Special report: New eruption vent (or vents) might have opened up in El Hierro volcano eruption

The current tremor data now suggests that a new vent or vents have opened or are about to open up just outside north-west coast of El Hierro volcano. The depth where the main earthquakes have been taking place is about 100 to 300 meters (but might be more). So far the largest earthquakes to take place in this area was a ML3.9 with the depth of 22 km. What is important in this is not the fact that the earthquakes are at great depth. But also the fact that a more shallow might not take place. As that was not the case when the eruption started in El Hierro on 10 October, 2011. It is unlikely that there is going to be any shallow earthquake activity before a new eruption vents opens up. As that was not the case on the 10 October, 2011 from what I can remember.

Current harmonic tremor in El Hierro. So far there has not been much change in harmonic tremor as can be seen here. But that can change without warning. Copyright of this picture belongs to Instituto Geogr谩fico Nacional.

I am not sure how strong earthquake this area can make. But I am guessing that it might well be in the upper Mb5.5+ range. The earthquakes that are now taking place are due to magma injection. Not a tectonic one. There is a difference between the two. But this rifting in El Hierro might trigger a earthquake close to El Hierro Island in near future, that earthquake would be a tectonic one. Not a earthquake created by magma movements.

So far the new vents are still unconfirmed. But there are signs in the harmonic tremor data that new eruption vents might be opening up or have already opened up. But at this moment I am waiting for a confirmation on this actually taking place. That is going to take a few hours, given the experience so far.

654 Replies to “Special report: New eruption vent (or vents) might have opened up in El Hierro volcano eruption”

  1. Thanks for this Jon. I don’t think I’d want to be anywhere near that tunnel today.

  2. J贸n, are you aware that what you’re saying contradicts all that has been said so far, at least by local authorities?
    I agree that both intensity and frequencies have dramatically increased in the last hours, but what makes you think that a vent has already opened? From the slight increase in tremor plots?
    I agree with you that this will probably be the most likely scenario, but I fear dtrong reactions from both, Canarian people and official scientists.
    But I’m with you, whatever may come. 馃檪

      1. If the GPS inflation has stopped. There is a good chance that El Hierro volcano has inflated to its maximum. But it is hard to know that for sure at the moment.

        The GPS data is a wait and see thing.

    1. I am in the business of sticking it up to…everyone if I have to. This earthquake activity is not something random event. It is due to magma movement in that area.

      This magma is on its way up, if it is not already there. It is soon going to be.

      1. Jon,
        Well lets have some debate on this. I dont think there is any evidence that magma is rising nor that fresh magma had been injected from below, throughout the whole period from July.
        To summaries my earlier posts:
        -EQs since July started at 8-12km and have trended deeper, and now are at 20-25km. 20km approximately corresponds the crust mantle boundary once flexure of the crust is allowed for. From magma injection I would expect the revers pattern: EQs trending shallower.
        -The big swarm of 8000 EQs from July to mid-October occurred in the crust and the remains of overlying Jurassic sedimentary layers. That activity has now stopped almost completely. That does not look to me to be the result of a magma intrusion.
        – the tremor started shortly before Bob was detected, suggesting to me that the two are the result of localised, small scale activity.
        -the GPS motion has been static during the present deep EQ activity at 20-25km. That also does not look like magma intrusion.
        – So what do you think about the whole sequence being triggered by flexure of the crust with mobulisation of local magma causing the EQs , not the injection of fresh magma and more heat from the upper mantle?

      2. J贸n, keap on sticking it to them. The center-piece of sticking it to them is of course that you have been way more close in your predictions than they have been.
        And I think you are right, either a new vent(s) or soon opening of vent(s).

    1. Sorry… I read Earl.

      Coffee hasn’t come on line yet. I thought you wanted to call it Earl, Bob’s cousin.

      I’ll nurse this cup of coffee and be quiet now.

      @Carl and Jack and Peter.

      From yesterday if you didn’t catch it.

      I managed to gear one of my spreadsheets to calculate confining pressure for each quake in the list. It takes in 2070 kg/m鲁 rock density and 1040 kg/m鲁 water density ( split difference of surface vs abyssal density).


      For all, sorry for the regurgitation, but Bob’s noisy cousin burred the last one.

      1. Peter, about zip for a threat as long as they are 3.5 and below.

        Its a frat house party at 4.5.

        A 5.0 will rattle your cage.

        5.8 will make you think that you are about to buy it.

        A 6.5 you might do just that. 7.0 well I should have attended church.

        A 7.5 and you are going to be in a church laid out with flowers.

        8.0 there wont be a church or flowers, you will just be laid out.

        8.5 ………………………………………………………….

        I am referring to total effects here. Anything past 6.5 is going to likely upset your orbital plane for two to three years. E.g. a 1.89 second quake in Italy killed over 300 people and destroyed 600 years of world history. The Tower of Pisa was tilted by a quake.

        Its all relative. If you live in a rocky area then it absorbs a lot of the force. Whereas I live here in Memphis on sediments and the entire place could go to the ground in a 4 -10 second quake, even though we are told this would last for about 3-5 minutes.

        Nice. I for one agree with Jon F. about the vents opening. Its spiking on the tremors and remember this mug is detuned so they can see them. I posted a picture over at Eruptions and I think its already underway. It will take the path of least resistance which is the water most likely. But this is a juncture where we disagree and that is about the landslide possibilities. Lahar/flank fault…call it what you want. The papers produced on it say that it will. The local head honcho of IGN says no. What the hell else could he say? He is a politician first and then geologist/sesimologist second.

        There is a tremendous amount of overburden on those hills and there are several inverted “U” shaped undercuts below those things. If Jonnys 5.5 scenario occurs with any duration it will drop that like your mother in law into the water.

        Effects? Only in order of magnitude if it does.

  3. J贸n:
    Looks like Enrique, from AVCAN, shares the same opinion as yours (Giggle):
    “About the Current Volcanic Islands (AVCAN) I would like to comment that the mathematical-seismic problem and I have to tackle is the following: for the cumulative seismic energy released curve or “devil’s staircase” to continue its development as until now, all we need to have is another earthquake equal to or stronger than the 3.9 Before 12h-14h.
    With these data, I estimate that this afternoon at about 6:00 p.m. to 9:00 p.m. there will be another (others) about 4 or the same so we jump to the next level of energy to 4.3-4.4 and that’s a problem.
    My personal recommendation: please do not use the tunnel Los Roquillos and take appropriate action to strong earthquakes, removing weight from the upper shelves, tables, pots and anything else that could fall. (Enrique)

      1. Por supuesto. Esta escondido en los comentarios anteriores:
        “Actualidad Volc谩nica de Canarias (AVCAN) Os comento el problema matem谩tico-s铆smico que se me plantea y es el siguiente, para que la curva de energias sismicas liberadas acumuladas o “escalera del diablo” siga su evoluci贸n como va hasta ahora, lo que tiene que haber es otro sismo igual o mas fuerte que este 3.9 antes de 12h-14h.
        Con esos datos calculo que esta tarde a eso de las 18:00-21:00h habra otro/s cerca de 4 o lo mismo saltamos al siguiente escalon de energias al 4.3-4.4 y eso es un problema.
        Mi recomendaci贸n personal, por favor no usen el Tunel de los Roquillos y tomen las medidas adecuadas para sismos fuertes, quitando peso de las estanterias superiores, cuadros, macetas y todo aquello que se pueda caer. (Enrique)”

  4. More at AVCAN:
    “The National Geographic Institute has confirmed this morning the direction of the Civil Protection Plan for Volcanic Risk (PEVOLCA) an earthquake of 3.9 magnitude, northwest of Frontera, located in the sea to 22 miles deep. The quake, which was felt by the population, occurred at 7:46 pm and is the largest earthquake recorded in the island after the onset of the eruption south of La Restinga.
    The 1-1-2 CECOES received calls from the towns of Isora, Guarazoca, Mocanal (Valverde) and Tigaday (Border)
    The evolution of seismicity in the north of the island has increased in recent days and scientists who are monitoring constantly shuffled all possible scenarios, but still can not be defined with sufficient precision. In this sense incline between the main options that the process reduces or evolve into an eruption located, most likely, at sea, with the features being developed to the south, whose parameters are stable. ”
    On deformation and stain:
    “According to reports from scientists at the University of Cadiz, and with reference to the deformation of the ground, continue two separate scenarios. The south of the island shows a remission in increasing deformation, clearly marked by the eruption process and that is evident in the data recorded in the GPS station of La Restinga.
    In the north of the island, seen in the deformation component increased to a lesser extent North and the East.”
    Throughout the day have been observed clearly the main emission areas in which it has been seen fragments of lava. Also during the October 29 confirms that the stain has already spread to the entire Gulf area

  5. I wonder why the quakes at ~14 km depths are always of lower magnitude.
    Maybe because they happen on a more ductile environment?
    So, isn’t it fair that we admit that there might not be any quakes at even shallower depths at all?

    1. Maybe there are smaller EQS at shallower depths but these cannot be detected amongst the tremor. I think an earlier post suggested smaller than ,ma1.5 would not be detected? or had uncertain locations so were left out of the data set?

    2. Well, why would there be quakes at shallover depth?
      As we know there was no shallow quakes before The Bobs of La Restinga, So why would there be shallow quakes before The Insurrection of Tthe Bob of El Golfo?
      I totally agree with you on this Renato, to wait for shallow quakes is probably a useless thing to do.

  6. Sissel: It’s on the same thread, but you need to collapse all comments:
    Machin Rodriguez Janay Well according to the government of the Canary Islands page THERE deformation in the north and in the east, but to a lesser extent. On the other hand, if you follow the exponential increase of energy release at this rate, as noted Henry, for today and tomorrow and we’ll get the 4.0. As I have understood to be so profound senses will be less than 4.0 of shot before the eruption, but it will still be pepinazo. There are not many hours to know and be able to draw further conclusions. I also think that the depth of the previous swarm was smaller and the formation of the devil’s staircase, the slower. Now are deeper but that ladder much faster than me so I feel are very similar. Are compensated, so it would not surprise me that we were a bit of another eruption. In the former case we looked at a site and the volcano we went for another without being able to see the connection, luckily those shallow sismitos gave us clues. Here you can spend the same, be looking for a site, and surprise the other. As it goes very quickly, I think it’s important not to lose any detail, no pistita, while having a global picture if we get the volcano for a site we did not expect at all.

  7. http://www.gobcan.es/noticias/index.jsp?module=1&page=nota.htm&id=144270

    Seg煤n los informes de los cient铆ficos de la Universidad de C谩diz, y en referencia a la deformaci贸n del terreno, contin煤an dos escenarios diferenciados. El sur de la isla muestra una remisi贸n en el aumento de la deformaci贸n, marcado claramente por el del proceso eruptivo y que se evidencia en los datos registrados en la estaci贸n GPS de La Restinga.
    En el norte de la isla, se aprecia en las deformaciones un aumento en la componente Norte y en menor medida en la Este.

    1. Giggletrans:
      According to reports from scientists at the University of Cadiz, and with reference to the deformation of the ground, continue two separate scenarios. The south of the island shows a remission in increasing deformation, clearly marked by the eruption process and that is evident in the data recorded in the GPS station of La Restinga.
      In the north of the island, seen in the deformation component increased to a lesser extent North and the East”””

      Cant see that here:
      Where do Cadiz get their GPS data?

      1. I think Giggle should have said

        In the north of the island, seen in the deformation component increased to the North and to a lesser extent to the East

  8. el buque oceanogr谩fico 鈥楻am贸n Margalef鈥 ha detectado plumas t茅rmicas en el Mar de Los Llanillos, que podr铆an estar ocasionadas por la emisi贸n de gases. De confirmarse este extremo, podr铆a estar produci茅ndose una nueva fractura volc谩nica, en este caso en el mar frente al Valle del Golfo.

    The ocanographic ship, ‘Ramon Margalef’ had detected ‘termic plumes’ in the sea – In El golfo sea -, From a blog ( not confirmed)

      1. Hope the confirmation comes very soon because this is extremely important for those who are responsible for “shelter and evacuation systems”!

      1. Even though Parvanehs explanation is absolutly correct for gas, I feel that I should clarify that here we have a column of warm water rising to the surface due to heat convection.
        I know, I am a bit anal here 馃檪

      2. I guess the new vent(s) release huge amouts of superheated water to the sea and create these hotwaterplumes. It would take a big amount of heat to make those plumes and the only likely source would be erupting hot water.
        The new erpution seems to be in full swing.

      3. The original messages said (in part):
        芦…que podr铆an estar ocasionadas por la emisi贸n de gases禄
        or in English
        芦…that could have been caused by the emission of gases.禄
        So it seems that they think that hot gas is heating the water, which could be the sign of a new vent having opened.
        It isn’t quite clear from the text whether they found hot gas plumes in water or hot water plumes in water.

    1. This may not be a result of the present deep EQs at 20km, but from the 8km deep activity in July, at the same coordinates. July EQs were in a layer of Jurassic sedimentary rocks ( limestone, shales, clays) that would if exposed to existing magma pockets create gas and steam. It would not suprise me if this gas has taken three months to find a route to the sea-bed 8km above. So has the ship found marine fumarole(s)?

    2. That confirms what I found on the satellite of the El Golfo earlier today.

  9. The people in the AVCAN group on facebook explain that the Tunnel of Rosquilles and a smaller road (the old road) that goes over the top of the mountain are the only way out of the Valle del Golfo. There is no real harbour, only a very small jetty for really small fishing boats. In the older days ships with goods would moor off the coast and small ‘chalanas’, punts would be used to get the merchandise on shore. There is also a old road that leaves el Golfo from the south and goes to La Restinga, and a numbers of smaller roads that are not really good to go by car – rather walking paths. There are appr. 3500 people in the Golfo area.
    Both the tunnel and the old ‘carretera’/road are sensitive to ‘desprendimientos’/landslides. People in the valle del golfo get worried…

    1. I can understand that they are worried.
      Yes, smaller landslides can happen during a quake, but there is not a big risk of a large landslide since the slideing has already happened.
      What I would do is stay away from the tunnel, not stand below a sharp escarpment, and otherwise stay as calm as I could.

      1. Karl is right. In the US the dummy depth is 3.2 as a fixing point with the hopes that someone elses equipment will triangulate a better depth. They can get the location pretty well but not depth.

    1. That was the earthquake expected for around this time, so the increase in accumulated energy release continues.

  10. Nonsense removed. Comment withheld in order to keep the comment system working properly.

    Edit by J贸n Fr铆mann.

    1. J贸n, could you please remove this crap! This is n o t one of this “theendoftheworldiscomingsoon.com” pages here!

      1. Assuming that was directed at me it was completely un called for. Insults are so easy.

      2. I think more likely Inge was directing it to the removed post from earlier that was from a crackpot.

      3. Oops, that was a reply to Brian. I haven’t noticed Inge being insulting to anyone using reasonable arguements.

      4. Sorry all the wires got crossed, I always create chaos. I was of course refering to Carl’s last cryptic post about hair-chroming. Apologies for creating the confusion.
        I’ll bow out now and take my ball with me.

      5. No need to bow out Brian, they are a friendly lot here but do enjoy debating different ideas. 馃槈

      6. Brian, none of these three comments were for you (Inge, Lurking and Carl) – they were for some weird guy promoting the doomsday, whose comment Jon removed and so these unfortunately showed up just after your comment.

      7. Also, it looks like threading doesn’t work anymore – this was supposed to be a reply directly to Brian.

      8. No, it was directed to a post which has been removed by J贸n in the meantime (thank you, J贸n).

  11. JDR Henry it has stuck, look at what I said…

    Volcanic actualidad de Canarias (AVCAN) I commented the matem谩tico-s铆smico problem I have is as follows, so that the curve of energies liberated seismically accumulated or “staircase of the devil” follow its evolution as it goes so far, what has to be is another earthquake equal or more stronger than this 3.9 before 12 h – 14 h.

    With these data calculation this afternoon to that of the 18: 00 – 21: 00 h habra other / s near 4 or just skip to the next step of energies to 4.3-4.4 and that is a problem.

    My personal recommendation, please do not use the Roquillos tunnel and take adequate measures for strong earthquakes, removing weight of the upper shelves, boxes, pots and everything that can fall. (Henry)

  12. Is this someone talking crazy or is this indeed correct?

    OOOh mylanta! Energy accumulaation making crazy rapid spike!, on this chart the energy doubled in the last 8 hours. on this one…the total enery has spiked significantly. [link to http://www.01.ign.es] 1.54E+12 we’re now at an equivelent of 1541 tons of TNT. That is 3,082,000 pounds of TNT [link to http://www.online-unit-converter.com]

    1. Well, to put it in perspective:
      In 1815, Mount Tambora in Indonesia exploded with the force of roughly 1000 megatons of TNT.

    2. You have to remember that the earthquake scale is logarithmic and the many small earthquakes will not contribute much to the total energy. When a 3.9 comes along you get a big jump.

    3. Thing is, if you are not used to EQs and know how to interpret them you get overly exited over the wrong things like this dude did.
      I wonder if he would have crapped his pants if it had been an 6M?

    4. But …. At 20km deep and over the 5sq km area of the EQs we have a mass of rock weighing 3 tons per sq m x 20,000 m depth x 5,000,000 sq m
      Which is: 300x 10^9 tons of rock
      So we have 300 billion tons of rock overlying 1500tons of TNT.

      1. Well, it is not 1500 tons of TNT, he converted joules into TNT way wrong.

        But aside from that, you are correctly, that is one hork of a dampener ontop of it.

      2. Yeah, but that would essentially be a repeat of one of the previous ones. Let me run an update and I’ll do that. This set doesn’t have all that have happened after it was made and I wanted to bring those out with a different symbol.

        It will be added at the end of the thread when it’s done.

    > ESTA MA脩ANA.

    1. Giggled:
      > Everything points to a sustained increase ACTIVITY ALSO REFLECTED
      > TREMOR IN THE SIGNAL HAS increased by around 35% from 9:30
      > DETECTED BY THE BOARD OF THE CUCKOO non-tip of the worthy.
      > WC doing crossword puzzles.

  14. El Cuco de la Benenerita, es el Helicoptero de la Guardia Civil. Asi lo llaman ya los canarios, que lo esperan siempre que hay que hacer un rescate., y que ha sobrevolado esta ma帽ana sobre el mar de la Restinga.

    1. Giggled: (Giggle is having a larger then normal problem with canarian spanish)

      The Cuckoo of Benenerita is the Civil Guard helicopter. So call and canaries, which are still waiting to do a rescue., And has flown this morning on the sea of 鈥嬧婻estinga.

      1. Is Canarian Spanish that different from that spoken by 450 million? If so Giggle has an excuse!

      2. Karmela (my mom), wants you to know that “canarian dialect” it麓s no so difficult like the language you speake in Iceland, wonderfull and unique place in the world. Especially when she tries to pronounce the names of some volcanoes, such as the volcano Eyjafjallaj枚kull (ufff. ..). My mom calls it “Follafolla” (excuse for the expression) 馃檪 But she promisses you do it perfect in a cupple of years 馃檪

      3. Extend Our greetings to your mother, and thank her for the news that she posts.
        Well, Icelandic is hard for us all you know, most people in here are after all not Icelandic.

    2. Something like this:
      The cuckoo of Benerita, that’s what the people of the Canaries call the helicopter of the Guardia Civil, which they always await to make a rescue, has overflown the sea of La Restinga this morning.

  15. Sedimentary rocks usually have marked faulting and fissures (especially limestones) Despite the weight causing pressure which may hamper the rise of magma I am of the opinion that the magma will find and easily widen these cracks and faults.
    Large quakes I suspect are due to the further sudden fracturing of the sedimentary rocks and the gush of magma then produced would create greater tremoring as it rises rather than smaller quakes.
    I may be totally wrong about this as I am not an expert.
    I do think the key to what is happening is in the sedimentary rocks and their behaviour under attack by up-welling magma. I know there is a huge amount of slip material on the sea bed but the force caused sudden “gushes” upwards as the magma breaks through the underlying sedimentary beds will easily displace this looser material.
    Once again my thoughts are with the people. I really hope the new vents are sub marines and I too would not venture into that tunnel until the larger quakes have ceased for over 24 hours.

      1. To be fair it’s not ‘accumulated energy’, it’s expended energy. It’s an accumulated total of spent energy.

    1. I totally agree with you on this one, limestone is one hell of a weak material and very prone to fracturing. It is after all a weak stone, so why would it all of a sudden turn into the perfect magma-stopping material. No, I do not by that at all whatever Peter says.

      1. I revised my opinion last night. The sedimentary layer dips deeper under Hierro as does the crust below it. So the swarm of EQs that began in July probably ocurred within the crust and the the remains of the sedimentary layer. That this layer fractured first is no surprise – it will be the weakest layer least able to resist flexure. EQs have now ceased there , the strain having been released during the EQs. No need to propose fresh magma there.
        The deep EQs we see now may also be the result of a rebound flexure at the crust/upper mantle boundary.
        So the flexure interpretation lives on.

      2. Well, then I stand corrected. But… I do not agree on there not being fresh magma entering the system. I do believe there is new magma pushing it’s way up that is causing the quakes that we are seeing now.
        And I think that magma is making us see the birth of a new Bob, this time it is Golfv枚llurleikaeldfjalli冒Bob that is putting in an appearance.

      3. It is a rather good epiphany actually that Don de Beau (Sorry if I remembered the name wrong) had. It fits with most things I can come up with. But, I do not know how much it will actually affect what is happening, par instance, Golfv枚llurleikaeldfjalli冒Bob (New Bob of El Golfo) seems to be thriving inside the inverted “hull”.

  16. Now something so opposite….
    Iceland is incredibly quiet. This afternoon nothing. I don’t think I have seen Iceland so inactive for sometime.
    I do not wish ill to happen but this is unusual.

    1. What do you make of this Diana??

      I have a thread on GLP. There was a discussion on another thread stating that the UK has some sort of Signals starting around 10am yesterday morning. Other people mentioned this to be Harmonic and that they hadn’t seen this before.

      Here is the link to the graph from BGS: http://www.earthquakes.bgs.ac.uk/helicorder/heli_dir_vhz/FOEL_VHZ_GB_00.2011102900.gif

      On looking at Icelands whole country Earthquake map, I noticed the EQs calmed down around the same time the UK started picking up this signal.

      Does anyone know what the signal is on the BGS site??

  17. The mag 3.0 plus quakes were all at 22km yesterday, in NW Frontera, and the plus 2.0s at 16km. Latest are mag 3.0 plus at 19km and plus 2.0 at 15km.

    So if this is the large ball of magma which Carracedo identified on 29 September, then Peter, you are right that no magma has risen above the crust at 14km, yet, other than what is already closer to the surface in other magma chambers, and extruding south of El Pinar and Restinga.

    But if this heat is rising through the sedimentary layer, and has already reached the surface in El Golfo, then would it not be accurate then to expect that the magma will follow? And that there is a lot of it on its way.

    Also – if it breaches the sedimentary layer may it not split along the rifting, and cause a large seismic quake at the surface? And a subsequent eruption too to follow?

    Is this what you are suggesting, Jon?
    The logistics of evacuating people where roads are not well developed need to be addressed sooner rather than later.

    1. Alyson
      see above
      I now think the big swarm that began in July was in the crust and sedimenarty layer – see above. (I had not earlier allowed for the crust and sedimentaries being deeper under the erupted mass of Hierro.)

  18. The 1.5mag at 12km could then be the one that has allowed steam to rise through the more porous layer.

  19. According to what I saw on EMSC, it looks like the quakes are starting to rise towards the surface. Not very comforting.

      1. I stand corrected.
        But, I must say that I have never seen original Bob having that heavy a stain. Look ontop of it, that dark colour. I wonder when that eruption will start to poke its head up above the surface.

      2. Yes, I agree with the stain colour – the last rapid eye photo was taken on 26 Oct, so 5 days ago. Perhaps it’ll now soon breach the surface.

      3. I hope that it will, it will be a spectacular sight to see. I guess we will soon start to see explosions as it nears the surface and the water pressure reduces.

      4. “Golfv枚llurleikaeldfjalli冒Bob”?

        Bob, the volcano playing golf?

        Golf or gulf? Now I am confused. 馃槙

      5. Golfv枚llurleikaeldfjalli冒Bob is a word play of El Golfo, that as you know means Gulf, not Golf, but it is more fun with a golfing volcano named Bob 馃檪

      6. Yes, it works both ways, very cool!

        Bob is like a character in a Russian novel with the endless variations on his name. 馃檪

      7. Yes, but one should always remember that Bobs names are many and that all Bobs are Bob. Hallowed be the name of Bob.

        I just hope that we will be able to see Golfv枚llurleikaeldfjalli冒Bob soon.

      8. Right now he is LurkingBob (with all due apologies to our real, not lurking, Lurking.)

  20. Suppose there will not occure (m)any big quakes if the layer the magma is being pushed against contains cracks, holes, tubes or caves.
    How well is the condition of all layers known? Is it logical to expect (big) quakes at all depths?

  21. Could someone please tell me if the unusual tremors showing at ALF and some other SILS in the same area are significant.

    Thanks in advance and please excuse my lack of knowledge in this area – I am learning fast !!

  22. To all the specialized volcano amateur followers and others. I know most of you will be familiar with this website but for those who aren’t, it’s worth a read. The website has the most recent news at the top. I like it because there is local knowledge being shared.


    Also interesting is this on the first report for today…

    ” Those people wanting to follow the discussions among specialized volcano amateur followers can click on this link. http://www.jonfr.com/?p=1707 We can warmly advise it. A lot of scenarios are being discussed.”

  23. There may be large quakes if rising magma and / or rifting causes the ocean crust / break rocks to fracture.

    But large quakes are not essential if the rock is already ductile from the heat generated from the magma or the preceding rock fractures. Also 10,ooo quakes in the area already will have had some effect on the sedimentary layer and may have made it easier for magma to rise.

    One fact that is worth noting is that El Hierro has not had many quakes prior to July 2011. I accidentally downloaded all quakes from 1975 from IGN today – the total number of quakes to date was 10,697 and we have seen >10,400 quakes since 19 July 2011.

    1. So I really do not understand why some people seem to think that an eruption cannot start until big quakes have reached the surface. That scares me a little.

      1. Hekla is a wonderfull example of this, it will just bopp a couple of measly quakes around 2 – 2,5 before going off. You would probably not even feel them, and even if you did it is by then way to late.

      2. Geeeee that was fast developement back in 2000!

        So you have to run like a jet-sheep if you are up at the Dalek eating hats when it starts…..

    2. Some interesting data froma summary of EQs to time of download (30/10/2011 18:14):

      All El Hierro from 31/01/1975 to 18/07/2011 99
      All El Hierro from 19/07/2011 to 30/10/2011 10,598

      For the timespan 19/07/2011 to 30/10/2011:

      NW and W Frontera 4,273
      SW and S Frontera 5,772
      Other Frontera 99
      All El Pinar 447
      Valverde 7

      I find it very hard to believe that the recent activity was caused solely by settling of the volcano following the collapse of the NW flank of El Hierro.

      1. “I find it very hard to believe that the recent activity was caused solely by settling of the volcano following the collapse of the NW flank of El Hierro.”
        I must have missed something here.
        What collaps of NW flank of El Hierro? There has as far as I know not been any flank collaps in historical time. So therefore any flank collaps can not have any influence on the EQs. Period.

        The current activity is solely induced from magma pushing upwards and hitting the barrier of the Moho up to the “dead zone”. The shape of the quake pattern comes from when the magma is flattened out against the Moho.

  24. For quite some time we have seen the stain of Bob spreading all around the Island of El Hierro. But what we have not done is to name a stain like that. It should have it’s own name after all. I propose Broti冒bleiuafBob for obvious reasons… 馃檪

    1. Oh, Giggle doesn’t like this, the best it came up with is “diaper broken by Bob”. So I assume you are referring to the not yet potty trained Bob…

      1. Yes, since we are refering to it as Baby Bob, I thought that an apt name would be… The broken diaper of Bob 馃檪
        For so many reasons a good name I think.

      2. I’ve now got it as ‘violation of the daiper’ Like it. Better than broken. 馃檪

    2. Sorry Carl. When I put that in giggle it tells me it’s Rumanian. Even when I put it into Icelandic , it gives me ‘broken’ but doesn’t translate the rest. I am putting 2 and 2 together however ……..:)

    1. Frysk, there is not second tremor at La Gomera, what you should know is that the scale of the El Hierro measurment device is scaled back ten times compared to La Gomera, so something that appears on that plot is actually looking ten times bigger than at El Hierro. So what looks massive on La Gomera is the same quake that happened at El Hierro. Do you understand this?

      1. I wasn’t referring to the spikes caused by the earthquakes on El Hierro, but the tremor picked up at La Gomera from El Hierro. It鈥檚 like a combination of two signals?

      2. Nope, it is one signal. Or more to the point, it is a combination of signals emaneting from El Hierro.
        And to be even more precise, there are also the intermingled background noise of all of the active sources of ground tremor. But I guess you meant the possibility of there being yet another source of tremoring that is significant and not being located at El Hierro. The anser to that is a reverberating and emphatic no.

      3. Nope, that’s not what I meant. But Brian Smith below describes exactly what i tried to tell. Thank you Carl.

    2. Shows up better on CHIE I believe

      30/10/2011 18:57:33 27.7830 -18.0471 21 Sentido 3.2

      there’s another spike just after the hour which follows the 3.2 … … … I think. 馃檪

    3. Actually most of the other seismograph traces seem to have a sine wave pattern imposed on them, like a continuous organ note. I find it difficult to believe it’s real but it does appear on quite a few of them. If it is real the ground is singing to itself.

      1. That would be really special. The last eruption on Sao Miguel was in 1713. These volcanoes have a lot a of potential to inflict great damage to the surrounding area. I guess Fogo would be the ‘best’ volcano, if one of Sao Miguel’s volcanoes had to erupt. All the other volcanic systems are inhabited these days, especially Furnas and Sete Cidades, whose calderas both host some of the cutest little villages I’ve ever seen. Plus Furnas has a very large and special botanic garden. It would be a great loss if an eruption would someday cause damage there.

  25. IGN pages don’t seem to have updated for over an hour now. Too many people viewing them perhaps?

    1. Nusiance isn’t it? I keep hitting the refresh button

      … maybe everything is hunky dory and gone back to normal.. 馃槈

      1. Haha! Glad I am not the only impatient one. I thought I would give it an hour but now it will soon be two hours. Sooo frustrating!

      2. Few more EQs appeared on the list now – up to 19:57 – but nowt on the tremor charts

      3. Thanks for telling me that as i was only watching the tremor charts. I was begining to wonder what had happened. 馃槷

  26. Forgive me for harping on about it but this continuous sine wave at 0.17Hz that I pointed out on many of the other seismographs (but presumably drowned out on CHIE) is true harmonic tremor isn’t it? From the movement of magma. It seems to be the strogest on the La Gomera station.

      1. Carl, forgive me but I don’t know how you can say that. We have here a waveform that started smoothly over about half an hour yesterday afternoon and has been going continuously ever since on four stations records. It has the same period range and almost identical appearance to other examples I have found on the web.
        If it’s earth movement it’s amazingly stready and started for the first time in weeks just yesterday.

      2. Sorry to kill of your theory.
        It is continues, but with a couple of increases and decreases. But it was there a month ago before the eruption started, it goes straight through, and it will be there next year. Background noise. If you look closely you can see how it slowly meanders up and down between 1/3Hz to about 1/5Hz.

        Here it is a month ago.

  27. It looks real to my nonexpert eye- well above instrument noise. Even seen on Fuerteventura.
    On the Gomera trace that last EQ did not interrupt the sequence I can see the wave continuing. That suggest to me its not associated with the EQs. So I think its something to do with Bob.

    1. Well it鈥檚 there, and perhaps Carl is right, tectonics. Maybe just a coincidence it starts to show up more clearly from yesterday? (my English s*cks, please forgive me)

  28. This is for Sissel – you were asking about the Ramon Margalef. Up to yesterday it could be tracked at http://www.marinetraffic.com/ais/ by entering the name into the “Go To Vessel” box but no longer it seems. The same was true at http://www.localizatodo.com/mapa/ but the name is no longer recognised in the “Locate a ship” search, up to Friday it was there including a photo of the ship. The Ramon Margalef does show up in the “Route done” search for days up to Saturday 29th (you can see where it has been round the island and at what times), while the “Last position” search gives a time of 09:06:53 on Saturday 29th. Not sure why it disappeared from live tracking on Friday and altogether on Saturday, seems a bit strange.

    1. John, do you think it could be perhaps something so simple that it is in some port and not moving? As far as I know, ships only need to measure their position with the AIS (Automatic Identification System) and transmit it, when they are actually sailing. So if Ramon Margalef is standing still in some port, refueling or whatever, perhaps its AIS is down, not transmitting anything and so these websites show it “out of range”.

    2. @ John Hayes
      The link beneath still works. But the ship cannot be seen where it is right now.
      The area is not covered by the system.

      reposting from 19:21:
      The vessel Ramon Margalef can be followed at http://www.marinetraffic.com/ais/shipdetails.aspx?MMSI=224511000
      but unfortunately not all areas are being covered. Seems like the sea west of El Hierro is not covered, te vessel is 鈥淣ot Currently in Range鈥. The last reported port it visited has been Puerto de la Estaca, not far from Valverde.

      1. Hi Sissel, you could be correct about it being out of range (though the grids seem to suggest it would have to be a long way west to be out of range), but it does not explain why the last known position is in the prohibited area. Not trying to make a big thing out of it, just curious.

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