Mount Sinabung erupting

Canal Volcan´s timelapse webcam capture of the eruption on 17 September, propelling an ash cloud up 6 km.

Thousand of villagers arount Mount Sinabung had to evacuate on September 15, 2013, when the volcano erupted the second time within 3 years after a long period of dormancy. Several people reportedly died of ash inhalation. This BBC gallery illustrates how returning evacuees were confronted by the new explosion on September 17, driving thousands more  out of their homes. The Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, Center for Volcanology and Geological Hazard Mitigation) raised the alert level on 15 September 2013 from level II to III and ordered evacuation (in Indonesian) in a 3 km exclusion zone. Several seismic and GPS stations deployed during the crisis in 2010 monitor volcanic activity and PVMBG reported repeated fluctuations from 2012 to 2013 which stabilized from July to September 2013. There were several hundred volcanic earthquakes in August and September prior to the first eruption. Darwin VAAC released a volcanic ash advisory on 17 September reporting the ash cloud rising to FL200 (20000 ft = 6100 m).


Disaster prone areas map of Mt. Sinabung according to PVMBG. The pink area bears risks of hot steam, lava flows, lava bombs, heavy ash fall and poisonous gases The second circle bears risk of hot steam, ash fall, lava and lava bombs. The third region is at risk of lava and ash fall and small lava bombs (PVMBG, full resolution map:

Mount Sinabung (Indonesian Gunung Sinabung) is a 2460-m-high andesitic-to-dacitic stratovolcano with many lava flows on its flanks. It lies 25 km NW of Lake_Toba which formed in a supervolcanic eruption 69,000 to 77,000 years ago. The youngest crater is at the southern end of four overlapping summit vents along a N-S line. Apart from an unconfirmed eruption in 1881 and some solfataric activity in 1912 the last explosive eruption happened during August-September 2010 shooting up 5 km above the summit. In the years prior to that eruption an InSAR time-series revealed 2.1 cm inflation per year which only partially reversed after 2010 until the end of the measuring period 2011.

Sumatra has a volcanic arc above a NE-dipping subduction zone. In contrast to Bali/Java, the Indian oceanic plate plunges under the Sundaland continental margin at a rather shallow angle, resulting in only 100 km depth from the volcanic centers to the potential magma source. Thus, Sumatra does not behave like a typical island arc subduction zone. Sumatra´s volcanism dates back at least to the late Permian starting with porphyritic basic lavas. Late Mesozoic volcanic rocks distributed along the Great Sumatran fault, a strike-slip fault which splits Sumatra by it´s entire length, include include ophiolite-related spilites (resulting from alteration of oceanic basalt), andesites and basalts. Quaternary volcanoes are more acidic, thus more explosive, mainly calc-alkaline andesites, dacites and rhyolites with few basalts, including the >2000 km3 Pleistocene rhyolitic Toba Tuffs. It is not clear whether recent volcanism in Sumatra relates to extensive fault movements, to the peculiar structure of the fore-arc or is not related to subduction at all. More details on the complicated geology of Sumatra can be found in this thesis (abstract).

Map of geological formation of Sumatra island and volcanoes (Wikimedia Commons)

Map of geological formation of Sumatra island and volcanoes (Wikimedia Commons)

Dfm found information on the 2010 eruptions of Sinabung here and in more detail here. Time series plots of the seismicity and cumulative seismic energy release during 2010 show no sharp increases during the three eruptions, suggesting that they were rather small. A 2D projection of a 3D plot of volcanic earthquakes may indicate a presumable magma storage volume at shallow depth. Hendrasto et al. 2012 describe two concentrations of the epicenters along a northeast-southwest lineament, near an elongated sinistral fault zone between Sinabung and neighbouring Sibayak, both being back-arc volcanoesSutawidjaja et al. 2013 classify the 2010 eruption as phreatic event and vent clearing after a 1200 years long dormancy.

Mount Sinabung from Simpang Empat, North Sumatra. Image by Drriss & Marrionn via Flickr.

Mount Sinabung, North Sumatra, from Simpang Empat appr. 10 km south east of the volcano. Four craters give the volcano a slightly elongated form with the youngest crater IV in the foreground. Image by Drriss & Marrionn via Flickr.

Fortunately there is a webcam (Badan Geologi,


Screenshot  showing the first eruption on 15 September 2013.

Granyia overlayed two screenshots taken at dusk and at night showing incandescence on the flank several hundred meters below the summit:


Screenshot by Granyia


Additional links and images (found by cbus and Milord P):*AdDgvo2rPo0IB-hA2*9WWJqGC/Sinabungcrater.jpg

Up-to date information and ash trajectory by BMKG:

148 thoughts on “Mount Sinabung erupting

  1. Nice post on the background, like it! May turn out to be “interesting” as in the Chinese curse “May you live in interesting times” however.

      • Only if I put on my tin hat, hack into the HAARP mainframe and make a call to my Lord and Master Nibiruu. 😀

        Seriously, Sinabung is not in any way part of or connected to Toba. It’s more that the 2010 and this eruption seem more more like throat clearers than bone fide main eruptions and with a volcano as little known as Sinabung which, apart from uncofirmed or suspected possible eruptions, is considered to have been dormant for longer than 10,000 years, a main eruption could be quite big. Anything from a large VEI 4 to a small VEI 6 seems reasonable BUT – it could be no more than a new eruptive period beginning with small- to medium-sized eruptions every three to ten years.

    • The fire in the lower right of the webcam image clearly is from a smoke stack of sorts. But I doubt that the huge incandescence of the flank facing towards the webcam has an artificial cause. If you compare to the upper webcam shot, there is a trace of ash flowing down the slope in that general area and a second ash or smoke cloud parallel and lower to the main ash cloud. So I would vote for lava or forest fire, too. 🙂

  2. Hi

    thanks to Chryphia for this very neat summary.

    I made the update for El Hierro.

    This is the El Hierro earthquakes update for september 2013 up to the 18th.

    The black circles are events for June, July and August 2013. Size for these quakes is divided by 2.

    On the first part there is an event by event animation, showing the date (look up the left scale of the colorbar for quakes’ color).

    The terrain color refers to elevation (see right scale on the colorbar).

    In the title you can see the current rank of the event vs Total, the day and time of the day, and finally the magnitude.

    Circle size is proportional to event magnitude (4 times for the current event relative to older events).

    The view is from the south. The major quakes so far for september are shown from 2.8 to 2, including today’s 2 and 2.1@2:28 and 2:41 AM.

    The second,third and fourth parts are day by day earthquakes animation. Date is shown on the title bar, views are from the East then from the South and finally from the south East.

    The fifth part is a rotation of all the earthquakes.

    The sixth and seventh parts are a rotation to a top view showing all quakes and back.

    The blue mesh is the bathymetry around the island.

    The last part is a zoom centered on the last event. I have changed the limits to get a wider view compared to the other sequences.

    There are 2 clusters, one located under El Pozo/ Sabinosa and the other more to the east of that under El Golfo and to the west of Frontera. For the second cluster the activity is still prevalent and is deeper, but there were also very little activity (but with a stronger mag quake) well to the west of Orchilla in a previously active zone. In particular a quake of mag 2.8 and depth 22 km on the 7th of september is located there.

    Nearly all the stronger quakes (about 2-2.1 mag) are located under the El Golfo/ zone.
    The “dead zone” is still there with maybe a few quakes getting nearer.

    Last remarks :

    – a lot of the quakes are near the area known as Montana Colorada / El Brezal (I think).
    – If you look at the quakes shown you will see that there is a triplet (10/13/17th all at 2.1 mag) which are very very close in depth and location. This is in this area.

    Data from IGN and NOAA, made with Gnu Octave (Linux version) and avconv.

    If the IGN would be so kind as to put back data where it was in the past I would be grateful. Data is still available but harder to get.

  3. Great post! Gotta love learning more about new and lesser known volcanoes.

    One small thing to note – When toba erupted 77,000 years back, this wasn’t the first time it erupted in a “super” way, and thus, toba wasn’t “formed” during that eruption. Toba has had three separate VEI-8 eruptions in it’s history. The eruption that took place 77,000 years back was just one of three such eruptions there.

    The 3 separate eruptions explains the otherworldly size of the caldera, as the caldera would be too large for the even ridiculous eruption that took place approximately 77,000 years back. For comparison, the La Garita Caldera in Colorado, source of the largest known tuff (Fish Canyon Tuff) has an approximate size of 2625 square miles. Toba’s caldera is approximately 3000 square miles. Between the 3 large eruptions, there are two known calderas, the old toba tuff sitting on the right side, and the young toba tuff caldera from 77,000 years ago on the western side.

    Milord would be interested to learn that this is an interesting case where the second caldera outgrew the first! While I do agree that most calderas likely start out with a larger eruption, then have subsequent smaller caldera forming eruptions, I think it may be relevant to consider that if there is a second caldera that makes a larger caldera than the first, it will often blast away evidence that the first caldera ever existed.

    • Good catch Cbus but yes, I did skull up on Toba a few years ago:

      Click to access ChesnerGeology.pdf

      Click to access Toba%20QI.pdf

      The most recent eruption was preceded by THREE “mega- to ultra-colossal” eruptions:

      Young Toba (74 +/-2 kA, VEI 8, 2800 km3 DRE)
      Middle Toba Tuff (501 +/-5 kA, VEI 7?, ignimbrite DRE >60 km3 + ash ??? km3)
      Old Toba (840 +/-30 kA, VEI 8, 2300 km3 DRE)
      Haranggoal Dacite Tuff (1.20 +/-0.16 MY, VEI 7?, ignimbrite DRE 35 km3 + ash ??? km3).

      As measured by ignimbrite DRE, the Haranggaol and Middle Toba eruptions were mid-sized VEI 6 eruptions but no figures are given for ash DRE. If they follow the pattern of the Old and Young Toba eruptions, the ash emitted would easily push them into the VEI 7 range. According to Chesner, it would seem that the Haranggaol caldera survived the Old Toba ultra-colossal eruption but that it and the Middle Toba caldera were obliterated while the Old Toba caldera was partially destroyed by the Young Toba ultra-colossal eruption. Hence we have a sort of reverse progression where in the north, the Haranggaol eruption and Caldera was smaller than the co-located and younger Middle Toba eruption and caldera. In the south, the Old Toba eruption and caldera are also smaller (if that indeed is the correct word) than the Young Toba eruption and caldera.

      The same can be observed at Yellowstone or at Taupo where there is no real discernible pattern in the two periods of of “mega- to ultra-colossal” eruptions. The first occurred between 280 and 240 kA and comprised one VEI 8 eruption bracketed by three VEI 7 eruptions. There is evidence from intermingling of fall deposits that the last two VEI 7 eruptions may have occurred at the same time. The second period stretches from approximately 50 to 2 kA with another VEI 8 bracketed by two VEI 7 eruptions.

      It would seem that the very largest volcanic systems capable of VEI 7 to VEI 8 eruptions do not follow a pattern of the first caldera-forming eruption being the largest and subsequent eruptions being subsequently smaller that can be observed in smaller volcanic systems capable of VEI 7 to VEI 6 eruptions.

        • Oh my God!
          Lurking thank you for that, I needed a joke of that caliber today after a night with ache from the blasted root canal, and here it was. It was your best dead pan sofar.

        • Dear Lurk, it is an old composite verb used by, amongst others I believe, Robert Heinlein:

          To skull up (Vb, comp, tr) – to learn as much as you can about a particular subject in a very short time, usually ahead of an exam.

          • Come on, admit it was a fun dead pan that Lurkmaster came up with. I am still giggling at the image of your brain skulling over Lake Toba between the Tilapia farms.

          • Eventually, I will save master Lurking from his inadequate mother tongue, American English. I think too highly of him to leave him stunted by a language that does not allow a full range of expressions. He deserves much better.

            (When Americans say URRRRbzz instead of Herbs, I’m half-way out of the sofa en route to grabbing a fire axe and planting it squarely in their forehead. And anyone who says “antray” mean “main course” is fit for an asylum. And when they say “raut” as in “the enemy was routed” instead of route as in route 66 – “No sillypants, it is NOT pronounced RAUT 66, it’s route 66.” 😛 )

            • Please do note that Henrik, as all Swedes, have been thought an English that is spoken by 400 Englishman and 8 000 000 Swedes (with a slightly silly singsong melody).
              The general Swede speaks English in either the way of BBC News, or as a Lord with a rod stuck up his arse. “Always speak with a stiff upper lip” was the mantra when I went to english classes in school.
              Normal English English is horrible and quite un-understandable compared to American English, it is just that Henrik seem to forget that all the time 🙂

              I normaly get accused of being from New England states. Do not know why. At least up untill I have had a few and my upper lip stiffens sufficiently, then I start going “Oh blimey, what a maaaaverlous nuisance” with the best of them… 😉

            • There you are mistaken. I began life that way but after a year in England, I came back speaking a Cambridgeshire working-class accent that took years to eradicate. Now, did you know that of all human languages, AmE is the one that has the lowest number of phonemes (the little bits of sound that make up words, in spelling you talk about morphemes as the smallest unit of letters)? Swedish has about 48 phonemes, English 35 and AmE 31 or 32.

  4. The day before yesterday Iceland looked like this from the space.

    The dust plume was carried out by the strong storm winds (at hurricane level) from the sand desert just east from Katla. Most of this ash originates at the place where a flood in 2011 (caused by a subglacial eruption at Katla) deposited large amounts of old Katla ash, at that flood plain.

    So this is indeed a Katla ash plume! But of old ash.

  5. Chryphia, thank you for the interesting post. especially the time-lapse. 🙂

    Any idea what speed the time-lapse is set to?

    • The dogie one is what I was trying to link, but I couldn’t find the URL for just that on. At the opening, the first dog, a medium terrier, is hanging from the guys crotch, latched on. Once a terrier latches on, they don’t really want to let go. The dog handler got it to release, then the other handler put two three (small) pit bulls on him. (he was wearing a dog training suit… you know, heavily padded, even at that, the pits looked like they were gonna take him down)

      (note, I say small since the pit-lab mix that my grandson has is by comparison… massive)

  6. Thank you Chryphia for the post. dfm again a good plot and still those quakes are right under Tanganasoga. I watch with interest!
    Can anyone in Iceland (or beyond) Tell me what volcano might be having a small belch here? I think it is not Hengill or fracking?
    19.09.2013 05:30:17 64.092 -21.409 7.3 km 0.8 90.01 4.0 km S of Eiturhóll
    There seems to be a few deepish tremors at this point.

  7. There has been an interesting earthquake swarm at Eiturhöll (Reykjavik side of Hengill) starting at 11km depth and that within 18 minues had gone straight up to 3.6 km (magma chamber).

    11 km is the depth of the MOHO in the area, and movement upwards and the speed of the ascent of the earthquakes is indicative of a deep feeding tube opening up in to Hengill, or widening as a pulse of magma started to move up.

      • But promising on the higher resolution images.
        I think there will not be much of a difference when they are checked. Just a few more of them.

        • You need to have a bronze bust of “Little Father” ontop of the mantle above the fireplace to get that access… All you have to do is order a bust of him and you are in 😉

        • Which one of them? Петр Великий? Иван Грозный? Александр III? Красный Царь Иосиф Виссарионович Сталин?

          Did you know that our King Johan III, hated Tsar Ivan and always referred to him in his letters, public as well as private and even official letters to Tsar Ivan himself, as “gräselig”. 450 years ago, the word had connotations such as “horrible, vile, of the lowest birth, repugnant, offensively dirty et.c.”. I.e. it was just about the worst adjective available at the time and from the morphology, it is quite possible that Tsar Ivan adopted it as an honorific.

          • I mas more refering to the latest of the Little Fathers, the one who is most abundant in bronze busts. Stalin.
            I have a statue in full size in a storage unit that I am planning to convert into a fountain if I ever buy a house again. It will always piss people off if you have a pissing Stalin passing his waters into the garden pond.

    • Well, you were right about the number of quakes but wrong about depths as they all were between 5-7 km deep with one at 8.3 but all higgledly-piggledly with no observable trend.

      • No, Hengill is actually one of Icelands largest volcanoes, and it has been “dormant” for a long time. So, when it erupts the next time it will probably be a very noisy event before the eruption.

        • Teasing me with Hengill stuff so late in the evening… Tssssss… How I love to read such things, and start to dream of events with “considerable” impact…

          • Well… you should not have to wait more than 40 years or so, tops, for your big event.
            While waiting you can contemplate Sinatubo.

            • 🙂
              I still have my bets on Istanbul for a “shaking one”. Volcano wise I let thoughts go like a feather in the wind.
              Right now the next natural phenomenon I hope to observe is a first winter without a fully frozen arctic, and thus there evaporation and development of a stable high pressure that shuffles cold air down here big time. Want to shred that new skis down heavily powdered slopes as soon as possible… But I’m afraid I can not spill out enough CO2 with my car to achieve that soon enough…

    • Yes, someone posted it a while ago.
      I am amazed that people actually drive around filming the car infront so often that they can capture stuff like this. The filmers would most likely be a driving hazard… 🙂

      • They probably have a camera set up in the car all the time so they have evidence they can use in case of an accident. It seems quite common in some countries. Remember how many videos filmed from cars there were when there was that enormous meteor in Chelyabinsk a while ago. I’ve just bought a hat cam to use on the horse, though I’ve not tried it yet.

  8. I would like to remind all Dragons that it would be appreciated if you could chip in your opinion in the Den!

    For the others, we are planning a few improvements, you will soon be brought into the process when we have wittled away a bit at the immense possibilities.

    • Soon it will become much easier to find the pages again!
      We are planning a remake of the site with quite a lot of improvements, and back to the original style of top menu that was so much easier to navigate in.
      Also, we are testing to comment-thread versions that are far better than todays, but at the same time works in the same way.

      I am really happy about what is about to happen, I hope you guys will be happy too.
      We are soon going to Beta-test the new site, and if all works out we will have the re launch a few days after.

      • Da bin ich gespannt.
        I actually quite like the set-up as it is at the moment, so I’ll be interested to see what changes are made. As long as you get the direction right and move towards improvement and not like Erik who seemed to make his blog progressively more difficult (a great shame but then, I guess we would never have had this place… something about silver linings).

  9. Up in the OWL country of E.Washington state near Richland. Beautiful day in the desert.
    had a nice shot of Rainier with a cloud cap but battery failed on the camera. Was occupied
    by two job (flyig) interviews one might be successful.Tri-Cities area of Washington State has an
    economy-5.5% Unemployment ..Ran into old flying friends too…Much to do there….

    • This one should be sticky plastered somehow somewhere as the best volcanology movie sofar. Everyone shoulld see this and learn, and then watch it again with Popcorn.

      When I was a kid I enjoyed Juicy Fruit Chewing Gum more than popcorn at the movies. Probably due to the movies always showing the Juicy Fruit ad…. I still do not eat Popcorn, and Juicy Fruit is no more. Only freckin Stimorol that tastes like a chemical spill.

      Childhood, everyone has some thing that has the capacity to wang you back to then.

    • Yes, indeed Sakurajima is stealing all the attention around here lately. I get the impression that the crater has moved since I started watching its evolution day by day. Is there any aerial photos to get some perspective of how much the vent has “moved” toward where the prevailing winds blow all the tephra in successive debris avalanches?

      • The crater hasn’t moved, although sometimes it may look like that due to wind blowing the ash erupting to one side or another of the crater.

        The crater has however grown quite a bit.

    • This reminds me once again to never trust a volcano to do as it has done before.
      Sakurajima was probably the most boring volcano in the planet together with Stromboli. And now all of a sudden it is doing all sorts of fun stuff.

      • There is a small, yet interesting anecdote I’ve learned from the Popocatepetl and Kagoshima posts thanks to Cryphia that can be loosely applied to SakuraJima. She posted this paper in the popocatepetl post:

        This doesn’t directly relate to Sakurajima, but essentially the paper provides examples of how volcanoes in Indonesia and Mexico with semi-open conduit systems such as Colima, Fuego, and Popocatepetl show almost zero inflation as they emit strombolian, and occasionally larger eruptions.

        This is interesting for SakuraJima because it’s not only more active than the aforementioned volcanoes, but it’s also inflating rather noticeably despite having an open system. I’m sure SakuraJima isn’t entirely unique in this regard, but it’s a small tidbit that’s interesting at the very least.

        But as you mentioned, SakuraJima (Or rather, Aira) no doubt CAN do anything as it pretty much already has done everything a volcano can do.

        Huge phreatic blasts? Check.
        Extensive effusive Lava Flows? Check.
        Flank Eruption? Check.
        Strombolian Eruptions? Check.
        Caldera forming ignimbrite eruption? Check.
        Fissure Eruption? Check.

        • Thing is that I am not entirly sure that it is the same magmatic storage area that is responsible for the inflation of Aira and the eruptions of Sakurajima. Yes, the root cause is the same, but I think it is divided somewhere deep down. Otherwise Sakurajima should have had a higher speed of eruption a long time ago.
          So, I think it has taken up untill now for the pressure to increase enough at depth from the Aira inflation to inflict Sakurajima with bigget eruptions.
          I do not know if I am clear at all… still on cup number one…

          I agree totally with your list. But see the big stuff as unlikely still.

          • Yeah, no doubt, and we’ll likely see much more significant spike in inflation prior to an eruption if it goes similar to how the 1914 eruption did (although that’s far from a guarantee).

            Sakurajima does have 3 separate magma chambers, which would seem to add to the complexity. The upper storage area (where blasts come out of) is primarily dacitic, whereas the lower chamber I believe is basaltic andesitic. Aira is probably a big blob of basalt and crystal mush, but who knows down there.

            One interesting thing I’ve seen before is that some suggest that there are actually two separate magma sources for Sakurajima, one of which doesn’t originate from Aira’s magma chamber, and comes somewhere from the south. I can’t remember where I saw it, but I believe there was earthquake data that showed what could possibly be a small “feeder tube” of magma coming up from the south as well.

            But yeah, SakuraJima is a complex and strange volcano for sure.

            • The big ones almost always are very complex internaly.
              That is why I like Hekla, it is about as complex, so it is like studying a much more active volcano with the same basic principles as the over-sized ones. And since Hekla is so very young it might even be one that in the end will do something large.

          • I really love it when you explain a case, all things kept in “proportion”, but in the end can’t let it be to give it an “open future” for a bit of catastrophe.
            “…it might even be one that in the end will do something large.”
            That is such a lot of fun when you have people in front of some hazardous stuff, show them that you’re no apocalyptic priest or something, and when you feel that they start to see you as a serious professional you scare the hell out of them to emphasize the importance of the measures you recommend. Doesn’t always work, but when it does, it’s the cases where prevention has good chances to take place.
            That’s one professional argument I have to wish for a bit of well dosed doom from time to time. It offers nice elements to tell credible stories that help the process of convincing “partners” to do what they should. Just a shame that you have to be so careful not to overdo it. You can quickly loose your image with that kind of stuff. But it would be so good to walk around and take advantage of my position to spread panic and dooooom… Mouahahahahaaaaaaaa…. *Just kidding…*

            • You know, when you retire you should become a Prophet of Doom!
              You would have immense fun scaring the living bejesus out of everyone around. 🙂
              I would do that if I had your occupation and had retired.

            • If they don’t let me retire at 65, I will from then on become a horrible employee, telling everyone exactly what I think of anything and especially of them, and using all I know to scare those silly enough to still listen to me. A bit like Butters in Southpark, when he turns into professor chaos, sort of, somehow, you know…

    • We have one here in the US… dunno how “natural” it is. You build on a flood plain, eventally that’s what you will get.

      It’s just a matter of time.

      The same could be said of building a metropolis in a bowl below sea level in an area renown for hurricane activity. (With an lake and inlet north of you can funnel up the storm surge on the leading edge of the storm… and next to a river that has meandered all over the state in the last few thousand years, with the only thing holding it in place is some wild arsed idea using designs thought up by a committee of government employees. The work of which typically goes to the lowest bidder… or the one with the best “connections”)

      I have heard many remark about how out of the ordinary Katrina was. Imagine, a Hurricane flooding out New Orleans. OMG, What are the odds of that?

      1) 1965 → Hurricane Betsy did just that. 40 years later… Katrina. How is this a surprise? No, really. How is another hurricane coming along and giving a repeat performance a surprise?

      2) Previous tp 2005, the levee walls next to the waterways that run into the city had work done on them to repair and re-enforce them. The contractor was in dispute with the Army Corps of Engineers because of the additional costs of trying to bring them into compliance with the contract specifications. [They kept shifting out of alignment] It seems the soil that they were built on was not as strong or as firm as the Corps of Engineers Geologists had stated that it was. The Judge ruled against the company and they had to eat the cost. Take a wild guess who employs the Judge. Yup, the Corps of Engineers.

      And that’s to say nothing of the really slow normal faulting that runs through the city. Part of the river delta in that area is dropping and moving south really really slow. So, anything you do to beef up the cities defenses above sea level… will have to be revisited at some time in the future. Hint… that’s what deltas do. Settle and compact. It’s alluvium for Gods sake.

      For the un knowing. Alluvium – “Sediment deposited by flowing water, as in a riverbed, flood plain, or delta.” Beneath that area… you have to go about 12 km strait down before you reach the bottom of the sedimentary deposits of the Mississippi embayment. Based on previous reading… it is very likely that the entire Gulf of Mexico basin is laced by at least 14 transform faults… from when that basin opened up. They are quiet now, (inactive) but there are still quakes that occur along them from time to time. (The Port St Joe fault seems to be the noisiest)

      • That’s part of what makes me happy to live in the great lakes area. We might not be a vacation destination, and we’re the least geologically interesting area in the country, but to a certain degree, there is some comfort knowing that you won’t have to wake up during the middle of the night during an earthquake or have to face an evacuation due to an incoming hurricane.

      • Don’t be too complacent. The Wabash Fault Zone is probably one of the arms of a failed triple junction. One of the other arm being the Reel Foot Rift area. (NMSZ)
        {and, between the two, is a Graben}

        Oh… you also have the Mid Continental Rift… Lake Superior sits inside of that. It’s older than the Reelfoot Rift. And allegedly, more dead. Tecnically, the Nemaha ridge is also related to it, but that ridge still shows activity near it’s southern extent. You see it as the oddball quake out in the middle of nowhere.

        [The Keweenawan Rift is a 2,000 km rift that …] formed when the continent’s core, the North American craton, began to split apart during the Mesoproterozoic era of the Precambrian, about 1.1 billion years ago. The rift failed, leaving behind thick layers of rock that are exposed in its northern reaches, but buried beneath later sedimentary formations along most of its western and eastern arms.

        • I’m probably far enough from those areas where even if something would happen there again (unlikely), it wouldn’t affect me. I live in the central Ohio area.

        • Keweenawan Rift… It will be fun when that one slides ontop of the Yellowstone hotspot. Then you guys will be renamed into SUDCUS, The Slightly United Double Continents of US.

          Edit: I hereby make dibs for the any term using SUDCUS. SUDCUS-event, and soforth. 🙂

      • I have about 230 meters of alluvium (stinky mud) under my hometown. At the river edge the houses move 2.5cm towards the river every year, and they sink 1cm. I live about 1 km away and my house moves about 1 cm towards the river and is at a standstill neither sinking nor lifting. It should be lifting 1cm every year from lithostatic uplift. 300 meters further away from the river a 40 kilometer long horst juts out of the alluvial plain. That one moves upward with 1,5cm. The horst is the southernmost edge of that famous ore bearing craton that makes up the far north of scandinavia.
        Nobody here understands that at any given time we can have a local 6M 0,5km away from a mud plain… Yes it is the most stable bedrock on the planet, but it is uplifting 0,5 cm more every year at the edge compared to the rest of the craton, and the surounding area.
        What is happening is that we have another faultline running paralel with the coastline, it is uplifting (as Finland very slowly crawls in under us as the entire Craton crawls to the northeast).
        I seriously suspect my house would just sink if we had a 6M…

        Oh, 20 kilometer upriver from the city there is a hydropower dam, the river is damed right across the faultline…

          • Not really, the faultline running along the coast was not known untill the seventies, and the horst being active was not discovered untill the nineties.

            What is more surprising is that they did not take landslides seriously untill 2002 when a house slid out into the river upstream from the town. Having a house floating in a recognizable shape through the city made the point quite clear. It was surprising having breakfast at a river café and watching it glide past.
            The owners where lucky, they had left for work just minutes before the house slid 500 meters out into the river.
            What makes it so surprising is that there are about 100 landslide scars upriver.

            “Honey, where did you put the house?”

            • I just can’t resist bringing up one of my favorite landslides when I hear of a house gliding past. The quick clay slide at Rissa. I’m sure all of you know about it and have seen the stunning pictures. But, hey, if there’s one new reader that discovers it, it was worth annoying the rest of you… 🙂 Sure, it’s quick clay, and not induced by a quake, but who could blame me for being stuck on that event since the first time I have seen it.

            • GeoLocos movie showes the same type of clay we are on. The salt part is though not the same so the waterbalancing is slightly different.
              But the slides look about the same. Only difference really is that the quick clay here cover a distance of 60 by 50 kilometer. And now I can see GeoLoco panting in excitement over seeing that slide out into the bay of Bottnia.

            • Not really a Darwin award, but I would not like this if it happened to me out in the ocean when I was sailing…

        • A mag 6.0, at up to 1 km distance from the epicenter, yields about 24.1% of G acceleration. Peak ground velocity is on the order of 23 cm/s.

          If there is a mud plain as close as you indicate… think “mush.” Lots-o-stuff is gonna be sinking from the liquefaction.

          Tell me, how many large buildings in that area are built with keels and a hull?

          • One… It is actually built with a barge like structure under it in concrete. The cost of driving enough of concrete poles down was to high. The rest will sink.

            All buildings are sinking allready, the speed varies on weight and displacement though.

            Edit: Buildings are limited to 14 stories for that reason.

            • Thanks Carl.
              Some of you guys in here are quite precious for my intellectual survival and emotional balance. These times at work it’s really mad and it takes a lot to live with what is not done and leave the office at “christian times”. But a “career” is a marathon, and not a 100m sprint. So the challenge is not only to show that you can actually solve stuff and do your work, but to also measure your efforts and guarantee that you will last and if possible not break down or burn out. Time is short and precious; and one should take care not to slide too deep into the virtual world where goodies like volcanocafe would be such a nice thing to get lost in and forget about reality. But then, when this very reality becomes too much of a pain in the a…, how welcome can it be to flee… A bit like homer in “under the sea”…

          • I actually once made people build a house following the “ship logic” on a landslide. It was quite high in the pre-alps and it was what we call an “alpage”, something a bit bigger than an average 1 family house, with habitation and Stabling for some dozens of cattle. After many discussions, also about how to build the access and stuff, it was clear that no “stable” solution could be found. So we chose the location in the middle of the accumulation zone of the slide, where movement is around let’s say 1-3 cm per year and quite horizontal, made the whole underground structure be one fat concrete box that “swims” in the mass, and thought of all conduits and such things as something that has to offer flexibility or to be changed after a few years. It’s the only time I advised to handle a situation that way, as I usually rather push them to seek solid ground with their foundations and to do everything around the house (meteoric water management, landfilling and stuff) to stabilize the situation. But it’s 10 years ago and when I walked by the house this summer, everything looked perfectly ok, no crack or anything in the structure. And even if there’s no measuring of the landslide, I think it must have moved several cm.
            But it was strange to write an expertise recommending to build a “swimming” house and I had no norms to lean on. Now that some time has gone by, even if something happens, it would be clearly shown that we cared for the situation and took a decision that seemed proportional and that has proven to work to a certain extend, but if something had “immediately” gone wrong, I’d had had a hard time explaining the case to the different courts and judges… 🙂

            • Thank you GeoLoco for that description, it came to life in a way I could never have described. Pretty much the same principle as in the 14 story hotel built in the barge thing.

              This will now be remembered as the “Morning of the Swiming Houses”. One never knows what will happen and be discussed about here.

  10. Welcome to a friday of changes… During the day you are going to notice that things are underfoot here at VC!

    You are welcome to follow it Live, there will not be a Youtube video of it after all. At around 11.00 the fireworks shoulds start.

    And now for a musical interlude while waiting!

    I mentioned a few days ago that I prefered to play the organ in Grote Kerk, Maassluis.

    I could not find it, so we are back to my second favourite organ, the Arp Schnitger that I put up a link when Ton Koopman played a couple days ago. But lo and behold what I found… Not as fast as Ton but still…
    The Arp Schnitger is the last organ that is tuned to the original A = 485Hz, and that gives it a very light sound.

    • This as background when you stay in front of tens of thousands of tremoring people and preach the doomiest end of days. And behind you in the skies, one can recognize Nibiru growing on its path to the apocalyptic collision with our blue space-vessel, through dark clouds in a dramatically red sunset due to ashes from multiple simultaneous mega-eruptions all around the globe that started with Hekla and Katla going caldera. Istanbul, LA and Frisco are no longer worth being mentioned on maps. Climate change has lead to a spontaneous glacier growth and Switzerland lies under 500m of ice and snow. Just glad I was cooking and the heat from my kitchen created a dome under which I will try to survive until the sun shines again on the newly shaped surface of a purified planet. Ladies, let’s repopulate the planet and tell our future children that they shall invest in space-exploration so that we cad suck earth empty and find a better place in another galaxy. If we make big orgies I could inseminate several potential mothers at once. Sorry, no more time for romance, we have to be productive. And don’t destroy Syria’s chemical weapons, we might use them to crush the local that will no longer be tolerated on our future home. Switzerland will be ready to help military actions with our few F/A18 and the Gripen we might probably buy. End of neutrality. Let’s juste hope the production of cheese fondue will not be interrupted.
      I hope my wife, kids, mother and boss don’t read that. Amen.

  11. OH WOW! The Morning of the Swimming Houses! In one short time for Coffee #1 I have learned so much. Geo Loco it’s good to see you 🙂 and thank you. What an amazing film! ( Although I am now trying to establish the safety of the house occupied by my step son near the river at Sarpsborg, Norway! )
    This film shows how vital the work of scientists of all varieties and subjects is and leads me onto my ruminations for the morning……. I have completed this simple questionnaire that popped up on AVCAN’s Facebook. Maybe others would like to voice their opinions. It does need translating but it’s easy and accurate by Giggle and Bing.
    Maybe we can add our voices to help those concerned in the Canaries.

    ……and now to have a shower behind my wonderful new shower curtain and my personal target of trying to remember and spell correctly all the Rare Earths that have been discovered since I first learned The periodic table. !
    (Winks at GeoLoco 🙂 )

  12. Welcome Ladies and Gentlemen to the Volcanocafé MK II!

    A post will be up shortly!
    While waiting, check out the new frontpage!

    Cryphia, come and bow to the audience!

      • Pretty is good, but anyway this here lives through people and their hearts and brains.
        Got a bit “darker”. Has a touch of obscure. The perfect setting for the moments when we would have to announce doom and stuff… 🙂

Leave a Reply

Please log in using one of these methods to post your comment: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s