for the result to be seen at the surface. For a brittle honeycomb structure at shallow depths at great amount of deflection must occur.

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