Posted on by Jón Frímann

Possibility of a new fissure has opened up in El Hierro volcano eruption

It seems by the harmonic tremor data that a new erupting fissure has opened up somewhere in El Hierro volcano. But given lack of visual observation I do believe that this fissure is at really great depth, and is not leaving any signs on the surface that a new eruption is taking place. Where this new fissure might be is unknown to me at present time. But based on the harmonic tremor data this new eruption seems to be powerful one. It should be expected that new fissures opens up a random while El Hierro volcano is erupting. So far the fissures that have been opening up have been short and out in the ocean. It should also be expect that erupting fissures stop erupting for no reason and with no warning at all. This seems to have happened as I am writing down this blog post.


The harmonic tremor from the eruption in El Hierro volcano yesterday. It can be seen on this harmonic tremor chart that the eruption was powerful all yesterday. Copyright of this picture belongs to IGN (Instituto Geográfico Nacional).


The harmonic tremor around 22:07 UTC. At that time the eruption was in full power as can be seen. Copyright of this picture belongs to IGN (Instituto Geográfico Nacional).


The harmonic tremor at 22:46 UTC. Notice how the drop is sudden when the new eruption fissure stops erupting. What happens is that the magma source that fed the erupting fissure did dry up. Why and how that happens in unknown to me. Copyright of this picture belongs to IGN (Instituto Geográfico Nacional).

This might mean that a new fissure might open up in the next few hours to days. Where that might happen is impossible to know. But as the fissures have been open up so far, it is going to be in a North – south line (about) in El Hierro volcano. What has however become a problem in my opinion is that the magma might have “boiled” the rock and made it soft. So it might not make a earthquakes before a eruption starts in it. This might be the case if the magma has been in the crust for the past 5 weeks. But the only example of that type of event that I know of was in Eyjafjallajökull volcano last year (2010), when a new fissure did open up suddenly and without any earthquakes or warning after 4 weeks of eruption. The reason for that was the same one on what I think might be happening in El Hierro volcano.

From what I can tell, based on data and earthquakes it does not seems that the eruptions in El Hierro volcano are over. As new magma continues to flow in from depth (the mantle). Until that flow stops, El Hierro volcano is going to continue to erupt. However there might be breaks from few hours and up to several weeks between eruptions, in that case no eruption would be taking place. This has its origin in the fact that this is a fissure rift events of shorts, a similar eruption took place in Krafla volcano in Iceland for over a 10 year period. Movement and flash inflation and deflation are also to be expected during this period in El Hierro volcano eruption. As it has many similarities of the eruption in Krafla volcano in Iceland. But it is not exactly the same, just similar. As Krafla volcano is on the inter-plate rift zone. While El Hierro volcano is on a hot spot rift zone, far inside the Africa Plate.

Update on the forum: There have been some technical difficulties with the whois registration. How that works out is not yet clear. I am going to short that issue out before I set-up the forum on the domain. In the case I have to register a new domain name. What happens in this case should be come clear next week I hope.

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

      1. And as you said there seems to be no earthquakes since a while, so I would say either this has stopped (for now) or you are again right and the new vent might not give many warnings in the form of shallower quakes.
        PS: I have been following your blog since the eruption in el Hierro started, thanks to you and thanks to all the people who contribute to this blog I have discovered how fascinating volcanoes can be, keep on with the good work!!

    2. Wonder if it is significant that the last recorded EQ for 17/11/2011 was:

      1113170 17/11/2011 20:10:39 27.6723 -18.0315 17 2.3 4 SW EL PINAR.IHI

      This is more towards La Restinga than the activity in the north.

      1. If Bob was mainly de-gassing from a ruptured gas reservoir, the EQ may have blocked the exit route for the gas, or de-gassing may have finished.

        In both instances, we wait to see what the magma will do.

        That’s me done for the night. Hope it is quiet in El Hierro and Iceland.

      2. Sorry, I seem to be talking to myself (a sign that I should be heading for bed).

        There is another possibility, given how quickly the spectrogram lessened – the magma may have met an obstruction.

        http://www.ign.es/ign/head/volcaSenalesAnterioresDia.do?nombreFichero=CHIE_2011-11-17&estacion=CHIE&Anio=2011&Mes=11&Dia=17&tipo=2
        http://www.ign.es/ign/head/volcaSenalesDiasAnterioresHora.do?nombreFichero=CHIE_2011-11-17_22-23&estacion=CHIE&Anio=2011&Mes=11&Dia=17&tipo=2&hora=22-23

    2. Human noise-I think it artillery training or the likes was mentioned or something along those lines.

      3. Lurk, next plot with terrain just make it a line drawing if possible for the island. They are now coming up from underneath. If this is invading a lava tube system and moving up then it will quake lightly and we might be able to kind of line it up with the .pdf about the caves that are already there.

        I couldnt get it how this thing formed up and your plot is starting to confirm the lava tube/cave connections. They are just deeper I think its all it its. The magma chamber might just be a huge lava tube thats filling in kind of a stupid non linear fashion.

        With the line drawing showing depth we will know if its invading the mountain by the plots.

        Agreed, they aint fessing up on all they know but what else could they do? If they acknowledge it, it will tank the already tanking economy there. Who is going to drive in a tunnel full of gases? Who is going to hang in a town if they know its going to go in the future?

        If they leave then the govt is going to have to house, clothe, feed, and educate them.

        Again, I think that they are going to make the call way too late. 4 hours my butt.

        A units in the military have to sortie within 24 hours of the go order. Towns people can do it in four. Pass the crack will you……

      4. Can’t do a line drawing in that program.

        I can do points, or I can d a surface plots (with lines) but I can’t combine the two.

        For the terrain plots, I can cut back on the number of data points that represent the terrain, looks kind of shitty, but you can get an idea of where everything is at spatially.

        Another option is to only do elevations from 0 km to 0.01 km. That will look a bit odd, but it will show only the coastal areas. That would leave the innards empty so you could see where under the island stuff was at.

      5. And alternate program, Diva GIS, allows me to mark up anything I can draw into the system, but I can’t go 3D/4D or rotate it. Static only.

      6. Thank you, Lurking.

        EQs are occuring on each side of the silent zone so it appears to be closing on my 2D plots but is still there on the 4D plots.

        The silent zone now appears to be tubular.

      7. @ M Randolph Kruger, EQs have been under the island ever since 19/07/2011, with a very brief respite when Bob first erupted. In fact the first occurred a bit to the North of the estimated location of CHIE.

        The “silent gap” is deepest under the island and extends up out into the bay of El Golfo. But EQs are now occuring on each side of it.

        Not convinced that IGN is deliberately or malicously hiding anything because they are making a lot of data freely available.

        Suspect the real issues are the balance between acceptable risk, economics and different views amongst experts; and, the fact the Spanish elections are imminent. Not an easy position for decision-makers.

      8. Or of course the problem could be a simple case of just how do you show 11,573 EQs easily on a web page.

    1. Thank you, Lurking!

      Ok, it was my impression only, no clear signs of layering in the data (I kind of saw a dead layer in the table, it was not there). However, If they pump down the water to a 0,5 – 3 km, these eqs at >10 km are very intriguing…

  6. I leave it in your hands Lurk. I dont have a clue how you do it but man thats goooood stuff.

    It was your first 3-D that got me thinking about tubes and slowly but surely and running the daily maps for the quakes simulatneously with your stuff you get a picture of a basically a big wad of magma starting to move. I think its too deep for anyone to really measure it properly and certainly not with just the gear they have in the Canaries. This needs a full 4D mapping, with plots from GPS, sonobuoys, seismos in proliferation. I think they also are having to hand plot those quakes so the data may not get published very fast.

    This also lends credence to two things I said. If it happens I dont think they will see it in time. I also think that they will not get everyone off that island in time if it does. Call it politics, money, economy or what…

    Hell, just call it Herculaneum and Pompeii. They sat and watched and the damned thing killed them all. Wouldnt leave…. Why?

      1. The Margalef mapping showed 2 newer vents – NW and NE of Frontera – out on the ridges where the northern promonteries extend, around the centre of the quakes in NW Frontera. I wonder if these vents are degassing more freely.

      2. Based on what was shown in the pdf… it would be a simple matter of whipping out a pair of binoculars and looking.

      3. Really?
        Where did you see that. I wished I could read more about it.
        Amazing volcano…
        Thanks, Alyson

    2. From what I saw on a documentary a year or so ago it is now thought that a massive pyroclastic flow caught them all, some must have been destroyed instantly, some burned, some suffocated. Could just be yet another persons hypotheses though.

      2. Yeah but it built for months. Even this one isnt going to go in an Atlantean Day.

        There will be few quakes to let us know if its going up into a tube thats open at the top. It will simply start gassing and say hello in a not so friendly way.

        Good Morning Renato.

    3. But Pompei and Herculanium had an excuse – no previous known / recorded studies of volcanoes. Pliny the Elder was the first known scientific observer in the western world at least (and it cost him his life) – his nephew survived to document the eruption.

      1. actually, the better minds of the thought was a dead volcano, i can’t provide a reference, but i have seen literature on it

  8. For the truly weird.

    P-Wave and S-Wave speeds observed at El Hierro vs the angle below the horizon to the the quake hypocenter. This angle is derived from the range to the quake and the depth of the quake and is the view from the receiving seismic station.

    There seems to be a marked change in velocity at an angle of about 58° to 61°. This is likely due to a change in propagation speeds between two different types of rock mass. The angle of incidence at this “critical angle” likely causes the odd speed shift.

    Only 8 quakes were used in this plot, there needs to be a lot more added to it before you can draw any conclusions from it. This is for information purposes only.

    http://i42.tinypic.com/feox2f.png

    1. That’s cool – if you get to derive station heights, and already have an error bound for their lat/lon location, then an accurate terrain map, should show all the areas inside the lat/lon area with altitude in that height range (plus/minus basement/story height), and that might let you narrow down the station locations even closer.

    2. For grins Lurk…. overlay the depth on a couple in the privacy of your own computer and see what they show. This has to be hard entering all this stuff but it might be telling. Nothing wild , say 10 or 20 of the bigger ones.

    3. Interesting. We would need to know the location and depth of the velocity changes for them to make much sense.

      I would guess the velocity could change where the P & S waves went through:

      ocean crust,
      sedimentary layer,
      old igneous or metamorphic rocks,
      old lava tubes,
      gas, and/or
      magma

      Which is for people with way more knowledge than I have.

    4. Lurking , do you have the coords/locations for all the ElHierro seismometers ?

      is it possible you are demonstrating a crude form of Tomography, where some of your trajectories(sp?) are going through a magma chamber, and some are not ?

  9. @Lurking, that plot on the ‘gap’ is once again very informative – but I wondered if you can run the same set (or a similar set if that’s easier) with a different camera pan?

    At the moment the camera seems to run around the horizontal/vertical – but given that the gap is a sloping feature, I wondered if you could do an orbit around the imaginary plane that would slice through the middle of the gap.

    I can see that there would be a few such possible planes – but any one of them would (I think) help with looking at those quakes in the gap.

    In the current horizontal orbit – looking from the side on view seeing the gap is easy, but from the “downhill end” the quakes above (and behind) the gap currently mask the quakes in the gap. and from the “uphill end” the quakes below (and infront) do the same.

    So trying to see if there are any linear features shown by the quakes in the gap is currently a bit tricky, but without the masking it might be possible?

    1. Maybe… but no promises. One of the few things I was able to get to work with freebasic was panning the camera. I do the plots manually rather than write a routine for each. If I can put an elevation increment into it I may be able to pull it off.

      I’m gonna have to look into it.

  11. Thank you very much, Mafl.
    I think I’ve missed those links among all the comments and my lacking of time to take a closer look.
    Yet, I didn’t find the mapping with the vents NW and NE of Frontera.
    They talk about two spots “near the volcano”, which I assume they’re to the South of La Restinga.
    But the videos and information are great and I have to give them a better try.
    Thanks again.

  12. My question is just from an ignoramus :

    – How come the vents are closing up ?
    Is it a lack of pressure, and if so, what causes it ?

    – If they collapse, how come magma wouldn’t just blow it up ?

    Also: Many thanks to Jon and you all, this blog is most interesting

    1. Not an expert myself. But magma rises becuase it is hotter and less dense than the surrounding rock. Pressure only builds up where there is more coming up from behind it than it can rise.

      Vents close because:

      1) the magma may cool so no longer rises;
      2) the magma supply may get cut off or run out;
      3) the magma may find an alternative route; or
      4) if the eruption is largely gas from de-gassing of the magma, the gas reservoir at the top of the magma reservoir may have emptied.

      A new vent may open if magma finds an alternative route out.

  13. Lurking, have you tried gnuplot? You can do pretty much anything you want with it, but it’s all command line driven and has it’s own plotting language, it’s a little hard to use, but probably a lot easier once you get the basics down.

    Also, thanks Jon & Lurking for the continued write ups, graphs, etc.

    1. I’ve looked at a few different ways of working with the data. GNUplot doesn’t integrate into Excel as a menu item. All I have to do with Dplot is to select my data, select the plotting function and go.

      Once Excel passes the data to the other program I’m in the other environment with all the functions that it has available.

      Sure, I could dump the data-set out as a csv and then import it, but that would start getting unweildy if I had to do that for every plot. Right now I only have to do that when bringing re-gridded data back from Dplot. Re-gridding is pretty handy for filling in massive data-gaps and making those “leaps of faith” between sparse data points like the widely spaced GPS info.

      I would like to have a better gridding method, one that I could tweak to allow for crustal stiffness, but like going with an actual statistical language like “R,” or trying to rummage out 30 year old knowledge of how to use Fortran… I’m faced with yet again of having to become familiar with another language rather than doing what I want to do, which is study and understand geophysical processes.

      But… I appreciate the heads up on GNUplot. With time permitting, I’ll look at it.

      2. Check your browser settings Jon, the spam filter and whatever antivirus you got. I fixed mine with that error by turning of Norton for a few mins. I got it then in fear turned it back on, then went back.

        No problems.

    2. I don’t see the web cam pictures at Armand’s site.

      The page says it requires Adobe Flash plug-in. Funny, all the other websites requiring the same plug-in work fine, this is the only exception for me!

  17. Yes it stops, but i thik this is normal because as i was saying this new activity was much for the left side in the panoramic view of La Restinga. I was seing this in the left corner, and only a part of it. It was vigorous…

  18. OT, but the volcano closest to me, about 60 miles away and picture perfect displayed in my office window, Mt. Baker, just had a 4.0 at a depth of only 5 km.

    On a related note, snow is early this season, and Mt Baker ski resort opens this weekend. WooHoo!

    http://www.pnsn.org/req2/

    1. Never mind, they moved the loc, increased the depth, an upgraded to 4.6…

      Now back to our regularly scheduled program.

  19. From AVCAN’s Facebook page:

    “THE MOCANAL, IN VALVERDE, RECORDED YESTERDAY THE QUAKE OF GREATER MAGNITUDE WITH A 3.6 IN THE SCALE OF RICHTER.

    18-11-2011… 11: 56 – Ministry of economy, finance and security during the Thursday there were a total of 17 earthquakes, although only one of them was felt by the population Red Cross offered talks to border residents to achieve standardization of emotions, after changes in their lives by the eruptive process the quake of greater magnitude of 17 registered yesterdayNovember 17, on the island of El Hierro, recorded a 3.6 on the Richter scale, as it has confirmed the National Geographic Institute (IGN) to the address of the Civil Protection Plan by risk volcanic de Canarias (PEVOLCA). This earthquake was felt at 16: 25 hours, with maximum of III (EMS) in El Mocanal, Valverde, intensity and was located four kilometers from the coast and 22 kilometers deep.

    In total, 11.644 events have been located since 17 July 2011.

    From the direction of the PEVOLCA recalled that the operational deployment remains in El Hierro waiting for the evolution of the eruptive phenomenon that occur on the island since last July.

    Tremor on the sign of the tremor, IGN notes that he maintained high levels of amplitude initiated the previous day until approximately the 22: 08 hours, when there is a sharp and remarkable decrease of the signal. In the analysis of seismic data do not appear evidence of a second source of tremor in the North.

    Deformation Deformations follow the same pattern of stability than in previous days in the horizontal components. There is a clear deflation in the vertical component of the stations in the South and East of the island, in the Gulf area, which shows a stabilization in elevation to the West and a slight tendency for deflation to the East.

    Stain on the English channel, are not appreciated visible signs on the surface, nor practically activity throughout the day. Afternoon notes issuance of fine material in a small area, but there is no record of the emergence of fragments of lava at the surface.

    Informative talks From November 12, Spanish Red Cross has carried out several information sessions in the municipality of the border, with the aim of achieving the normalization of emotions, feelings and behaviors that develop people after living a traumatic event; give people the tools they need to respond to a situation of emergency or profiuron, as well as facilitate a series of recommendations to care for your mental health.

    The talks, which have been given at the headquarters of the Association of the elderly “Los Roques de Salmor”, have been followed by more than 200 people in the municipality, most of them elderly people seeking response to their concerns give the influence that is taking the eruptive process in their lives.

    In this regard, the recommendations are offered both for the affected families and friends. In the case of living process in first person, they are encouraged to seek company and talk about what happened; organize time and kept busy, and do things that do them feel good, helpful and supportive. If it’s family and friends of those affected are encouraged to promote strengthen these linkages; understand and accept anger and other feelings of those affected, and avoid comparisons on the damage suffered.
    (Translated by Bing)”

    http://www.facebook.com/#!/pages/Actualidad-Volc%C3%A1nica-de-Canarias-AVCAN/163883668446

      3. The dots? that is where the various stations are for different types of measurements, (seismic, GPS, geochemical). The zones that PEVOLCAN uses as ‘zones’ are rather villages or municipalities, like, La Restinga is part El Pinar, so when La Restinga is in Red Alert that means El Pinar is the municupality affected.

    2. I do not think that this will be usefull to predict earthquakes. If you read carefully: “during crushing and grinding of typical terrestrial crust rocks in air, O2 and CO2 at atmospheric pressure,” These conditions you won´t find before an earthquake and mostly not during an earthquake either.
      But: “exoelectrons emitted by high electric fields, resulting from charge separation during fracture” These conditions you WILL have during an eruption, so you may use Ozone as indicator for an ongoing volcanic eruption.

    3. The weakness in their method for deep Eq prediction is there’s no oxygen down there – so no ozone could be made. At the surface where oxygen would be available its probably too late for ozone measurement to be useful re Eqs. If ozone could be used to detect creep in rocks about to landslide I dont know, but rocks fracturing could be monitored with geophones so ozone method perhaps a bit ott.
      There’s literature on electric field generation by deep fracturing rocks that has been proposed as Eq predictor but I suspect not substantiated.

      1. The problem with electric field generation due to stress generating is, that you must be in place and record the field over a long time to see if there are significant changes. Changes may be very different from place to place and difficult to filter out from noise.

    4. Hey, if it loosens the purse strings and gets funding from the government over the long term, I’m sure that they would be more than happy to research further.

      Whats a few million dollars in grants between friends.

      1. 🙂
        long term funding and government? That´s not easy when the government is not able to think longer than in 4 years election periods and geologists for this time think very short in a “70 year between two major quakes episode recording”

      2. Which is why the never ending press releases. A legislative body typically has incumbents whose persistence in office is a direct function of the amount of bacon they bring home to their district.

        L = $ × ( C / E )

        L => Length in office
        $ => Bacon sent to district
        C => Corruption events
        E => Press Exposure

    5. As I recall , there where installed som ozone sensors at geotermel boreholes in south Iceland in the seventies as an experiment for earthquake early warning.
      I don’t know it was still running in 2000 EQ’s
      Anyway, it is not a new theory.
      I think I remember talk of inert gas subsiding at pthe plate boundary an being relased before large EQ’s.
      Same thing with chemical ratios.

  22. Jon this looks interesting. Is Theistareykjarbunga waking up?
    http://hraun.vedur.is/ja/oroi/ski.gif
    Friday
    18.11.2011 15:57:51 65.860 -16.966 7.6 km 0.5 99.0 1.7 km SSW of Þeistareykir
    Friday
    18.11.2011 15:30:43 65.864 -16.950 6.1 km 1.9 99.0 1.2 km S of Þeistareykir
    Friday
    18.11.2011 12:44:55 65.088 -16.112 9.7 km -0.0 99.0 8.3 km NE of Upptyppingar
    Friday
    18.11.2011 00:04:18 65.864 -16.947 5.8 km 0.8 99.0 1.2 km SSE of Þeistareykir
    Friday
    18.11.2011 00:04:18 65.860 -16.887 1.1 km 1.5 60.53 3.5 km ESE of Þeistareykir

    1. Ummm.. I responded to this a few hours ago but it didn’t show up.

      Here it is again.

      Two static sets that populate the quakes over time. No rotation so that the 3D stands out, but the incremental plotting I like. I’ve been monkeying around with trying that, but short of having to learn a new language have been unsuccessful. Instead I get caught up with keeping abreast of the unfolding events or trying to second guess what Bob is up to.

      1. My way is just to explain what I mean : magma chamber to the North (El Golfo) and eruption to the the South (La Restinga) …
        I don’t know why, but I think about “subsidence” (the weight of El Hierro island) …
        After it means about magma take the easyeast way !

        So, If you consider the earthquake before eruption, during and after, it don’t think stupid.

        I’d like to show 4D animation ! (3D+time)
        I have IGN localisation of earthquake, but nothing to do with that …

        I’m an old Fortran programmer, trying to do best, but I like Fortran, so I’m waiting for more until I’ll do best ! (in a long time …).

        No time for me to do that, so the challenge is open !
        (but I think about)

      3. Good job, could you redo it, but use the color scale as a graduation of seismic intensity from .5 to 4.0?

        I haven’t seen how the seismic intensity trend in relation to location and time.

        I would conjecture that a pattern would emerge from looking at the data that way.

      6. The rough time lines were a lot of activity in NW, W and SW Frontera (mainly SW Frontera) prior to a sequence of EQs at El Pinar before the emergence of Bob. The activity north of the ridge resumed very shortly after the emergence of Bob but deeper and larger EQs.

        If you want a more detailed time line, watch the animation provided by avcan.org.

      8. Okay Karen… Now I challenge you to do the same thing that I asked for out of Lurk and I am sure he is figuring a way to do it. Boy is a genius.

        Anyway. You go to zero at the top of the graphic. I think you need to establish the top at 6000 feet, then bring it down to zero so we can see if quakes are occurring IN the mountain. Hard as hell to tell and especially with dome quakes. You have to be parked nearly on top of the mountain or along the same strata to get good readings. E.g. Redoubt was monitored from a couple of miles away in the hut. Mostly because they didnt want to lose their gear. Later as it started to cha-cha, they flew up and set up gear on the backside and wow it got crazy after that for readings in the mountain.

        This is because the quakes are up in the mountain and not below it. Thats where the magma will show up if its breaching it at the bottom somewhere.

        We are kind of fortunate that the island is big enough to instrument it as it is.

      9. You do realize that backing up to a higher elevation would require that quakes are recorded for those levels.

        Usually, all depths are referenced to a baseline, in this case, I think that is sea level.

        Quakes shallower than about 0.1 don’t get a depth, nor do the ones with poor resolution.

        For example:

        2011/11/10 18:11:12.02 0.56 0.52 27.8627 -18.0447 2.8 2.0 4 0.0f 14 7 287 0.11 0.15 m i uk IGN 1111895

        It had a lateral location error of 2.8km for the semi-major axis and 2.0 km for the semi-minor axis, oriented along 4° bearing for the major axis.

        This is actually pretty good resolution, and fits with a lot of the other quakes that they have in the catalog.

        But with a depth reading of “0.0f” it’s a pretty good bet that it was either above their reference datum or that they just couldn’t work out the location. Given the good values for the lateral position, “above the datum” might be a valid read.

        We can make some assumptions, but they would be highly suspect, that blank depths may be “above the datum” and inside the mountains.

        Dunno if I want to make that leap and post it in public. I would not want to freak people out for a whimsical evaluation on my part.

      10. Also, since I’m on the subject. My batheymetric data became suspect when I plotted the La Restinga quakes near the Bob jacuzzi. According to the plot, they were above the seafloor. That’s why I tossed that layer out a while back. It’s good as an overall reference, but close-n-tight it was worthless.

      11. The whole island is a mountain so unless the quakes are occurring on or below the seabed, they are occurring in the mountain.

        It’s the quakes that seem to be occurring in the sea that have me perplexed.

      13. Lurking, I spot checked some of the blank depths against avcan.org;s animacion to verify whether or not I should keep them in.

        Read somewhere that EQs can occur in the sea. Unfortunately I did not pay too much attention to it at the time as it did not relate to what I was researching. Could de-gassing produce small EQs in seawater? Or the discharge of very hot materials into sea water?

    2. The GPS station that IMO has are on there web page map. But others have no map that I know of. I am not sure how many map University of Iceland has online of there GPS hardware.

  25. When remembering electro-plasmatic response… Welding springs to mind, what if ? Love that stench of the sea shore, and Bill that was a dud thread link, tho’ food for thought

  26. Well Karen there’s a very clear size vs latitude pattern there, but without it being 3d or 4d it hard to pull any conclusions out. To bad I always let my staff do the data crunching for me. I would do it myself.

      1. @ Lurking: Great plot. And that is cool software; I am really envious. Is plot for all EQs since 19/07? And do you have a feel for where CHIE would be on that plot?

        @Pablo: You can get 90% of the picture from 2D plots – enough to confirm that El Hierro, especially NW, W and SW Frontera, is not a very comfortable place to be right now.

        Where the magma is going to emerge (if it does) is going depend entirely on where the magma finds a route through the rock.

      2. I’m not the author of the video posted yesterday.
        But i’d like to boost it until now, and with time scale.

        @Lurking : are you using Surfer and/or Voxler ?

        I miss time, but from tonight I’d like to begin some search to find some freewares …

        Have a good day.

  27. It seems to be more activity on Restinga web cam now, but there is also a possibility a trick of light and tidal current.

    1. It was more apparent earlier, so I think this is nothing. Thanks John for this great blog, and the job you have done. Great staff here too.

  28. Jon your geophone is registering Eqs that IMO doesn’t appear to have recorded! Do we know why?

  31. also reposted from way above:

    @Lurking / anybody
    do you have the coords/locations for all the ElHierro seismometers ?

    @Lurking:
    is it possible you are demonstrating a crude form of Tomography, where some of your trajectories(sp?) are going through a magma chamber, and some are not ?

    1. I can reply to the second question. Lurking’s plot shows the energy released by the earthquakes to date: cooler colours = less energy and hotter colours = more energy. So the plot is showing us the density of EQs by lat & long. But note that larger quakes release a lot more energy than smaller quakes.

      EQs tend to occur round the magma reservoirs where rock fractures from either heat or pressure. So I am guessing that the plot will not be a complete picture of the tomography because it will not include all the heat from the magma, itself.

    2. Seismos, yeah. CTIG and CHIE I have. They are publicly released.

      The other ones are not, and I haven’t gone through enough back plots to be comfortable in releasing their locations. My error is still about 800 to 1900 meters.

      Back plotting is a pain in the arse to do, but it’s the only way I can get the data since there is obviously a problem with my haversine usage. (used in doing bearing/distance calculations to the new position). Three separate routines put all the seismos somewhere out in El Golfo bay. I’m pretty sure they aren’t there. (saltwater plays hell with electronics).

      I just have to bite the bullet and slug lots of coffee and do the back plotting. Essentially it’s the reverse of localizing an earthquake. I take the known quake positions and track back to the station by converting the “dist” to km and localizing it.

      Here, a worked out example for those that want to “play the home game.”

      http://www.01.ign.es/ign/none/volcaDetalleTerremotosFasesDat.do?evid=1113510&zona=2

      Is a Mag 3.3 quake (mbLg 3.3) that occurred at 18:27:04.70 on 2011/11/1.

      The position of the quake was at 27.7780 -18.0396, and has an error ellipse of 3.6km by 2.2km oriented along a bearing of 169°.

      A snippet from the rest of that page shows:

      CCUM 0.03 165.3 P 18:27:08.436
      CCUM 0.03 165.3 S 18:27:11.040
      CTAB 0.05 234.7 P 18:27:08.380
      CTAB 0.05 234.7 S 18:27:10.920

      CCUM is at 0.03 distance. This is not in kilometers, it is in degrees. This is the distance along the surface as measured by the central angle from the center of the Earth. Seismologists think and talk in this language when relating waveforms.

      How do you make it into something we can use? Pretty easy… actually.

      In radian measure, a full circle is 2π. The length of an arc times the radius will give you the distance of the arc in whatever units you have the radius measured in.

      So, 0.03° in radians is 0.000523599 (I used Excel’s RADIANS() function)

      Which Earth radius you use will determine just how good your result is. I’ve looked at a lot of them, but found that the IUG radius works best. It’s 6,371.01 km. (http://www.iugg.org/)

      0.000523599 x 6371.01 = 3.34 km. (I rounded the result)

      Going back to the list, you will see that CCUM has an azimuth of 165.3°. That is the bearing from the quake to the siesmo.

      Locate the quake – 27.7780 -18.0396 cut a bearing of 165.3° out 3.34 km and bingo. You have a probable location of station CCUM. It’s probable because you have a lot of errors that are in that data. Mainly, the 3.6km by 2.2km error ellipse of the quake.

      This is where it gets tedious. Those errors don’t throw out your position. One cool aspect about errors, is that they average out with enough data. If you work through this with enough quakes, you will get a fuzzy little ball of positions where CCUM is supposed to be. The middle of that “centroid” is going to be the most likely position.

      Will it still have uncertainty? Yes. But it’s gonna be close enough that if you walk to that position you could look over at the actual piece of gear and take a close up picture of it.

      Provided you have worked through this excessive with enough data.

      I provided this explanation in case I get distracted or too frustrated to do it myself.

      1. Oh yeah, the P and S time stamps. Subtract the event time (18:27:04.70) from the arrival time (18:27:08.371) and that will tell you how long it took for the wave to travel there.

        3.671 seconds.

        At a distance of 3.34km that gives a P-wave speed of 0.91 km/s.

        Abnormally slow? No. The wave was going almost straight up. Normal propagation speeds show up once the wave has traveled a bit… you can see this as you plot the distances and time to the various stations.

      2. Just started reading up on P and S waves.

        A P wave with a speed of ~1km/sec would be travelling through water. And 27.7780 -18.0396 is only about 1km out into the bay NW of Frontera according to Google Maps.

      3. Don’t get caught up with the water/non-water speeds.

        All waves traveling near vertically are slow when compared to down range. It’s a known effect and is one method that can be used to determine depth.

    3. Robert Somerville

      “is it possible you are demonstrating a crude form of Tomography?”

      No. It’s probably related, but all I have done is to identify a “critical” angle between two layers of rock. I don’t even know how to localize how deep that is at.

      Take a glass of water, stick a pencil in it. Notice that the pencil seems bent at the water/air interface. That’s because the index of refraction between air and water is different.

      All I have done is seen an artifact caused by a change in the velocity of propagation between two rock masses.

      At least that’s what I think it is.

      Carry an exploration of that much much further, and determine what the delay times should be as compared to what they are, do that a lot of times, then you are in the realm of tomography.

      1. i sort of agree with you but sort of don’t … if its a only a refraction artifact we will experience refraction (Snell’s Law) all along the interface between the two layers (not just there, at that angle, which is quite a steep angle to see very strong refraction effects) . it depends on the extent of the interface , if its a spatially localized interface you are talking about, i agree with you … my 2c worth

      2. perhaps at that angle , your ray path is actually intersecting a near vertical faulting plane or rift, which could perhaps explain the spread of your data (if it not some kind of measurement error, of course )

      3. i should have added/said ” intersecting the fault plane at a shallow angle”

      4. I can’t really sit with the intersecting the “fault plane” idea.

        These are the plots of the speed from several different quakes at different locations. (yeah, but all on the island), so it’s not one specific path your looking at. Just a collection of speeds that show a tendency to “not be smooth” at that angle.

        However, your guess is as good as mine. I don’t know what it is either.

      5. Check the lava tubes in the areas boys. They would deflect the crap out of the signal and really screw with the times.

        Or, check the type of rock underneath. I got it from good sources that the 1800 foot level is loaded with metamorphic crap which is made up of basically old ash thats compressed.

        I think we are all going to be surprised by something soon myself. None of the normal things we are used to are working.

  34. Wow, major change in CHIE tremor record at 17.12. Anyone know what happened?
    No earthquakes reported to go with it.

    2. my random guess is that when the vent in the south closes itself, the pressure in the north becomes greater and we have more quakes as the magma pushes the ceiling of the reservoir, when the pressure in the north (reservoir) is too much it blows open the vent in the south again and there are lesser quakes as the pressure is released during the eruption.

    3. Looks like more magma moving. May be whatever obstructed it before has cleared (either via earlier quakes or melted). Or a new vent.

    4. From: http://www.volcanodiscovery.com/view_news/2450/El-Hierro-volcano-Canary-Islands-Spain-increase-in-tremor-and-signs-of-a-possible-new-submarine-vent.html

      “El Hierro volcano (Canary Islands, Spain): increase in tremor and signs of a possible new submarine vent near La Restinga

      During our observations from near the south coast at La Restinga yesterday, we could not observe any activity at the surface of the water. This corresponded well with a sharp decrease in tremor measured by the Instituto Geográfico Nacional (IGN).
      Today, we could see areas of the ocean surface flattened by likely upwelling water rising from below, at a much closer distance to the shore than the previously active vent area, at only about 300 m distance from shore and slightly to the east as compared to the former area. Volcanic tremor has increased significantly again. We suspect that a new vent might be forming or has formed in this area. Whether this leads to another “jacuzzi” or boiling water area is only speculation at this point. The situation remains interesting.”

  36. An interesting feature, for me at least, is on the La Palma spectrographic analysis

    http://www.01.ign.es/ign/head/volcaSenalesDiasAnterioresHora.do?nombreFichero=EHIG_2011-11-19_17-18&estacion=EHIG&Anio=2011&Mes=11&Dia=19&tipo=2&hora=17-18

    At the point in time that El Hierro declared business as usual some sharp spectral lines appeared at about 4Hz, 5.5Hz and 7Hz. In the past I had dismissed these as local noises but I now see they are part of the tremors coming from El Hierro.

    1. The smudgy lines at 1 to 2 hz are certainly reflecting activity on El Hierro.

      I have tended to think the higher frequency lines were local noise, especially as there was some this morning.

    2. I’m not so sure. Look back several hours, and you’ll see those lines come and gofrom time to time. Bsides, the sharpness of the peaks in the PSD suggest man-made to me, harmonics of something vibrating at about 1.33 Hz. Perhaps more significant is the increase in amplitude around 1Hz, also showing as a knee in the PSD. It’s there a couple of days back when the tremor was high, but not in between when it was lower.

    4. Brian, that is almost sharp enough to make a Canary Island tartan!
      Do you have any idea what causes those transverse lines?

      1. To get a horizontal line you need to have well defined single frequency component. You can get that by exciting a resonant system or by doing something repeatedly and regularly. A diesel generator or air conditioner would fall into the latter category, an organ pipe or whistling kettle the first. Examples carefully chosen.
        I believe a very narrow line of constant value is more likely to be a resonant system like a constant fluid flow through an aperture into a chamber. But then it could be a desk fan 😉

    1. Please do not email me doomsday nonsense. I am either going to replay it and tell you that it is nonsense. In the case you do not stop. I am going to ignore you and move all your future emails into the spam box.

    2. @Anon. This isn’t a doomsday site; it focuses only on Iceland and specific other areas of volcanic / EQ interest. There are more appropriate sites that cater for those more interested in doomsday scenarios. I presume that you can find these via Google. Suggest you address any emails discussing doomsday matters directly to these sites.

    1. Really nice pictures. Gives us a feeling for the island at the present time. Thank Joke.

  44. AvcanFB

    pepinacillo a las 03:11 y otra vez desprendimientos de rocas en el Risco de Tibataje a la altura del caserío Pie El Risco. ufff

    Translated.

    pepinacillo at 03: 11 and again mudslides of rocks on the cliff of Tibataje at the height of the foot El Risco hamlet. Phew (Translated by Bing)

    buenos días, el 3.7 de las 3:15 nos despertó, y estuvimos oyendo caer las piedras en el Risco, la caída de piedras duró mucho, casi un minuto, y una de las piedras cayó sobre algo metálico CLONG!…

    good morning, 3: 15 3.7 woke us up, we were listening to falling rocks on the cliff, falling stones, lasted nearly a minute, and one of the stones fell on something metal CLONG!… (Translated by Bing

  46. After the two earthquakes early this morning one was a 3.7 a lot of the people on El Hierro are saying on AvcanFB that there have been landslides and they have heard falling rocks .

      1. That line appears to be caused by the Ramon Margalef being in the North of El Hierro then switching of it’s tracking data before it again switches it on in the La Restinga area. Why they should do such a strange thing i will leave others to explain or judge. Someone posted this link on another blog
        http://i1112.photobucket.com/albums/k499/sissel59/RamonMargalef20111120141917.jpg
        As you can see it clearly switched off the tracking instruments for a period unless it had technical difficulties. Odd.

    1. Brian – I would venture the line bisecting the Island is the Ramon Margalef’s track taken from an AIS track. AIS = automated identification system and is a VHF radio based tracking system used for all vessels above 500 tonnes. The receiving station is most likely on Tenerife or Gran Canaria and as VHF is a line of sight radio system it cannot track vessels behind the island. AIS signal frequently drops out too so the track just joins the dots between the last and next positions. Look at http://www.marinetraffic.com as an alternative tracking source.

      1. It really doesnt mean anything Brian. Its a point that they are using and could have gotten a sextant reading, GPS or the VHF/Loran stations to within about 14 feet. They likely are trying to box positions of each vent in and around Bob Maximus. I for one would stay the heck out of El Golfo as this is getting more interesting by the day.

        But the line?

        Its called splay. Run a straight line out to infinity. Now go back to the start and deviate from that line .0000000001 for grins and then start out again. Doesnt mean anything until you get out about 1000 miles and start to notice the line leaving you. But, the Margalef is likely trying to plot the possible fields of seismic activity for size by more than just the visuals of the eruption jets using just that to see if there is any linearity to them. E.g. a fault under the island.

        They obviously cant go out and sit on top of the vents-too dangerous and their gear sucks for this kind of operation. They need a swimmer type and dont have one. About the best place for that is Woods Hole and a certain gentleman there only plays with his own toys.

        But, if we simply plot the quake boundaries, then make hourglass patterns over the maximum reaches of each, they might find something significant. Make location points that would be more visible to the eyes on paper than out at sea.

        Not much else they can do. They stick their equipment into the water its going to cook it because its a dipping type and not a swimmer. That water is also very acidic. Hey lets not forget to mention the hazards to the crew. Its happened before when a Japanese research vessel was sunk by a geyser eruption. Just rolled it over and like 50 something people went into the water and were killed. Wasnt very big but the water was so turbulent that even with life jackets on, they wouldnt float.

    2. Brian Smith says:
      November 20, 2011 at 13:23

      “What does the line mean?”

      It means that the system/program doing the plotting is connecting position reports that are not linear (in time) and that have a break in the data.

      I’ve saw this time and time again in tactical data systems when there was a large jump in the reports. Its no big deal.

      As for why the gap, well, it could be they switched it off, it could be problems with reception. As mentioned elsewhere, a lot of this stuff is line of site… (radio line of site). VHF is 30 Mhz to 300 Mhz and you know how reliable FM is in mountainous terrain. (88-108 Mhz) El Hierro is a mountain. A mountain with lots of minerals (probably including oxides of iron).

      An alternate cause would be a cloud or rain interfering with a satellite signal. Even though it’s good, INMARSAT had issues with storms.

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