Soputan Volcano, Indonesia erupted Monday January 4 and again on January 5. The plume went nearly 13 km into the atmosphere on Jan. 5. Winds at the time pushed the ash generally north and east of the volcano.
There was a partial dome collapse on January 6 which sent a pyroclastic flow down its flanks.
Local authorities cleared out a 6.5 km radius of the volcano and as of this writing have not allowed residents back near to the volcano. There are no known deaths or injuries associated with this eruption.
Eruption photos and a video can be found here: http://thewatchers.adorraeli.com/2016/01/05/major-eruption-of-soputan-volcano-indonesia/
Webicorders can be found here: http://webcams.volcanodiscovery.com/Soputan
Darwin Volcanic Ash Advisory Centre image page on Soputan can be found here: http://www.bom.gov.au/info/vaac/soputan.shtml
Current Darwin VAA page can be found here: http://www.bom.gov.au/info/vaac/advisories.shtml
Soputan is around 1,800 m high and is a relatively new volcano. Its flanks are not thickly vegetated. It is located on the North Arm of the Indonesian island of Sulawesi. Nearly 1.7 million Indonesians live within 100 km of Soputan.
Soputan is a subduction driven stratovolcano producing primarily an andesite / basalt mix. Eruptive style is Strombolian to larger. It is a very active volcano situated on the southern rim of the Tondano Caldera. It also sits on top of a fault line.
Most of the activity takes place out of a summit crater. There was a flank vent named Aeseput that formed on its NE flank during a 1906 eruptive sequence. It was active for about 20 years following its opening and was the source to some fairly major lava flows.
The volcano lies some 2,300 km ENE from Krakatau. It lies some 1,300 km NE from Tambora.
There have been around 40 eruptions from Soputan over the last 600 years. Intensity of eruptions have been in the VEI 1 – 3 range with the last three prior to this month being VEI 3. They were in 2015, 2012 and 2008. The last two were VEI 3. Though unlisted, I believe the 2015 eruption was similar in size. Length of recent eruptions is 2 – 5 months.
The volcano does build domes which periodically collapse resulting in pyroclastic flows down the side of the mountain.
Soputan is one of the four active vents of the Tondano caldera system. It along with Lokon-Empung are the most active of the Tondano vents. The other two vents are Sempu and Mahawu.
Tondano is a 20 – 30 km diameter caldera system formed some 3 – 6 million years ago. Dating of lavas laid down pre-Tondano have been dated at some 2.19 million years. It contains a more recent Pangolombian caldera measuring some 5 by 3.5 km. The caldera system has no known historic eruptions over the last 10,000 years. One paper dates the Tondano Tuff at some 871,000 years old. I would suggest this was deposited by the Pangolombian caldera eruption rather than the Tondano eruption. Links to these papers are in the Additional Information section below.
However, there are at least five somma stratovolcanoes built in and around the caldera system. A somma stratovolcano is defined as a stratovolcano that partially or completely fills an existing caldera. The word “Somma” derives from the ancestral volcano that Vesuvius has built itself upon. The stratovolcanoes get sufficiently large and go caldera.
The caldera is filled with pyroclastic cones, obsidian flows and geothermal areas. A lake fills the eastern half of the caldera. The caldera-forming eruption produced several hundred km3 of material. That estimate may be low. There are active attempts to extract geothermal energy from the caldera system at the Lahendong geothermal field which is located in the Pangolombian caldera.
Eruptive products of the caldera eruptions were primarily andesitic in composition with tuffs, ignimbrites, tuffs and breccias. The caldera is laced with faults.
Carl le Strange wrote an article about the caldera system over 3 years ago in the former Volcano Café. https://volcanocafe.wordpress.com/2012/09/27/did-you-notice-the-erupting-supervolcano/
Sulawesi sits at the junction of three major tectonic plates. These include Eurasia to the west, Pacific to the East and Australia to the south. There was subduction and multiple collisions followed by Miocene and younger extension. The north arm is bound by a major fault line to the south and has rotated some 90 degrees clockwise.
This is part of the tectonic mess described in previous posts where the intersection between the three plates listed above has created a number of microplates which all jumble against one another.
The northern arm of Sulawesi is part of a volcanic arc. Volcanic activity is subduction driven by the Bird’s Head Plate subducting under the North Arm from the east. The Molucca Sea Plate is also subducting under the North Arm from the SE. There are two subduction zones converging on the Molucca Passage. One is the eastward moving Sangihe subduction zone at the north tip of Sulawesi. The other is the western moving Halmahera subduction zone along the western margin of the Molucca Sea Plate. This is the only known example of an active arc-arc collision consuming an ocean basin by opposite direction subduction.
The North Sulawesi Trench is located to the east of the North Arm. A second volcanic arc from Sangihe Island to Minahasa formed due to the subduction of the Molucca Sea Plate to the west. The oldest volcano was active during the Miocene, some 20 – 5 million years ago.
It is this combination of active close subduction and jostling of microplates that appear to make large quantities of magma available for the volcanoes of the North Arm of Sulawesi.
Crust thickness under Soputan is greater than 25 km.
Soputan is a relatively new stratovolcano with a vigorous magma supply. It and its three active neighbors are busily rebuilding themselves within the Tondano Caldera to the point where they have large enough systems to go caldera. There is nothing I have come across that paints them or Tondano any more or less likely to go caldera again than their predecessors.
These are large, active volcanoes occupying a several million year old caldera. And they continue to be busy and dangerous.
Click to access Overview-of-the-Lahendong-Geothermal-Field-2004-Pri-Utami-et-al.pdf
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.
Sinabung and Fuego show strong thermal anomalies today. Here is a timelapse video of a pyroclastic flow of Fuego today:
LikeLiked 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.
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.
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)
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).
In Chile, Planchón-Petero has been set to alert level Yellow yesterday. This is the third Chilean volcano after Copahue and Villarica.
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
New post is up! 🙂