Posted on by Jón Frímann

Special report: New magma intrusion into El Hierro volcano, Canary Islands, Spain

Few days ago a new magma intrusion did start in El Hierro volcano, Canary Islands, Spain. But this means that the pressure is increasing inside El Hierro current magma still. The new magma is going the same path as before, and is forming a new sill north-west part of El Hierro volcano. It seems that this magma has not yet encountered the magma that is already inside El Hierro volcano. What happens when the new magma encounters the slightly older magma is a open question. But I am sure what happens is going to be interesting and is going to create a new eruption vent in my opinion.


The new magma intrusion in El Hierro. It is not yet in contact with the existing magma in El Hierro. It is hard to know exactly what happens when the new magma gets into contact with the magma that is already in El Hierro. Copyright of this picture belongs to Instituto Geográfico Nacional.

What is really interesting about this new magma is that this seems to be a new intrusion from a new conduct below El Hierro. This conduct does not appear in the earthquakes that started in July 2011 to today. There is a great risk that more new conducts are going to open up under El Hierro in this same manner. But this means that new magma can start to flow into El Hierro at new point under El Hierro. But that is always marked by a increase in earthquake activity where a new magma intrusion starts in El Hierro. This new magma intrusion into El Hierro appears to be rather small at the moment. But it is most likely going to grow over the next few weeks.


Current harmonic tremor levels in El Hierro volcano. Given by the current harmonic tremor level this eruption remains small. But the harmonic tremor is poorly to not being detected on nearby Canary Islands. The spike in the tremor plot is a earthquake. Copyright of this picture belongs to Instituto Geográfico Nacional.

It seems that IGN did rescale the tremor plot in the early beginning of the eruption. Making me draw false conclusions on what was going on in El Hierro. But it seems that the eruption is stable and has been from the beginning. But so far this is a small eruption, based on the tremor data. I say it is small because the harmonic tremor is not detected about ~60 km away from El Hierro. As a example in the eruption of Grímsfjall volcano, the harmonic tremor was detected clearly up to ~200 km away from the eruption. But the harmonic tremor signals how much magma is moving inside a volcano up to the surface. But not how explosive the eruption is. But explosions can and are detected on seismometers when a eruption goes explosive.

If anything major happens in El Hierro. I am going to update this blog post.

568 Replies to “Special report: New magma intrusion into El Hierro volcano, Canary Islands, Spain”

  1. I must confess that I fear Peter Cobbold’s take on this.
    Maybe because I am relating his reasoning to the “halo of ductile rocks” explained by de Silva over EB. But I must have understood both wrong. So I hope. 🙂

    1. We haven’t yet seen a halo pattern in the EQs. If it is there, it is hidden; or, there is more to come.

      The pattern is interesting. Look at the cummulative pattern of the 10,356 EQs to date on: http://www.avcan.org/?m=Animacion This shows the surface distribution of the EQs (note: if there is more than one in a location, it shows the most recent, not the shallowest).

    2. Looked more into “halo of ductile rocks” and, while doing so, found:

      “The sub-surface plumbing of many restless volcanoes consists of a pressurized network of near-vertical magma-filled cracks, known to volcanologists as dikes. Heat radiating from these molten dikes produces an envelope of thermally softened crustal rock that behaves in a manner much like toffee, that is, slow deformation of the rocks is ductile (flowing) but fast deformation causes brittle fracture.

      Within this halo of ductile rock, hypersaline brine and caustic gas, leaking from crystallizing dikes, accumulate in lens-like reservoirs at pressures equivalent to the weight of overlying rock.

      Sudden, high deformation events, such as those associated with an earthquake, a major landslide, or the intrusion of a new dike, can cause these normally ductile gas reservoirs to fracture leading to rapid expulsion of hot, caustic fluid to the surface. (source: http://www.gly.bris.ac.uk/admissions/PhDprojects/eruptions.html I am still looking for their sources).

      This fits the pattern of EQs in the two days before Bob started to erupt (check out avcan.org).

    3. It was Lurking’s plots that convinced me that EQs trended deeper with time, and rose in magnitude with depth. That needs explaining. And it does not fit with magma forcing its way up from depth to cause the EQs. In that scenario EQs would start deep and progress shallow with time. ( I ignore Bob- a sideshow to the main events *). There is evidence for tectonic processes contributing to Canary volcanism, and these might be more important than plume-driven processes. I have failed to find a review that is not hidden behind pay walls, but this snippet from Mantle.plumes.org is interesting:
      http://www.mantleplumes.org/Canary.html
      quote: “”A unifying model: This suggests the origin of the magmas is a mantle anomaly.Tensional stages generate fractures that serve as conduits for magma liberation and compressive stages produce uplift of islands manifest as sets of flower structures. This model explains the magmatic and tectonic relationships from the Upper Cretaceous to the Miocene in both areas (Anguita & Hernan, 2000). The objections to this model are that there are still several open questions on the geology of the Canary Islands and Atlas Mountains. It is thus necessary to explain more about the space-time magmatic and tectonic relationships in each island, in the archipelago zone, and in the Atlas chain from the Miocene to present.””

      I suspect the distribution of EQs in time is lending support to the concept of “Tensional stages generate fractures that serve as conduits for magma liberation …..”

      * Why? A tiny number of shallow EQs contributed to Bob. and I remain convinced he is a sideshow:
      1. Volume erupted is tiny compared with volume of deformation (IGN stated 50million cubic metres)
      2. The tremor has not followed the jacuzzi’s behaviour. When the jacuzzi was oscillating tremor was constant.
      3 Bob has not resulted in deflation.
      4 Bob is almost silent now but the tremor continues.

      1. I am not sure that we have a single event here. I suspect that we have a combination of two or more:

        1) tensional fracturing and possibly rifting;
        2) background movement of the plates contributing to 1);
        3) magma rising from a plume or hot spot; and,
        4) ductile rock.

        I think Bob does need explaining, even if he is not the main event. Fracturing of a gas reservoir occurring part of one of the above processes is a possible explanation. The reservoir was somewhere under the main “blob” of EQs; it fractured; and, the gas escaped via a weakness in the rock or via an old lava tube to produce Bob – a large gas emission with a small amount of rock debris and possibly lava.

        But as the tremor is contunuing and is large enough to show on the neighbouring islands stations, Bob is far from being the whole story.

      2. The bulk of the tremoring activity seems to be from the rapidly inflating Theistareykjarbunga volcano. She seems to have had a rather hefty period of harmonic tremoring.
        It even saturated two stations completely.

    4. Sorry, but what is a “glitch” in this connection? I have a little idea, but what does it mean here?

      1. A glitch is a short-lived fault in a system. It is often used to describe a transient fault that corrects itself, and is therefore difficult to troubleshoot. The term is particularly common in the computing and electronics industries, and in circuit bending, as well as among players of video games, although it is applied to all types of systems including human organizations and nature.
        The term derives from the German glitschig, meaning ‘slippery’, possibly entering English through the Yiddish term glitsh.

        Source: http://en.wikipedia.org/wiki/Glitch

  4. According to Diario el Hierro, the poeple of Frontera are not happy with the lack of explanations of whats going on, the tremors seem to have relocated and increased in frequency and magnitude (3.1 this morning), the twice daily press conferences have stopped and now theres nothing comming out the responsible organisations. They don’t know if they can swim, fishing, or eat fish from other areas. Nor do they know whether or not events will follow the same pattern as in La Restinga.

    http://www.diarioelhierro.es/t26496/pag02.asp?BD=ESPECIAL CRISIS SÍSMICA&id_registro=140530&Id=26496&BDi=INICIO&nt=p&Md=

    1. Hopefully the authorities do not think that the worst has gone already…

      If you have followed this blog, there are still three viable options left how this is going to continue:
      #1. This was it, and the activity dies over time.
      #2. The activity continues more or less the same for the time being. On the longer term this can lead to option #1 or #3.
      #3. The real (very likely effusive) eruption is coming. When, nobody knows really. We just have to wait and see.

      The option #2 is definitely the worst for the locals, as uncertainty about the very basics of everyday life will persist for longer time.

    2. Seems like the authoroties do not feel much responsibility towards the locals. The least they could do is giving information – they know what is in the water, and I do not think you need to be an expert to say that you schould not swim in it, drink it or eat the fish or other sea products at this moment.
      About seismicity – they do not know what will happen, and of course do not want to scare people – but in my opinion: saying nothing is the most scaring they can do.
      Shutting your eyes for the problem does not mean it is not there.

    3. Silence, or what appears to be false reassurance, is scary and generates rumours. It must be worse when you have had a volcanic eruption near by, a green stain and the ground is literally shaking beneath your feet. Unfortunately the situation is wait to see what happens next.

      We know that the situation is being monitored – we can see it on avcan.org and IGN but not all the local population are not professional or amateur volcanologists. They need to hear it from the authorities.

      The authorities should maintain at minimum daily press conferences while there is EQ activity. If there has been no change – just to state that the number of EQs since the last press conference, their depth and quality and confirm they are still monitoring the situation. Clearly, as soon as it is known what is in the sea should be reported that day as a formal press release and discussed in the next conference. An early update on evacuation procedures might not be a bad idea just in case they are needed.

      1. I agree. The point the authorities need to drive home most is that these EQs are deep, and small . They should invite the locals to watch the IGN EQ data in real-time, here ( for anyone new to this site):
        http://www.01.ign.es/ign/resources/volcanologia/html/eventosHierro.html
        What Hierrans should be informed to look for are shallower EQs – not ones and twos but clumps of them. And bigger ones that m2 or so.
        Magma is not going to appear on the surface instantly – it will almost certainly be preceeded by EQs rising shallower. And the authorities should point out that a volcano that liberates its strain as many small EQs is less dangerous than one which stores it up and releases it in one big EQ.
        Iceland must have teaching materials on volcano behaviour that could be quickly trnanslated??

      2. Yes they do, a lot of it. But I do not think that IGN wishes to have any help from them…
        I am afraid that we will see quite a lot of these deeper quakes as the larger El Golfo magma-reservoir is activated due to a rift opening up down to the MOHO. Yes, that is what I think we are seeing now, a deep rifting fissure opening up. And that could be real bad news since a rifting fissure can haul much more magma than a normal feeder tube.
        What I wanted to say is that I think we will only see a very brief EQ-episode before it opens up. Remember that Baby Bob pretty much did not have any shallow EQs. So I guess we will not have that over at El Golfo either.

  5. I don’t know that they have shut their eyes to the problem, but I do wonder if they’ve spent too much time patting themselves on the back following the birth of Bob, and have taken their eye of the ball just a tad regarding the overall situation.

    The overall lack of information is something that has been whispered about for the last few weeks, but I also think that explanations of the information would not go too far astray/be of more use.

    In a press conference early last week, a reported asked about the water analysis results and was told that ‘they wouldn’t be giving out that information because they wouldn’t understand it’.

    1. I’m afraid that statement makes me really wonder what is in the water. When people tell me I won’t understand something it just makes me think there is something to hide. Not good public relations.

      Being open and honest is best in this situation.

      1. would it be fair to guess that the gas into the water was of the same composition (and proportions) as the gas in the rock that Carl le Strange’s lab’s analysis gave?- that would seem likely to me – but I’m not a volcanologist 🙂

      2. It would be fair to say they are likely to have come from the same source.

        Icemine Ltd’s samples will only have the gases in it that remained trapped in it so while they are a good indicator, the mix of gases in the air and water might be different.

        But I would certainly take the results of his analysis seriously and use these as an indicator until we see full results of local testing published.

  6. Hi guys!
    It seems that EHIG station start to have an easy increasing in tremors.
    http://www.ign.es/ign/head/volcaSenalesAnterioresDia.do?nombreFichero=EHIG_2011-10-26&ver=s&estacion=EHIG&Anio=2011&Mes=10&Dia=26&tipo=2
    Actually is located on other island
    http://www.fomento.gob.es/MFOM/LANG_CASTELLANO/DIRECCIONES_GENERALES/INSTITUTO_GEOGRAFICO/Geofisica/volcanologia/B12_Red_sismica_+Islas_Canarias.htm
    What could that means?? magma intrusion on larger scale? Anyhow this Ehig location is in N of El Hierro, let’s say toward the deep magma intrusion of the last few days.
    Any other ideas?

    1. Probably still El Hierro. All stations are reporting a fairly strong signal on the spectrograms at low frequency. The tremor at El Hierro may be strengthening. The higher frequency at EHIG is probably local background noise.

      Interesting that both spectrograms / wave forms have missing areas: CHIE at 8:50 to 09:00 and EHIG between 08:00 and 09:00 today – probabl just conincidence or gremlins in the system.

  7. Actually the noise shown on the spectrogram seems to be man made. Probably some relation to normal working hours. If you go back you see that the “noise” starts each day around 7-8 in the morning and ceases around 5-6 in the evening.

  8. I have been doing some speculation on the current status. I fear that there might be open up a fissure event in the new area where they earthquakes are now happening.

    When is impossible to know. As things are not clear yet. But this is developing fast and is dangerous status in my opinion.

    1. Jón, so with the second earthquake area is that unusual? It seems to me like it’s two eruptions at once, no? Or at least it’s two rising magma areas at once. I suppose they are both connected to the same increase in rising mantle pressure? Anyway, to me, it seems unusual. I’m just an observer though and no expert.

      1. It is not unusual. But it means that even more magma is now collecting under El Hierro volcano. That is something that needs to be closely watched by the local geologist. As this magma is more then less likely to break a path to the surface in a new eruption.

        This might just be a normal pattern for El Hierro. But due to how long it is since last eruption, it has never been seen by humans before.

      2. But they are deep: 20-25km – and small.
        MOHO at 14km.
        It has a long way to rise.
        The pattern we see at present could fit with the trend to deeper EQs over time since July- see the tectonic/tensional mechanism I outlined above.
        A process driven by plume ‘pushing up’ from below may not be happening – it may be that a tectonic process has bent the upper mantle resulting in fracturing (hence the EQS) and is allowing magma to penetrate the relaxed pockets in the upper mantle.

      3. This is what I find dangerous, Peter, about your hypothesis: those “crackings” of more superficial faults towards the depths. And if you are right about the fact the the weight of El Hierro could be causing this “sinking” effect of the heavier crust into the “chambers” beneath loaded with magma, I don’t know what to expect. But I don’t know if I got it right.

      4. I’d like to think that the fact that the EQs are currently deep and small so are less of an immediate risk. However, I can’t. Not least because there have been 9 EQs with a depth of less than 14km in the last 10 days.

        Even if the EQs were all small and >25km, new magma may be rising to meet existing magma so what appears to be a rise needed of 25 km is may be <5 km.

        Don't forget that there were shallow EQs NW of Frontera and under the ridge well before Bob.

        I think Jón is right at this stage to emphasise the possible danger.

    2. I am not sure. See http://dialnet.unirioja.es/servlet/articulo?codigo=286492

      “The island of El Hierro is geologically somewhat younger than La Palma and, becau­se it formed over a stationary source of magma, it presents, in comparison, a perfect, concentric development, with superimposed volcanoes and a regular three-armed rift geometry. The activity of the subaerial volcanism began in El Hierro with the develop­ment of Tiñor volcano on the NE flank of the island (approximately from 1.12 to 0.88 ma), with the emission of massive typical basalts. The volcano developed quickly, with different stages of growth, the eruption of Ventejís volcano being the terminal explosive stage, and probably the precursor of the collapse of the NW flank of the edifice some 882 ka ago. The emissions of the new volcano -El Golfo, approximately 545 to 176000 ka- totally filled the depression of the lateral collapse of Tiñor volcano, the lava flows of which then spilled over the flanks of the earlier volcano. The beginning of the construction of the El Golfo volcano seems to have taken place after a relatively long period of activity, probably coinciding with the maximum development of the Cumbre Nueva rift on La Palma. The initial subaerial activity at El Golfo was characterised by basaltic lavas that evolved to trachybasalts and trachytes, and finally towards more diffe­rentiated eruptive episodes indicative of the terminal state of the volcanic activity of the El Golfo volcano. The excessive growth of this volcano triggered the failure of its north flank, generating the spectacular scarp and present El Golfo depression. Subsequent vol­canism, from emission vents arranged in a three-armed rift system (rift volcanism, with ages ranging from 145 ka to 2500 years, with probably prehistoric eruptions), implies the much more moderate continuation of the earlier predominantly basanitic-tephritic volcanic activity. “

    3. That’s a landslide scarp.

      If El Hierro ever had a caldera, it’s torn up and buried with the El Golfo slide debris.

      That doesn’t mean that the shape of El Golfo escarpment may not have been related to the caldera boundary, but from what I have read, it doesn’t have any direct relation to one. Additionally, the exposed dikes tend to follow the shape of the rift and not a radiating circular pattern.

  10. re H104:

    I’m starting to wonder whether the last few readings (before apparent instrument death) were in error … I suppose if some of the Japanese GPS were close , we could cross-check …

    1. Yes the maesurements had got noisier ( bigger errro bars) gradually since it was set up. Erros bars on others are quite consistent.

    1. Unfortunately it make the crust/mantle boundary seem shallower that reality. They mark it ‘manto’ – it is actaully around 14km deep. The present EQS are mucg deeper -20 to 25km, well off the bottom of their cartoon.

    2. While it is not confirmed whether the deep quakes in El Golfo are new magma arriving or deflation, it is my view that they are a source of hot magma from the mantle, which is moving into the system from the north and putting pressure on what has already travelled south before it. If the cooler magma is on the move, under El Hierro, and degassing has occurred to the south, followed by the birth of Baby Bob, then the slower moving and still rising, magma may still contain gases which could vent from anywhere on the island.

      It is difficult to evidence this viewpoint at present, however, and other theories may be more comprehensive.

      1. The Golfo EQs are very deep and small. Any magma that might be moving there has a long, long way up to go to reach the surface. The lower bound of the crust is 10km above those EQs at about 14km.
        The magma that fed Eyjafyatlajokull rose from about 18km to 8km over a period of many days – we watched the EQS get gradually shallower. So on that (crude) basis Hierro has way to go yet before any serious amount of magma reaches the surface ( it it does at all).

      2. Hi Peter

        I would not dispute your observations on the depths of the quakes in El Golfo, notwithstanding the 2 quakes at 2km depth further north in the area, and the possibility of weight having a bearing on softening the magma, is not one I had considered. My concept however, is of a north-south trending of magma following previous routes, or strata, with fresh hot magma putting pressure on pre-existing pockets of cooler magma, softening them, and releasing gases, rather than flowing direct from depth straight up to the surface.

        The El Golfo risk then might be if the existing routes are blocked by slow moving magma then a new eruption site may be created further north, or closer to the shore and Frontera.

        Please note I am not a volcanologist.

      3. I’m not even a geologist! ( biologist).
        If we accept that, irrespective of whatever cause, magma is rising where the EQs occur than the most significant observation has to be the sharp cut-off at about 8km depth. OK there are a few EQs above that, but out of the 10,000 to date the vast majority have been deeper than 8km. Since there is a layer of sedimentary rock about 3km thick between 5 and 8km depth the magma has to traverse that to get to the surface. Its a mix of limestones, shales, and clays older than the Atlantic. So when heated we could expect a lot of steam pressure and carbon dioxide: a gassy concoction, some of which I reckon has found its way to the surface as Bob. But there may be more to come up. If magma rises as a result of pressure from a plume below, the layer of sedimenary rock will offer little resistance. But if the magma simply follows fracturing resulting from tectonic forces putting Hierro under tensile ‘strectch’ thats different: the sedimentary rock could easily accomodate tension -its layered and will slide easily ( so we see no EQs there.). So magma below it has to melt its way through – and sedimentary rock has higher partial melting temperature than magma. I have no idea what that delay could be before magma melts through. My guess is that we will see gas/steam escaping to surface first – so more Bobs, but perhaps on land.
        Just a guess.

    3. That’s uh… a bit incorrect.

      Essentially, the artist took the cross section of the island and melded the general structure of a volcano directly under it.

      First, that ridge line was never the top of the volcano. If you extend the slope and trend of the unfailing region to their intersect point, it’s quite a bit larger than the placement of the underlying “feed system” graphic indicates… and very off center.

  12. Yes the measurements had got noisier ( bigger errro bars) gradually since it was set up. Erros bars on others are quite consistent.

  13. I know that I know nothing and that I may be wrong, but if I lived on El Hierro, and had the choice to leave the El Golfo side of the island I would go now.

    1. I agree and am saddened by the fact that the government does not think their people are intelligent enough to understand what is going on. They withhold
      information from their own people. This increases both the risk and fear for the residents. Try as they might they cannot sweep “Bob” under the rug and return to life as before. The area maay not be a tourist venue for quite a while but think of the possibilities if they would start asking geologists volcanologists etc to come to the area…real info sustained economy etc

      1. Do not assume that the authorities have the same info we do. There’s a good chance that they haven’t made or seen plots like Lurking makes.
        Even if they have, they may be looking at the data and drawing different conclusions than we are.
        This is probably the largest collection of minds analyzing this volcano right now, so we may come up with things that others don’t. At the same time, we are not experienced geologists, so we may be drawing false conclusions.

  14. New Book on Canary Island geology by Prof, Carracedo.
    He must be rellay pi$$ed off – having a book ‘put to bed’ (printed) just as Hierro wakes up!
    Giggle translate from
    “”” Voice of Tenerife

    This volume suggests that the researcher and director of the Canary Islands volcanological station dedicated to the origin and evolution of the archipelago will be released this Wednesday, November 26 at the Cultural Space of CajaCanarias, at 20 hours

    [Img # 6852] CajaCanarias Cultural Space in Santa Cruz de Tenerife will host on Wednesday October 26, at 20 hours, the presentation of a major compendium of the geology of the Canary Islands that the teacher, researcher and director of the volcanological station Canary Islands, Juan Carlos Carracedo, has developed around the origin, evolution, age and volcanism of the islands.

    This work, published by Editorial wheel bearing impressive progress in the field of geology, and more specifically the Canary Islands, has experienced in recent decades. Aspects such as the origin of the islands, the characteristics of the volcanism, the risks it may pose and how their landscapes arise, among others, are phenomena which aroused widespread interest, justifying and advises its disclosure.

    The author in this book applies the theory of continental drift to explain the formation of the archipelago, moving into the recess of oceanic islands in the global tectonic and adapting these ideas to the origin and evolution of the Canary Islands.

    The statement “a picture is better than a thousand words” has no place in this publication has more than 450 color illustrations and, although it has required a great effort, the abundant graphic material that accompanies the text allows a better understanding of the ideas developed by the scientist and researcher in this study.
    The purpose of Juan Carlos Carracedo is to continue to work with two new publications. In this sense, the idea that raises the volcanologist is collected in a second volume of two parts, one focused on the Canary Island magmas, generating eruptions, emitting products and the resulting forms, and a second part will deal with the Islands large structures, topography and landscape, while the third volume of this collection include the geology of each island individually, and their most prominent geological features and itineraries discussed to facilitate observation and enjoyment.

    Juan Carlos Carracedo

    Doctor in Geology from the Universidad Complutense de Madrid, Juan Carlos Carracedo (Miranda de Ebro, Burgos, 1942) has devoted his entire professional life to the study of volcanic oceanic volcanic islands, particularly the Canary Islands.

    Since 1981 is part of the Higher Council for Scientific Research (CSIC), which is also a research professor and directs the Canary Islands volcanological station 30 years ago. Today also is an associate professor at the University of Las Palmas de Gran Canaria, integrated volcanological research group GEOVOL.

    He is the author of more than one hundred papers in journals of geology and volcanology, and has published dozens of popular science books, mainly on the volcanology of the Canary Islands, among which ‘Paleomagnetism and volcanic history of Tenerife’ (1979) , ‘Physical Geography of the Canary Islands’ (1984), the series ‘Volcanoes of the Canary Islands’ (1978-2008), ‘Geology of the oceanic volcanic islands’ (2003), ‘Volcanoes National Park Teide’ (2006); and ‘Teide Volcano’ (2006), among other volumes.

    Carracedo has worked as a technical consultant and presenter in numerous television documentaries and a variety of Spanish and foreign issues volcanology of the Canary Islands.

    He has also participated officially as volcanologist in monitoring various rashes, among others, the Teneguía in La Palma, the Nevado del Ruiz volcano in Colombia and the eruption of Iceland Eyjafjallajokull, in more recent.”””

    1. Why? He will sell more books and, presumably, Volume 4 will be out soon.

      At least the conference was not based in La Restinga.

  15. Do the Canary Islands go through the same exact stages as the Hawaiian Islands? Or are they a bit different?

    1. No volcano or volcanic process follows a script.

      They follow general trends, such as various stages in development, but nothing exact.

  16. There are people that thrive on scaring the shit out of everybody else. It’s human nature.

    People, in general, tend to relay information badly. Each step of the relay gets embellished a bit and misunderstandings and nuances of the telling magnify and wane.

    Modern people like to sue for whatever reason. This has gotten so bad that we have developed our own sub-species of human that has had some well known human characteristics (ethics/morals/soul) atrophy so that it could specialize in litigation.

    In order to keep this degenerate subspecies from trying to feed off of you, you only say what needs to be said to protect people as much as possible/feasible. Virtually anything you say, or don’t say, will be spun up by the rumor mill into grandiose disaster scenarios.

    Over alerting on the other hand, means that people won’t listen to you when you have something really important to say that could save lives.

    It’s a fine line to walk.

    We follow this stuff day to day, most people think about fishing, eating, selling stuff, swimming, or getting laid. Seismology just doesn’t sit in the forefront of most people’s attention. At present, there are no clear indications that something really bad is on the way. All we have are somewhat plausible scenarios of what could happen.

    Just because it could happen doesn’t mean it will happen.

    Chemicals in the water. The ocean is big. Stuff dilutes pretty quickly. Almost all volcanoes generate a fairly common array of chemicals.

    Water, Carbon dioxide, Hydrogen sulfide , Sulfur dioxide, Hydrogen fluoride, Hydrogen bromide, Hydrogen chloride, Nitrogen oxide, Nitrogen dioxide

    How much of each depends on the volcano. Other, rather poisonous compounds can be in there too. Chemical detection and analysis is about the only area where I think the authorities should put forth a stronger effort. People have to eat, and if the fish have a problem they should be told.

    2. Good one, you just forgot the aluminium compounds, those can be really nasty for humans. But here I leave over to Peter Cobbold, as a Biologist he is much better suited to answer toxicity levels of unusual aluminium compounds.

  17. Quote

    magma chambers”? i think there is one giant monster
    out-of-control caldera forming under the entire Canary Islands!

    Is this possible?

    2. No its not possible.
      Fig 11c here is a diagram of what the crust and upper mantle under Hierro is probably like – lots of small pockets of magma with a meshwork of sill and dykes, and no distinct magma chamber:
      http://eprints.ifm-geomar.de/7993/1/915_Stroncik_2009_TheMagmaticPlumbingSystemBeneath_Artzeit_pubid12801.pdf

      If you mean is there a mantle plume there? Maybe, but that is not universally accepted. Five possibilities for formation of Canaries are summarised here:
      http://www.mantleplumes.org/Canary.html

  18. Energy is rising .

    La Gomera had a spike today similar to what Fuerteventura did yesterday (although this has been blamed as a technical fault) but why should La Gomera show a spike today aswell seems to be a bit of coincidence.

    I live on Fuerteventura and have been watching the recent developements and to be truthful I am scared .

    We and the people of El Hierro dont seem to be being being told what exactly is happening on El Hierro .

    1. Why scared? Fuerteventura is 10 million years older than Hierro (at least), has mostly already completed its slide into the sea, and is no longer thought to be over the fabled ‘hot spot’. Nor are the Canaries are on the edge of a tectonic plate ( subduction zone) so massive EQs are unlikely. So stick with us, keep asking questions – it will reassure you that things doen happen completely randomly.
      That said, I would not be happy living in the north of Hierro under the escarpment. The thought of a landslide happening with no warning is too much for me. The thought of a rare large EQ triggering one puts me off, also hydraulic loading from abnormal rain ( climate change) and the apparent sparsity of GPS monitoring sites along that ridge. By comparison an eruption should give lots of warning.

    2. I agree better information should be provided if only to show that the authorities are keeping an eye on the situation (I am sure that they are but people do need the reassurance right now).

      Don’t forget that Turkey has had a large EQ and is suffering large aftershocks. The stations are detecting some of these in addition to the activity on El Hierro. Also really weird spikes are probably from technical problems with the equipment.

    1. South East Flank of Mt Etna in Italy.

      At least that is where the seismo is for the image you linked.

  20. I have managed to get back upstairs to my faithful Computer Hal. 🙂 What a relief 🙂
    Whilst I have been inactive Burfell certainly hasn’t!
    http://hraun.vedur.is/ja/strain/str_corr/index.html
    That is quite a hiccup.
    It is sad to see that the poor islanders on El Hierro are still wondering what will happen as are we all.
    I hope nobody has said “All is over and well”! It must be so difficult worrying about your home and future.
    I fear that Baby Bob may just be a precursor to something else as deep quakes are still occuring in a similar pattern as the start of this present episode back in the summer.

  21. I have managed to get back upstairs to my faithful Computer Hal. 🙂 What a relief 🙂
    Whilst I have been inactive Burfell certainly hasn’t!
    http://hraun.vedur.is/ja/strain/str_corr/index.html
    That is quite a hiccup.
    It is sad to see that the poor islanders on El Hierro are still wondering what will happen as are we all.
    I hope nobody has said “All is over and well”! It is too early to make such statements. The local people I am sure are intelligent enough to hear things as they really are without any fobbing off or semi truths.
    It must be so difficult worrying about your home and future.
    I fear that Baby Bob may just be a precursor to something else, as deep quakes are still occuring in a similar pattern as the start of this present episode back in the summer.

      1. Put your gnome in the corner with the other ones… you can pick it up on the way out. 😀

    3. Welcome back and actually, I have a question about reading these strain graphs. From what I understand, these are measurements from a rod that has been put into a borehole inside a mountain. If the values are positive, that means that the borehole is stretching itself outwards, i.e. the walls are being pulled one from another. And if the values are negative, the walls of the borehole are being pushed against each other. So of interest are times when things go from plus to minus and back very quickly, as that means that something is “moving” within the mountain (earthquake, tremor).

      Is this correct or am I completely misunderstanding it?

      PS: captcha is weirdly appropriate for this blog: mention pericolo -> danger (pericolo in italian) should always be mentioned to the public

      1. You are correct, even though this is a bit to simple view of it. But it gives you enough understanding of what is happening to understand it, and mor than so 🙂

        The moving back and forth are a sign that you are entering interesting times. But the real sign is when you have Burfell going hard into the negative (and I mean hard on a scale you have not seen) and at the same time all other stations go 1/4 as hard into the positive. That is a full blown transient.
        No we can see on average 1 transient a week, and they can last up to an hour at a time. But they are still much to week. The largest transent sofar has been 1/10th of the one that opened up Hekla for the 2000 erupton.
        A transient is a slow, unyelding wave of mountain movement. It is the absolute other end from the harmonic tremor. Imagine a wave with a frequency of 1 wave per hour.

  22. the people are nervous, hear noises and feel many quakes in Frontera and El golfo too . Avcan more than 7 hours they doesn’t write a comment on Fb.

    1. My thoughts are with you, Maria.

      As you can see from this discussion, we have searched the internet for expert information, and it seems no-one really knows what is happening.

      But today is the day I would decide to make my way to a boat, to another island at least, if I was living there, just in case.

    2. I suspect most Icelanders who know about these things as they have an eruption every 5 years will be chuckling ! I hope that an Icelander will reassure your Hierro friends.
      The EQS are deep:
      http://www.01.ign.es/ign/resources/volcanologia/html/eventosHierro.html
      and mostly small:
      http://www.01.ign.es/ign/layoutIn/volcaListadoTerremotos.do?zona=2&cantidad_dias=10
      These two sets of data will keep Hierro inhabitants up to date without waiting for AVCAN. Its good they are alert, they need to be, but they can watch in near real time for terremotos getting shallower.

    3. I would be scared too if I were on El Hierro. Suggest people report what they can hear, feel (EQs / tremors) and see to Avcan; it is useful data to them. Can you comment on their FB wall? Hopefully, Avcan will give an update soon.

      If I were you I would have a bag packed with all essentials in it. And if I were Avcan and the Spanish government, I would have a well-rehearsed plan to get people off the island fast, just in case you have to use it sooner rather than later.

      Icelanders will understand better than us Brits what you are going through, including the uncertainty. I doubt they are chuckling at the moment. Jon certainly isn’t.

      1. Fimmvorduhals – the initial fissure eruption that preceeded -was known as a tourist eruption. The locals drove up over the ice to take a look – even the plonkers from Top Gear went to look.

        Icelanders are educated in the lore of earthquakes and eruptions and swarm of deep small EQs would be noted bit would not cause panic. And they know they get their evacuation alerts by text message. And Frontera?

  23. Fuerteventura is only 240 mles away from El Hierro if there is a huge volcanic explosion (which I hope to god there is not ) would not the ash reach us here what about poison gasses and if the landslide at La Palma does go into the sea would we be hit by a Tsunami.

    Sorry if you think I am being neurotic but these questions are going over and over in my mind.

    1. Judith / Maria
      You are obviously a little scared by what’s going on. Perhaps reading all of this blog, written mostly by people who are not resident in the Islands but have a keen interest – which produces much analysis, influences your train of thought and enhances your state of fear. Yes, ‘Bob’ has popped up and created a lot of interest and people have had to move from their homes as a precaution at La Restinga but otherwise, little has changed since July. The EQs still happen of course and they may or may not develop into something.
      Read ‘Lurkings’ posting above – all very valid.
      Perhaps if you are resident on El Hierro, you might make some small preparations in case something does develop – but this might take weeks, years – or it may of course just fade to nothing.
      The Canaries are beautiful islands – enjoy the sunshine with a beer or two and don’t get too carried away with it all.

    2. Gaseous plume dispersion over a distance of 240 miles is quite large and the prevailing winds generally move to the west, away from Fuerteventura. Currently the surface winds are trending towards the NW.

      Personally, I’d be more worried about strangers lurking around the neighborhood than El Hierro.

    3. One of the best bits of advice I was given was worry about the things that you can do something about (that you are responsible for), not the things that you can’t.

      240 miles away you will probably be alright: volcanic ash, etc., would most likely be an inconvenience, unless you had a health problem; and, a tsunami, you are probably far enough away to get some warning. But if you are on a beach and the tide rushes out suddenly, get off the beach to higher ground.

      No-one can give you 100% guarantees but where you are, don’t lose sleep over it.

    4. Have a bag packed with a little cloathes (I mean little!), passport, and your purse and medicins, and have it handy.
      Do not swim, do not drink (well first of all it is salt-water) the sea-water, do not eat the fish.
      If you follow that advice you should be quite safe. The risk that you would be right ontop of a fissure volcano when it erupted is most likely smaller than you being hit by a car.
      A landslide, well it could happen with or without a volcano. If it happens it will not be that big.
      Relax, but be ready. And if something happens, move away in a calm fashion.

      1. @Carl, is this excellent advice for people on El Hierro?

        Judith is at Fuerteventura.

      2. That would be the advice for people at El Hierro.

        For someone at Fuerteventura the advice would be to take a siesta or pour a fresh cup of coffee, maybe a glass of vino, and definitly a nice supper.
        Nothing the Bobs could throw up would affect them.

  24. Maria
    Dont you think aswell the Spanish Goverment should be doing that now anyway for all the residents until they know 100% what is going on. If the people need to be evacuated where are they going to go and how. El Hierro is an island and the only way off is by boat.

    1. There is also the possibility to fly them out using big military aircrafts. I am sure this has been taken into consideration by government people, as far as I remember there have been some military persons on the island. There are for sure some plans in some drawer (as we say in Germany).

      I have been living for years in Iceland which has a lot more volcanoes than the Canary islands and Icelandic friends always told me that there would be really more reason to fear a car crash than a volcanic eruption. And in your case it is far away.

      1. Alyson, Peter Cobbold, KarenZ, Jim, Judith , Charly, Lurking First of all thanks for the support. Secondly, I’m not on El Hierro, I think there is a little confusion: I have family in Tenerife and Las Palmas and friends in El HIerro too and I ‘m worry for them. Thanks to this blog many fears have vanished, but it is difficult to transmit calmness to people living in this tiny island and inadequate, insufficient government information doesn’t help. People are distressed.. many persons take pills to sleep, Few people have internet. There are many old people. A friend has just said to me that the school of Frontera has a few cracks the situation it is very difficult. I read some of your comments to my family and friends Once again thank you very much all who write in this blog, although often I don’t understand the scientific terms, from what I have to read two or more times, even so it calms to read you guys. Thanks.

      2. Try to tell them to take it easy, and just have passport, wallets, and 1 set of cloathing packed in a small back-pack (with a bottle of fresh water in it), so that they can ecacuate efficiently if needs be.
        And if they have to evacuate, that they do it calmly, because even if an eruption happens, a car crash is still more likely to kill them than the actual volcano.
        But the most important thing is to tell them to relax. The risk of them dying from an eruption is actually quite small since Bobs are mainly effusive (lava-flows) volcanos.

  25. The Hierro eruptions are not explosive, they are fissure eruptions like Hymaey which we watched in the early days of colour TV in UK

  26. I am from Gran Canaria and I can tell you that there is nothing to worry about, there will be NO tsunami on la Palma even if Cumbre Vieja decided to erupt in the near future, like it did in 1470, 1585, 1646, 1677, 1712, 1949, 1971 and nothing happened, no Tsunami, no mega-earthquake, just low explosive strombolian eruptions. Then this volcanic unrest is in el Hierro, so there no need to worry about La Palma in the first place. Even in the possible, but improbable, case of an inland eruption it would be a “quiet” one and the wind, which most of the time blows in a north-south direction would carry the ash away into the open atlantic. So you do not need to worry about any apocaliptical-megadisaster theory invented by a bunch of “enlightened idiots” in any of those “end-of-the world” sites ; )

  28. Anyone happen to know why the IGN GPS site haven’t been updated since the 24th?

    (HI04 since the 20th.)

    In Prof Sagiya’s network also is behind… with the exception of FRON which shows data for the 25th.

    1. No idea.

      When I looked at the Professor’s network earlier today it looked up to date on all pages to 25/10/2011 but someone made a comment earlier on this post to check HI-04 data against the Professor’s network.

      1. As of 18:58 26 Oct 2011 UTC…

        VALV – 2011.7930 0.0110 0.0070 -0.0005 2011 10 17 290 2
        FRON – 2011.8150 0.0185 0.0333 0.0318 2011 10 25 298 2
        REST – 2011.8095 0.0314 0.0072 0.0496 2011 10 23 296 2
        SABI – 2011.7629 -0.0115 0.0220 -0.0056 2011 10 6 279 2
        PINA – 2011.8122 -0.0058 0.0173 -0.0139 2011 10 24 297 2
        JULA – 2011.7903 0.0021 0.0012 0.0036 2011 10 16 289 1
        FARO – 2011.7930 -0.0442 0.0054 0.0045 2011 10 17 290 1

      2. Don’t know why there are 2 sequences of numbers for each station; I was going by the data with “1” at the end of the line – but when I checked later you are right data is missing / not been updated.

      3. II think that extra number at the end denotes recalculation of the position. When plotted they wrap back on themselves at nearly but not quite the same point.

        I’ve looked at the raw RINEX files for some of the stations in IGN, and though I can’t decode it, it’s still a LOT of data.

    2. I have noticed that IGN is sometimes a few days behind in publishing the distance charts, that seems to be normal with them.
      This time there may be a reason though: GPS can be unreliable during geomagnetic storms and there was one of level G2 – Moderate from the 24th around 18:00 UTC to noon 25th of October.
      That may have had an influence on the quality of their GPS data. However, I don’t have any information on whether this is the case or not.

    3. They all went to the MAKAVOL2011 conference on La Palma and have not caught up with the data?

      3. Oh that’s good. Pack up the whole crew, shut down automatic updates (provided anyone bothered to write one) and head off to seminar/party.

      2. Red alert have been decreted in the Hudson, and they are evacuating people at 40km away from volcano. It seems that 400m long fracture has opened and a white vapor and gases column rises 1km from the summit.
        I think we will have explosive fires here

  31. Giggle translate:
    “””ANALYSIS OF SEA WATER NOT RECOMMEND THE BATHROOM IN AREAS AFFECTED BY THE SUBMARINE ERUPTION.
    26/10/2011 … 15:20 – Ministry of Economy, Finance and Security
    This is a precautionary measure even though the parameters obtained are within the normal
    …
    The Directorate General of Public Health of the Canary Government has moved this morning to the direction of Civil Protection Plan for Volcanic Risk (PEVOLCA) recommendation not to make the bathroom in the areas affected by the volcanic eruption, “until the give scientists terminate this phenomenon. ”
    Following the analysis performed, and after assessing the results, it is found that for pH, the averages are somewhat lower than normal data in such waters. The remaining parameter values ​​are considered normal, except in the case of sulphates in excess of existing values ​​in the seawater.
    While the process is scheduled from Public Health, the sampling of bath water to perform continuous monitoring of the parameters involved.
    Although the Royal Decree 1341/2007, of October 11 on the management of the quality of bathing water set as parameters of bathing water quality only the determination of microbiological parameters associated with possible contamination, given the peculiarity of if considered necessary, in addition, bacterial counts, pH, conductivity, turbidity, and sulfates.
    See more
    CANARY ISLANDS GOVERNMENT NEWS”””

    So its about as dangerous as this:
    http://live.mila.is/lonid/
    but with a few dead fish thrown in?

    1. No. Basically they are saying do not take (swim / drink) in the sea / sea water until the scientists give the all clear. There are increased acidity and sulphates in the water.

      HsSO4 and metal sulphates are not good for you.

  32. from AVCAN fb voa Giggletranslate:
    “””Last earthquake has been moderate esntido in the border zone, and seems to have made ​​a noise which is what people have noticed this afternoon, explaining what was missing from the news of saltpeter smoke this afternoon.
    1107934 26/10/2011 18:40:51 27.7395 -18.1053 27 2.9 4 W FRONTERA.IHI If you have felt, do not forget to complete the questionnaire (Enrique).”””

    Thats SW of Sabinosa under the ridge. BUT 27km deep. Thats along way down, I’m surprised a mag 2.9 would be detected by ear.
    What’s this with the ‘salpeter smoke’???

    1. Saltpeter smoke = mistranslation, I think.

      There was some discussion at AVCAN yesterday evening about this photo:
      http://www.facebook.com/photo.php?fbid=2600825064452&set=p.2600825064452&type=1&theater
      Apparently people thought this was related to the volcanic activity, but it turned out that it was “salitre de mar”, which I understand is salty sea foam being blown by the wind or something like that. However, google translate gives “saltpeter” for “salitre”.

      1. Here’s what AVCAN says about this “smoke”:

        Pues parece que se va confirmando, es lo que se llama “espuma de mar” que es el salitre que sale de la zona costera y se eleva por los acantilados, cogiendo una tonalidad terrosa por efecto del sol. Gracias Mariela por compartir las fotos, vale más una imagen que mil palabras.

        Well, it seems to be confirmed, this is what is called “sea foam”, which is the salt raising on the coastal zone, following the clifs and takes an earthy colour/hue in the sunlight. Thank you Mariela for the photos, one image is worth more than a thousand words.

      1. @Inge: Yes, but here, for sure, this is giggle mistranslation!

        Try this, go to translate.google.com and choose Spanish to English.
        Type “salitre” and press translate -> result: saltpeter
        Type “salitre de mar” and press translate -> result: sea salt.

        In the context of discussing the foam from the sea, as in the avcan photo, I think the second translation is the one that makes sense. 🙂

    3. Sea foam is a type of foam created by the agitation of seawater, particularly when it contains higher concentrations of dissolved organic matter (including proteins, lignins, and lipids)[1] derived from sources such as the offshore breakdown of algal blooms. These compounds can act as surfactants or foaming agents. Source: http://en.wikipedia.org/wiki/Sea_foam

      Some sulphates are also surfactants or foaming agents. Aluminium sulfate is a foaming agent in fire fighting foam.

      The smoke could be anything. Hopefully, someone has tested it thoroughly.

  33. This is a corporate health warning to the population at El Hierro Island.

    We feel that we should issue this warning after seeing this comment by the authorities on El Hierro Island. The comment is about the chemical composition of the pollutants in the water outside El Hierro. This is what the authorities on El Hierro answered to a reporter who asked what was in the water.
    “they [the authority] wouldn’t be giving out that information because they wouldn’t understand it [the public and the reporters]”

    It is also telling that the only chemical analyzis of anything coming out of Baby Bob (the volcano south of La Restinga) is the one we (Icemine, ltd) did as a private company.
    And judging from the results from these stones our guess is that the chemicals in the water is in the same “familly”.

    For safety!
    Anyone on El Hierro should stay away from the water due to likely high content of acidic chemicals, sulphuric compounds and of probable high levels of aluminium content, that is beyond what is safe for humans, to either swim in, drink of, or eat the fish from. The fish is most likely heavily contaminated due to very high aluminium levels exceding what is safe for human consumption.
    Do not eat, do not drink, do not swim untill believable laboratory tests have been published. If you live on El Hierro, or are a serious journalist, you should collect your own water-sample and send for testing outside of Spain.

    This warning is based on laboratory testing on the floating “stones” from the Volcano outside of La Restinga. This warning does not take into account chemical compounds that could be hazardous aside from acidic compounds, sulphuric compounds, and aluminium by-products. But, it could well exist other harmfull compounds ejected from the Baby Bob volcano.
    Respectfully;
    Icemine, ltd

    [Any blogger out there is hereby allowed to quote this. But do not quote my acronym from here, quote the company name, Icemine, ltd.]

    2. Agree with the above statement 100%. The water is killing fish so it cannot be good for people.

      That might also have been what the Spanish authorities were trying to say but Google’s translation is a little confused.

      1. High CO2 is probably what was killing the fish. (Are they still dying?)
        pH is within limits: huge buffering capacity in sea water. Sulphates not a worry at pH7.4
        Aluminium is toxic as citrate but most other forms will not cross epithelia ( our skin or guts, or fish gills)

        OT!! Silico-aluminates are used in milk substitutes.
        But beware an instant cake-mix additive, maltol, which acts like citrate and helps aluminium get into the blood:
        http://en.wikipedia.org/wiki/Maltol
        ( its banned in EU, but has been used ( is still?) in USA.

        Other contaminants? Heavy metal accumulation in fish/ seafood etc could be long-term issue.
        I would not swim in it – but I’m not sure that would be a rational decision.

      5. pH 7.4 is about as acid sea water can go while still buffering an acid load. Add a little more H2SO4 and it will go to lower pHs very quickly.
        I presume that is what the authorities’ words “within limits” meant, within the limits of its buffer capacity. But they might have a different notional criterium – although pH 7.4 is absolutely benign of course ( as in blood).
        SW titration curve here:
        (page 4 of pdf)
        http://www.jbc.org/content/63/3/767.full.pdf

      6. The authorities are not very clear.

        The paper you linked to seemed to be looking natural carbonation in sea water; not the immediate effects of a hefty slug of SO2, CO2, H2SO4 and possibly H2S from a volcanic eruption. Until the latter is fully tested, the impact probably isn’t known.

  34. @Carl, Lurking, Jon, Peter or anyone else who can explain: I’ve a question about the strain graphs, which I put higher up, but it’s probably lost in the thread by now. So, here it is again, it’s about this:
    http://hraun.vedur.is/ja/strain/str_corr/index.html
    and this in particular:
    http://hraun.vedur.is/ja/strain/str_corr/str_corr_01d_4.png
    From what I understand, these are measurements from a rod that has been put into a borehole inside a mountain. If the values are positive, that means that the borehole is stretching itself outwards, i.e. the walls are being pulled away from one another. And if the values are negative, the walls of the borehole are being pushed against each other. So of interest are times when things go from plus to minus and back very quickly, as that means that something is “moving” within the mountain (earthquake, tremor).

    Is this correct or am I completely misunderstanding it?

  35. Latest from Earth Quake Report:

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

    “Update 26/10 – 18:35 UTC : PEVOLCA, the combined committee of authorities and scientists is stating in a strong message that the population of the island is NOT alone in this crisis situation. They are reaffirming their constant vigilance to deal with the situation.

    Update 26/10 – 18:25 UTC : The Canary Islands parliament has approved a series of measures to support the economy of El Hierro from last September and as long as the volcanic crisis would last.

    Update 26/10 – 18:20 UTC : The El Hierro authorities have strongly advised NOT to swim in the eruption contaminated waters.”

  37. Ha ha! We posted at the same time, Karen!

    The meeting on the island will be ongoing still, I guess.

    1. I guess so; there was als0 going to be a meeting for the local residents this evening at 20:30 local time.

    1. Just in time for the start of their meeting and just out sea from Frontera. – was it felt I wonder ?

      1. Yes, people at Avcan facebook page report feeling it in Frontera, Las Lapas, Pinar, …

      3. An Icelander would just pour a fresh cup of coffee, and continue thinking about smelting aluminium or counting sheep. Maybe go fishing even. But any Icelander would not think much about 1 mag 3 quake.

      4. I’ve seen data in a Berkley paper that indicate that imperceptibility starts about 2.0 to 2.1 if you are almost on top of it.

        The problem is I can’t find the @#$ reference.

        I tried to put together my own perception curve but got distracted by other geologic events. (El Hierro, Katla etc…)

      5. I can tell you can feel quakes less than 2 very well. We had a swarm of small quakes in the southern part of the Netherlands, must have been back in the 90 ties. Several times the building shivered and loud noises were heard. For one of them I thought a big truck hit the concrete building. It was very scaring to me, as I am not used to earthquakes and never will be.

      6. @ Lurking: this is not a proper reference, but googling brings up this: http://seismo.berkeley.edu/faq/rate_of_seism.html

        which says this:
        “The threshold at which people report feeling an earthquake is approximately magnitude 2 (under ideal conditions, ie, not moving and in the immediate vicinity of the epicenter). The threshold at which some damage is reported (such as broken windows and objects knocked off shelves) is approximately magnitude 4. The threshold at which damage to weak structures (unreinforced masonary) occurs is approximately magnitude 5.5. “

      7. @Sissel
        Qukes are felt also due to ground conditions. If your house is built on mud, the risk of feeling them is much higher then otherwise.
        And if I am not totally misinformed the Dutch ground is of the slightly muddy conviction… 🙂

      8. Some people are sensitive to very small quakes, especially if they already have balance problems; it also depends a bit on where they are and what they are doing at the time.

        Also don’t forget that people are nervous and are watching for the next quake. They are not in lab conditions.

      9. A magnitude 5 EQ is equivalent (according to British Geol . Survey) to the explosion of about 1000tons of TNT.
        Now from Wiki on the Richter Scale we see that: “”….a difference in magnitude of 1.0 is equivalent to a factor of 31.6 ( = (101.0)(3 / 2)) in the energy released; a difference in magnitude of 2.0 is equivalent to a factor of 1000 ( = (102.0)(3 / 2) ) in the energy released.””
        So a mag 3 EQ is equal to the energy released by exploding 1 ton of TNT. Now, at a depth of 25km that is unlikely to do much damage at the surface.

      10. @ Carl

        That is true, the type of ground is important. Suppose I live in the most “rocky” part of the country but there are also clay (sounds better than mud!) layers in the underground. And the epicentre was very close.
        (This was not the 1992 5,8 magnitude quake, that was a nastier one, category nightmare in my experience.)

      11. Yes, the ground conditions are very relevant, even if you are far away. I felt the Assisi earthquake back in 1997 (google tells me it was 5.6M, see here: http://historyofgeology.fieldofscience.com/2010/09/26-september-1997-earthquake-of-assisi.html) – at the time I lived in a place at about 400km direct distance from Assisi. When the earthquake occured, I was on the 5th floor of a building built in a part of town that 2000 years ago used to be a lake and hasn’t completely dried out since, so the ground is very muddy there. The building I was in swayed just ever so gently for about 2-3s one way and 2-3s the other way – it was a very strange feeling, unlike an earthquake at all (and the area there is very seismically active, so I do know how “normal” earthquakes feel, shaking or rolling from side to side, etc.). It was very peculiar. According to the local news, people located at the other side of town, which is on solid ground, didn’t feel anything at all.

    1. Alyson, I think it is the 3.0M, because time is the same on both earthquake record as well as on tremor plot, 20:29 GMT.
      What is more interesting though is that there was an almost as strong earthquake (2.9M) at 18:40 and I don’t think that produced such a big spike in the tremor chart, just a little tiny one. Here’s the previous earthquake:
      1107934 26/10/2011 18:40:51 27.7395 -18.1053 27 2.9 4 W FRONTERA.IHI
      Check the 18:40 time in the tremor chart, it’s in the red line:
      http://www.01.ign.es/ign/head/volcaSenalesAnterioresDia.do?nombreFichero=CHIE_2011-10-26&ver=s&estacion=CHIE&Anio=2011&Mes=10&Dia=26&tipo=1

      1. Magnitudes are measured on decimal logarithmic scale, so a 3.0M is 1o^0.1 stronger than a 2.9M, which is not that much, 1.2589x more. Why was then one visible as a big spike and the other one not so much?

        To my amateur nonvolcanologic mind that would imply two things:

        – “strength” (magnitude? but tremor is not measured in magnitude, is it?) of the tremor is as that of an earthquake of size 2.8M or 2.9M, so that the 2.9M gets hidden in the tremor

        – or, “strength” of the tremor is less than that, but its source is close to the location of the 2.9M earthquake and so that one can not be separated from the tremor signal, while the 3.0M earthquake was far from the tremor source and so was more visible, in spite of being just 1.2589 times stronger.

        But I’m not a geologist nor a volcanologist and I’ve no idea what I’m talking about.

      3. Location of 2.9M at 18:40 (green pointer):
        http://maps.google.com/maps?q=27.7395+%09-18.1053+%09&hl=en&ll=27.746442,-18.098946&spn=0.080063,0.169086&geocode=+&t=m&z=13&vpsrc=6

        Location of 3.0M at 20:29:
        http://maps.google.com/maps?q=27.7894+-18.0448&hl=en&ll=27.769532,-18.027191&spn=0.160093,0.338173&sll=27.746442,-18.098946&sspn=0.080063,0.169086&vpsrc=6&t=m&z=12

        And where is CHIE located, do we know? A quick check on IGN website brings up a link to a kmz on Google Earth:
        http://www.01.ign.es/ign/layout/sismologiaEstacionesSismicas.do

        And this shows CHIE more or less here:
        http://maps.google.com/maps?q=+27%C2%B043%2737.31%22N++17%C2%B057%2738.21%22W&hl=en&ie=UTF8&ll=27.72122,-17.95578&spn=0.320327,0.676346&sll=27.769229,-18.027191&sspn=0.320186,0.676346&vpsrc=6&t=m&z=11

        So then both earthquakes are about the same distance from the CHIE station, if I am not too much mistaken?

      4. Also… it may have had a different orientation. The initial dispersion of energy and what it passes through sort of determine what you get at the sensor… as well as reflections. (path effects)

      5. I was thinking about that. And also about why people feel earthquakes on higher buildings.
        Think if a seismographer on one of those cliffs and another at a shallower, flat, level, they would record it differently, wouldn’t they?
        As for the distance, many people felt the big Chilean EQ in Sano Paulo, and very few in Rio. And the difference in distance is almost irrelevant

  41. Cun un saludo de simpatia y agradecimiento por la informacion que dan de nuestros volcanes, mas extensa y fiable que la que nos da el IGN: Gracias .

    1. Usted es bienvenido. Por favor recuerde que no son profesionales. Sin embargo, sí sabemos un poco acerca de los volcanes. Volcanes son nuestro gran interés, por lo que hemos aprendido mucho acerca de ellos.
      Sólo recuerde que no sería mucho más preocupado.
      Lo siento por mi, no bien el español.

      You are welcome. Please remember that we are not professional. But, we do know a bit about volcanos. Volcanos are our great interest, so we have learned quite a lot about them.
      Just remember to not be to worried.
      Sorry for my lousy spannish.

    2. Karmela,
      Gracias. Estamos sobre todo aficionados aquí y dependen de los datos publicados por el IGN. Espero que usted está aprendiendo un poco sobre los volcanes. La gran mayoría no de repente estallan. Así que después de los terremotos en el mapa IGN es una buena idea – sobre todo de los que viven en el Hierro.
      Peter (y Google Translate)

      1. Forgot the english:
        Karmela,
        Thank you. We are mostly amateurs here and depend upon the data posted by IGN. I hope you are learning a bit about volcanos. The vast majority do not suddenly erupt . So following the earthquakes on the IGN map is a good idea – especially of you live on Hierro.
        Peter ( and Google Translate)

    3. Glad the information is helpful. Please note that there is a combination of thoughts and discussion from a mix of professionals and amateurs here. We can only speculate on the facts published so far, we do not know for sure what will happen.

      Hope Jón can provide another useful summary soon.

  42. @ Maria
    Just a message of support to your friends and family and any other residents of El Hierro.
    My thoughts are with you all . Like any waiting situation in life it is the uncertainty that causes stress. Please pass on my message and tell people to pass the word that they have unseen friends from many parts of the world watching and thinking of them.

      2. Here I just had to ask… Are there unfriendly hugs?
        I have only experienced friendly hugs, and the other normal sort of hugs. Thoughts from a rambling mind.
        Hope your leg does not pain to much?

    2. @ Maria, Please also let them know that I support you, your friends, family and everyone else on El Hierro. Thinking of you all – as friends and wishing you well.

      @Diana, hope your leg is recovering and you are able to rest it. Sensible shoes are dangerous – I have had all my accidents in them!

      Friendly hugs.

      1. Maria:
        Nosotros aqui en Brasil tenemos nuestros pensamientos vueltos a los Herreños!

  43. @Carl.

    I sent you a graphic via E-mail. Do you think I should go ahead and make a plot of it?

    1. Sorry, going through a bucket-load of mail as we are speaking… Checking…

      Found it before posting this.
      Would definitly be a good plotting, but put in the caveats you put in the mail, just to be sure.

      1. The main problem I have with it is the data cut off. Even though it’s a “new” plot, the lack of fresh data makes it somewhat “hindsighted.” Sort of like 20/20 vision to the rear and totally blind to where the road is actually going.

        I’m gonna try and fold Prof. Sagiya’s data in first.

      2. Yes, but sometimes looking in the mirror is the best one can do… At least you do not get lost if you see your house in the mirror while walking into the dark. 🙂

        But I agree, it would be even better with Nagoyas data in it.

      3. Now I am really curious, what are you two going to prove with this? The location of mysterious HI04?

      5. Now I am really curious as well.

        I am off to make a coffee so I am awake when I look at the plot – or will the caffeine be unnecessary?

      7. Heh, a real cliffhanger. 🙂

        Someone said the other day that this blog is better at keeping suspension than a crime novel. True. 😀

  44. I know its just a coincidence, but small movement in Tenerife:1107976 26/10/2011 21:30:19 28.3228 -16.5049 12 1.2 4 SE LA OROTAVA.ITF
    I hope Teide is not getting jealous for seeing his “small brother” Hierro focusing all the attention XD

    1. Interesting, level 5 warning RED, with an expected time of start of the eruption set to hours to days.
      Cernageomin are good at what they are doing since they are very used to volcanic eruptions. I forgot them in my acount of good volcanic authorities of the world. They are about as good as PHIVOLC, and for those who do not know, PHIVOLC are really good, almost as good as USGS and INGV, but not up to the IMO yet. But then, no one is that good 🙂

  46. http://www.diarioelhierro.es/t26496/pag02.asp?BD=ESPECIAL%20CRISIS%20S%C3%8DSMICA&id_registro=140544&Id=26496&BDi=INICIO&nt=p&Md=&rf3=1&rf3=1
    It seems that the Powers that be are saying it is unlikely there will be an eruption on land …However there is still tremors going on and they will be vigilante.
    Tomorrow (Thursday) it is hoped to get pictures of babyBob and to take more water sample.
    Really not much else new but at least the authorities are playing it safe!

    1. ‘The CSIC volcanologist Joan Martí, does not believe that increased Border seismicity is directly related to the issuance of magma. However, it should be considered to”remain vigilant”to determine if the prelude”new”eruptive activity.

      Sergio Gutierrez, Valverde (26.10.2011. 20:43 pm)
      The scientific community Ramon Margalef ship that is studying the eruptive phenomena on the island El Hierro does not believe the surge of seismic activity is related to Border issuing magma, though, argues that “have to remain vigilant” to determine if it is “the prelude” to an eruption, because”it was there (in the north) where he began the first part of the outbreak we’re seeing now.”

      This is a volcanologist said Wednesday CSIC Joan Martí, who appeared at a news conference with scientists from the Spanish Institute of Oceanography (IEO) and the Scientific Committee of Civil Protection Plan for Volcanic Risk (Pevolca) to report campaign that from Sunday the ship performs “Ramon Margalef” in the waters of El Hierro.

      According to Marti, “what we are seeing very clearly is that there is magma beneath El Hierro, about 20 or 25 miles, and previous eruptions magma say comes from that area, just what we see is alive,” said. However, Joan Martí said the current data and seismic tremor level and above those provided by the scientific campaign,”to the conclusion that there is a very low probability of occurrence of an eruption on the ground”he said .’

      courtesy of google translate.

      I guess we will just have to wait and see

      2. He also said (translation by Google, http://www.diarioelhierro.es/t26496/pag02.asp?BD=ESPECIAL%20CRISIS%20S%C3%8DSMICA&id_registro=140544&Id=26496&BDi=INICIO&nt=p&Md=&rf3=1&rf3=1)

        “For his part, Juan Acosta, the IEO, said that the most remarkable among the data collected by scientists have located is located in the waters of El Hierro volcanic structure with an almost perfect circular cone at the end of a fault zone.

        The underwater volcano with a crater about a hundred meters high, is a kind of vertical valley and on the volcanic edifice has detected a rise of fluid, a gas column “important” that reaches the surface and gives place a visible spot for days at sea of ​​El Hierro.”

        Is this a new fault zone they are talking about? Or is it an existing fault that runs under El Hierro.

      3. It is the southern rift zone of El Hierro that runs out into the sea at La Restinga and continues a good lenght as the seamount of Mar des Calmas.
        That rift had a fissure eruption and created something that looks like a miniminiminipiddly version of Hekla.

  47. I hoped Powers (=Weapons?) would tell that they just hired the greatest Garibaldi ferries to evacuate the islanders if necessary… and if not necessary, offer them a free two weeks cruise to relax after everything they have been through….

    1. *miff mode on*
      Nope, if the shit hits the fan they will do the comon thing in the mediterranean.
      They will dump the crap solidly in the hands of the nordic countries. First we will have to send the ships, then we will have to pay the bill, rebuild the island, pay that bill, then we will just for good measure get horked with a pre-emptive bill for all the volcanos in Italy and Greece just because they feel slighted. Sorry, it is just that I have lost count of all the countries we have bailed out, are bailing out, and know that we will have to bail out… For horks sake, we are just 20 million, we can’t pay for the entire world…
      *miff mode off*

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

    “Update 26/10 – 20:15 UTC : Big news for tomorrow …. Ramon Margalef will put his diving ROV robot in the water in the north of El Golfo! The El Golfo bay is the location with the most of the current earthquakes (” empezará en la zona norte del golfo a la espera de que se normalice la situación en el sur, y así poder ver la situación en el fondo con mayor precisión”). The responsible of the second phase Mr. Fransisco Sanchez told La Provincia that he hopes that the situation in the south will improve enabling a visit that area.”

    Anyone know what prevented them from using the ROV in the south?

    1. Acidity and heat in the water. Apparantly they almost lost their ROV the only time they tried.

      It is very good news that they are going to ROV El Golfo, that would be most usefull. And also a bit worrysome. With one side of the mouth they are saying, no more eruptions, with the other side they are ordering ROV examinations on the other side of the Island. Weirdisimo Maximales.

      1. They are saying probably no eruption on land. But they remain vigilant. They are silent about what could happen at sea but are clearly concerned.

        Suspect this is more a PR & Google translation issue which is confusing things. Don’t know how big the team they have is.

    2. Very poor visibility, heat and a chemical brew that does not agree with delicate electronic systems.

  49. Another kilometer closer to the surface – 15km depth just before the mag 3, NW Frontera. Indeed Sissel, I would have thought the offer of evacuation might be there from the authorities, in some form, by now.

    1. When it is at 8km I would start to get uncomfortable, because it is at that depth it goes silent.
      As said before. Even during an eruption a car crash is more likely to kill you than the actual eruption. See Eyjafjallajökull, 2 dudes 1 car, did they die from the eruption? No, their care gave up when they got stuck trying to drive up the mountain. 1 piece of dude thought it was a good idea to take a walk and frooze to death. And that was the only death there.

      2. Yes they did, but first they drove the car into crevice, one dude stayed in the car and the other took a walk. Then the fuel ran out. But by then help was on the way to the slightly smarter dude.

    2. Like Carl I look for EQS above 8km- there seems to be some sort of cut-off there – you can see it clearly on the EQ map. Even if the EQs pass that depth ‘barrier’, there is no large, defined magma chamber nor conduit under Hierro so its not going to erupt fast. Even if EQs arrive at 8km the magma has to force its way through 8km of rock , melting and fracturing it, so nothing is going to explode big-time. On its way through 8km to 5km the magma will heat a lot of sedimentary rock to make steam and CO2. Those gases may well get to the surface well before the magma, giving plenty of advance warning. So I think the authorities are correct- plan evacuation routes by all means, but now is not the time to suggest one.

      1. Some recent EQs with a depth of less than 15km:

        1107780 25/10/2011 18:50:18 27.6697 -18.0593 12 1.8 SW EL PINAR.IHI
        1107289 23/10/2011 13:16:53 27.5804 -17.9589 7 1.6 S EL PINAR.IHI
        1107002 22/10/2011 10:47:25 27.8795 -18.0727 2 1.6 NW FRONTERA.IHI
        1106833 21/10/2011 14:56:20 27.8938 -18.0912 11 1.6 ATLÁNTICO-CANARIAS
        1106824 21/10/2011 14:35:37 27.7129 -18.0195 13 1.8 W EL PINAR.IHI
        1105916 17/10/2011 16:17:52 27.6413 -18.0426 12 1.7 SW EL PINAR.IHI
        1105909 17/10/2011 14:42:06 28.4617 -16.8283 10 1.8 N BUENAVISTA DEL NORTE.ITF
        1105798 17/10/2011 07:07:33 27.6873 -18.0374 13 2.1 SW EL PINAR.IHI
        1105776 17/10/2011 01:31:24 27.646 -18.0708 13 1.5 SW EL PINAR.IHI

        Note: that there are a 2km and a 7km in there. Avcan.org shows a few more shallow ones.

  50. There’s 28mM sulphate in normal sea water.
    Ammonium will be almost all as NH4 ion so not particularly toxic, unlike the gas.
    H2S and SO2 are nasty though , but sea water data not very useful -need aerial measurements- could be what is killing fish – as well as cooking.

    2. You are probably right that it is not deadly in and of itself. But, I still feel that it is much better to be safe then sorry.
      Especially since they now have even warned people from bathing.

      1. Presumably there is a risk if you swallow the stuff and you might also inhale more gases. You could also get irritation to eyes, skin and respiratory tract.

        Suspect the concentration may also vary and be unpredictable.

        Better to be safe than sorry.

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