Short update on El Hierro volcano eruption

This is a short update on El Hierro volcano eruption. As the situation is changing fast this past few hours.

It seems that the eruption in El Hierro volcano is gaining strength and power. The harmonic tremor on the seismomter that is on the El Hierro Island it self has started to get saturated again. It also have been unconfirmed reports of the south fissure growing in size. But so far nothing has happened in the north part of El Hierro volcano. Even if there have been many earthquakes in that area. But this area fell suspicious silent this morning. So something might be up in that area. Update 1: A string of earthquakes happened around 12:00 UTC in this area. Suggesting that something is still up there.

The harmonic tremor at 13:52 UTC. Notice how the tremor has started to saturate the seismometer. Copyright of this picture belongs to Instituto Geográfico Nacional.

What happens next is anyone guess. But people need to be aware that fissure eruptions are sometimes long in terms of the length of the fissure. But that phase normally does not last long, as soon the eruption is going to isolate it self into few craters on the fissure. I also recommend that people read Erik Klemetti blog post about El Hierro from yesterday. If you haven’t already done so.

800 Replies to “Short update on El Hierro volcano eruption”

  1. And concerning our meeting in July 2012, my bet for Katla eruption also goes for next year.

    I think Katla only needs a flurry of magma from the depths rising up, that makes a part of its full chamber blow upwards. We know the chamber is full and magma has been moving from it upwards, but pressure is not enough, and this is because Katla needs a new input from deeper below. I think when it happens (can be next year but also much later) it will take 1-2 months, like Eyjafjallajokull. So the sign I am waiting for will be some major deep earthquakes slowly moving upwards and resulting in quite large shallow earthquakes. We do not know when this is going to start.

    It is interesting the theory described a few threads earlier that Hekla and Katla seem to cancel each other. They are not that far apart, so some mechanical link could actually exist between them, but I am not sure of it. Whether one relieves pressure from the other, or if magma from the hot plume, beneath the crust, could flow either to Hekla or Katla. I don’t think we have a clear idea how magma moves at very great depths and whether there would be a common link to close volcanoes or not.

      1. … looks like it’s going to be a few volcanoholics in the mountains of Iceland mid-July next year? – interessting:)

  2. I was commenting about Icelandic volcanoes and actually I realize now how interesting is the situation at El Hierro! With the eruption nearly reaching above sea surface! Exactly like Surtsey! Nice videos and photos!

  3. Diana,I am a regular (two or three times a day) reader of the blog but rarely comment as I don’t have anything useful to add. I have often seen your comments and in the smallness of the world I think we may be neighbours! If I say KL I presume you will know I don’t mean Malaysia? Home is remote and up in the hills. Nice to meet you all.

    1. Eeee Lass! Th’as just O’er t’hills. 🙂 Well if other people can speak in tongues I might as well add a little Lancashire/Yorkshire dialect 🙂 Good to meet you:) I rarely have anything useful to add my only expertise here is in Sheep.. We have a lot round us don’t we?

      1. PS my daughter lives on a farm on the tops between Todmorden and Hebden Bridge. I was there today.

      2. And I live in Yorkshire and work in Lancashire and know the Dales and KL quite well! Hello neighbours!

      3. Eee by ‘eckithump! I used to be in Huddersfield until we moved to China. There seems to be a definite focus oop there… something to do with the sheep, perhaps? They’re probably in league with their Icelandic cousins, spreading their fiendishly woolly influence.

      4. I loved Hebden Bridge. I lived between Rochdale and Littleborough up till 7 years ago when I moved to Skye. I miss the bakery shop in the middle of HB. They had some seriously good cakes.

    1. Very interesting video. A overlook of the pictures of the day(s). But I prefer turning off the music.

      1. BTW… that’s one of the reasons I don’t do audio in my animated plots on Youtube.

        My musical taste may not agree with someone else’s.

        Imagine a mix of Ramstein and Bizet’s Carmen.

      2. How about Grieg… that would suit our Nordic friends? Hall of the mountain King? Dance of the Trolls?

      3. My cousin used to tear up the piano with Grieg. I was amazed. Classically trained she is now a housewife.

  4. IGN and CSIC scientists have noticed ash particles in the steam coming out of the jacuzzi’s. We have the impression that the Ramon Margaleff may have informed Pevolca, as the oceanographic ship was seen on the grey stain close to the vents.

    Update 05/11 – 20:46 UTC :
    Joke friend, the La Restinga Human webcam , just arrived from the village. She said that a car with loudspeakers is driving through the village calling for the evacuation. UME (military emergency unit) is helping with the evacuation. People are calm and are overpowered with what happens.
    At first people of La Restinga thought that the big black bubble was a boat. They were really surprised that it was the volcano getting more active.

  5. Personally… I am cautious. I try to be pragmatic and not let my fear or concern drive my life. So… I try to couch everything I speculate on with the simple fact that what I observe… if it is outside my field of expertise… is just the observation of an armature.

    The last thing I need to do is to scare the crap out of somebody. I’ve had those little panic stages in life and it isn’t fun. (Tornado took the roof off a house I was in and a few years later Ivan damned near shredded my neighborhood)


    It is highly likely that I am wrong.

    During the early stages of this event, to the north of the island a series of quakes occurred over several weeks. Doing a time – position plot, it seemed that magma was being emplaced in structures paralleling each other. Each new batch of quakes would run alongside of where the previous quakes had occurred.

    This when on for a while, then the swarm moved south, increased in depth and magnitude, and then Little Bob was born. I have stated before that I think the swarm hit the far southern side of the island’s base and had no where else to go, the quakes sort of stacked up like they had hit a wall. My guess is that was the stress cause (probably magma) fracturing the rock there.

    How it got from that depth to the surface with virtually no quakes is still being kicked around on this and other forums. My money is on the Jurassic sediment base being much weaker than volcanic rock (gabbro) of the crust.

    Now we have Bob getting ready to peek it’s head above water, and the current focus of seismicity is back to the north under where the original “dike fill” event happened. Only this time… it’s really deep. No bones about it, it’s clearly in the mantle.

    But above this swarm, and lower than the “dike fill” region, is a collections of quakes set apart from either group. Statistically, if you look at the depths of the “dike fill” quakes, this new batch is within the 95% range of the depths for the “dike fill” batch. It’s almost spooky seeing how clearly they follow that lower boundary.

    Now, if that’s spooky, this is totally unnerving.

    In the mantle quakes, you can see batches that seem to be angling upward towards that “stand apart” group. And the over all trend of those clusters seems to be getting shallower.

    Now… a caveat. The human eyeball-brain interface is designed to seek out patterns. It’s a species survival thing. This also means that we tend to see patterns in everything. It could be that, or it could be real.

    I can’t state one way or the other.

    So.. if this is real, and it eventually crossed into the area where the “dike fill” quakes were at, what happens? The whole she-bang is still north of the Island, and the only surface manifestation of this activity is a putative little volcano that we have called Bob. (well, in this forum).


      1. If that was the cluster from 23rd then the vertical alignment has gone, for me anyway.

      2. 18.055 again. Can you focus in on that in 3D?

        I wonder if ‘thin sections’ in 3D would be revealing – say 5km thick NS, and full width? (all time points)

      3. As always Lurk, you show us the big picture of what I was thinking.

        Yeah, what if ? Thats a big question. If you align them with the islands to the North, you might get your answer. Maybe not vents but maybe thats how they got there? Or worse, they are things to come in the future and directly on and around El Hierro.

      4. They look like clusters of EQ’s occuring on certain days. If we knew the direction, possibly magma or gases rising.

        If gases, it might explain why there are fewer quakes in the dead zone as they are could go through the more porous sediment layer without much noise.

        You could do a quick check on the specific days against’s animacion.

      5. i was trying to work out a scenario in my head where the deeper zone is feeding into upper zone, and the upperzone is feeding magma across ,and with some vertical displacement,into the NorthWest rift (a zone of weakness), and then into the Southwest area (Restinga area)

      6. if this has any validity that would make the Northwest rift superficial area prime target for an eruption (Tangarosa ?)

      7. Robert nope, the island is shot through with caves that are old lava tubes…Kind of Hawaiian if you look at them. It only takes a breach into one to bring it to the surface and on the island to boot.

        The bad thing is that they are in some really crappy areas for landslides and if it got impinged, stuck, boulders in it then it could break through and cause the overburden to fail due to lack of support.

        I think we are going to be very surprised by this mug in the next couple of weeks. I wouldnt put anything past it either. I do fear they will evacuate it too late.

      8. Robert… My thing is that both current areas of crap in the water are two vents. Likely for me the main show is going to pop up soon. Basic macro thinking here. If they are both just vents and not the main show we will start seeing gas coming from other places, along with cracks, magma? and of course another main tube.

        The guys over at CERI are not flustered at all when they told me that this vent thing has them wondering too about the transport to the surface. They do buy Lurks crappy sediments with no resistance idea to a certain degree.

        One guy referred to that picture in Spanish of Hierro and the old volcano. Most of them crack in all sorts of directions off of the main tube. One guy went out on a limb and said that he would hate to be on that main road about 7 SW of Frontera in about two weeks. I asked why and he said he thought this thing was going to crawl up onto shore and under the island and show up there + or – 3 miles and form a new cinder cone.

        I said thats going to have to break a lotta rock to do that… His reply.. Yep !

        Time as they say will tell. I do agree with him that the main show hasnt been seen yet, but it does explain how its being transported vertically and laterally at the same time. He pointed out that we should look a the cave system on the island itself. Its shot through with them..Swiss cheese and he indicated that those are likely soemthing like the lava tubes of Hawaii.

        Kind of makes sense but it hasnt manifested itself that way yet. Be kind of wild if the lava used the tunnel as a vent wouldnt it?

      9. Not sure how to work/think about the “cave system” scenario into this ? any old lava tubes of potential interest would have been crushed after burial to a certain depth, say 1-2 Km for sure …

        IMHO , i think the intersection of the new rifting (interpolated) with the WNW rifting would be a particularly good place for the main event , ie two intersecting zones of weakness/fracture with near vertical access from the shallower seismic zone … Anyways, time will tell …

      1. Haha, I knew I had heard of an armature from somewhere, I worked in electronics for a while, when I checked it I couldn’t see how you could be one. Although as it is spoken of as a copper wire ( a live wire?) wound round an iron core (El Hierro) I suppose it could be made to fit. 😉

      2. I almost replied with “Coil in which voltage is induced by motion through a magnetic field” but the reading was so interesting, I forgot about it! But now I remember…. 🙂

    1. OT I think i know pretty well being edgy, since i have wolff-parkinson-white syndrome+ “faulty wiring” in my heart, been through one heart surgery, and in waitng list for another. Meaning i could drop dead anytime, anywhere, so there is no point worrying about it, just enjoyn every moment you’ve got

      (i’ve had 15 bears so excuse me for babbling…(bear=karhu[Finnish]=beer)

      1. Hyvää!
        Wavin hello to resident of brother country!
        Also a bit beered, thankfully not beared 🙂
        Better then my former work mates name, translated into the russion version of Urs Dynamit 😉

  6. Please, to any photographers reading this – set the clock on your camera accurately and display the time in the frame. We need to correlate the time of Bob’s sea surface disturbances to the CHIE tremor. It looks like its geysering – pushing up a column of water followed by gas, then a recharge period. But that’s just aguess – we need the evidence.
    (Yes I know the clock spoils the pictures)

    1. Peter, it’s possible to do that even without date/time shown in the picture. You just have to take a look at EXIF info embedded in the picture itself – bit more complicated, I know, but useful. EXIF info is rarely lost, even if the picture is edited.
      For example this one:
      EXIF info: Author: Demi Alvarez; Date taken 05/11/2011 20:04; Camera: Canon EOS 5D Mk.II; F-Stop: f-8; Exp. time: 1/500; ISO: 250; focal length: 105mm (might be useful if you want to calculate size or distance of object, but can’t remember the formula).

      1. George,
        Thanks did not know that -right click on view image info and its all there. No secrets with this digital magic.
        Just have to hope the time was set up OK.

      2. So here goes: time stamp on this photo of Bob starting:
        Looking at CHIE for that time:
        We see that the photo time preceeds the spike by 5 minutes, which was at 18:55
        Before I kill off the idea, I plead that the camera was not timed accurately!

  7. Carl already mentioned it earlier on: some kind of periodicity showing up in the graphs. At that time he estimated it to be around 48 minutes. AVCAN FB now reports a 40 minutes cycle:

    La actividad sísmica continúa alta, con sismicidad sigue moderada en la zona del Golfo y con una señal de tremor volcánico en la zona de la Restinga, con un comportamiento variable y se marcan pulsos de unos 40 min terminando con cada pulso con una especie de explosión.

    It looks like it’s speeding up? Anyone any ideas about the process that could explain this cycle?

    1. My guess is its like big geysir. Cold sea water flows down through cold rock – perhaps an old dyke structure and fills a conduit from the bottom. That conduit is not cold but has walls in close contact with magma at several 100s degrees C that was already in place – possibly from earlier eruptions in the area. As the water enters the conduit it is rapidly heated and climbs up the conduit. It boils and sets up a 1Hz vibration as the stem bubbles collp[ase under the pressure at 2km depth or so. The 1Hz you can be seen on the trnor plot as the dark red line near the bottom:
      The 1Hz line takes about 10 minutes to get started after the previous euption- on this plot that is at about 18minutes. Up to baout 52 minutes the conduit fills with more water – say 2km column which heats up. But as the column of hot water approaches the sea bed the water pressure is lower, so the boiling superheated water boils off steam and gas. That steam and gas push water out of the top of the conduit. The eruption starts – on the plot its the vetical yellow line at 52 mintes. With weight taken off the top of the water column the rest of the column gushes out geysir fashion. There are two or three coupled together- see three yelloe spikes. Once the suprheated water has erupted the the 1Hz trmeor is lost , cold water enters at the bottom of the conduit and again takes a few minutes to get hot enough to start the 1Hz tremor again.

      Given measures of: the period between gushes, the temperature and area of each gush at thesea surface, and water depth there, it should be possible to estimate the water volume in each gush and the rate of energy input (power).
      Nothing tricky just a calibrated infra-red aerial camera.

      1. Easy to see when you look at the hourly graphs – every 40 -50 mins or so. Not noticed this before – gets more interesting each day !

  8. Note: It´s calculates that the “geyser” can find it no more than 60 meters deep into the see. The fissure continues opennig and approaching to the coast.

  9. In AVCAN fb comments several people from El Mocanal (near Frontera, I think) now reporting that the ground there is moving slightly up and down, as if they were on a boat on the waves and that they are getting a strange feeling, pressure in the head and feeling when you get seasick on the boat. A couple of others from La Restinga commenting back that this is how they felt just before Bob’s eruption started…

    1. Sorry, correction, just checked and Mocanal is near Valverde.
      This is a brilliant resource if you want to find any small place on the island (use Busqueda – search and then change layers to topographic map 1:5000):
      I think it was Son de Boeu who recommended it, thanks again.

      1. Oh thank you for the link! It’s just what I needed. :).

        The vertical wave motion mentioned in the posts… could that be a sympathetic vibration to long wave harmonics in magma filled conduits? Im trying to read this paper but it is a little above my head… Okay a lot above my head 🙁

        “Instability in flow through elastic conduits and volcanic tremor”

      2. Wrong place, look again at the list and you will find two El Mocanal the first is on Gran Canaria but the second is in the middle of El Golfo 4km WSW of Frontera. Right in the middle of the debris zone.

      3. In fact I have been using it for weeks and also posted it some time ago (that was when searching for IH04; you can also find a lot of information about GPS stations on the Canaries here) but still do not know all the functions it has. Very useful!

      1. Lurking, would the debris zone from the collapse have the same consistency as, say, the alluvials below Mexico City that amplified seismic waves so much?

  10. On his blog Manfred Betzwieser just updated:
    Ein evakuierter Anwohner erzählt: “Nur wenige hundert Meter von der Strandpromenade entfernt, habe sich plötzlich im Meer ein Spalt geöffnet und Rauch und Lava ca. 10 m in die Höhe geschleudert und eine Druckwelle habe ihn dann erfasst.”
    Means: A person being evacuated told: Only a few meters from the beachwalk, a fissure opened and smoke and lava was thrown into the air 10m high, then he was hit by a preasure wave.

  11. May everyone on El Hierro remain safe. Have there been any published guidelines as to what might trigger an evacuation from Frontera? Ursula’s post does not sound good.

  12. Other stations reporting seem to be about 30min behind, so we’ll see when we get that data.

  13. Rescaling can be seen by the blue vertical line if you go to the hourly graph. I thing it maybe rescaling, but there was indeed a drop before the rescaling, although such drops also occurred iin other parts of the day but picked up again 30 minutes later.

  14. ====
    Ursula says: November 5, 2011 at 19:17

    You know what is also curious, I took this screenshot of Ramon Margalef’s route 45 min ago (at 18:31),, sitting basically on top of Bob/jacuzzis:


    Yes, worrying.

    shows last known position of Ramon Margalef as at 18.17.46, right over the volcano.

    All the other boats in the area show current time (eg 24.41.xx etc).

    I hope what I fear may have happened, has not happened.

    1. I don’t think you need to name your fear. Surely if anything bad had happened to the boat though the news media would have picked up on it immediately?
      I am very naive at times though, so I sincerely hope your fears are unfounded.

      1. So did that one, you will have to type it in.
        The link says :-

        An explosion from the Bayonnaise Rocks submarine volcano in Japan’s central Izu Islands breaches the sea surface on September 23, 1952. These cockscomb-like projections of blocks and ash are characteristic of shallow submarine explosions. This photo was taken 5 seconds after the explosion penetrated the sea surface. Five minutes later the eruption was over and the sea was again calm. The suddeness of these powerful explosions proved to be fatal to 31 persons on a research vessel that sailed over the vent the following day

      2. I think you are right Rusty. There must have been an awful lot of people looking out to sea and watching the boat. The boats in port don’t seem to be registered on that plot.

      3. The boats in port are registered I’m afraid, even when they have been there for a long time, then the status may become “moored”. I have been looking for the R. Margalef on the localizatodo site all evening but even using the search facility doesn’t bring it up. I guess they have felt watched and switched the signal off. So I hope…

  15. My girlfriend is coming on holiday to fuerteventura in 2 weeks, is there any reason to worry about El hierro ? If I were going there, i’d definetly get a trip as close to bob as possible(I’m a bit nuts, and dying anyway.So nothing to lose…)

      1. It have to be more than that. Gran Canaria is about 250 km from El Hierro, and Fuerteventura is even further away than that. I think what Nathan said about 350 km is more correct 🙂

    1. Stoneyard- my friend’s mum was diagnosed with WPW 40 years ago and is still going strong in her late 70s. 🙂 But go and see Bob anyway.

      1. WPW is’nt the one stopping me, i had one “faulty wire” corrected in last surgery, 2 were left,(in additon to WPW) since they were non leathal, and would have required specdial equipment to be fixed. So now i’m waiting again..

    2. No. Not really. It´s only a little volcano which can explotes one of these days….

  16. Just to draw your attention to my reply a little way back. The place El Mocanal, where the ground is waving up and down a bit as actually in the middle of the El Golfo slide about 4km WSW of Frontera. No doubt that sort of soil behaves a bit like wobbly jelly and may be amplifying the seismics.

    1. sedimentary stuff like old ash is wobbly during EQ’s.
      I was on sand in a 5.4 and it is like the sea very much…

      1. I hate to say this but looking at the earthquake plots this is right where the EQs trend upwards although the shallowest that registered is at ~12km depth.

      2. I do worry that small EQs may not be detectable amongst the tremor from Bob, wherever they are under Hierro.
        The swarm from July to Aug were all around mag 0.5 to 1.5,
        Lurking’s plot here:
        Is it possible that IGN is blind to hundreds/thousands more of that mag, but at shallower depths?
        Perhaps residents of Mocanal could hear them with their ears to the ground, time them and count them and phone the authorities?

      3. There have been some post Bob but not many.

        Overall, the small ones have, however, tended to occur between: 27.625 and 27.85. -18.0 and -18.10. And while small quakes have been occuring at all depths, EQs <5km have been only the smaller ones in the range 0 – 2.

        So whatever is occuring mainly in NW and W Frontera at the moment is causing larger quakes. New magma breaking through from either from a new source or from the main magma reservoir.

    2. Just completed a really tedious analysis of where the EQs have been occuring:

      Note that most EQs are occuring in NW, W and SW Frontera. Tanganasoga is in the middle of that area.

      Full comment is currently stuck in moderation.

    3. That may not be a good place to be right now.

      Lat 27.7255 Lon 18.024 (both approx per Google maps) is close to the centre of the EQ distribution – plots below.

  17. Looks like I’ve been missing a lot from today.
    Just a short note to say that the name for Bob, in Spanish, is Pancho (AVCAN). 🙂

    1. Well.. I don’t think it’s a direct translation.

      Pancho is the mythical Halibut that is rumored to dwell in those waters. They named Bob after the Halibut.

      By the time they had come up with the name we were already calling it Bob… or some Icelandic language twist on that.

      1. notice on the first one the apparent heat (or unknown vapor) optical distortion above the water mound

  18. @Peter Cobbold

    5km at 27.5°N is about 0.0451° (110.8 km/degree)

    The bounds of these plots are 27.745°N to 27.835°N and whatever longitude the data was in…. which came out to about 7.8 km worth of usable stuff, sans the crap out on the far east area of El Hierro in the water (one or two quakes)

    So.. this is pretty much an up close and personal with the swarm… or part of the swarm.

    To me, nothing really stands out as trying to go skyward.

    3 (well, 4) D as requested.

    End on view looking north since that one is more confusing than helpful

    Both of those only use data from the 10th of October to present.

    So… since it was already opened… All quakes since the start in the same box.

    Again, looking north.

    That last one showed something interesting. See that glob of yellow? That’s where whatever made the quakes passed through as it was heading south where it then dropped in depth.

    Cool. I think that was the magma path.

    1. Lurking, any chance of seeing the first set of data looking west, normal to the rift.

      1. That clear zone is really obvious. I wonder if it is ‘underplating’ under the crust? Going to have to read more…. but maybe tomorrow.

    2. Or, another idea, could you colour the first set of data just in three clusters, as you had them above in discussion with Peter? Then show in N-S, in E-W and as 3D? That could perhaps show something…

      1. Color coding is done by the whole plot. All points use the same scale. I cheat with the island and terrain layers by setting those data points to some arbitrary time or magnitude.

    3. Lurking,
      That yellow blob would be well into the sedimentary layer if the crust dips 2km under Hierro’s erupted mass. So it could be well on its way up now. I am concerned. As I posted above, small EQs may not be detectable above the tremor noise, or not locatable. And the last time the EQs were at around 8km they were small, 0.5 to 1.5. The sensed ground trembling at Mocanal 1km from Tanganosoga ( see above Brian Smith 23:32) would not I think be expected from deep EQs at rate of about 1 to 2 per hour, 20km deep. Maybe its Bob – but he explodes evry 40 minutes or so. So I am seriously concerned by the sea sick feeling at Mocanal. But it might also be infrasound from Bob, a 7hz harmonic maybe?-that would be less worrying.

      1. Wouldn’t that be the one they discovered when everybody gathered in the bunker to watch a rocket lift-off and wound up shitting themselves?


      2. I think the french invented a prototype battlefield weapon maybe 30 years ago , but aiming it poved the problem – it backfired on them.
        Guts upset somenting awful at 7Hz.

      3. I remember this but it was even further back, more like 40-45 years. There was a big article about them in a science mag I was reading then.
        They had managed to make it directional by the use of huge phased arrays of trumpets that looked like something out of a Terry Gilliam cartoon.
        I beleieve it is now done by using two directional beams of ultrasound having a 7Hz beat frequency.

  19. Latest news: The personal who is responsible for overseeing the hydrophones in La Restinga forgot to connect the computer to electric current.

      1. Fit and forget data capture?
        What about real-time monitoring? – we could have done it for them here, 24/7.

    1. First a flat battery on H104, then a flat computer.
      When did Hierro get electrickery? – some lack of familiarity?

      1. HMMM… <— The famous last words, if you hear/see some xpert saying this, take cover!

  20. Disregard My last coment, 19 bears have eaten my brain….i’m going to go to sheep now, godabunga night everyone.. 😉

    1. Qué barbaridá, paez el Moby Dick… Si, ye’l meyor semeya del día, gracies Son de Bueu!
      It looks like Moby Dick wagging his tail…

      1. “Bobonwaternosewithgass 🙂
        *set omg mode* Just amatör, not expert… but here anyways is my rambling. Maybe not worth reading even. Serious matters. Seriously Hope the Population will be moved OFF as soon as possible. Before more serious occurr. Not shure they will.

        *set thinking mode* Is bob on the move, or is this sister entering the stage? Its now nearly a month from start of the eruption, and I do not see many ask for ´precise location of the vents´ nor see a good map of this/these. Where is a live web camera of La Restenga town and surroundings? Is there more than one eruptin vent? Was this volcanic explotion in exact same place as Bob is supposed to be? Forget “innocent” Geysir ideas! Active Volcano is there. It will show better, I think. Is the press in the area slow on getting info? It matters. Find very little real info posted on this site. Always many rambling about what will happen, fewer about what has happened and report the exact place it happened at.
        Hope someone will do something about try get “a fix” on the spot that these explosion(s) occurr at, by taking bearings from two different spots, preferably spots easy seen on Google Earth or a medium scale map and are a as many kilometers apart as possible. Then two people with simple (indentical (scout)) compasses could do this: First find true north, fix compass, then read bearing direct to spot on sea. Report. Simple.
        *set thinking mode off*
        *set lurking mode*
        …hoping someone then can plot results …. perhaps someone with proper Thedolites already have done this but results buried under rubble of bureocracy…
        *set “sleep on this” mode*
        *set omg mode off*

  21. Did you know that some geologists found riolita (or traquita, I´m not sure) inside Tunel de los Roquillos, on the walls? I am told that it´s the only place on the island where exist this mineral on the surface.

    1. The panacea that has been throw about with the mixing evident in the pumice floating about on the water being traquita instead of riolita (Trachyte vs Rhyolite) is a bit… well, in my book, dubious. But I’m just the suspicious type.

      Trachyte mixes are less explosive than Rhyolite mixes… but they are almost identical in make up. The big difference being in the silica content.

      Trachyite: The mineral assemblage consists of essential alkali feldspar; relatively minor plagioclase and quartz or a feldspathoid such as nepheline may also be present.

      Rhyolite: The mineral assemblage is usually quartz, alkali feldspar and plagioclase.

      And they are neighbors on the QAPF diagram.

      1. Well. Difference understood. My question is this: If it has found any of these minerals on the surface on El Hierro, does it mean that in the past there was an explosive-type eruption in that area of ​​the island? And if it does, is it possible that will happen again? (I hope not)

      2. What a ridiculous question. I know that there was a big erupcion and that´s what Golfo was created…

      3. How you get from one to the other depends on how the fractioning process goes along in the “reservoir.”

    2. The “Roques del Salmor” consist of trachyte. From there a narrow band of trachyte lava runs along the upper edge of the northeastern Gulfo valley, representing the last phase of the golfo-volcano. (Carracedo)

    1. Translation of Jens page. 55,000?

      This map shows the evolution of the ash cloud from a hypothetical hydromagmatic eruption on the island of El Hierro. It is estimated the top of the column of ash 13,123 feet in a (4 km), a duration of 48 hours of continuous eruption of ash and a concentration of 2 on a scale of 4.

      In the first two boxes you see the evolution of the cloud of ash between 35,000 and 55,000 feet (FL550-FL350) and in two seconds between 20,000 and 35,000 feet (FL200-FL350). As has been capped at 13,123 feet, is the reason why in they do not see anything. Where can observe the evolution of the volcanic plume is in the boxes (SURFACE-FL200) and (COMPOSITE).

      We recall that this evolution is a hypothesis and have chosen the worst data for what would happen in the worst situations. The purpose of this is to use this tool to learn more and create a little debate.

      Wont be any debate if it goes to 55,000. They should evacuate if they think that its going to to do this.

      1. El Mocanal is fairly close to the centre of both the lat and long clusters, if the coordinates per Google maps is reasonably accurate.

  22. @Ursula 22:31

    Another possible cause for the rolling ground is increased pore water pressure. Something (vibration) may be causing a temporary or localized “quick condition” .

  23. La Cueva de Don Justo is a lava tube located at the southern tip of the island, between the mountains of Hiram and the fishing village of La Restinga, near the Mountain of the Dead, about 100 meters from the road linking the towns El Pinar and La Restinga.

    A single entry gives access to the top of the crook and from here develops on a a north-south line with a length of 1,360 meters and a vertical drop of 135 meters, finishing near the coastline. Its interior is very labyrinthine, with a total development of its galleries of 6315 meters, with several crosses and overlay of tubes which are the results of a prolonged eruption, being the third longest in the Canary Islands after Tenerife Wind Cave and Cueva de Los Verdes on Lanzarote. In some sections there are up to eight parallel galleries, often intersecting or overlapping.

    Note the presence of stalagtites in the roof. The humidity is high and the temperature is the highest recorded in Canary caves, ranging between 21 and 22 degrees Celsius. The cave fauna is home to varied and interesting, highlighting troglobites and some species, like the cockroach Loboptera Ombriosa Meridionalis, spider Spermophorides CIEJ Justoi Anophthalma Collart, all endemic to El Hierro and the last two only known to Don Justo.

    Neat, so now we know about the lava tubes and its a confirmation really. If it breaches into a tube that comes to the surface someplace there is going to be an eruption and in a place we aint expecting it.

    In 1963 it founded a caving and mountaineering Hierro, whose foundation was signed in writing within this cave.
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    Go to: Start page

    1. Yeah… about those caves.

      “The humidity is high and the temperature is the highest recorded in Canary caves, ranging between 21 and 22 degrees Celsius.”

      Thats 69° to 71°F. Thats also a bit higher than most other caves that people lurk in. (Lurking should be an Olympic sport)

      “… Caves also played a role in the development of a major industry in St. Louis; the brewing of beer. Before the invention of refrigeration, the only place that a brewery could lager beer was in cool caves. Missouri’s caves, at a constant temperature of about 56°F (13°C ), were a perfect place to lager beer…”

      “… Wind Cave for instance, the mean annual surface temperature is 47°F(8°C), yet the temperature in most parts of the cave (away from the tour routes) is 55°F(12°C) …”

      Wind cave is kept warm from the geothermal gradient in the area.

      So here we have El Hierro, laced with caves… sitting at a relatively balmy 21°to 22°C.

      Talk about your residual heat.

  24. Looks like Katla is jealous of all the attention bob has been getting, looks like a mini swarm starting

    1. Jón – with all that is going on in El Hierro, maybe you should make a separate post about the Katla swarm, and folks here could try to keep their comments on the appropriate threads….

      ‘Cause we’re always so on topic, you know. 🙂

      1. I am waiting on the Katla volcano earthquake swarm. I want to see how it changes before I write about it.

        But this is a dike intrusion into Katla volcano caldera.

      2. Thanks, Jón.

        I hope it’s nothing major. Soon we won’t know where to direct our attention!

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