39 comments on “Cotopaxi – or How to Paint the Danger (+ Updates)

  1. Very nice and quite complete, thanks Granyia. I also find the look of the pyroclastic flows on the B&W picture intriguing.

    By the way, I just found this. Very nice views from a drone on bardarbunga eruption. There is even some views of the lava funneling in a lava tube. That’s what a movie should be like 😉

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    • Hi dfm, thank you! Yes, this is a fine video, wasn’t it at that occasion when he lost his drone because it had flown too near to the lava and was partly melted? And for a striking contrast:

      Found this and two or three more somewhere on Twitter, saved two pics but not the source, sorry.

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      • I think they burned a go pro camera. Thanks for the pic the contrast is indeed there.

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  2. I am adding updates on Cotopaxi to the end of the post. Added a timelapse from just over an hour ago. It really seems to get worse…

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  3. Another screenshot Cotopaxi. It looks almost as if the source of ash is not quite at the summit where the crater is, but it could be the angle of view. Another question is, why is the plume constantly going downslope and then high up in a distance? It doesn’t look as powerful as I would expect a pyroclastic flow to look, and it couldn’t expell an ash flow constantly without some oomph behind it, or could it?

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    • Thanks for the post, another good ‘un. I too have been pondering these odd “pyroclastic flows”. Here’s a few thoughts. (1) It’s a timelapse (and on a loop), A real-time video *might* be more revealing. (2) What is the wind direction? I get a distinct impression of an ash plume being blown sideways (the webcam, presumably, being directly upwind) producing ashfall on the far side of the volcano only -the snowfields facing the camera are still white. (3) repeated PFs at such an early stage in an eruption, -phreatic explosions, no large ash column to collapse, no dome collapse to produce block-and-ash flows, no reports so far of lahars- takes a bit of explaining. Avalanching of loose ash + fresh snow?

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      • Thanks Michael! My idea was – having read that former lahars and PFs never produced layers of clay, even not in the distance, because they did contain very little to none of fine ash particles – that the tephra is very coarse. And with low explosive power behind it, it would sink near the crater and roll down the slope.

        On the other hand, with lots of hot ash falling onto the glacier, the first lahars could well be under way, maybe that is what we are seeing.

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        • Could well be. What’s your idea on the ashfall only on the far side of the cone? A vent below the summit, or strong persistent winds? After my previous post, I remembered seeing something similar in one of the photo souvenir books about St Helens in 1980. One photo (from April) showed the plume from a small explosion drifting downslope, like a very small PF(except that it wasn’t); another showed the effect of (relatively) hot ash falling on glaciers; proto-lahars, black with rock fragments, moving downslope but re-freezing before reaching the snowline – maybe what we are “seeing” here?

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          • Remember the Ontake explosion with the many fatalities? There were pictures of a big dense ground hugging cloud coming down, exactly like PF, but again, it wasn’t. I wonder if this could have to do with “phreatic”? Admittedly, the explosion is triggered by overheated steam, but the resulting huge amount of debris is just cold old rock from the conduit/walls. Count in the freezing temperature on a glacier and low explosion strength – and you might have a cold ash flow just falling down the slope, missing all the heat-related forces. Then, it hits bottom and causes the big cloud we see to the right in the image. Does this sound plausible? The smaller clouds we see on the slope itself could well be what you described from MSH, proto-lahars (is that an official term?)

            As to the direction, I think it is the wind only. However, I have tried hard to find an image that detailes the top of Coto enough to discern a place for a potencial second crater. The best would be NASA’s SAR SRTM elevation model, where you could discern, using your power of imagination, a second crater directly adjacent. (GVP speaks of “nested” craters) – so, who knows what’s going on there at the moment? I have added the NASA image to the article.

            NASA image: https://volcanohotspot.files.wordpress.com/2015/08/coto09.jpg

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            • Cotopaxi, Ontake, St Helens (before May 8 obviously)…phreatic explosions at the summit of a steep and glacier covered cone. How about this idea: ashfall on steep slope covered with fresh powder snow triggers, essentially, a ‘dirty avalanche’. Snow avalanches do after all produce billowing clouds like those of PFs (it’s the same physical process, gravity driven density current). If the ash is a bit hotter some ice is melted, moves downslope as a lahar.. but the temperature isn’t especially high, and the whole thing re-freezes before reaching the snowline. Proto-lahar isn’t an official term, but it seems to fit the phenomenon

              I think it must be the wind, not a flank vent; opening of a new vent outside the main crater would be fairly dramatic in its effects, surely?

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              • The question of the source of activity has been solved by the the photos I linked to below – they show that the plume is coming out of the main crater. Probably the rim is just somewhat higher on the SE side, obscuring the view.

                Still puzzles me though, how that strange behaviour of the plume comes about. This photo (seen from Quito) shows how the ash moves “quietly” down the slope and then goes up in a mighty plume a distance away.

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  4. Does anyone have a new link for the Montserrat Volcano Observatory – Soufrière Hills? The one I had been using hasn’t been working for a couple of weeks. (http://www.mvo.ms/)

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  5. Great post Granyia! I guess Cotopaxi is high enough and cold enough at the top to generate its own katabatic (downslope) winds, but then they are normally more of a night phenomenon. Could be a factor when the volcanic activity is weak? Or not!!

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    • Hi ukv, and thanks! 🙂 I don’t know much about the katabatic winds, but would the conditions for them not change during eruptions?

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  6. In the news there has been a short line about Sakurajima, which should be erupting and the nuclear power plant nearby.
    Does anybody know more about it?
    Sorry for changing the subject!!

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    • There’s been a lot of discussion about this on Erik’s blog. The nuke plant isn’t really ‘nearby’ – about 60km or c.31 miles. Unless we get Aira Caldera, The Sequel, it’s far enough away to be safe. Or safe-ish, anyway, if there’s heavy ashfall in its direction they may take it offline as a precaution.

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  7. A series of marvellous images on Flickr of Cotopaxi, taken during the flyby on 18 August 2015 by the Ministry Security Coordinator Ecuador – must see! – They do show that the activity is clearly in the main crater.

    VOLCÁN COTOPAXI

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  8. I read that Colima (Mexico) had blown its entire lava dome out of the crater during its violent eruptions a few weeks ago, but I wasn’t aware that it was so obvious to see: not only the dome is gone but also parts of the outer rim are missing. Looks nice now with that bowl on top 🙂

    Btw.
    would somebody be able to make sense of this Spanish sentence in English? With Google translator I could not.
    “Escríbannos cunado ya envíen la información que ocultan”

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    • You can also see the avalanche flume down the flank of the cone from the part of the missing outer cone. It is the lighter color stripe on the middle right hand part of the image on the right. Cheers –

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    • the word ‘cunado’ is misspelled, it must be ‘cuando’.
      The construction of the phrase is not a typical Spanish syntax either , but I think it can be translated as:
      Write us after they have sent (or disclosed) the information that they are hiding.

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      • Thank you both Leonardo and rafael for your help! Somehow it is sad that we have to suspect and to speculate about hidden information at all, because this is how rumors are created.

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  9. Hmm, a spanish speaking friend translated it – in german it doesn’t make a lot of sense either…
    “Schreib uns, wenn sie die Information schon schicken, die sie verbergen..”
    “Write us, if they send the informations, they are hiding..”
    Sorry for my poor English!

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    • Possible translation: “Write us. We won’t know it if you don’t sent it.”

      Where’s Reynato when we need him? Cheers –

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  10. Thanks for your translation efforts, Wood +friend and agimarc! I think agimarc is right, because it was in a newspaper’s twitter message. My inherent sense for conspirations tickled me, I thought it might have been a concealed call to readers (“you”) to send in all information (observations) they might have because the authorities (“they”) were hiding them. 😉

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  11. Not sure what is happening in Etna, she’s steaming like hell. Looks like Cotopaxi in white! There are no obvious changes in the tremor charts, and in the seismograms I see nothing that wasn’t there yesterday. But I have to admit that I am not very good at reading Etna’s Seismograms. Anyone else? It seems the steam is coming from two places in the N or NE…

    Seismograms: http://www.ct.ingv.it/en/real-time-seismic-signal.html
    Webcams: http://volcams.malinpebbles.com/pubweb/Etna.htm

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  12. Thank you, and wow, what a sight!


    http://volcams.malinpebbles.com/pubweb/S-Amerika.htm#RE

    This hotspot is a busybody, the fourth time this year! From the reports: The precursors were the same as last time, sharp increase of volcanic earthquakes and strong inflation, indicating the inflow of magma a few hours prior to the eruption.
    Following recognition of OVPF staff around the edge of the caldera in the evening:
    A long crack was put in place since then Rivals Crater has grown up towards the summit
    6:59 p.m.: second phase of opening further upstream
    8:09 p.m.: third phase of opening further upstream
    Around 9:15 p.m. / 9:30 p.m. opening a crack in the northwest. Under the Bory.
    The fountains are usually high enough, the flow is strong.

    Photograph obtained by superimposing a day image on an image taken a little later than 21:00 (local time):

    OVPF website: http://www.ipgp.fr/fr/ovpf/actualites-ovpf

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    • thanks Granyia. They just got brushed by tropical storm Dany, but apparently there was not too much damage.
      The situation with the Grande Soufriere is stable but some signs show there is still activity. There are regular quakes in the volcanic structure and the temperature of many hot springs is going up, but the evolution is going very slowly.

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