13 comments on “Mystery at Momotombo

  1. Indeed a mystery. I set up a script to pull down the webcams every 5 mins or so a few days ago, and it seems to be going off once or twice daily with small to midsized explosions – perhaps some of these fires are set off by ejecta from one of these. There is a medium sized explosion in progress right now in fact (approx 8:40AM local time). I wonder if this will just peter out eventually or if its gearing up to something larger, i.e. >VEI2 – the seismographs around it looks fairly calm except for a persistent tremor (which could be some other signal bleeding in I guess): http://geofisica-ew1.ineter.gob.ni/sismogramas/welcome.html

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  2. Thanks for the link, Tom. Pretty busy volcano. Given the number of explosions and lava flows since December, I would guess the throat is pretty well cleared by now.

    The thing that bothered me was the notion of cracks in the base of the cone. I take those as a very big deal, as cracks only show up a couple ways (in my experience) – either a flank collapse landslide caused by gravity, or one caused by inflation (like Mount Saint Helens). Either would very quickly progress to a large caliber eruption. I don’t think we are seeing cracks. I think we are seeing brush fires. Cheers –

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  3. Yup, it does look like brush fires. The local reports does mention “cracks” around the base of the volcano, though giggle translate may lose something in the translation. As you say, it doesn’t seem likely that this episode will turn into something large. However, there seems to be increased seismic activitiy in general in NI atm, enough to make INETER ask USGS for assistance (and USGS interested enough to assemble quick response team to look closer at it).. It is a bit weird that so many volcanoes rumbled to life simultaneously. NI has a pretty violent history with both fairly large explosive eruptions and very large seismic events so lets hope it does calm down.

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  4. Hi agimarc, nice post, thank you! Of course I had been watching Momo and reading (till end of last week, I am not up to date, though). I agree with you that the big fires on the NE side are trees burning. Your last picture is NOT the daylight equivalent of the Ufo-like one, as it was taken weeks earlier, when there hadn’t been an eruption for ages, on the opposite (southern) flank of the mountain where there is only grassland vegetation.

    INETER has not only mentioned the cracks, but also described them in one of their early reports as: cracks in the lower flanks where (during the eruption) small amounts of lava come out igniting the surrounding vegetation. Those were NOT on the northern/eastern flank where most of the ejecta roll down but on the S/SE side (later also SW). If you saw, in the weeks between eruptions, an animated gif of the every minute images from the south camera at night, you saw that they are not stationary but flaring up here and there, tens, some even hundreds, of meters apart. I thought that very hot gases were the source at that time.

    I have collected daily Terra/Aqua Modis Fire images from Worldview to make an animated image that shows where the hot spots had been in the weeks without eruption, but I had to abandon the plan when Momo turned to erupting daily. These things couldn’t be distinguished from all the fresh hot tephra and burning plants.
    What I could make out was sort of an “active line”, roughly SW/NE trending across the edifice, of fire spots, showing in Jan/Febr. when there hadn’t been an eruption for weeks.

    Sometime last week a Nicaraguan news channel announced the arrival of US scientists, one of whom was quoted to say that they were going to investigate about a crack in the SW side of the crater wall.

    I have not given all the sources now as I am somewhat pressed for time, but if someone is interested I will take a look and see what I have saved.

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    • My (lay-woman’s) explanation for the cracks would simply be that, in so young a volcano the ground is still poorly solidified, leaving voids for hot gases or even lava to ooze out when magma is moving in at a low depth. I never thought of of flank collapses or such but I admit to having thought about the possibility of a ring fault.

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      • Howdy Granyia – thanks for the additional information. I remain skeptical of cracks in the base, though if they are actually there and leaking stuff, that will be worrisome and will really get my attention as it would seem to me to be a lot more dangerous mountain than it currently seems. Will be real interested in seeing what the investigating team comes up with. Wow. What a journey! Cheers –

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        • http://ineter.gob.ni/lluvias/volcanes%202%20de%20febrero.pdf

          VOLCÁN MOMOTOMBO
          En las nuevas observaciones realizadas por el equipo de especialistas en Vulcanología del INETER, confirman la existencia de fisuras en el flanco sur y sureste del volcán, por donde hubo salida de pequeña cantidad de lava durante las explosiones registradas el pasado fin de semana, observándose incandescencia durante las noches. Este tipo de fisura en los flancos del Momotombo ha ocurrido en varias ocasiones durante erupciones pasadas. (Emphasis by INETER)

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  5. Fairly large explosion again last night… There is definitely something going on the flanks/along the base of this volcano -.I guess this could be the mentioned cracks? The locations appear to be fairly stationary vs screenies from other nights. These screen captures from last nights event are 3 minutes apart: http://imgur.com/a/6KQf2

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    • Thank you Tom, the middle one looks funny, as if the moon is falling on the volcano:) – From what I have seen on the webcams, I don’t think you can see the cracks at this time – if they are active at all now. This cam (which shows the eruptions on the funnel side) looks almost from north. The cracks could mainly be seen on the other, (south side) webcam; and only at quiet times when there wasn’t any fresh stuff on the slopes. Some burning of uncertain origin could be observed at two or three larger spots on the northern cam as well, on the left (east) slope of the mountain; if that was also from cracks they must have ignited some trees there.

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      • Yup, you’re right (reread the reports). When I found the local news article shortly after my first post, it somehow got a image sequence that’s taken with a shorter interval than the source I have. In that sequence one can see clearly that what I interpreted as glow from cracks at the lower slopes actually is where the material ejected from the explosion came to rest after avalanching down the sides. The large “blob” on the lower right seems to be where a pyroclastic flow meets and ignites vegetation.

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