15 comments on “January 4 eruption of Soputan Volcano, Indonesia

  1. Thanks a lot, agimarc! Soo… do I understand right that the Moluccan Plate is subducting in two directions, west under the Sangihe Plate (? lime green) and east under Halmahera Arc (Plate?)? If there is not a strong spreading center east of Sulawesi, the Moluccan Plate would appear to disappear… On the Schematic of Sulawesi Tectonics graph there is an area marked “Extension”, would that be extension by spreading?

    Another question, in the View of Subducting Plates, how did that slab of green Eurasian Plate get underneath the Sangihe Plate? Is not everything bordering the Eurasian Pl. from S/E supposed to subduct under it? If the Sangihe plate has been created exclusively by volcanoes bringing up the magma from below, it might be that the lavas have been layered on top of the Eurasian Pl., but would that make that layer a separate plate?

    And a third, if the Moluccan plate is getting consumed completely, for how long will it be called a Plate? I mean, if a plate has merged and mixed with the magma in the mantle, how can scientists still discern it long after it has gone? I know, chemical composition may play a role for a while, but that will blend in with time too, and anyway, deep drilling seems not to be an option for chemical analysis. So, ist must all be gray theory…


    • Howdy Granyia – good questions all. Standard caveat applies, as most of what follows are WAGs (wild ***ed guesses) at some level.

      – When I said the area was a tectonic mess, this is what I meant – a bunch of microplates / platelets jostling around and have for a while. Like we have seen in Vanuatu, sometimes what subducts under what swaps back and forth on occasion especially at the complex intersections.

      – Ran across something last year that pointed at a newly identified layer of the mantle around 600 km deep where there is what amounts to a phase change in the rock, making it a bit more dense.


      – You can see subducted plates for a quite long time as they melt. They are both cooler and wetter than the surrounding mantle. It takes a while to dehydrate the subducted plate which also changes the way they show up. The water rich stuff tends to be lighter and goes up. They show up as regions where earthquake waves travel differently than the surrounding rock that is not subducted plate. Essentially you are seeing them via sonar. Of course, if they are still connected, they show up via earthquakes as they subduct.

      – One of the interesting things about the depiction of the flat slab of Euasian plate under Sulawesi is that we typically see flat slab activity associated with caldera outbreaks like the Farallon under Utah and Colorado 35 MY ago and the Rivera Plate under the North American Plate with the Trans-Mexican Volcanic Belt some 5 – MY ago. The only caldera I have found on the North Arm of Sulawesi is Tondano, though I haven’t looked closely at the rest of the arm.

      Cheers –


  2. Sinabung and Fuego show strong thermal anomalies today. Here is a timelapse video of a pyroclastic flow of Fuego today:

    Liked by 1 person

    • The airport in Guatemala city (GUA) has been closed since ~8:00 PM due to ash from the ongoing Fuego eruption. – posted on Twiiter by Greg Waite, the man who is doing the Fuego webcam stuff.


  3. For the first time in almost three years the Masaya (Nicaragua) lava lake is hot enough, or its level is high enough, to appear as a hot spot on MODVOLC’s thermal imaging. Just one green dot, but still… I’ve been waiting for it.


  4. I would like to recommend this to all volcano freaks who have a little time on their hands for a great read: A team of 6 young scientists with a lot of enthusiasm and inventive minds plus 1 Land Rover are on the Trail By Fire tour, visiting 15 volcanoes – from the high peaks of Peru to the Southern tip of Chile, to provide the first accurate and large-scale estimate of the flux of volatile species (H2O, H2, CO2, CO, SO2, H2S, HCl, HF, and more) emitted by volcanoes of the Nazca subduction zone. Not only are the reports well written but also enhanced with lots of images and videos, and on a map you can see where the LR is just now. The last post was from the crater of Lascar in Chile. http://trailbyfire.org/news/

    Image: January 15, 2016 – from: “The smell of sulphur: volcán Tacora” (which is the northernmost of Chile)


  5. Watching Popocatepetl (Mx) tonight… after a restless day with frequent explosions now fireworks at night! The alert level is Yellow/2 or Amarillo F2.


    • From Cenapred’s Popocatepetl report for today (01/24 18:45 UTC)
      During the last 24 hours, through the monitoring system at Popocatépetl volcano, was observed a continuous ongoing activity that started yesterday at 10:03 am and last until 2 am today (video 1). It restarted today at 8:44 a.m. and continues at the time of this report (video 2) , (video 3). This activity is related to the cycle of creation – destruction of the dome. Which it is considered within the definition of the Volcanic Traffic Light Yellow Phase 2. (emphasis by me, http://www.cenapred.gob.mx/reportesVolcan/BuscarReportesVolcan?optBusqueda=1&idiomaReporte=ing).


  6. In Chile, Planchón-Petero has been set to alert level Yellow yesterday. This is the third Chilean volcano after Copahue and Villarica.


  7. Just finished riding thru a 6.4 Richter. Quake was centered 55 mi. SE Iliamna at a depth of 88 mi. 160 mi SE ANC. These parameters will change over night. House is still shaking a bit. Perhaps it is just me. Festivities kicked off at 0130 L. Lights and power are still on. Some things on the shelf were tossed over. No injuries here. Assuming I can get back to sleep, more in the morning. Cheers –



    • Wow now, that was even an M 7.1 must have been a good shaking! I hope you and yours are okay and all have electricity! The description by the USGS says its depth and mechanism indicate an event within the interior of the subducted Pacific plate, rather than on the shallower plate boundary thrust between Pacific and North America. It looks like the Pacific plate is breaking as it bends down. As do some roads on the surface, drive carefully! 🙂


      • UAF Seismology Lab has it listed as a 6.79 Richter. Too deep for volcanic. Have a door that doesn’t close any more. Will have to pull it down and adjust the top a bit. 30 – 50 aftershocks in the Cook Inlet region so far. Most in the 2 – 3+ range. Largest was a 5+ which I didn’t feel around 0530. No known road damage in ANC. Looks like there was some in Kenai (near where Motsfo lives). Cheers –



        • Not that it matters to me half around the globe, but why can they not agree on a final Magnitude for an Eq before publishing a number? Not even internally: – http://earthquake.alaska.edu/event/12496371 – I can just hear Scientist A shouting, “I tell you, it was a CLEAR M7.1!”, with Scientist B grumbling in his beard, “Say what you will, I am going to publish the M6.7 on my site, because it is RIGHT!” And where does that leave Scientist C who was going to use the data in an important study?


          • Howdy Granyia – I think it has to do with gathering data from multiple sources and putting it thru the various models. The most famous local example was an upgrade of the ’64 quake from an 8.6 to a 9.2 after 40 years. It takes time to gather the information about the quake. My experience has been that the initial estimates are low and gradually increase over a week or so of additional data. This one started out as a 6.4 and went to a 6.8 by morning. The international guys arrived at 7.1 early and haven’t wanted to budge much. It’s been only 15 hours, but will be most interesting to see where it ends up.

            Note that most of the data gathering is not automated, as the rotating drum seismographs are at best analog devices. Cheers


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