El Hierro – Day 7

Photograph by Cestomano. The lighthouse of the Orchillas was once known as the end of the world. Under this lighthouse is where the new magma chamber is forming.

This will mainly be a short update. Not much new has happened during the last few days, I will just try to explain why.

What we are seeing now is the formation of a new part of the magma chamber(s) under the island of El Hierro. The progression of earthquakes that we have seen moving roughly from Tanganasoga volcano towards the WSW is magma following a weak seam between two rock layers in the crust. This is creating a rather low, but wide, layer filled with magma. You can think of it as a cake, where the magma is a layer of custard cream between two pieces of bread.

Initially I thought that this layer would not be able to take a lot of magma before the magma would break through into the two older layered magma chambers that were created before the last eruption. My line of thinking was that as soon as that happened magma would move up into the old feeder channel leading towards the volcanic vent known as Bob south of La Restinga.

Image by IGN. The darkblue and read area is where a new magma chamber has started to form like a stacked layer in a cake.

Instead a large quantity of magma has gushed into this new formative magma chamber, which is continuing to grow. There is a rule in fluid dynamics that state that as a bladder (balloon) grows the rate of growth will decrease as the volume increases. This is why it takes more and more magma to keep the pressure at a constant level during the expansion. This is why we see fewer earthquakes as the size grows. It takes a larger amount of magma going into the system to create the pressure for the earthquakes to happen. We will also soon see that the rate of rapid uplift will be decreasing. Do not take this as a sign of the risk for an eruption decreasing. It is quite the opposite. Why? The rate of magma arriving is still constant, so, in due time it will break through.

Magma seems to have entered into the old feeder channel to Bob, how far up though is anyone’s guess. But, it seems to have stopped flowing upwards now, probably due to the opening being plugged up.

Instead we are now seeing a small amount of earthquakes entering into the zone between 16 and 8 kilometers from the surface. What is most likely is that we will see more of them during the next 48 hours; with a bit of luck we will be able to pinpoint the formation of an earthquake stack. That would be good since that could point towards a general area where there could be an eruption. Currently that is pointing towards the western area of the island, but that might change rapidly.

Image by IGN. A few earthquakes have started in the 16 to 8km depth range.

When the magma enters the region 8 kilometers and above the earthquakes will most likely stop, or be few and far apart. The reason for this is that there is a layer of old sediment there. Then there will be a brief flurry of earthquakes as the magma breaks through to the surface, unless it finds an old lava-tube, then it would be a quiet onset of eruption. The eruption would be of basalt or basanite, so it would most likely be a quiet effusive eruption. In the beginning it could be more vigorous due to gas pressure release.

I would still not rule out that the eruption will happen somewhere along the old feeder channel that lead out to Bob. If that happens I believe the eruption to happen somewhere closer to land than during the last eruption. It could also happen on land.

During this second phase of the eruptive cycle the level of information given out has been much improved. IGN is now giving out real GPS data instead of cumulative data. That is a huge improvement. Also Pevolca has started to write reports that are filled with technical details that helps a lot, and removes any chance of people accusing them of hiding data. If IGN and Pevolca keep up with this new openness they will find that people will be much happier. So, from us a big thanks for this new approach.

I would also like to point out to the political establishment of El Hierro that the last eruption will in the end be a big boon for the Island. Before nobody pretty much knew that El Hierro existed. Now many do. And that should in the end raise the number of visitors, especially from the rather large cadre of volcano aficionados. So, instead of trying to hide your volcano, flaunt it a bit. Be proud of it, and people will come to watch your beautiful island.

CARL

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980 thoughts on “El Hierro – Day 7

    • Luisport, could you just sum up in English what this is?
      We do like to be able to understand you know :)

    • This lady talk to a friend on phone abd he tells that now is forbiden to go to La Dehesa and El Julan…

      • Okay, then it seems like they are going into red condition for that part of the island.

        I guess we will have the official announcement of an exclusion zone later today from Pevolca. A sensible decission. Most likely they have detected heightened gas emissions, or have tremor data pointing towards magma moving up under there. We ourselves noticed that the earthquakes have started above 16km.

        • I am deadly curious about what has all of a sudden happened at IGN and Pevolca. This is not like it used to be. Either they have hired a PR-genius, or there is someone from Iceland there. Feels all of a sudden more like IMO, compared how it was before.
          I like this new style, they have anyhow grown a pair.

          • I think when Bob first happened they had never had to deal with something on that scale: having an emergency and a huge amount of outside interest clamouring for information. They were playing catch-up all the time and stress leads to irritability and so on. They have now had a respite period and been able to re-evaluate what information they have and how to give it out. Result: they are calmer and feel more ‘in-charge’ and therefore able to share their information quickly and we are happier so not bombarding them with criticism! Everyone calmer! :-)

          • You are probably right, and I also suspect they have been in contact with collegues at (I would guess) IMO and INGV.
            Anyhoo, much nicer now.

          • I was going to say that maybe they realized that the Icelandic model of handling volcanoes has its advantages… but you beat me to it.

  1. I agree wholeheartedly with you Carl. El Hierro is now famous because of it’s Volcano…….It would be better for the Islanders not to have a Volcano at all, but as it has one…. Make the most of it. Lots of people in the world love to see Volcanoes. Look at Hawaii and Iceland!
    Little El Hierro is now a “Must see” on many people’s holiday list because of the volcano!I
    I would also like to thank everyone concerned for the information you are publishing. It is good to be able to follow El Hierro;s Story. I would also ask “Could we have the webcams back please”?
    Maybe this is planned when it is more clear which area is likely to be affected.

    in passing! I have lost all the Mila webcams in Iceland this morning. It could be because I installed the latest Flash player yesterday. Is anyone else having problems please?

    http://eldgos.mila.is/hekla/

    • There has been a lot of problems with the latest version of the flash player. Especially if you are using Firefox there would be problems. I works fairly well with IE and Chrome.

      I think they will put the cams back up when they know where to point them. Problem right now is that they would likely just throw money away if they install them since they would most likely be at the wrong spot.

    • I have lost them all too Diana and did not install the latest Flash player! So I guess it is them rather than us that are having problems!

    • Yes Diana, same here, no pictures and nothing new installed. It must be them that have the problem.

    • I do not get anything from Mila but checking Yellowstone Old Faithful live cam, which is flash, I get the feed. I have IE10 on Windows 8.

      • Thank you all for your replies. Happy now that it isn’t me! :D
        @ Carl. Yes I agree it is best to wait and see before starting live webcams off again. …..But I still miss watching the sea from La Restinga.

        • Me too…
          I am hoping that it will be out in the sea, but a taaad closer to land so we get ashy water gushing up now and then.

  2. And now off to the city for a cup of coffee.
    Have a nice afternoon of volcano-spotting.

  3. ‎01/07/2012 08:45:39 27.6691 -18.1289 23 3.1 mbLg W EL PINAR.IHI
    3 minutes ago · Like · 1

  4. BBGN, I know things are hotting up, but I am tired, will keep an eye open again when most of you go beddy by’s

  5. Looks like a large one at 11:12.

    he vuelto al fb ahora 11,12 grandote, desde las entrañas..

    I returned to the fb now 11,12 big, from the bowels… (Translated by Bing)

    about a minute ago · Like.

    Fanny Luisana Tula Reboso Fuerte en los llanillos frontera 11:12 uff

    Strong in llanillos border 11: 12 uff (Translated by Bing)

    a few seconds ago · Like

    http://www.facebook.com AVCAN

  6. ‎01/07/2012 08:50:30 43.1721 -13.8565 4.1 mb ATLÁNTICO… no pinta nada pero curioso

    ‎01/07/2012 08: 50: 30 43.1721 – 13.8565 4.1 mb Atlantic… does not look anything but funny (Translated

    http://www.facebook.com Avcan

  7. Magnitude ML 4.2 Region CANARY ISLANDS, SPAIN REGION Date time

    2012-07-01 10:11:40.9 UTC Location 27.66 N ; 18.13 W Depth 22 km

    emcs.

    • just checked before turning in, that is a wopper, but further out in the sea and deep, they must be on tender hooks on the island, it is one thing to be rational, but when the ground shakes under your feet it is different

    • That earthquake was really disgusting…
      Normally you have a sharp transient in the beginning followed by another sharp transient. Those are the S/P waves. They ramp up almost instantenously to max values due to the rock fracturing at high speed. In this case we have almost no discernible S/P wave transients. Just a tinsy winsy starter quake.
      Instead we have a “slow” and massive build up. Almost all of the quake is made by magma gushing. You can see a tinsy little M2 quake starting it, and then the magma makes the rest as it roares in and in turn rips apart the bedrock as it goes on.
      The amount of magma moving in that quake is ridiculous.
      During the day several cubic kilometers have moved, and this one alone is probably around 1 cubic…
      Problem I am having right now is to understand where all this magma is coming from. The rather weak Canarian hotspot is not supposed to be able to do this.

      Also, thank Gódabunga that this is a flat horisontal intrusion. If this had been a top to bottom fissure á la Laki El Hierro would have been in trouble. For once all those layers of various material is good news.

      Caveat: The figures above is my own ballpark calculations, I have not had time to really calculate it.

    • judith
      VERY interesting article. On a similar note prof. bill maguire of university college london has done some work on the possibility of a las palmas slip and the possible effects. don’t know where to find the info. though.
      been following the site for about a year now – learnt a lot from people whose knowlege and expertise i have come to admire and respect.

      • Commenter Lisa in here has written quite a lot about that article of Maguire.
        You can find here writings in her comments on the previous post. Really good criticism on his paper.

  8. Update 01/07 – 10:42 UTC
    – A new strong earthquake was felt by the population at 10:13 UTC. Based on the graph it must be certainly a M+3. IGN just reported a Magnitude of 4.2 at a depth of 22 km. Epicenter in the Las Calmas Sea.

    Update 01/07 – 09:52 UTC
    – Yesterday evening we still wrote that the earthquakes were concentrating below land and at the western tip of the island. During the night and certainly the last several hours, the AVCAN map below shows clearly that seismicity has moved again into the Las Calmas sea
    – IGN has listed 50 earthquakes so far today (a little less than yesterday at the same time)

    http://earthquake-report.com/2011/09/25/el-hierro-canary-islands-spain-volcanic-risk-alert-increased-to-yellow/

  9. EMSC gives a 4,2 that has probablu been downgraded fro IGN:
    2012-07-01 10:11:40.9 2hr 06min ago
    27.66 N 18.13 W 22 4.2 CANARY ISLANDS, SPAIN REGION

  10. Nevado del Ruiz: More than 2000 people have been evacuated from the nearby areas.
    Meanwhile, Etna seems to get ready for another show. Strombolian activity detected on the graphs.
    We are witnessing to build ups for eruptions both in Spain and in Italy, exactly on the day of the soccer final. Synchronicity? El Hierro x Etna? :)

    • LOL!!! Now who will get to celebrate with fireworks? Or maybe Hephaistos, the limping God, does not like football/soccer?

      • So he kept Hera in the chair until his drunk half brother intervened. Interesting, since Hera was not his mother. I can see Dionysus, pickled to the gills, sluring out “Hey man! That’s no way to treat your mom!” and then the obligatory tussle as they fall off the porch and spooking the dogs from underneath.

        Yeah… Greek Gods were definitely a dysfunctional family.

        • Not to forget…
          Zeus disregarded the normal way to get a daughter. He grew a headache, split his forehead with a hammer, and out jumped Pallas Athena.

          • A metaphor that says “girls are a headache”. Quite the philosophers, those ancient Greeks.

            :verystraightface:

          • The comic magasine MAD had a strip in the 70s with fake Shakespeare quotes.
            “Women Horatio,
            is an itch that men happily scratch”.

            In Swedish:
            Kvinnan Horatio, det är klåda vi män gladeligen kliar.

  11. Good afternoon all
    As you may guess, the average depth of quakes has increased again based on today’s activity – to 20.3km. Average strength has also increased to 2.3 mag.

    I’m curious about the .5 – 2Hz banding though shown on the chart for EOSO and others – more intense than usual. Something must be causing this – is Bob in fact still venting ?

    http://www.ign.es/ign/head/volcaSenalesAnterioresDia.do?nombreFichero=EOSO_2012-07-01&ver=s&estacion=EOSO&Anio=2012&Mes=07&Dia=01&tipo=2

  12. Tremor at Etna is on the rise again. It is slightly high than the 2 spikes of a couple of days ago.

  13. Avcan Latest Comments.

    ,,NOTE SPECIAL AVCAN – EVOLUTION OF THE SWARM EARTHQUAKE-VOLCANIC ISLAND OF HIERRO – 19 – 07/01/2012.In the map of seismicity of updated today, we have 81 earthquakes and form ball earthquake-volcanic swarm follows there, down to the SW of yesterday and the South with regard to tomorrow is, in fact the two strong earthquakes that are further to the South, and seems deeper are passed as the again, as in the first swarma rarity, or the model of density of the island of the IGN is not quite correct at that depth or the island is really a rarity there down, since it is not normal that the magma moves down. The latter are aligned mostly in NNW-SSE direction. (Henry),,

    http://www.avcan.org/mapas/AVCAN3507.jpg?d=1341151369

  14. Part of the German blog updated today.

    translated.

    ,,and can only watch. Observe and draw his conclusions. We have experience from last year. The further development will show whether the volcano now again so behaves. It is the force of nature which do not look in the maps can be and can provide surprises.It is to see no end of quakes. Like ocean waves, they rustle regularly at short intervals used. A ML3, 6 Quake (IGN graphic above) yesterday evening at 21.43 P.m. was be felt also in the North. This tremor had its starting point in 20 km depth off the coast at the southern tip.This morning, I observed a military machine, a reconnaissance aircraft over the island the first time. It probably comes from the military base in Gran Canaria and is concerned with thermal screen shots and information measures on the southern part around the center of the quake.Not spectacular, but to think! After weeks for the first time a tremor of ML2, 1 at La restinga in 19 km. While focus all on the Western tip of the island, Eldiscreto is back with a sigh. My theory has always came from the revival of Eldiscreto. To read the articles in recent weeks. All activities under the tip stuck in the same depth, between 17 and 21 km. The above the magma chamber surfaces are likely to massively and not to penetrate. When the magma rises, it will search the lowest resistance and these are the old Känäle to the Eldiscreto. We will see it.,,

    http://elhierro1.blogspot.de/

    • Thanks that was really nice. I just woke up, popped on the kettle and jumped on the comp for a quick catch up. What a nice way to start the day, watching the beauty of El Hierro.

    • Thanks Judith for that – it is sad to see La Restinga affected so badly by Bob though. It does look such a nice place to visit. It looked deserted – perhaps this was taken during the evacuation ?

      • Thank you Judith. It is a beautiful but rather sad clip. However it’s good to know that after the eruptions the sea will return to being able to support life again. That blow hole which must be a volcanic tube is amazing. Having watched the cams so much last year I feel I know La Restinga well but it is interesting to see the town from a different perspective. These clips of El Hierro certainly make me want to go visit. I image I could have a very tranquil holiday there.

        • OOops Not Image…. Imagine!
          Oh! Carl that is a lovely picture of the lighthouse too

  15. Brought forward for Peter from the previous thread.

    Ref: Peter Cobbold (July 1, 2012 at 00:11)

    I think there might be three old vertical structures in that paper – the two in yellow and the dark blue one. I’d argue that the dark blue was oldest as it goes deep and covers wide circle ( caldera?) seen at 30 and particularly 15km deep, centred on the oldest part of Hierro . The eastern yellow column perhaps erupted through it post-collapse?
    So the cone shape of the swarm might reflect it occupying a vertical space that has not previously been a ‘conduit’. Its difficult to tell from IGN eq maps if the swarms at around 15km depth is constrained by the dark blue western edge to the ‘caldera’. Do you have eq horizontal at that depth to superimpose on their fig 3 panel h?

    Provided I understand what your asking…

    15 km panel with 14 to 16 km deep quakes, pre 11 June 2012

    30 km panel with quakes deeper than 16 km, pre 11 June 2012

    An observation…. the El Golfo quakes in the 15 km panel seem to be partially circling something. But it could just be wishful thinking on my part.

    • @ Geolurking, thank you. I cant detect any relationship between eqs and the microseismic structures.
      Intruiging tho’ that the false colours around Restinga rather resemble the stack at Sabinosa- pity the sea got in the way of the measurements there. Maybe theres another satck under Bob?

  16. Good post as always Carl.

    This El Hierro stuff is keeping us all tense. I’m glad i’ve been able to watch this taking place, as this might be one of the most exciting (if it happens) eruptions for decades.

    Also, Tokachi volcano in Japan is showing signs of life with Incandesance being observed at one of its craters. The alert is still normal.

  17. Etna looks like it could be smoking now.

    Of course it could also be just clouds but to me looks more like smoke.

  18. Julius Sebastian AVCAN As said, it appears that for the past earthquakes, it appears that moves slowly to the area of Sea of Calm but pointing to the Restinga, short, the initial intrusion would start below the zone of the Gulf, to ascend would go through it occidiental island at its center, would bend to the lighthouse area below Orchilla steps forward into the sea of Calm and would proceed to turn into the area of the Restinga. All a very winding road to the lava … http://www.facebook.com/pages/Actualidad-Volc%C3%A1nica-de-Canarias-AVCAN/163883668446

    • It certainly is a tortuous route and this adds to the tenseness of watching. I cannot say often enough how my thoughts and best wishes go out to the Islanders.

  19. Yes, No doubt about it now, Etna is erupting again but no lava visible yet. Wonder if it will be just smoke again?

  20. Now a shallower quake in El Hierro, 16km
    1153224 01/07/2012 13:36:47 27.6179 -18.1216 16 1.6 mbLg SW EL PINAR.IHI

  21. Pingback: Hot times in Hokkaido | Zoopraxiscope

  22. Volta Joke According to this report, means that little or no evidence of gas detected at superficie.Es deformation, which worries me … I liked that the Pevolca has referred in his report on the maxim ” have felt “in the case of the earthquake finally assessed in 4 of magnitude, this mañana.Ha been a gesture of understanding in which people communicate, think, who has felt an earthquake of greater magnitude … On a possible eruption I left some questions in the pipeline, perhaps alguin who is knowledgeable in this forum, I can clarify … The next thing: back then, when that eruption was latent in the Sea of calms, in front of Naos, the authorities explained: “There is an area / radius of 1.5 to 2km arround the point of eruption, which may eventually fall piroclastos.Los ash fall mainly to the direction where the wind takes me … and now .. question in this case, if a rash eventually performed, and on the ground, would it be like? To cerrer meant, I am aware that the prevailing winds in this zonna where the epicenters now they are towards the south, was the sea, and I imagine that not one of the largest RISKS …. http://www.facebook.com/pages/Actualidad-Volc%C3%A1nica-de-Canarias-AVCAN/163883668446

    • Interestingly… the SO2/H2S release may be an unreliable indication of pending activity.

      …Western Canary Island lavas were sulphur undersaturated…

      …Consequently, large-degree partial melting may lead to complete sulphur removal in the mantle source and an S-undersaturated melt rich in the HSE (c.f., komatiites), whereas low-degree partial melts (e.g., western Canary Island parental melts) will have variable proportions of HSE resulting from incomplete break-down of sulphide and HSE-rich mantle phases.

      From “Evidence for distinct proportions of subducted oceanic crust and lithosphere in HIMU-type mantle beneath El Hierro and La Palma, Canary Islands” Day et al

      • I think that paper might be antiquated.
        The new magma out at Bob was not really that low on SO2. And this new magma comes from whoever knows.

          • Yepp, before the last little hooplah in El Hierro.
            Funny, when I checked the measurments for today, the SO2 was higher in Gomera than in El Hierro… :) And not a little bit… 150 percent above.

  23. This is the sound of El Hierro this morning, converted from the seismic trace on the link below, by GLP user Tardis Blue, using the link below.

      • That’s very cool! Hauntingly beautiful. . . Wish there was a site to pull up with just the continuous audio—just to keep open in the back ground as going about daily business or chores. Would instantly know what was going on just by sound! Imagine your house filled with this calming ‘music’. Oh, oh—imagine at bedtime going to sleep with nature’s sound of El Hierro!!!! IGN should definitely add a SOUND button! They could begin a trend, ‘ Be lulled to sleep with Spain’s El Hierro’s sounds of nature!’ Or might it say sounds of Elvis? Thanks.

    • Just great. Very soothing. Where can one get it ? Also it sort of “speak” to me because it is like fluid movements. How did they made it ?

      • He took it off the links I posted at 17:01 . I have no idea how he did it but my hairs on my arms were standing up listening to it . For some reason it really unnerved me it was as if Bob was talking to us or the earth.

        • Not sure…. but if you are talking about audio, there was a post a while back where someone had taken a quake plot and run it through an audio synthesis program that generated audio based on the content of the picture.

          The problem was that it was fully artificial and the program would make sound based on whatever it was… the Mona Lisa would produce and audio track just like a CHIE spectral plot would produce an audio track.

          While quite pretty, it is of little use other than marveling at what it came up with. In other words, entertainment value only.

          Now… another “thing” that can be done, is to take the raw waveform data (such as you can get with the seed files via IRIS) and pass them through and audio system. If you have an extremely good audio system with no low end filtering… you can replicate the feel of the tremor, because you definitely are not going to hear it. It’s below human perception.

          Programs like SeisGram2K can transpose the frequencies up into the range of human hearing, and I have listened to a few quakes like that. It’s more than entertaining… it’s down right eerie. You can sense the arrival of the wave as it plays back and you can hear what sounds like a spatial echo as it bounces off of nearby subsurface structure.

          With El Hierro… none of the waveforms are in the IRIS data fees. (I looked). I think there is one station over on Gran Canary that is, but unless it’s a strong quake, you aren’t going to hear anything.

          IF raw waveforms were available for El Hierro, there would be all sorts of immersive fun we could have.. but it’s not there. Sorry.

    • that is unreal, maybe it is this sound that animals hear and know how to interpret, humans have a lot to learn yet

  24. Carl – what’s that entry below Newby’s post of 16.30 ?? :
    ‘Pingback: Hot times in Hokkaido | Zoopraxiscope’
    It links to an external site – dodgy ?

    • There seems to be a problem at Mila, so they are most likely going to fix them tomorrow monday.

    • Hi Dean! They’ve been out all day – but we don’t know why. Maybe some technical problem.

    • Well I can’t think of a more deserving city.

      Okay, I take that back, there are probably several dozen good people who still live there. I hope they stay safe.

    • BTW… imagine what it’s gonna be like down town. A guy in front of me was walking along from the train station and was passing in front of a gap between two buildings…. the wind knocked him over. Perfectly calm on either side of the gap, but 40 mph gusts in the gap.

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