Volcanic Organs and Gandalf’s Pipe

Gandalf, sorry Etna, huffing and puffing.

Back when I was a kid, I had two interests in life, physics and playing music. In music my favourite instrument was the church organ. Over the following years those two interests merged into one as I got interested in how soundwaves form, and onwards into what I usually call waveform theory. Waveform theory is applicable to many things from large scale physics all the way down to quantum electro-dynamic interactions, and volcanoes.

I also have a deep-rooted love of deducing on my own complex things from basic principles instead of root learning mathematical formulations. The reason for this is that I can’t memorize things if I do not understand them fully, and the only way of doing that for me is to walk my way from basic fundamental principles to the end result.

Combine that with a brain that refuses to see any problem from a single point of view and that rapidly tries to deduce five different solutions to a single problem from fundamental principles and you get someone with a propensity for over-heating the piece of lard that is the human brain.

Music and physics have always been integrated as a whole for me. In a sense of it I learned more about mathematics from the grand fugues by Bach, then I ever did by studying mathematics.

As things went on my love of Fugues, Riemann, inventing ways to cheat the lightspeed limitation and playing music was in the end slightly interrupted as I discovered that kissing girls was also quite nice.

I thought I should give a short personal backdrop for the third part of this article. But before returning to huge organs we need to contemplate Gandalf’s Pipe.

Gandalf’s Pipe and the Art of Smokerings

Gandalf fighting a Balrog complete with smoke ring. (Photo by U.S. Army Spc. William Hatton)

I must thank Janine Krippner for the idea of the first part. She trumped out a question to the Twitterverse about the physics of volcanic smokerings instead of using google.

So, for the edification of Janine Krippner I will explain Gandalf in a physics 101. This explanation will work for anything that has a somewhat round opening of the barrel and has a temperature and pressure differential happening.

I will first explain it from the point of a gun and then go for pipesmoking before ending up at a volcano.

Smokerings are governed by 3 effects, and Wikipedia gives a good explanation for one of them. The 3 effects are central piston driving force, friction of the colder outer air, and the Coanda effect.

The central piston driving force comes into play since the air in the center of the smokering vortex is travelling fast than the air on the outside of the smokering. This gives the inner side a positive energy surplus. Also, the same effect applies to warm central core air rising.

The outer air is colder than the air in the centre and colder air causes more friction than warmer air. This functions as an air brake.

These two effects will cause a vortex to form with the inner side spinning upwards and out (from heat and piston force) and a slower outside (from air breaking due to friction). The beauty of this is that the ring will be self-centring and will not disperse rapidly. As long as the principles are acting the vortex will happily spin about.

This pretty much explains what is happening if the heat differential is large, or the piston force is great, like from a gun barrel or a volcano. The problem with this is related to Gandalf and his poor mouth.

As any pipesmoker trying to blow a smokering can attest to is that it is harder to produce a smokering than you would assume. You have to blow out the smoke slowly (low piston force), and the smoke will come out at body temperature in a room that is normally room temperature.

Gandalf could probably conjure up dragon fire temperatures as he blows smoke, but for the rest of us we find that there is a decided lack in both piston driving force and temperature differential.

And this problem affects poor Etna as she blows her smokerings out of volcanic gasses. Problem here is that these circular vortexes of gasses does not emanate with great force, nor at a great temperature differential (for coming out of a volcano).

To explain this, we have to go back to early aeronautics and one of our most forgotten geniuses, Henri Coanda. As he designed an aircraft in 1910, he discovered that the exhaust gasses tended to stick to the surface of the fuselage.

In the aircraft example it was the tiny force of the ambient air pressure the forced the gasses towards the fuselage and there the friction takes hold of it and drags it across the skin of the fuselage. In a barrel, volcanic vent, or indeed a mouth, it is the pressure differential of the exhalation that pushes the gasses/smoke against the sides of the “barrel”, there the friction takes over and creates a vortex embyo even before the smoke has left the mouth.

Obviously, I have simplified things a lot here, but the basic parts are accurate. And since a barrel is a pipe of sorts, we are now ready to discover why Mayotte is a church organ.

Notre-Dame de Mayotte

Looking out over the ocean from Mayotte towards the possible future volcano. Photograph from Wikimedia Commons taken by Christophe Laborderie.

On the 11th of November this year an earthquake occurred near the Island of Mayotte. The combined seismic energy release was equivalent to an M6.1 earthquake. The duration of the seismic signal was longer than 20 minutes and it had an unusual monochromatic waveform.

What surprised me was that even trained geophysicists stated that this was a mystery. The surprise on my part comes from having seen this type of signal from volcanoes prior and during eruptions. Both the eruption of Tanganasoga in El Hierro and the 2014 eruption of Bardarbunga produced the same seismic signals at far lower signal strength.

With a 7-year head start on things I could smugly point out that I knew exactly what it was with a certain degree of certainty.

The easiest way to explain it, is to start with the humble organ pipe. So, please watch this video for the basic physics of how an organ pipe works.

Now, let me recapitulate that video to give some fundamental principles.

  1. The longer the pipe, the lower the note will be.
  2. The higher the air pressure is, the louder the note will be.
  3. The higher the air pressure is, the wider the pipe must be. Otherwise the note will start to transpond into higher frequencies.
  4. Fluid will also create a sound when going through an organ pipe.
  5. A volcanic conduit is to all points and purposes an organ pipe.

Geophysicists are very good at finding and explaining different types of earthquakes. But when an earthquake sized signal occur it is easy to get lost, especially when it is not even remotely caused by an earthquake.

We know from the prolonged and very energetic swarm of regular earthquakes that something is happening there. And from the trajectory changes at remote GPS-stations we know that it is something sizeable that is intruding in the waters outside of Mayotte.

Earthquake waveform of the Mayotte M6.1 Seismic Event. Signal recorded at Kilina Mbogo in Kenya.

Even before this large seismic organ note we knew that there was a volcanic embryo forming in the waters outside of Mayotte. It is believed that the volcanic region is driven both by the cracking of the African continent and the African super-plume.

Not an unreasonable assumption since it would take something fairly momentous to produce a volcanic organ note of such prodigious sound force. As such it is the loudest single frequency sound ever recorded.

Since we know the frequency and the volume, we could even in the end be able to get a fair assumption of the length and width of the volcanic conduit (organ pipe). Even though we will never be exactly sure of the result, we could at least remove the more outlandish candidates of length versus width.

We could then in turn make assumptions about the volume of magma that moved during the event.

Musical Coda

All of the large organ pieces by Bach work like immense mathematical formulations based on rules. They are the grandest example of the musical expression of mathematics and physical foundations of our Universe.

And as a coda to this article I would like to present to you my favourite organ piece, The Toccata, Adagio and Fugue in c-minor.

If you listen carefully at the beginning you will hear a question being asked, it is then explained in the next two bars through what is in essence a mathematical formulation. And as you keep on listening you will realise that the question is in effect the same as the answer and is super-symmetrical.

As the piece evolves the same question will come back and be proven through the variations of the theme. And in the grand finale you have five simultaneous lines of questions and answers solving the problem from five different points of view.

This is exactly how I see our glorious Universe, and it is hauntingly beautiful.



110 thoughts on “Volcanic Organs and Gandalf’s Pipe

  1. When I last swam
    I managed to do perfect bubble rings with my mouth .. as I layed myself on the pool floor ( to sink you exhale first )
    And using the remaining little air in my lungs
    Perfect ring bubbles large ones. I guess this is much harder to do than with air

    • I wonder if this would work with warm steamy breath during winter, if you exhaled very slowly or maybe super fast. I will give it a try. still fascinated by the boiling water in a mug turning to steam when tossed in the air, I feel compelled try try it when temps dive below 0.

  2. I’ve followed this website since it was established, followed Jon before that. It’s one of the sites I visit several times aday to see you guys discuss, very interesting indeed! Since I know very little about earthquakes and vokcanos, other than what I have learned here; so a “lurker I am”.
    Last week, on the Train to the airport (Oslo) there was a very short story on the monitor about an earthquake that had stunned geologists. According to the story (Three lines of information) this earthquake went all around the Earth and lasted for 20 mins (I think). I have tried to google this, but have not found any information on the web.
    Anyone here that have seen, or know anything about this?

      • Thanks 🙂 confirms what I stated above – do not understand much about the technicaleties, but I find Your discussions very interesting 🙂

        • Just scroll down to the bit beginning

          “On the 11th of November this year an earthquake occurred near the Island of Mayotte. The combined seismic energy release was equivalent to an M6.1 earthquake. The duration of the seismic signal was longer than 20 minutes and it had an unusual monochromatic waveform.”

          And all will be clear 🙂

    • They need to come to the UK and teach our lot a lesson. I’ve had pot-holes rip tyres off my car wheels. If they can do that in Alaska, why do we have to drive on roads that make the Grand Canyon look like a blip? Bah!

      • these are only temporary fixes….. hopefully will work until summer when more permanent paving will be attempted. … don’t feel bad, we have so many potholes every spring due to thawing we loose tires too! and those take forever to repair.

  3. Very interesting, particularly the detail about the resonance being picked up by seismic instruments around the world. Some animals, and some people, seem to have sensors for infrasound and ultrasound produced by tectonics in their immediate environment. I am intrigued by the possibility that certain types of events might produce a reaction at a remote location.

  4. Thank you Carl. Fascinating! As a very mildly autistic person I adore J.S. Bach’s music with its precision and mathematical niceties (although I have absolutely no head for figures). It is both predictable and still absolutely creative. Few other composers have ever reached his abilities. (OK, fan-rant now over!).

    And to see it applied to Mayotte is like honey on teacakes.

  5. Just brilliant, Carl, i even read this to my Hubby trying influxes to my voice as i imagined You would sound. Music is both basic and mysterious. i suspect that we are all instuments of the universe but some of us are off key. 😉 i’ve long been interested in the ultra sound of volcanoes as St. Augustine at the southern end of the Cook Inlet, gives me the “ebeegeebees” whenever it erupts but Redoubt, which is much closer, doesn’t. i cannot tell You how bad Augustine makes me feel= it’s like fingers down a endless blackboard which goes on and on without end….. realllllly bad… and yet nothing is in the normal range of hearing. ( Becoming aware of all the intersecting patterns of the world, as a child, i suspected a Pattern Maker. ) really enjoyed this one…. Thanks! Best! from confused motsfo staring out at my back yard with rain watering my green grass and rechecking the calendar… no snow…. it’s all gone! and almost 5 degrees C. amazing

    • I wonder if what you are ‘hearing’/feeling comes from VLF sound waves – these are known to have quite uncomfortable physical effects; and perhaps the shape of the conduit at Augustine and/or the way gases resonate in that conduit might have something to do with it? Think we need input from Carl here

    • Tremor from some volcanoes can indeed have some unpleasant effects on the human body. Such as headaches, nausea, vertigo and so on. It depends on the volcano, local ground effects and the frequency. So I am not at all surprised that you feel off by the volcano Mots.

      • I’m one of those too. discovered that when I was enjoying the presence of Mt. St. Helens. (Which is a lot like Augustine, as I recall.-a potentially nasty composite volcano) I would get headaches and sinus conditions, Annoying to say the least. and this was before May 18th, 1980..
        That summer I flew a single engine Piper Pacer to Ketchikan. two
        1.the ferry ride between the Airport and Ketchikan proper is no fun in
        bad weather.
        2. i was talking to an old Alaska sourdough-who just parked his DH Beaver
        next my little putt-putt. He said: “Yep Volcano weather happend all the time
        something blows up north …St Helens is just another Volcano messin’ with the weather.”

    • later in the day: ok, so now there is a light powdered sugar dusting the yard… has stopped but still only half way up the grass…..

    • Well Mots, good luck with trying to envision what I might sound like. Most people usually guess that I am from New England, but with a bit of odd linguistic quirks from Englishes all over the globe.
      Unless obviously I am in a goofy mood. Then I turn into an ever so slightly anemic version of Ya’mehcan. One of my odder talents is being able to fluently talk like a 18th century Carib/Jamaican pirate operating a sound system outfit at a bar.

  6. Thanks Carl Interesting comparisons and Yes, Bach is also my top favorit composer! Perfectly pure logics in musiv form!

    • Completely impossible to say since there are no good nearby instruments. All we can say that it is noisy, and that something rather big moved.

      To further expound, Bardarbunga was the previously noisiest volcano in regards of magmatic signals with at least five M5 seismic signals produced by movement of magma. So, hearing something 32 times more energetic is rather stumping.
      On the other hand, this is on the arse end of the African superplume, and we know that can move a lot of magma (and split continents).
      But even saying that there will be an eruption is beyond what we can do due to lack of finer details in the seismic signals, and stating the size…. well that would require a cup of tea leaves and psychic due to the lack of equipment.

      • If Holuhraun was preceded by magma-movement signals of a certain strength, and this new signal is 32 times stronger, would that suggest that the African superplume might be about to barf up a Skaftar Fires sized event somewhere near the signal’s epicenter?

  7. I’m still a fan of Toccata and Fugue in D Minor. That one will peel the hair off the back of your neck.

        • Well, they are really nice shoes. ← {I can’t believe I just said that…}

          No, I’m not some foot freak. Many years ago (pre-mil service) I used to sell shoes and appreciate well made footwear. And with as many boots I have worn into oblivion I tend to favor more common sense designs.

          And now that I am completely distracted, steel shank boots are a virtual necessity if you are going to be working aloft climbing around ladders for any length of time. Without that, your arches are done for.

  8. Coincidentally, Markus and I had the same teacher on organ.
    Here he is playing my favourite organ piece the Toccata and Fugue in F-major.
    The Organ is the organ from my home town Luleå in Northern Sweden. The Bishopry Church had a massive Grönlund Devil¨s Organ, quite a more Oompf in that compared to the two examples I put in before.
    As a kid I used to sit there late in the evening early night practicing.

    • so aware of the air componet….. wanting and waiting for the organ to ‘breathe’ 😉

    • Nice that someone else also made the connection to Bárdarbunga.

      As the eruption of El Hierro began there was very little information about the volcanism on the Island. For instance, it was not known where the central volcano and it’s plumbing system went. So, we had to do the legwork ourselves.
      Geolukring in here has the distinction of being the one both finding the feeder system of Tanganasoga and the dyke going out to Bob (Tagoro) through some very interesting data wrangling.

      At the time there was no name for the vent, so we held a vote and the vent was named Bob after a character in Blackadder (and obviously because of the bobbing restingolitas).

      In effect we named it a year prior to the name Tagoro being picked.
      Now you know why a large portion of the non-spanish speaking world calls your volcano Bob.

      • Yeah, we were quite amused at watching the media bobble-heads trying say Eyjafjallajökull, since no one had named it, we gave it “Bob” just to see if the bobble-heads would think it was a trick and wind up messing up that name as well. I was really hoping they would inadvertently use a long “o” and make it boob.

        As for wrangling out the feeder, what got my attention was that the initial quake set neatly outlined the main vent for Tanganasoga. You could clearly see the shape of the plug. Later the swarm filled in the intrusion area and made a nice cluster. Then it did the weird and the swam dove down under the keel of the island. That part extending down into the old sediment layers of the Jurassic era basin (now metamorphed into Phyllite). I was really thinking that it would come back up a scarp face fault on the other side. It almost did, but shot over to south of La Restinga. The white part of Bobs Floaters is mobilized Phyllite from that deep ancient basin. The dark chocolate looking stuff is the more juvenile fresh magma. Taken together (whole rock) they come out as Rhyolite, but individually (the dark intrusions) are more Trachyte. Local geophysical “scientists” got into an argument with a mainland university over how to classify the material.

        When we found out they were going to name it after a legendary carp or something, we stuck with the “Bob” nomenclature. Dunno how Tagoro fits into the whole scheme of things… but it is their vent.

  9. Excellent Carl and indeed its pretty view of the universe you have
    This reminds me of string theory somewhat

    • The basic idea of string theory is indeed beautiful with undulating circlets being the fundamenta of the Universe. But the theory built upon the basic idea produced gibberish in the end.

      This has nothing to do with string theory, but personally I think that we live in the beginning of another Golden Age of physics.
      A few years ago parts of experimental physics started to produce results not predicted by theoretical physics, or that is “off” from the expected result, take for instance the Higgs Boson, it turned out to have to low energy compared to the theory.
      Obviously there are a minimum of 4 possibilities why the Higgs Bosom lacked energy.
      1. We have an infinite series of even Higgsier Bosons out there to find to explain away the missing energy.
      2. Higgs was wrong somewhere.
      3. Our fundamental understanding of parts of physics is flawed somewhere.
      4. Or that the Universe itself is flawed somehow.

      Alternative 3 and 4 are obviously the more intriguing.
      If 3 is true we have work to do for a long time. And if 4 is true then we indeed have a problem to solve somewhere in the deep future.

      Anyways, that is why it will be no Nobel prize in the future for Higgs. Theory and proof must always match each other. He might though get to share a prize later on when someone has found the missing energy and explained it.

      • The latest theory on the Universe is -1. All to do with expansion and Higgs. Not being a cosmologist, physicist, (nor, in fact, intelligent I can’t offer anything other than that.

        • So unintelligent that I missed right the bracket off after ‘intelligent’. And that’s supposed to be minus one. Sigh. I think I’ll go back to watching the Borrowdale Volcanics for any upcoming eruptions…

          • Since I seem to have forgotten the aftermath of this. Did someone explain the energy lack, and he got a shared prize, or did they crap up and give it for a failed theory?

          • dunno about that,I wondered if it might be something like the recently mentioned ‘negative mass’ (which is said to explain darkmatter+darkenergy)?

          • Higgs explained why particles have mass (actually it wasn’t just him: other were involved in the theory). The missing mass is not his problem: that is just another particle that we haven’t found yet. Once it is found, it will have Higgs to thank for its mass.

          • He did predict the range of the energy, so it is a bit problematic that it was not found in the expected range.

            Well, good to know that we down the line will have a Higgsier Boson about to be discovered 🙂

  10. Just read the update from hawaiitracker today, and the most recent live update, and they talked about the two DI events at kilauea this week and how the tilt at pu’u o’o goes flat during the events, showing a connection. It hasn’t been addressed much but a month or two ago I remember there was a suggestion that the current DI events are caused by the deeper south caldera chamber and are actually much larger than the scale suggests, and this would also be reasonable if the east rift mostly starts at this point. Pretty much it shows that pu’u o’o and the summit are still connected freely and also this extends at least some way beyond pu’u o’o. This really means the current period of activity post pu’u o’o is going to probably be not too different to the period of 1975-1983, probably not large eruptions on the rift, but the summit could see some action, however after the summit fills up enough (might only take a few years or less) then more eruptions on the rift will probably happen and likely on the rift section just beyond the pu’u o’o complex down to heiheiahulu. There is also a certainty now that the system is pretty well intact and undamaged beyond the upper levels, so it will likely be business as normal in a not long time, though there could be some interesting summit activity in the immediate future.

    My guess (though I have a not great track record with these so far 😉 ), next eruption is in the caldera, if at the bottom of halemaumau there might be resumption of the lava lake and it could be long lived, if on the ring fault or upper ERZ, it probably won’t last more than a few days and be like other eruptions in these areas like 1982, 1979, 1974, 1973, 1971. If an eruption happens between mauna ulu and pu’u o’o, it might be a little larger, and like the 1977 or 1965 eruptions, with pretty low volume but being brief and intense and with maybe long lava flows that will be in the park, a flow on the north side of pu’u o’o could be a problem though after all that area was filled in in 2015.
    If an eruption happens downrift of pu’u o’o though I think it could be quite a lot larger, and evolve into a longer lived vent. Basically halemaumau or downrift of pu’u o’o it could be large and long lived, but anywhere else is probably a small eruption or number of eruptions.
    The magma conduit in the ERZ seems to be moving downrift, it started in the upper ERZ and until recently was in the middle, and now it is going beyond that to near heiheiahulu and I guess will eventually reach a point where everything will just break entirely with large scale collapse being the likely result. The fact that didn’t happen this year with an eruption that was so big it was previously considered impossible on kilauea probably means things still have a long way to go, are still not peaked yet and may repeat this years sequence possibly several times, and that the true terminator event might have the potential to dwarf even this years eruption, a sobering thought and definitely not the best case scenario that many are hoping for right now, Kilauea is well known in the present, but it’s past is one of the most unknown of all volcanoes, more is known about the ocean floor than about kilauea beyond 5000 years ago. A lot more study needed to to be done on the ERZ lava ages especially in the puna area but now that might be impossible.

    Well I did it again… ©longturtlehawaiicomment 🙂

    • Baugur was a much bigger vent than fissure 8
      Baugur was almost 500 meters long its so big that Oasis Of The Seas can fit comfortabley inside the spatter rampart and not be seen at all.
      As you say Holuhraun started off much bigger than Leilani 2018.
      During peak phase Holuhraun reminded me of Mordor or Io or Hadean Earth.
      The glow and clouds and barren landscape was an amazing sight.

      Both Baugur and Fissure 8 never formed shields as eruptive rates where too high.
      Both had an impressive channelized system the lava channels of Leilani and Baugur are the largest ones I have ever seen in my 23 years of life so far. Both Leilani and Baugur was connected to lava channels that where over 10 kilometers long and 100 s of meters wide too.
      The volcanocafe volcano map 3D globe haves some satelite shots of Holuhrauns drained channels.

    • @#Turtlebirdman
      I found another thickness map of Holuhraun flow field
      Its avarge is something like 20 meters with many areas going up to 30 meters.
      The 1,4 to 1,6km3 estimates coud be correct, the flow field is also around 20 km long.
      Holuhraun is all massive Aa lava, very massive Aa lava.
      The flow field is very thick and massive. 1,4 to 1,5 km3 is the current most acceptable models.
      Here is another flow field thickness map

      Beacuse its so very thick Aa in some parts.. it will form nice collumnar joints and cool solwy
      Kilauea IKI rootless lava lake will likley do some amazing collumnar joints when it have completely cooled as it is so very thick.

      • I guess the point still remains though, unless holuhraun exceeds 2 km3 the leilani eruption was still the bigger eruption even if holuhraun has a higher volume. Technically the biggest ‘fast’ lava eruption since 1783 was tolbachik 1975 which was about 1.7 km3 or more, and the biggest lava eruption full stop being pu’u o’o though with a few exceptions pu’u o’o was slow.

        It is worth noting though that 3 of the 8 effusive eruptions that have exceeded 1 km3 in the past 100 years have been from kilauea, which is another point in favour of its ridiculous supply rate. Pu’u o’o also exceeds the volume of all the others combined.

        Hekla 1947-1948 – 1 km3 total
        Mauna ulu 1969-1974 -1.5 km3
        Tolbachik 1975 – 1.7 km3
        Sierra negra 1979-1980 – >1 km3
        Pu’u o’o 1983-2018 – 8-9 km3
        Holuhraun 2014-2015 – 1.5 km3
        Leilani 2018 – 1 km3
        Sierra negra 2018? – <1 km3

        It is also pretty incredible that the most recent 4 of those eruptions were all in the past 5 years and were all simultaneous with 2 of the others…
        2010-2020 (especially 2018) is truly the decade of effusive eruptions, there hasn't been anything bigger than VEI 5, so it could be considered low activity by some, but more lava has erupted on land this decade than any other since the 1780s…

    • Awwwwww I miss the Holuraunish evenings at Mila Webcams and the yellow fountains dancing behind the spatter ramparts and the glowing sky and lit up pyrocumulus clouds.
      It was beyond magnificent.. beyond magnificent.
      I remebers strongly the lava channel that flowed away from baugur like a glowing road.
      I called that lava channel “saurons/ morgoths road” it glowed intensely with tornadoes and dust devils over it. Most intense was it in August, September an October 2014. The show made news in Sweden and Swedish Televison SVT vent to Holuhraun with volcanologists from uppsala university.
      Holuhraun made me many friends over FB and Gmail and a whole “volcano” family now I haves to talk with. Eldgosið i Holuhrauni

    • Holuhraun at peak strenght
      Its so strong that it reminds me of Puu Oo s early fountains and mauna Ulu fountains

    • Despite Holuhrauns high temperature 1188 C to 1200 C
      There was a supprsing complete lack of pahoehoe overflow
      features close to the vent channels ( overspills ).
      Leilani had that defentivly close to the lava channels and the vent Fissure 8 channel edges.
      Both Holuhraun and Leilani lava flows are almost completely Aa lava.
      Holuhraun likely had a diffrent compostion and viscosity than Leilani.
      Both eruptions where very fluid and Hawaiian but Holuhraun never produced any smooth overflows from its channels. ( only the lava channels in Holuhraun was smooth. )
      I think Holuhraun coud have been little more viscous than Leilani despite the same temperature.
      But in general both where very fluid and fast moving in the vents.

      Here is a overview of Holuhrauns compostion according to Haskoli islands
      “The basalt is vesicular and with about 2 volume % (vol.%) ofvisible plagioclase crystals, reaching up to 3 mm in diameter along with trace amount of clinopyroxene and olivine crystals. The groundmass is dominantly composed of brown silicate glass, but microlites of colorless and elongated plagioclase, short prismatic clinopyroxenes and olivinesare presentas well (see photomicrograph). These crystals are randomly oriented and make up about 20-25 vol.% of the rock. Sulfide blebs are present in trace amount (<1 vol%).Element concentration maps produced by scanning electron microscopy show that the sulfide blebs are Cu-Fe-sulfides"


      "The high vesicularity of the basalt indicates degassing at shallow depth in the conduit and at the surface. Loss ofvolatiles (mainly H2O)raises theliquidus (i.e. melting) temperature of the silicate melt, which promotes enhanced crystal nucleation without drop in temperature and results indegasing-induced crystallization of microlites. This abundance of microlitesexplains the relatively high viscosity of the basaltic a’a lavaformed by the 29 August 2014 event."

      The high eruptive rates during these 2 eruptions generaly forms only massive Aa lava flows.
      In Hawaiian eruptions high fountains and fast open moving lava rivers is what makes Aa lava flows.
      Fast eruptive rates makes Aa lava, and the two lava fields consists mostly of Aa lava.
      Fast eruptive rates makes Aa lava and smooth lava channels.
      In general the two eruptions where very similar with fast eruptive rates and massive lava channels and mostly Aa lava flows and fluid dome fountaining in the vents.
      Both Holuhraun and Leilani and Puu Oo formed generaly Aa flows as the lava cooled and never allowed to form tubes and shearing the crusts into rubble.

    • In general fast moving eruptive rates = Aa lava
      But as the data says.. Holhuraun coud have been somewhat more viscous than Leilani
      despite both where very hot

    • Something I did notice with my gif is how the eruptions seem to generally trend up the east rift starting in the pu’u o’o area and then going uprift more. I dont know why this is exactly as it also coincides with an increase in activity (not decrease like might be expected) but that could be seen as another support for activity resuming below pu’u o’o in the more long term.

      Places that I think are most likely for the next eruption,
      summit/halemaumau – 90%
      summit-elsewhere – 50%
      swrz – 10%
      upper east rift (hi’iaka-makaopuhi) – 40%
      mittle east rift (makaopuhi-pu’u o’o) – 70%
      lower east rift (pu’u o’o-heiheiahulu) – 70%
      lower puna – 20%
      anywhere else is very low.

      Also, something regarding the plumbing and connections within kilaueas east rift, during the deflation associated with this years eruption, the summit sank, as did the rift between mauna ulu and heiheiahulu (where I think there is a lot of shallow magma and where there is widely believed to be an open conduit), but the part between mauna ulu and the summit did not deflate abnormally, which means that this area has no shallow magma and probably also no true conduit, and this area doesn’t erupt either so that is another line of evidence. The east rift probably derives its magma from a somewhat deeper connection. This is supported by the recent trend of eruptions beginning on the rift without any summit eruption first, and by earthquakes often not appearing until well down the rift and distinct from the summit. The two are connected but it must be at a pretty deep level and with different structure than the simple assumption of a direct path at about sea level (which is too shallow anyway for how powerful some of the eruptions on the ERZ have been.

  11. Just a note:
    The 2010 event in El Hierro formed a new cone (which was informally called “Bob”) that already has an official name: “Tagoro”. However, it is correct that you refer to Tanganasoga, because it is the main volcano and the new cone is only another one, part of the same volcano (as the other 500+ El Hierro cones).

    And, since I’m writing, a little question:
    There is a lot of seismic activity in the “volcano of Enmedio” (“enmedio” means, “halfway”) between the two main islands (Tenerife and Gran Canaria) … Could it reach the surface (although it will not be seen by my eyes)?

    • To be exact, the seismic crisis started on the 17th of July 2011, and the eruption on 10th of October 2011. At the time there was no name for the vent, so we named it Bob. The official name was if I remember correctly assigned a year later after a mythical fish.
      It is the common form to state the parent volcano in general and the vent for the particular eruption. Problem comes with those few cones that tend to erupt often. That is why we say the Holuhraun eruption often instead of Bardarbunga, since this is the third known eruption at the Holuhraun volcanic fissure swarm.

      Enmedio is an interesting volcanic feature. It would obviously take a few eruptions for it to poke up through the surface. But it is definitely a possibility that it will occur in the distant future.
      As far as I know there has been no clear volcanic signals and that could be a sign that this is a tectonic event. But, as we know from Iceland, tectonic events on top of a mantle plume has a tendency to turn volcanic if they continue for an extended time.

  12. Very nice post!

    Cloud rings are not uncommon but the explanations are varied. The come from explosions, but that doesn’t narrow it down much. Etna blows rings. I have seen one covering quite a fraction of the sky that late was found to have come from a re-entry of a rocket. It caused an explosion high in the atmosphere. Meteors can cause cirrus cloud rings. Supersonic aircraft can do it without exploding if they cross a cloud layer. The one below was caused by a fireworks.


    • Explosive eruptions will generate really big cloud rings, tipically at the onset of the eruptions forming the head of the plume as it rapidly rises. The ring is not so well appreciable but it is the same process of a ring vortex behind it. It is present in many different situatuions, in growing cumulus clouds or downbursts hitting the ground. All that you need is a mass of fluid with a spherical or cylindrical shape moving through another fluid and tipically for this to happen a density diference is required, in downbursts it is a blast of cold air and rain dropping from above while in an old lamp I had and in Etna’s rings it is an overheated fluid rising through another one. Alternatively meteors, airplanes or rockets can obviously generate movement of the air without the need of this difference in density

  13. Jesper, have you compared the volcanocafe map with google earth? The google earth image is taken before the eruption. You can see that the crater row existed before and was reused from the previous eruption. There are some new features now that are not in google earth: a couple of new craters, the large older crater to the south is partially filled with new lava and there are visible cracks in the ground running all the way towards Vatnajökull.

    • In Google Earth Holuhraun cannot be seen only the older pahohoe flows thats covered in Fjöllum river sediments.

      In Volcanocafe globe a large part of the new lava field can be seen
      But the Baugur main vent is missing.

      • Ah, I see now the stitching is a bit strange. The bottom part of the crater row is new, but the top part is from before the eruption. Still, the eruption reused and remodeled the old crater row.

        • Thats the same old crater row in both photos
          The right one is just more detailed a better satelite shot of it

          • I marked where I beleive the stitch between old and new is. There is a distinct difference in detail on the different sides of the red line.

            Top part of the crater row is pre eruption, but bottom part is new.

        • amazing the details are
          But its the same crater row just under diffrent ligthing conditions and camera.
          The satelite is many 100 s of km abobe earths surface.. I woud enjoy even more detailed space photos.
          Thomas A: is there any ground photos from there before the eruption?
          I guess its an arera very rarely if ever visted at all

    • In September there were some high definition satellite photos of some parts of kilaueas eruption that could be added to the volcanocafe map until google earth updates, it includes all the main fissures except 17 and 18, and also where kapoho was. They are on HVO website.

      On google earth you can go to dates after 2015 and see holuhraun in full, why it isn’t the default I don’t know because it is cloud free.

      There still isn’t a full picture of kilauea after this year, but the latest pic is from May 19 and actually shows an erupting fissure with lava rivers flowing from it (I think it is fissure 20). It is always interesting seeing eruptions on google earth, there is a good view of nyiragongos lava lake too, and kilauea, and I think also villarica.

      • The later images of Holuhraun do not have full resolution. You can’t zoom in. That’s probably why they are not default.

  14. Look at the bottom big one. It’s partially filled with new lava in the right picture. Directly above, there are three new craters not in google earth. The google earth image has a lot more detail if you zoom in a bit more.

    • I think I’ll just stop trying to use my phone for comments. I don’t want to break the flow of every single comment tree.

    • same here.. it does the same
      I just blame trump and my old school bullies why nothing is working for me
      I hopes this vc issue gets fixed soon enough.
      Volcanocafe commenting can be very glitchy for me too.

    • Current VAAC (Darwin) shows FL250. That works out to about 83.69 m³ DRE/s. (using Mastin et al and yields similar results to Sparks et al)

      For them that don’t know, DRE = Dense Rock Equivalent. Tephra (ash) can be as much as 3 to 4 times the volume of the Dense rock. Ash is essentially pulverized rock.

      Note; Both Mastin and Sparks equations are based off of the heat energy needed to generate the buoyancy of the plume. Though it may sound fancy and precise, it is not. Per Mastin et al, the value calculated can be off by a factor of four. However, I have used Mastin et al over a series of consecutive VAAC reports and come pretty close to calculating the resulting VEI after it’s all done and over with. Right now I don’t have a good source for all of Manam’s reports. Darwin has rearranged their site.

      My method for doing the VEI calculation is to use linear interpolation to fill in the missing data on a second by second basis and then doing a integration of the values. Yes, this leaves a lot of room for more errors, but it gives a decent ballpark estimate of the VEI. Quite suitable for our purposes. (general discussion) I’m guessing their site rearrangement was due to inadvertently affecting airline travelers, so I’ll echo their statement about volcanic ash reports.

      “Any enquiries regarding interruptions to scheduled flights as the result of a volcanic event must be directed to the relevant airline/s”

      The last report they have shown for Manam is DTG: 20181209/0315Z

        • Well, people get excited and tend to emphatically state what they see. Sometimes they get it wrong, sometimes they get it right.

          Fact: Volcano go boom. That was reported correctly. While we may not get overly excited by a vulcanian blast, a first hand viewer would be suitably impressed. I know I would be. I’ve never seen a volcano up close and personal… it’s part of my life mantra of “Don’t be there.” (It’s a survival mechanism. So far the most energetic thing I’ve seen is 16″ battery doing gunfire exercises off the Socal Oparea while in the firing line. We were a ship or so back of them.)

          • Exactly why I made sure to mention the near-certainty of VEI 3 in my VD report (and decided against mentioning “large” in the title)! Seemed to do the trick…

  15. I remember the seismic crisis and its strange path under the island before the eruption, but the locations of the swarms occurred after it were even stranger…

    The name Tagoro comes from a berber word that means “a circular place to gather” that probably was given due to the approximat shape of the undersea cone. And extending to the fact the eruption gathered many social and scientific attention.


  16. v

    All the lava flows on kilauea that I have been able to find that date after about 1700. There are other flows in the 1600-1700s range further up the rift but poorly exposed, so I ignored most of them except pu’u honuaula, kapoho crater and heiheiahulu. The rest are maps released by USGS and pu’u o’o and 2018 are traced by me.

    /Right place? Not so much! See comment below.

    • (This is actually meant to be on its own, it is just a gif I wanted to post and it is better placed on its own so it is more visible and allows for separate discussion)

      /See the new rule. One thread per topic.

  17. A quick reminder, try to stay in the comment thread/tree.
    I cleaned away a couple of redundant or misplaced comments.
    We will leave anything that is containing good information/reasoning, but if it is misplaced and redundant we will ever so gently mop up a bit.

    • To expound a bit here.
      Kilauea is a nice volcano, but due to the shear amount of commenting that is done by a few commentators it kind of took over and hid all other discussions about volcanoes.
      As per usual we will never curtail discussions in here. But, we felt that something in the end needed to be done.
      Therefore we decided to try a solution, and that ended up being the Kilauea rule. You can discuss it to high heavens, but 1 thread per article. Feel absolutely free to make it a kilometre long tree if you wish.
      This way all the other discussions don’t get lost in the flood.

      We will not spank anyone for a mistake, that would break our own “be nice” rule. And trust me that even I am not exempt from the be nice part. My colleagues are quite adapt at yanking me in the ears if needs be. Rules are for everyone.

      • To encourage keeping related comments in the same tree, is it possible to:

        1. Increase the number of reply levels (with reduced indentation so they will still fit on the page). Now there is a maximum of 5 levels after which you have to go back and reply to a comment higher up the tree to get your comment below the current discussion. If no more levels are desirable, then a reply link that creates a new branch at the same level (i.e. equivalent to manually going up the tree to find the last functional reply link) would be helpful.

        2. Add collapse/expand to comment trees and branches.

        3. Find the bug that makes my comments end up in unwanted places 😉

        • 1. We can’t change the identations, so five is about as many as we can fit.
          2. I do not know if we can do that.
          3, Those of us who are not codiots like are looking at it, but there is a risk that it may be related to your phone.

      • There isn’t much going on at Kilauea right now either but what if there was to be a big eruption or particularly interesting event for some reason or another. I imagine that in a situation like that, like the Leilani eruption this year, there would be many commenters wanting to talk about very different topics. How should the rule be applied in a situation like that?

  18. Etna is still erupting from the new south east crater.
    Mild strombolian actvity and spattering and short Aa lava flows.
    The Puttisiddu vent is building a new scoria / spatter cone inside that crater.
    Magma is high and open now in Etnas magma system.

  19. High-altitude clouds can be Vulcanian (like this or Redoubt) or even Strombolian (Rabaul 2014). And I said VEI 3 because 6 hours at 45,000ft is quite strong and it did also have a 50,000ft event in August and activity has continued regularly since then so it is the same eruptive period; but the VEI scale isn’t typically assigned exactly when below 4 anyway as these are of course not considered as major eruptions. There is a video of this event by the way:

    • Toba and La Garita must have been an completely crazy sight…
      Imagine all the volcanic lightning flashing everywhere!
      Toba and La Garita was an show in empty theatres… playing infor empty public….
      No photographers where there to see this awsome sight.
      We needs a timemachine.
      Imagine a really long exposure photo of Toba in action: lightning mania!
      Likley so much lightning in the skies thats its hard to see what it is when the photo is done.
      Puyehue, Calbuco flashes are sourely nothing compared La Garita or Toba flashes.
      The deadly Tambora was flashy too: but beaten in an instant by Toba and Garitas ash flashes.
      I wish there was a program that coud simulate the Volcanic Lightning in VEI 8 explosive eruptions.
      As fast as VEI 8 plinian and explosive eruptions can be the convection is very strong: they likley made Superbolts similar in strenght to jupiters bolts.

      I imagines ashcloud shields to bringed darkness to much of South east Asia and North America.
      And the pyroclastic flows.. a grey angry cauliflower wall from horizon to horizon.
      In La Garita a 100 km wide area sanked maybe 5 km as the 5000km3 dacite ash plinian was erupted and the caldera formed as the magma chamber emtyed.
      Of course +VEI 8 explosive grey eruptions impress me too.
      Toba, Yellowstone, Taupo, and La Garita: lightning mania!

      • I have read somewhere that Toba ash has been identified in sediment layers in Africa’s Lake Malawi – that is nearly 7300 km from Toba Caldera itself. Ash was being blown westward well over the Indian Ocean – remember that trade winds within 25 degrees of the Equator blow in this direction – from east to west, except maybe during El Nino events. I also remember something about ash from eruptions in what is now Yemen about 27-30 million years ago having also been detected in the seafloor of the Atlantic well off the west coast of Africa.

        If one applied the same logic for La Garita, it’s likely that ash from there could have gone well over the North Atlantic and perhaps as far as what is now the UK and Germany! Remember this was – and still is – outside the trade wind belts.

  20. Hi Folks,
    Long-time lurker here with just the occasional post. As the lull between Hawaiian and Icelandic eruptions continues perhaps we can solve our Eruption Withdrawal Symptoms (EWS) and chat about a broader range of volcanoes. I’d love to hear more about the European mainland volcanoes outside of the big four, (Vesuvius, Campe Flegre, Santorini, Etna (Although I would welcome more about Etna’s internal plumbing. As far as I am aware I think the magma comes from deep, is this unusual for its location?) In an earlier article the Spanish mainland was mentioned as being interesting, Frances Massif Central, Alban Hills and even Germany’s Eiffel. I love this blog, its inclusiveness and reasoned science but it may have become blinkered (possibly deservedly to Hawaii & Iceland).

    Yours in Science

    • I know nothing about these, but I would love to.
      And this is my opportunity to congratulate the author of the post. I love it.

  21. There were two earthquakes along the Veidivotn system this evening. But they haven’t been verified yet. Possibly deep quakes and around M1.5-M2. Interesting… But per se, it does not mean anything.

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