The Long Wait?

Holuhraun lava in daylight. Screenshot from a video by Kristinn Ingi Pétursson,

Holuhraun lava in daylight. Screenshot from a video by Kristinn Ingi Pétursson,

Yesterday, the Bardarbunga crisis celebrated its first month. As our readers have already remarked, the IMO has put out an update that summarises the earthquake data over the past month. In all, some 25,000 earthquakes have been registered by the automated system of which no less than 5,900 have been manually checked by a seismologist. That is approximately 200 earthquakes per day on average or eight quakes per hour, during “rush hour”, quite a few more. This is really quite a staggering achievement by the IMO!

Summary of earthquakes from August 16th to Sptember 15th (IMO)

Summary of earthquakes from August 16th to Sptember 15th (IMO)

Yesterday in an interview carried by Icelandic News Agency MBL , Volcanologist Ármann Höskuldsson said that the Holuhraun eruption is abating. This could indicate that the first scenario might be about to happen: “Subsidence of the Bárðarbunga caldera stops and the eruption on Holuhraun declines gradually.” However, at this stage no such conclusion can be drawn as the subsidence continues even if the eruption may seem to be in decline. However, the IMO today claims that “Measurements show that the lava field in Holuhraun continues to expand. There are no signs of decreasing lava production” and ” The subsidence of the Bardarbunga caldera continues with the rate of about 50 cm over the last 24 hours.”

If we look at what could possibly be one of the best clues available, the chemical composition of the lava, there are some interesting comparisons to be drawn with those for the 2010 Eyjafjallajökull. First, Holuhraun as released by the IMO on Friday, September 5th:

Chemical analysis of lava from the Holuhraun eruption (NordVulk)

Chemical analysis of lava from the Holuhraun eruption (NordVulk)

The four first samples in the table were taken from the lava erupted in Phase II of the current Holuhraun eruption. The last sample (HRW-04) is from pre-existing Holuhraun lava, i.e. from previous eruptions in the area. The key elements to look at are SiO2 and MgO. The percentage of SiO2 indicates how evolved the magma is. Juvenile, basaltic magma usually has an SiO2 content of around 45%. The first of the evolved magmas, Andesite, usually has an SiO2 content in the 55% – 60% range. The second, MgO, can give an indication as to how fresh from the astenosphere/mantle the magma is. However, this seems to vary slightly from location to location. Now on to the Eyjafjallajökull samples from 2010:

Chemical analysis of lava from the 2010 eruptions at Fimvörduhals and Eyjafjallajökull (Niels Oskarsson/NordVulk)

Chemical analysis of lava from the 2010 eruptions at Fimvörduhals and Eyjafjallajökull (Niels Oskarsson/NordVulk)

As is readily apparent, the SiO2 content of the first fissure eruption at Fimvörduhals was substantially lower and consistent with juvenile basalt whereas the samples taken from the main eruption were basaltic-andesitic to andesitic in composition. The reverse is true for the MgO content, indicating that the Fimvörduhals eruption consisted of juvenile magma more or less directly from the astenosphere/mantle.

Volcanologists have mentioned the likelihood that the magma erupted this far at Holuhraun may be more evolved magmas that have been pushed out by the initial intrusion and subsequent continuing collapse at Bardarbunga, something that the above chemical analysis may support. Also, the report by Guðmundur Heiðar Guðfinnsson and Sigurður Jakobsson published by the IMO on Monday, September 8th, suggest this may be the case as they identify the magma as partially being “olivine-normative tholeiite” (0-5 wt% ol). The SEM analysis of some samples indicates that the (Holuhraun) erupted magma contains minor amount of plagioclase phenocrysts (<1%) and even scarcer olivine phenocrysts and they conclude that the lack of Fe-Ti oxides suggests that the samples had quenched before Fe-Ti oxides could form. As this is evidence of evolved magmas, it supports the conclusion that the magmas erupted this far are older and evolved magmas from the Bardarbunga magma reservoir. This view has been confirmed by the foremost theoretical volcanologist, Professor Haraldur Sigurðsson, on

Furthermore, the HRW-04 sample from a previous, older eruption is very similar to the recent ones. This indicates that the current modus operandi is not something new, that at least one previous eruption has followed the same pattern of a new intrusion pushing out older magmas from underneath Bardarbunga. This may be heartening news as the present subsidence of the caldera then most likely also is not a new feature, that it has happened at least once before without the entire system going into a full-scale caldera eruption and thus, that there is an improved chance of this not happening now. To judge by the current depth of the caldera, this must have happened several times previously. The salient question is if this time, the caldera will collapse far enough to trigger the ultimately inevitable great eruption.

Thus the long wait begins. Just how long is anyone’s guess.

Henrik (a.k.a. Pyrite)

Only the IMO and the Allmannavarnir can issue volcanic warnings and only London VAAC can issue Flight Warnings.

We know a few wish to go there right now. But, remember to stay on the where the wind is not blowing, this is a very gassy eruption high in SO2. Even one breath of the exhaust could kill you, so please respect any and all warnings from the appropriate Icelandic authorities!


1,268 thoughts on “The Long Wait?

  1. Could someone explain why and or how the caldera seems to inflate or rise? And when it rises/inflates, it does so for hours at a time. I know that the more reliable is the blue line, and only over a period of time. But, the areas of this graph that I am talking about are either from 2 days ago, yesterday, or several hours. I have arrows pointing to them. Thank you. Perhaps this was discussed and I missed it….if so, sorry could you post a link to that discussion. Thanks again. Source IMO.

    • We may be over-reading the GPS readings. It’s just one instrument, and it’s subject to noise and error. Plus, it’s sitting on a glacier 700 meters above the actual rock of the caldera. Maybe ice shifting from caldera rim down towards the bowl might push the unit up a few cm at odd times. Who knows.

      I’m thinking the recent period of hugely erratic readings (the kangaroo on crystal meth period) might just have been from satellite GPS waves bouncing around and between rain/snow/clouds, confusing the instrument. The coincidence of dense fog with these erratic readings might not have been a coincidence.

      • I am afraid I have no idea of the answer to this question but I would rule out the weather because the fog has been around for days but the oscillations on the chart have been worst in roughly the last 18 hours.

        • Good point. One would hope such GPS units are designed to avoid interference from mere weather.
          Dang. We need a webcam aimed at the GPS unit !!
          Maybe the sharks were playing badminton with the GPS unit. 😉

    • Hi. I’ have been writing some posts on my blog.
      I think you should all read them and do something about it.
      But I will highlight a datum: The tides pace in Hofn and Reykjavik seam to have something to do with the time the earthquakes occur, and it makes a lot of sense, which you all can read under the tags Bardarbunga, global issues, climate change, global warming.

      No thanks, we deal in science, not mumbo jumbo and wishful thinking. But thanks for the offer… …strewth!

  2. A new summary map. This time, instead of laboriously tracing around a lava field diagram then transferring the tracing to the map, I tried out the “overlay image” function in Google Earth and it actually worked for me! 🙂 (I’ve tried this before with less than stellar results so I was pleasantly surprised this time 🙂 ).

  3. Interesting reading….

    Environmental loading effects on GPS time series.

    Metsähovi is a permanent GPS-station in Finland. It is situated on the south coast, with the distance to the
    Baltic Sea being only 15 km. The effect of tidal loading is small since its distance to the ocean is 800 – 1000 km, therefore the other loading effects can be seen more clearly. We have studied the effects of non tidal loading of the Baltic Sea and loading caused by atmospheric pressure and water storages on solid Earth in the height time series of GPS. When all known factors are taken into account, the variance in the GPS height time series diminishes up to 31%. Regression coefficients for the different factors were found to be –0.2 mm/hPa for the local air pressure, -9 mm/m for the nearby tide gauge recording and -0.05 mm/mm for the total water storage of Finland. The effect of local aquifers and global soil moisture need to be studied more carefully, because all the water storages correlate and give therefore similar results.

    Click to access Environmental%20loading%20effect%20on%20GPS%20Tervo_et_al.pdf

  4. Also an update on the 3-in-1 map:

    ♦ Blue lines indicate a direct correlation between a ‘quake and a drop in GPS; green lines are from M5+ quakes which appear to have no direct effect on the GPS, and blue dash lines are from M4+ quakes which occurred at the beginning of a more gradual decline in GPS.

    ♦ Indicator lines (blue, green and dashed) have a gap where they meet the GPS lines in order that the trend of the latter is not obscured by the former.

    ♦ I thank avalonlightphotoart for the original idea of plotting the larger earthquakes against the GPS graph, and all those who suggested including both the depth of ‘quakes and their compass locations. Depth and location are recorded below those quakes which appear to have more significance with reference to the GPS graph.

    • Excellent graph … thank you 😊 …Bardy seems to have been far more restless the last 36+/- hours again. Plus side she seems to be following a nice steady linear rate of subsidence which gives some source of comfort for now. Still to see if a semi rhythmic pattern establishes to her earthquakes again as we saw early Sept. (for give me ….armchair amateur volcoholic -all talk no trousers!)
      .. keeping fingers and toes crossed for nothing spectacular to happen… after the excitement of todays Scotland staying as part of GB (phew!!) we have the trip home for the Ryder Cup and then a flight back down to Africa…

    • It seems to me as big drops are in correlation with larger EQ in the last five days than was before – resently 5,3/5,4 versus 4.7/4.9 before. Just stating the obvious. Not sure what that would mean if anything.

  5. Sorry, cloud-spotter at it again: is this a giant tornado? I’ve been watching it for about 20 minutes & it hasn’t moved – though it probably will have before I manage to post a picture!

    • This is “Thermal” (not twister, but may have rotating motion also) where hot air (from lava) rizes, also drawing moist “surrounding air” with it, and condensating before reaching the “daggarmark” (condensation level) in the clouds around and abowe. This “phenomen” (updafts) is frequent where Seebreaze Front (not here) meets “Warmer-Land-Wind” on normal summer condition´s in Iceland South-West (where we frequently soaread these in our sailplanes). Visible height of this might be in order of about 100 meters (visible) cloud.

      • Thank you! That makes great sense to me; I know a little bit about thermals here in the UK (one of my brothers loves to hang-glide) and how they often form over the same geographical features like cliffs & steep hills, though we don’t often “see” them like that. It’s more or less exactly where the billowing black cloud formed the other day that had several of us newbies fooled.

    • opps, meant 4,5 (not 4-5ish), obviusly “just 4,2” (but then quite enough)

      *as advance Friday riddle: “SIL meter phone connection blown up by Coalition Forces Jets”*
      *brand not patented nor produced*

  6. I would like the opportunity to apologise for any of my comments that have insulted other readers,the integrity of this comments section and any one who is involved in running this blog.I have found myself out of my depth in the company of the highly knowledgeable persons who frequent this blog on a regular basis and have overstepped my boundaries.I have been a fool and to admit it,i shall continue to follow this blog but my contributions if any will be very limited.Thank you for the enjoyment☺

    • Don’t be hard on yourself, chap. At least you have a go at contributing- something I wish I had the courage to do but my knowledge is low, although I do enjoy everybody’s opinions and nod and hmmmm along, raise eyebrows here and there, and occasionally add a pic or irrevelant YouTube link. And hats off for saying Soz, but you’ll never please everybody.

    • I’m not a dragon, but nice of you to apologize. There is only one really important rule here. Be nice and be respectful for other persons opinions. Not something you usually find on the internet. It takes some getting used to if your not familiar with it 🙂

    • A word from the sometimes wise:

      1. Check the sarcasm.

      2. Chuck the derogatory and disrespectful tone and posts.

      3. Geyser Söze/Geyser Trollze/Rhyolithic Troll/Moron… keep one name and stick to it. I’ve no bloody idea who I’m talking to.

      4. Personal opinion: use your own real name. I do. You get more credibility thereby.

      • last name change☺Not everyone has your level of credibility or background Mike least of all me.☺and no that is not sarcasm.I cannot go into data specific’s and quote scientific papers where I have little understanding,but I think I have more knowledge about the subject then most journalists 😃

    • I have enjoyed your contributions, incl. sarcasm and humor. You have never pretended to be an expert. It is confusing though when people change their names; part of the effort in following the blog is to learn who is who, and who knows what.

  7. Im wondering WHY the IMO (Also in the latest rapport from 19/9-14) are so sure that a stop in the subsidence of the BB Caldera and an end to the eruption at the Holuhraunfissures, will result in everything slowing down and stop.

    In their possible scenarioes, the subsidence either stops – and it all stops – or the subsidence becomes huge and then several things could happen…..

    I read this, like the development in the ongoing subsidence in it self – according to IMO is determing whether BB will erupt.

    Im also reading now, in the latest rapport, that the analysis of the lava erupted indicates that it origins from a depth of 10 km or more….which feeds right in to my instinct telling me, that the eruption is feeding directly from magma inside earth – possibly through the BB hotspot.

    Please feel free to correct me and comment. Ill really appriciate it

    PS: How can I upload a photo to someone here (Mopshell)?

    • If it’s on the web, just enter the URL. If it’s on your PC, you need to upload it first to FB, TinyPic, ImageShack or any other image host.

    • Why do they think all or nothing? Because there’s only so far the subsidence can go before something fails and sets off the main caldera one way or another.

      Ultimately, this will not resolve peacefully. The question is whether that’s six weeks, six months or six decades.

      There are widely divergent theories on what the exact relationship between all the moving parts are and how much room the caldera can safely “give,” but the easy part is that it can’t fall indefinitely.

    • Hello Metta, an attempt at a reply! I am a total novice in volcanoes and in igneous and metamorphic geology generally (some background in sedimentary geology); my background is mostly in life and social sciences. I see you hold posts in your local government in Denmark, and so you must be very concerned for the welfare of the people toward whom you have taken responsibility, and I respect that. I have read many posts from you on VC and on VC’s Facebook page, and most if not all of them are asking for definite predictions and for confirmation of your ‘gut feeling’ or ‘instinct’ that there are huge tectonic changes occurring that could result in really cataclysmic events in the near term. But to my understanding, VC is a science blog, and science does not deal with certainty. The appropriate places to look for certainty are religion, astrology, etc., not science. And in science, ‘gut feelings’ have validity only according to the experience and understanding of the person with the guts! If someone, with or without formal training, but with decades of study and experience, has a gut feeling about their subject, then it is given a certain amount of respect—-until the person presents theoretical and/or ground evidence to back up their gut feeling OR others present evidence to invalidate it. Those of us with no formal training, experience, or deep understanding of geology, volcanoes, tectonics, petrology, etc., should realize that our gut feelings are either indigestion or our imagination at work, not to be taken seriously. Respectfully . . . . mj

      • PS now I realize that I probably should have emailed this to you privately . . . did not know your personal email was connected to your avatar.

      • Im so very sorry that you concieve me and my questions that way. Thats definitely not my aim nor my approach to volcanoes.

        Im asking when there is something I dont understand or cant explaine scientifically ( Mostly because I dont know the words and the terms in english) – like my last question about whether all the other 2coomotion” in the area is likely to just stop if the Caldera stops sinking and the fissures stops eruption.

        Im in no way wanting or looking for a disaster og any size – and frankly by now – I really dont think any “Very big” thing will happen in Iceland now – or any other place for that matter…Thank God for that!

        Im just fascinated by volcanoes and by geology – and thougt it was alright for me to ask in my way – also trying not to write way to long comments…like when I write that I feel og my gut tells me – its often because I cant put all the small pieces of graps etc Ive watched and litteratur Ive read, into a small comment…

        I would never be found on a religious or superstitial site – Im not religious nor stupid or naiv just because Im new to volcanoes.

        • Mette, I do apologize if I have misunderstood your questions! I did not imply that you should go to a superstitious site, I was only trying to clarify the scientific approach, by comparison. Asking questions is just fine, and they all contribute to the blog.

        • PS no, I don’t think you are looking for a disaster—the opposite!—-some of your comments have sounded very, very worried. Again, I am sorry that I have not understood you. I will try to remember more that English is not your first language, and it is easy for me to misunderstand.

          • Thanks a lot – I appriciate that a lot. It was helpfull – I got to think about how much ive learned and now know – and did not know a month ago – and how many “stupid” questions ive asked meanwhile – AND I got a sense of how VERY serious and scientific this blog is – and had an insight telling me, that you are righ – seen from that perspective some f my comments and questions here, has been “out of line” – in sincerly apoligize for that at hope or forgiveness.

            Ill think not just twice but three times – before I write or comment something from now on.

            Best regards and lots of humble respect


            • Oh, I don’t think your questions have been out of line, and I hope you will keep asking! I have made some pretty dumb posts myself.

            • PS we are all just learning! Most of the people posting on the blogs are not scientists or volcano experts.

  8. I got very worried when all of the earthquakes began and at this particular volcano. It would cause so much trouble and devastation for much of Iceland in my opinion. I know we love the show,of main craters and the major ash column etc. I actually drew a little diagram of what I thought might be underneath the Ice and what I came up was the main crater and several fissure lines that came out from below the main crater. So I believe that what we may have below the ice is an extremely complicated system that is more likely to have fissure eruptions. It would take IMMENSE pressure to make the main crater to blow..

      • Whether that power is there I would sort of doubt but anybody including myself can be wrong. I did the best I could to be realistic Should an eruption not occur

        I would expect Grimsvotn to go he like normally does unless his behavior has been messed with due to this Bardy event. He is more understood here at VC. Bardabunga is rather new territory. Well what would expect with a volcano that has erupted 70 time since Iceland was settled(Grimsvotn that is.)

  9. i have sat quietly reading and understanding most of it…out of everything i read , watched and viewed while off work sick for 4 weeks (quite handy) the one question is….why and not just in iceland do people build on old flood plains :P…WHYYYYYYYYYYY … is not like the cause of the flood in the past ever left and the risk must be huge…just not understanding this…but then again im blonde and play EvE online…

    • In England it is because of nowhere else to build, population increasing dramatically with each new wave of immigration and no new places for houses to go. Too small and island – too many people.

    • I have often pondered the exact same thing.
      All those idiots risking getting wet to have a view… On the other hand I bought an apartment at the ocean side and will most likely get my feet wet come next autumn storm 😉

    • The same thing can be said about building on what in essence… is a sandbar. We call them barrier islands, they are always moving, (pushed along by long-shore currents) and hurricanes generally devastate them. Yet they build and build. When wiped out, the insurance pays and they rebuild. Statewide insurance rates climb higher and higher, just to cover the expense of paying for the freaking idiots who build on the barrier islands.

  10. yes that is the I word but in iceland they built the electricity station…and only the sheep were there to protest hehe!

  11. Oh my! Clovis just had the biggest EQ in a year’s time! Not good…. 3.9 is big for Clovis, Califfornia. ( Long Valley ). I think Bardabunga is gonna get a big something or other before 7 hours from now. Will be a gamechanger if so. Check back later!!

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