The forgotten volcanoes of Chad Part II

The spectacular nested caldera of Emi Koussi. Photograph by David Evans.

The spectacular nested caldera of Emi Koussi. Photograph by David Evans.

In the previous part I wrote that we would be investigating some of the largest sub-aerial volcanism on the planet as we took a closer look at this the largest known sub-aerial volcanic system in the world. And now it is time to look at volcanism on a stupendous scale.

But before we do that I suggest that you read the previous parts in this series in order if you have missed them since I am writing them in a geographical timeline:

The Volcanic Dome of Tibesti

The bedrock under the Tibesti Mountains is 500 to 600 million years old and consists of an intrusive metamorphic base overlaid by sedimental overburden. As such it is an old and hard piece of continental crust. It is situated next to the West Saharan Craton, an even older and harder piece of continental crust.

The Tibesti Mountains covers 100 000 square kilometers, or roughly the same area as Iceland and we will spend time comparing these two volcanic centers.

The first difference is age and magma origin, Iceland is an approximately 14 million year old volcanic center based on a localized mantleplume originating from the surface burrowing down into the mantle to a depth of 270 and 540 kilometers. The Tibesti is instead a 40 million year old broad mantle upwelling originating from a layer between 80 and 150 kilometers deep.

Iceland is a part of the Mid Atlantic Rift and is as such a part of a continental divide that is fully formed whereas The Tibesti Mountains is part of a formative continental divide that yet has to succeed.

Emi Koussis central volcanic shield is so large, that even from an airplane you can only capture parts of it.

Emi Koussis central volcanic shield is so large, that even from an airplane you can only capture parts of it.

Due to the shallow and highly ductile crust under Iceland the crust can’t hold enough magma to create large eruptions, instead we see frequent small to medium sized eruptions ranging from 0.01 to 30 cubic kilometers per eruptions that occur between once every three to seven years.

The 120 kilometer thick and hard crust under The Tibesti Mountains can hold and constrain vast amounts of magma and this causes eruptions to be infrequent but very large in scale when they occur. Normal eruptions are thousands of years apart and ranges from medium sized to small trap formations, with sizes ranging from 1 cubic kilometers (to be seen as a minimum) and the maximum known eruption is in the 15 000 cubic kilometer range.

The ductile and thin crust under Iceland can’t constrain a large doming so the average uplift of Iceland is 50 meters whilst the doming at The Tibesti is about 700 meters. Now, ponder the amount of forces that is needed to lift an area that is 100 000 square kilometers and 120 kilometers thick an average of 700 meters, the mind shudders. In the end that much uplift and shear energy could not be contained and the crust started to rip apart.

The origin of the volcanism

WikiMedia Commons.

WikiMedia Commons.

As the mantle upwelling lifted the crust above fractures started to emerge that the magma could enter. Due to the extreme thickness of the crust this process took a long time and the magma melted first the intrusive metamorphic rock above it. And that rock contained a lot of metals and rare earth mineralization’s.

At this stage you had hot basalts being pushed upwards with enriched re-melted crust riding above it and then the slightly colder re-melt entered the water rich sedimental rock. The result was tremendously explosive as large scale kimberlite pipes and diatremes erupted at supersonic speeds and large ignimbrite sheets formed prior to onset of basaltic volcanism. This is the moment where the bulk of the ore bodies formed that we discussed in part 1.

Another way to think about the opening stage is as a VEI-8 sized industrial disaster spreading heavy metals and radiogenic material all over the local area and into the atmosphere. It is not something that I would like to see in my lifetime.

Six phases of volcanism

Detail from Tarso Toon showing layered ignimbrites covered by basalt flows and ash layers. Photograph by Alain Beauvilain.

Detail from Tarso Toon showing layered ignimbrites covered by basalt flows and ash layers. Photograph by Alain Beauvilain.

A while ago I was asked how you know if a mountain is a volcano or not and I jokingly answered that if you pick up a rock and you find Clive Oppenheimer happily grazing it is a volcano. I do not understand how he finds the time to write about every single volcano on Earth, but this time I am very happy that he grazed upon The Tibesti Mountains.

In a paper he wrote with Permenter they divide volcanism in the Tibesti Mountains into six phases. These phases are probably not that distinct, but they create a good enough timeline of the evolution of volcanism there.

  1. During this stage the uplift and extension of the crust is believed to have reached its maximum and large scale basaltic eruption centers formed in the central parts of the Tibesti Volcanic Complex. Volcanoes that formed during this period are Tarso Tamertiou, Tarso Tieroko, Tarso Toon, Tarso Yega and Ehi Yéy (volcanic plateau).
  2. Mainly at the Eastern TVC: Diatreme eruption and large ignimbrite sheet flows as the fissure that would form Emi Koussi opened up, initial formation of Emi Koussi via trap-forming basalt floods.
  3. Central TVC: Effusive and explosive eruptions at Tarso Yega and Tarso Tieroko as they went caldera and birth of Tarso Voon. Eastern TVC: Formation of the elongated fissure shield volcano part of Emi Koussi and formation of the large shield volcano of Emi Koussi.
  4. Western TVC: Formation of Tarso Toussidé and Tarso Tôh. Central TVC: Extensive tephra eruption as Tarso Voon goes caldera. Eastern TVC: Continued formation of the Emi Koussi fissure shield and the Emi Koussi central shield volcano, both at diminished speed of effusion.
  5. Western TVC: Tarso Toussidé becomes a nested caldera in a series of eruptions and birth of Ehi Sosso. Central TVC: Minor eruption at Ehi Mousgou. Eastern TVC: Formation of nested calderas on Emi Koussi.
  6. Western TVC: Formation of Pic Toussidé, Trou au Natron and Doon Kidimi. Eastern TVC: Pyroclastic flows down the flanks of Emi Koussi, intra-caldera eruptions and formation of vents and cones inside the nested caldera.

Here it is important to notice that all of the phase 6 volcanism has happened during the last 2 500 years as witnessed by the Toubou people. Even the name of Toussidé means “The Mountain that kills the Toubou”.

Even though that “minor” eruption of Pic Toussidé is far from the largest the resulting trachytic to trachyandesite lava flow covers an impressive 200 square kilometers and resulted in the collapse of the 8 kilometer wide and 1 kilometer deep Trou au Natron caldera that dissects the older 14 kilometer wide ignimbrite caldera of Yirrigue. It may be the only time in my life I will call a 45 cubic kilometer eruption “minor”, but at the TVC it is a run of the mill small eruption.

Pic Tousside from the distance. Photograph by Alain Beauvilain.

Pic Tousside from the distance. Photograph by Alain Beauvilain.

For those who enjoy spending time searching for lost eruptions during the Holocene in various ice records I think this eruption from Pic Toussidé may be a fruitful ground.

I am not going to write extensively about the active volcanoes in the Tibesti Volcanic Complex, instead I will just put it into context by a few not so well known records. The Emi Koussi complex is built up by more than 15 000 cubic kilometers of lava and it is both the largest fissure volcanic shield volcano on Earth and the world’s largest continental shield volcano. With fissure volcanic shield I mean a shield volcano that has formed along the entire length of volcanoes fissure swarm. And yes, it is the only known example of this type of volcano.

At Emi Koussi the Era Kohor natron filled crater is a powerful reminder that even though this brute of a volcano is not any longer at the peak of its power it is still fully able to produce notable eruptions. Era Kohor is an unusually large crater that is 3 kilometer wide and 350 meters deep that formed during a VEI-6 eruption. There are also similar sized Maars and numerous pyroclastic cones inside the two 15 kilometers wide nested calderas at the summit of Emi Koussi.

The range has numerous hydrothermal fields and the latest to form is located at Trou au Natron at Pic Toussidé that is nowadays happily percolating rich mineral deposits. The numerous and large calderas are topped by Tarso Yega that has a 19 by 20 kilometer caldera that is so large that you can fit the entire Katla Volcano inside the caldera.

As time went by volcanism has switched from extremely explosive over to highly effusive and back towards more explosive events. At the same time the size of the eruptions has diminished.


Trou au Natron Caldera with the natron deposits behind a trachyte lava dome. Remnants from a minor 45 cubic kilometer eruption. Photograph by Alain Beauvilain.

Trou au Natron Caldera with the natron deposits behind a trachyte lava dome. Remnants from a minor 45 cubic kilometer eruption. Photograph by Alain Beauvilain.

Even though the Tibesti Volcanic Complex suffers from smaller eruptions it is still active and the TVC will erupt sooner or later. Even though volcanism here has generally lost in size it is still amply capable of producing VEI-6 eruptions or effusive eruptions in the order of tens of cubic kilometers. As such it is a volcanic region in dire need of both studies and monitoring.

In the next installment about the forgotten volcanoes of Africa we will visit an even grander location of volcanism. And this time we will actually look at volcanoes that you yourself can go and visit as a tourist, time to go to one of my favourite parts of the Sahara!


Here is a selection of sources used for this article and series. As always I am thankful for the works of Haraldur Sigurdson for The Book Of All Things Volcanic.

Permenter & Oppenheimer: Volcanoes of the Tibesti massif (Chad, northern Africa)

Burke: Origin of the Cameroon line of volcano-capped swells. J Geol 109:349–362

Derouelle et al: The Cameroon Line; a review. In: Magmatism in extensional structural settings, the Phanerozoic African Plate

Furon: Geology of Africa

Gèze B, Hudeley H, Vincent P, Wacrenier P (1959) The volcanoes of the Tibesti (Sahara of Chad) (in French). Bull Volcanologique 22:135–188

Goodell PC (1992) Uranium potential of the Tibesti and Hoggar massifs, north–central Africa. Geol Libya 7:2627–2637

Vachette M (1964) Radiometric ages of crystalline formations of equatorial Africa (Gabon, Central African Republic, Chad, Middle Congo) (in French). Ann Fac Sci Univ Clermont 25:1–31

158 thoughts on “The forgotten volcanoes of Chad Part II

  1. Amazing Stuff Carl, enjoying this series immensely.

    Oh by the way

    Did you notice this has been corrected?

    • Thanks!
      I enjoy writing it even though it is the hardest series I have done to date.

      I had missed that it was corrected, I look at a different graph.

  2. There was a genetic bottleneck created about 250000 ybp and when you think about these massive eruptions taking place all over Africa it would not be surprising that the bottleneck was created when the species was close to being wiped out by one of them

    • In other words, just confirming what we’ve known all along, magma created from subducted slabs has a lot of water in it. Without the water, we wouldn’t have arc-based volcanoes in the first place.

    • I do not like the phrasings in that article.
      It sounds like there is actual water down there. There is absolutely NO WATER below Uturunku in any form of a lake or a reservoir of water. Instead what the scientists in question is talking about is the H2O molecule content of the magma. And that is something completely different, and the numbers given is actually average for pretty much every known subduction volcano on the planet.

      • And in case anyone finds that a bit odd… the water is taken up in the molecular structure of the minerals themselves. It’s part of the serpentinization process. For you California denizens, Serpentinite is an end product of that process when ultramafic rock has been modified. You may find outcrops of it while wandering around the mountain trails. Just remember, that used to be ocean crust at one time.

        “Soil with serpentine is poor in calcium and other major plant nutrients, but rich in elements toxic to plants such as chromium and nickel.”

  3. Please, no jokes about Florida and chads. We use magic markers and crayons now.

    • I did not know that there was so many retirees in Florida named Chad?
      (running away to hide)

    • To be honest, I voted against some oddly worded proposal that were to apply to “certain persons”. If it’s gonna that vague, I’m not for it. Tell me what it’s actually for and I’ll concider it. I also voted to not retain any if the judges presented. To me, that’s not an automatically renewed position. You better earn the privilege of staying in office. Usually, if I’ve seen the judge try cases first hand, I’ll vote to keep him if he’s seemed fair and followed the letter of the law. Start making stuff up on the fly and I have no use for him.

      Several years ago I sat in on a court case and remembered one judge in particular who was confronted by a mindless onslaught of “precedence” and “what ifs” by a lawyer. The judge silently sat and listened to him, then shredded the lawyers argument. When he came up for confirmation, I voted to keep him.

    • And am I the only one that measured the line speed and did time-distance calculations to find out that I only had about 5.55 minutes to wait?

  4. Klyuchevskoy seems to have suddenly stopped erupting, KVERT has lowered the alert level to yellow.

    • Regarding the discussion the other day regarding the possibility of a flank collapse on Klyuchevskoy… well it could be that the probability just went up if the main vent just plugged. I doubt that it ran out of magma.

      • Klyuchevskoy has frequently “stopped” erupting, although the stops tend to be short-lived. I wouldn’t personally anticipate a stop in eruption signaling any worthwhile change here.

        Unfortunately, if there were a change that could signal the advent of a flank collapse, we likely wouldn’t be able to see it coming as there just isn’t the requisite instrumentation there for us to know. One thing about flank collapses is that they can occur almost out of the blue due to generalized instability, so that’s always something to consider. With that said, a viscous dome pushing through a narrow vent would be the most likely trigger, so the tell-tale signs would be extensive seismicity, a change to more viscous magma output, and extensive localized deformation.

        • As Klyuchevskoy has been erupting straightforward basalt through its whole historic record, the probability of a high-viscosity flank dome is fairly low, I would think. Although flank eruptions (cinder cones and lava flows) are pretty common.

    • Yes, this was noticed. Not sure what it means. We did consider the possibility of ice on the GPS!

      • There’s also quite a lot of small quakes visible on the grf drumplot that are not registered on the quake lists. I have seen the same thing on several other stations the last few days. Tremors that would normally register, but for some reason never show up.

        • Could it be ice quakes? The machines record them but the human reviewers manually weed them out of the quake lists since they’re only interested in rock quakes.

          • One should also know that the system weeds out all small earthquakes that it can’t get a lock on. The normal reason for this is that it only shows on one seismo and as such is impossible to locate.
            Earthquakes like that is highly local in the vicinity of a particular seismo and will look far larger than they really are.

    • I am still pondering a lot of options for that one. We will have to wait and see what happens.
      And, also for me or someone to get the time to do a bit of computer modeling on it. Probably someone else since I suck at it.

  5. Amazing work you have done here Carl. Well written and very informative.
    Thanks 🙂

  6. Thanks Carl. Very interesting story. Genetic bottlenecks? Yes, these enormous eruptions must have had impact alos on long distance. Would it be possible to guestimate effects at various distances from the volcano and on how long they could have lasted? More and more Africa turns out to be, not the safe paradise for human evolution but more like a modern computer game chasing small groups of survivors with a never ending string of disasters. Tuff selection pressure indeed!

    • The genetic bottlenecks only apply for asians and white dudes.
      The African population that stayed in Africa was never bottlenecked in the same way.
      The gargantuan volcanism we are discussing in this series must be mentally offset by the spectacular size of Africa. Even this humongous volcanoes are just small flees on an elephant.

      • The main genetic bottleneck probably was the migration out of Africa. The involved a sea crossing to Yemen and probably only involved a few thousand people. That was far more important than volcanic eruptions. Even Toba.

        • Did they cross the sea to get to Yemen? Why would they?
          It would have been much easier to walk through egypt into the Arabian peninsula and then follow the coast of the Red Sea.

  7. The past few days there has been an earthquake swarm underneath Mauna Loa, but at a depth of 45 km(!). It is straight underneath the summit.

      • They had a swarm of these in 04 but it was much more active back then. From HVO long term monitoring section.

        “In July 2004, the numbers of earthquakes beneath Mauna Loa increased markedly. From July through December 2004, about 1,700 very deep, long-period earthquakes occurred beneath Mauna Loa. These earthquakes were located over 40 km below the surface, and was a different type of seismic swarm than had ever before been recorded beneath Mauna Loa. This swarm coincided with an increased rate of deformation interpreted as magma influx into the shallower reservoir about 4 km beneath the summit area. The increased rate of inflation continued for another year after the deep seismic swarm ended at the end of 2004. An eruption never occurred at this time and the seismic swarm and deformation were attributed to an intrusion of magma into the volcano.”


        • It didn’t erupt at the time but it did get close. Summit inflation shot up for the 6 months after. But this is not necessarily a repeat of that episode.

          • You have a point, notice how much it inflated in the period before, during and after the 1975 eruption nd how much it uplifter after the 1984 eruption. Then it slowly fell a few years before there was a slow small inflation after the 2004 earthquake swarm.
            I have seen this pattern at other large volcanoes, that it takes more than one large deep intrusive period at the root chamber before magma down in the deep is pressurized enough to gush up to the upper chamber in sufficient amount to produce an eruption.
            The current episode is probably much more likely to lead to an eruption than the previous and something tells me that the 1975 eruption was preceded by several of these deep magmatic swarms, but that there is no instrumented record of it.

          • I wish they would update this chart to include 2016 quakes and inflation!


  8. It would have been but they didn’t follow this route. The Sinai route attracted an early human population (more than 100,000 year ago) but they died out or left little genetic trace: They got no further. The climate probably closed this route, as the Africa side would have been very arid.

    The Yemen crossing happened may be 80,000 year ago, at a time when sea level was lowest. Later when sea level rose the route seems to have been closed or little used, based on gene flow. Either the distance got too large or more likely, the fact that the other side was already occupied was a hindrance. Migrations by boat tend to fail where people already live on the arrival side. Boats carry too few people and arrivals tend to get killed easily. That is also why Australia was populated only once. The route uses island hopping near Australia, and all the islands were occupied.

    • This was an answer to Carl’s Yemen question above. It got misplaced. I blame the FBI.

    • Hm, 80 000 years ago they could walk over there. At best the Red Sea was a mud puddle. After all we are 30 000 years into the glacial period and the ocean was something like 150 meters lower.
      It was probably a nice and cool place with coniferous trees and large game animals galumphing about to whack over the head.
      The passage at Bab El-Mandeb is 250 meters deep, but right after the deep channel you get a depth that is less than 100 meter at both the Seven Sisters and the Al Zubair Group. They probably had a nice stroll along small lakes, hills and some streams to jump across.

      Here is a nice Nautical Chart thingy that is free.

      • … and the Persia Gulf was a warm fertile valley at the time. There are still a large number of fresh water springs in and around the islands in the south east corner of it. Pishon, Gihon, Tigris, and Euphates all flowed down into the valley. It would have been a very nice place to be when glacial max was going on. Relatively warm and lots of vegetation and food. Nothing remains though. I’ve talked with EOD techs who have dived the seabed there. It’s all scoured out and has relatively little sand.

    • I would suggest that Genetic “Adam” and “Eve” were both genetic bottlenecks in Africa around 250000 ybp, how else can the lack of human genetic diversity beyond this point in time be explained?

      There is recent research suggesting Australia was occupied 49000 ybp which is fascinating in itself

      • Do note that 98 percent of the genetic variety is in Africa, this kind of proves that the bottleneck only applies to us who meandered out of Africa.
        I am not convinced that leaving Africa was a good idea…

        • In order to get a single Human Y Chromosome Haplogroup A00 founder it means the root of the human genetic tree was the only surviving human genetic specimen weeded out from other Haplogroups that existed at his time at about 250000 ybp, well before humans migrated out of Africa

          We all descend from this one individual male, so there was no variety at some point in our history.

          • There is a problem here.
            The Turkana record does not show that event in data, or in other words, it does not show a period of diminished population. Something else must be at play. But, I am not going to argue this since I am not a geneticist.

          • For any non-scientific reader…
            Do note that I am not arguing the facts of the geneticists.
            I am just pointing towards what may be a problem for the model in a different set of data. This could in turn be used by the said geneticists to improve or remodel their theory so that it conforms with the discongruity.

            After a bit of speed-reading on the subject I am generally intrigued by the A00 haplotype and I did not that it was not as monohaploistic as it seems since there are at least 3 different types of A00 and that the spread-pattern is rather bizarre.

          • I have had my Y Chromo sequencing done

            This is my genetic Y – haplotree going back to Chromosomal Y “Adam” , the last group BY9002 has a common ancestor about 750 ybp.

            Each step represents some sort of genetic bottleneck of one kind or another, from this I can trace my individual migration out of Africa to Ireland within current migration theories


            Everyone on this planet connects back to A0, all of out genetic trees starts here

            Of course there are other explanations for the original bottleneck but I think one of the logical explanations for the bottleneck could be the result of a eruption that reduce modern mans population down to just a few members.

          • Here is one explanation of what can have happened (temporal logics is okay in the sentence, semantics not so much since I should use could but then the logic would have been buggered).

            Adam-A00 has a mutation that is the A00 clade. He happily has a bunch of kids and slowly the A00 spreads across Africa while other haplogroups co-exist. In the end something between 10 and 30 percent of all men are A00 members.
            In comes a decease with the deadliness of tuberculosis. Let us now say that it kills 1/3rd of all non-A00 per generation and that for an unknown reason the A00 men are on natural genetic vaccine from it. After ten generations there will be only A00 men putzing about without there ever being just 1 man left.
            In this case there could have been anything from 10 000 men to 100 000 men at the same time, all the time.

            The point above is just one way the patrilineal A00 clade could have come to rule the world without there being this ginormous pinch of population.

            Why did I use tuberculosis as an example?
            Simply because I come from a part of the world where 1/3rd of the population died per generation from it. In fact Northern Sweden is the hardest hit by the decease in the world. And it is also the place for the funkiest mutations. Weird blood groups, odd genetic deceases, other quirky mutations and so on and so forth. And this happened in the span of a few generation. Probably those mutations was beneficial towards TB and would have become the prevalent genetic traits if not for vaccines and penicillin.
            One of those mutations resulted in small-p blood-group, a rather quint type that only exist up there and in a fishing village in Portugal. My maternal grandmothers uncle was a sailor and carried the gene to Portugal.

            Another decease we have still on a regular basis is the corona-virus (Winter vomiting decease), one third of the population in northern Sweden is immune to it (thank heavens I am one of those who are immune).

          • Only problem here, no eruption of sufficient size happened at the time to affect all of Africa.

          • Yes, this is a very reasonable explanation and is probably the most likely bottleneck mechanism in all of human history

            So to try to keep this not so off topic lol

            Early humans at around 250000 ybp would have found obsidian and very useful raw material for tools/weapons and this is what makes my mind wonder that they could have concentrated close to volcanoes and been susceptible to being wiped out close to extinction

            Maybe even a combination of several things caused this?

          • Another thing to keep track of is Back to the volcanoes, there was no single large enough eruption to cause a thorough bottleneck at the time.

      • There are several ways to get genetic bottlenecks. Near-extinction is one. Migration is a second. Secondary migration is especially bad: the gene pool is already reduced because (say) the Somali coast was populated by a smallish group of wanderers. They increase in number but not in diversity, and some of them walk/swim across to Yemen. Out goes your gene pool bath water. And once you have a limited variety, normal processes will get rid of some of the inheritance, just like some names die out and isolated villages end up with just a few names. It takes one generation where a family has no non-breeding male, and gone is that DNA. The female side can suffer the same.

        Going back to a single Adam and a single Eve does not mean noone else was there. In small groups the competition can die out quite easily. It does mean that at some point there weren’t that many people involved in your migration.

        • Yes, it is fascinating how an individual that lived long ago can have such an impact on our species.

          Example, 80% of Irish males descended from one man (L21 Haplogroup)

          • It really puts into perspective how incredibly inbred we are in Europe.
            I still return to the fact that 98 percent of human genome variations are to be found in Africa.
            Also, it is good to remember that Haplogroups is just one set of genes, there are many others that cause variations. We have all heard how few sets of mitocondrial DNA we have outside of Africa (we are all coming from 7 women if I remember correctly), but as soon as we go to Africa we have loads more of females that people descended from.
            In Africa you can have larger genetic differences between two villages that are close by than you would have between Aborigines in Australia and Scandinavians.
            Scandinavians and Irish should really think about only having kids with people from Africa since we are so incredibly inbred.

          • About the only lineage thing I can came is an odd name with no direct translation to English… but likely harks back to the early migration period and only makes sense if it is rendered in elder furthark runes. Basically “the guy with the Devine gift of a torch”

        • 25,000 years ago was the sudden demise of the mammoths in Siberia. Studies have shown that their last meal of grasses and flowers was eaten before they were swept away in a muddy flood, and then quick frozen into ice that remains. There doesn’t appear to be any evidence of a shift in the poles that might have moved their location further north suddenly, but they coexisted with humans at that time and then vanished in an instant climate change

          • This story dates back to the discovery of the Berezovka mammoth, found in frozen gravel indeed with grass in its mouth. There were no glaciers in the area at the time. Te question has been how it could have frozen quickly enough not to get eaten by a predator. Over time the story grew in the ‘thousands of mammoths’ but there was only one. Other frozen mammoths are from different times and different regions. They are found fairly regularly but there aren’t that many and each is different. Some got stuck in a swamp, a well known danger for an elephant on the tundra. the Berezkov mammoth had a broken leg, and likely fell of a cliff. One possibility is that it fell into a deep snowbank and was hidden from predators. It probably froze, as dead animals in Siberian nights, over a few days.

            I remember when living in the US seeing a dead cow in a ravine on the way to work. Over the next months it just stayed there. The coyotes never found it.

  9. Kilauea looks like it is close to overflowing on to the floor of the caldera (light is still low on the current picture). Hvo mentioned in today’s briefing that it was close to the top several times last night. We should have a new picture in a few min.


  10. Grimsvotn close to erupt?

    Isn´t it time for an eruption of Grimsvotn?

    I mean Grimsvotn is a easy to predict volcano, as once cumulative seismic release reaches a certain level, a new eruption happens. Usually every 3-6 years.

    The last eruption has been in 2011. I think we predict that the cumulative seismic release would reach eruption levels by late 2016 and 2017. And judging the recent swarms of Grimsvotn and sudden fast inflation… hmm, every sign points to an eruption nearing in Grimsvotn.

    Grimsvotn is easier to predict than Katla or Hekla.
    Anyone has a link for the cumulative seismic release?

      • I disagree, and I think perhaps Carl can also take in account what I will suggest.

        Historically, Grimsvotn exhibits great variation of frequency between eruptions, depending on much hotspot activity is going on.

        There are periods where Grimsvotn rarely erupts across a few decades, such as between 1938 to 1983, when the hotspot activity was supposed to be very low. Earlier in late 19th century or early 18th century, when the hotspot activity was high, Grimsvotn was erupting often, every 3-5 years. Sometimes Grimsvotn even erupts every 1-2 years.

        With the approaching peak of hotspot activity, I expect Grimsvotn frequency to increase, irregardless on whether the 2011 eruption was big. So I would expect eruptions every 1-5 years in the two decades ahead. In fact, there is probably a large pool of intruded magma remaining from that eruption still available to erupt; this was fresh hotspot magma (the last pulse in Grimsvotn since Laki). So I expect also the cumulative seismic release threshold to be lower than in 2011. I even expect a slight risk of a rifting event towards the southwest or across Thordarhyma (which is dormant since 1910).

        Anyways, even Grimsvotn can be unpredictable, because its a volcano. But I remind myself of the large picture; we live in interesting times, when Vatnajokull volcanic activity is predicted to become increasingly high.

      • Lets assume that the next eruption would require a lower threshold.

        2004 eruption required 4e14, 2011 eruption required 3e14 of seismic moment. Lets assume next eruption would require 2.5e14

        At a steep rate, similar to the last year before the previous two eruptions, that threshold would be reached by day 2300, which would be around Sept 2017. But if seismic moment really accelerates and curve becomes steep, then such a threshold could be reached by day 2100, or around Feb 2017. If things go slow as they have been in previous months, then that threshold would only be reached by 2019 or 2020.

        • My thoughts are that a prolonged and intense magma influx could acceleration things quite quickly. I assume something along those lines is what caused that jump we can see. A few more of these and who knows, As we head into the new activity cycle, all bet’s are off.

          What interests me is when it does erupt, will it fall short of the Last threshold and continue the pattern? And what is happening in its innards to drive the change, is the threshold really changing or is there something else going on that we just can’t see.

    • There are some anomalous readings at Grimsvötn that are highly localized. So far I suspect local inflation from hydrothermal sources.
      I am still leaning towards there being between 3 months a 3 years before an eruption occurs, I may though change my mind soon when I run the next predictive modeling for it (I do that monthly).

        • I did do that in a simplified form in this article

          I will most likely never do an article about exactly how the model works from a mathematical standpoint since it would be so math heavy that only Albert could follow it.
          And since Albert is a better physicist than me he would feel obliged to point out 22 different ways that are better to do it and the comment field would be filled with mathematical comments. And that would A) bore everyone except me and Albert and B) it would be detrimental for my ego being reminded exactly how much better a physicist Albert is compared to me 🙂

          So, the general description in that article is about as far I will ever go into depth of modeling Grimsvötn.

          • Nah, it would be A that is the correct answer.
            I am very happy when Albert points things out to me.
            In the end I am just an ordinary ph.d. that left academia a long time ago and Albert is… … well Albert, and I enjoy learning new stuff from a true master at his craft.

  11. Carl, this article is outstanding! Its pure joy!

    Recently we have had a series of really really good articles in VolcanoCafe.
    Clearly the best spot to read on volcanism on the entire internet.

    The size of this shield volcano is absolutely off the scale!
    How does it compare with Hawaii?

    And ohhh how I would wish to visit these Chad volcanoes…. But I am aware of the danger

    • Thank you Irpsit, we are trying hard to raise the bar for volcano writing and it is heart warming to hear that you guys are noticing 🙂

      I am no expert on Hawaii, but it is several times smaller than the Hawaiian brutes. But the area of the Hawaiian volcanoes is smaller.

  12. Always keep track of your stuff. This is how most IT jobs begin.

    True story: My grandson knocked a friend of his girlfriend’s laptop off onto the floor and broke the screen. I got him to order the parts and swapped him the labor to repair it for yardwork. I made out on the deal because I am pretty adept at what I do. In fact, I was so impressed with the ease of working on it that when I had to get a new laptop, I bought the same model. It’s not as durable as some of those ruggedized dell models, but it is quite easy to get into an service. I know of one Dell 6400 that has been through hell and back, but those things are a pain in the neck to get in and out of. But you do have to hand it to them, they will take a beating. In a way, I think my grandson is a bit cursed when it comes to technology. He was at a party and lost his phone, so he had a friend call him so he could find it. When the fire started ringing he knew he had a problem. He fished it out and it worked fine after it cooled off… for about a week. Until he stepped on it.

  13. And there’s the “witch of November”… right on schedule. (Same sort of system that got the Fitzgerald)


    • And as with all things weather. The pending low is now projected to track more to the east than a typical November witch. (Which is actually a variation on the “panhandle hook”.)

    • Heh… the attempting to form November Witch took a wrong turn and petered out. 😀

      With frost and freeze warnings in Tennesee… there probably was not enough convective energy to support it forming up.

  14. And 2016 is relentless… truly the year Music died.
    Leonard Cohen died at age 82.

  15. Friday
    11.11.2016 17:20:03 64.622 -17.391 0.1 km 3.5 99.0 6.8 km ESE of Bárðarbunga

  16. NOTICE: Some people have erroneously been reported as dead on Facebook.
    For those of you who are not dead… Welcome back! If you are actually dead, and you’re reading this, you’re probably a Zombie. A really confused and atypical one that hasn’t quite grasped the events leading up to this point.

    From the link, Facebook’s response;
    “For a brief period today, a message meant for memorialized profiles was mistakenly posted to other accounts. This was a terrible error that we have now fixed. We are very sorry that this happened and we worked as quickly as possible to fix it.”

  17. I know this is a random thing to say, but does anyone else think Mount Osorno, Chile has an uncanny resemblance to pre-collapse Mt St Helens? Especially when you look at pictures taken from the nearby lakes, like this for example:

    • You can say this about probably 60+ volcanoes around the world. It’s not that you’re wrong, but pre-collapse, St. Helens wasn’t really anything particularly unique in terms of volcanology.

      Beautiful picture however!

      • It was unusually pretty. A smooth cone is a sign of youth, by the way. It means the erosion hasn’t put the wrinkles in yet. So in a way, yes, beauty is a sign of danger.

    • I agree with cbus05. Other than being quite symmetrical, Mt St. Helens was pretty much a typical stratovocano. Being symmetrical just pointed towards it usually having pretty even and consistent eruptions with nothing really odd going on.

    • Reminded me of Taranaki, another nicely symmetrical cone Ifrom certain angles) With a history of flank collapses.But like cbuso5 says, there are many similar

      • That’s what got me thinking, near-perfect cone, major explosive history, long dormant, next to lakes, hard not to draw comparisons! Or maybe it’s just me; the 1980 blast being loooong before my time!! 😀 It means whenever I see images/pics before it happened, I can almost “see” the weakness in the old north flank (good old dose of hindsight!). Of course I’m not saying next time Osorno, or similar, wakes up, it’s gonna be 1980 all over again, but it’s one of those “what if?” moments. If you consider where the mid-1800s eruptions occurred on St Helens, it’s maybe not that surprising it was that flank that ended up going, and as far as I know that didn’t happen at Osorno, so maybe just ignore my rambling!! xD xD

        • Mind you, St Helens (and the Russian one that I can never spell that blew in ’56) both had a pretty explosive recent history with stonking great summit domes; Osorno, as I recall, is a mostly basaltic andesite cone, rather like Llaima and Villarica. Lava flows, Strombolian fireworks etc. Obviously I wouldn’t rule out a collapse, but Taranaki –or Colima come to that,– would be a better bet IMO

  18. Saturday
    12.11.2016 01:21:50 63.992 -19.690 0.8 km 0.7 99.0 1.1 km W of Hekla

  19. For those who are waiting for a new article…
    It will be up tomorrow, and there is a good reason for the delay.
    Felicitations upon everyone!

  20. An italian expert Luca D’Auria has stated that the fault line between Tenerife and Gran Canaria could cause an earthquake of M6 and above.

    Translated from Spanish:

    The Italian expert, 41, charged with monitoring between 2003 and 2015, Vesuvius, one of the most dangerous volcanoes in the world, said in an interview with this newspaper, that “the magnitude of tectonic earthquakes is directly associated with the extension of fractures of the crust, and between the two main islands of the Canary islands is great.

    According to Professor of Geological Engineering at the Complutense University of Madrid, Luis Ignacio González de Vallejo, the fault between Tenerife and Gran Canaria has a length of “at least” 35 kilometers and points out that it is a dimension “considerable “. For this reason, Luca D’Auria warns that major earthquakes in this area have the epicenter in the alteration of the earth’s crust. Nemesio Perez, director of the Environment Division of ITER and scientific coordinator Involcan, remember that Canary is located in an area of ​​”intraplate” (low seismicity), “but we know that we have to live with that fracture also , it is related to volcanic activity. ” Do not forget that close to the fault lies submerged, known as the volcano in the middle.

    In his first statement, made to DAILY WARNINGS, Luca D’Auria defined yesterday the draft of the new seismic network with a very graphic phrase that reflects where you want to set the bar of the investigation. “We aim will hear the silent activity Teide, which is speaking to us and we have no precise instruments to detect what is telling us , ” he said.

    Full articles can be found on :

  21. And to cheer every one up, here is the news that the UK attempt to land on Mars almost succeeded. It turns out Beagle-2 did land in one piece after all, and did take data. So the science worked. But one of the solar panels did not fold out fully and blocked the transmitter. So the poor thing worked in complete isolation and noone will ever know what it discovered. A robot after my heart – it behaved just like a real scientist.

    The EU now requires that data from EU-funded science is made available to everyone for free. I guess beagle-2 didn’t quite manage that standard yet. Not even the instrument access every got access to the data.

    • hm. Not sure I quite see enough evidence for their claims. One of these cauldrons they attribute to an impact, and the other to sub-ice volcanic activity. Melt water is one way of making cauldrons, and it doesn’t matter how you get the water. Any water will carve out deep holes because water is denser than ice – it sinks. But there is no liquid water on Mars which is a bit of a problem, and in all cases where liquid water has been claimed, other explanations have surfaced including CO2 sublimation. Anything that can make a hole can make a cauldron. The size of the Hellas structure suggests an impact (it is really quite large) but it may have been an ancient one. Say a sand-dune filled crater (which are common), later covered by ice (Mars has an unstable climate and ice is intermittent everywhere, at least over a few million year). If the sand compacts, the ice above can collapse. There will be other ways. I wouldn’t go for volcanic activity as the first choice to explain a cauldron. At least on Mars.

      • Thanks. The cone-like shape is curious. btw, the new mini-series “Mars” stars Monday on the National Geographic Channel and the first episode is available now for streaming. They claim scientific accuracy. I blame you, Albert, for my new interest in Mars..(and Pluto, and …)

        • National Geographic is accurate and certain. Science is accurate and uncertain. Economists are inaccurate and certain. Politicians are inaccurate and wrong.

          • National Geographic used to be accurate. But it’s now owned by Rupert ‘The Dirty Digger’ Murdoch, so who knows for the future?

  22. New Zealand city defence warnings of Tsunami:

    This is a local source event – we don’t have info about specific locations. The tsunami threat is for the East Coast of all NZ #eqnz
    12:28 PM – 13 Nov 2016

  23. What’s up at Iceland at the moment?
    Volumetric borehole strain and drumplots are serious nervous and doesn’t look like weather either?

    • Must be the sensitive instruments capturing the strong quake on the other side of earth in NZ I guess.

  24. NZ is rocking tonight, had a 2m + tsunami so far, it looks like a Alpine fault rupture ?

    • Yeah, but from Facebook comments it appears the tsunami sirens do not go off everywhere…

  25. Kaikoura (wherever that is) has a sizable tsunami, about 3 meter peak to peak judging from the gauge. The water first went down before the first wave hit. Three so far. Wellington has a smaller tsunami, less than 1 meter so far. It seems to have just arrived in Christchurch, perhaps a similar size to Wellington but the first wave peak hasn’t arrived yet.

    • Kaikoura is east of the epicentre, I suspect that the tsunami may not have been from the main shock but from strong M6+ aftershocks just offshore. I’m still waiting for news, phones/power down. Most of Kaikoura should probably be okay, but there are some homes at low elevation in the area.

      • Thanks. The first wave peak seems to be arriving in Christchurch now. I am looking at the tidal gauges

        • Yes – just looked and GNS have shifted initial location of the first larger aftershocks inland, and they’ve also revised the magnitude down to the high 5s.
          So that’s two concerns – undersea landslide in the area probably generating significant but not devastating tsunami this time is confirmed by observation, plus if the M7.5 was the main shock, then we haven’t had the largest aftershock yet..

          • Don’t know why but I can’t post a reply below yours. But anyway nooooooo! I don’t want that to be known in future as a foreshock. I don’t like the progression either, nor the comments from USGS I posted below.
            But hopefully it’ll be okay. Stay safe.

          • Actually – looking at GNS locations for the aftershocks, perhaps it’s just reactivated the fault in the Grassmere area – from the “Seddon” quakes there a couple of years ago. It just looks like it’s unzipping north from the pattern you can see, but possibly isn’t as the faults run more SW/NE than the line of aftershocks seem to show.

        • No tradition here of major foreshocks. But earthquakes have come paired here before. In 2013 there was the double M6.5 in Blenheim, less than 2 months apart. In 1929 there were two M7’s near Christchurch, three months apart. What I find interesting is that todays quakes exactly fill in the region between the 2010 M7 quake west of Christchurch and the 2013 Blenheim quakes. I think it is resolving tension displaced by those quakes. It started near the Christchurch end, and moved north to Blenheim, possibly jumping fault on the way (that is a guess).

          For the future, not risking italian justice, I would think this region is less likely to be hit again soon. Looking at historical quakes, the main risk seems to be on the opposite side of the coast. There is a big gap between Christchurch and the Mount Aspiring region which has been awfully quiet for a century. The region just south of it (opposite Dunedin) has had some big quakes in 2003 and 2009 (and in the 1930’s before that), but the region in between has had only weaker quakes. There may be a reason for this though

          • It’s very very hard to say. Sure in the well defined Alpine fault itself, that fault is “predictable” in the sense that it’s got known displacement/movement North and South, it’s “locked” with about or over 8 metres of lateral and several metres vertical displacement locked and ready to spring since the last event ~300 years ago, and it’s very “reliable” in terms geological history on time between major events. It’s loaded up and ready to go now, about 10% probability per decade, increasing of course every day. (if it doesn’t let rip today, the chance of it letting rip tomorrow is higher).
            That was my immediate reaction during the quake last night, I expect the Alpine Fault quake will feel much the same, I thought it was – but when the strong shaking subsided after a minute or so I started guessing that it wasn’t as was somewhere else. Strong shaking from the expected Alpine Fault rupture should continue for 2-5 minutes. It will be quite a ride.
            The faults in the North Canterbury Marlborough region where the quake just happened are a contorted complex mess. Anything could happen at any time, and it has in the past. IIRC, fault ruptures in that region in the late 19th century showed the first direct irrefutable evidence of lateral displacement in large quakes, with fence lines across the fault showing several metres lateral movement.

    • Kaikoura is a small somewhat isolated town on the sticky-out peninsula half-way between Christchurch and the north end of the south island. Best known for tourism and whale watching. We got there often.

      Aaaaaaand there’s the tsunami warning sirens just gone off down my street right now – 02.38 local. I’m at the top of a hill so not going anywhere!

      • Note how both Kaikoura and Wellington show a spike at the same time the water began to recede in Kaikoura. That was probably one of the quakes, perhaps even the first one. An underwater slide near Kaikoura seems probable, directed away from the coast as the water first receded.

    • Kaihoura is a major tourist area for seeing whales and dolphins. A 3m tsunami would overwhelm one area of the town in a low lying area by the sea.

      They also have fantastic crayfish…

      • An almost one meter rise in the land may have saved the town from the tsunami wave?

        • According to photographs taken by a VC member on Facebook the uplift was two meters. The images was really good.

  26. I’m in Christchurch about 100km from the epicentre here. No damage to our house – nothing fell over. Was interesting. It looks like it was on a fault that’s not well mapped though there are many fractured faults in the area. Duration of initial strong shaking was about a minute.
    No – it was not the Alpine Fault. That was my thought as the quake was under way, as it was clear from long period and strong lateral motion that it wasn’t very close.
    There appears to be considerable damage in towns close to the epicentre, though it’s slow getting accurate news. With luck there shouldn’t have been casualties, mainly low timber-framed buildings, built to gradually more stringent EQ building codes since the 1930s.

  27. I’m guessing the waves on the Low Pass Filter drum plots are from the NZ quake? These are new plots and this is the first activity I have seen on ghem

  28. Here’s some initial comment on the quake – some of it not exactly comforting to read:

    So far it doesn’t look to be the Hope Fault, rather (and perhaps more concerning) it seems to have ruptured across the Hope Fault”, USGS seismologist Professor Kevin Furlong said.

    A massive 7.5-magnitude earthquake which has struck the South Island, triggering further quakes and tsunamis, may not have been generated on the Hope Fault.

    “So far it doesn’t look to be the Hope Fault, rather (and perhaps more concerning) it seems to have ruptured across the Hope Fault”, USGS seismologist Professor Kevin Furlong said.

    “…Most/many aftershocks extend to Cook Strait implying that the rupture may have extended quite a bit to the north.

    “One concern is whether this has involved any of the subduction plate boundary that starts up at Kaikoura and extends along the [east coast of the] North island.

    “At a minimum it may have changed the stress conditions on the main megathrust interface – we are exploring that possibility right now.

    “The main event is quite complex and may explain some of what you felt (and the different magnitude reports).

    “It appears to have initiated for about 40 seconds with something that might be seen to be about a magnitude 6.6 or 7.0 event and then it had a big pulse of rupture lasting for the 100 seconds or so (and constant with a Mw 7.9) which is what the USGS now has it as.”

  29. Something funny: the Kaikoura tidal gauge obtained an offset during the quake. On the measurements, you can see that the water level never came back to the pre-quake level but dropped by 50 cm or so. That is also visible on the raw measurements (which include the tide: the quake happened near high tide). As if the gauge itself came up by that amount.

    • That’s an interesting spot Albert and reminds me of the late Harold Wellman’s wooden models of the Alpine Fault. I know this EQ is on a different fault (Hope?) but I wonder if it is part of the same process that is building the Southern Alps?

    • Or maybe the algorithm that removes the tidal levels is in error. From GeoNet: “De-tided readings are only available for sites where the tidal model has been computed. An initial model requires several months of data to be collected first.”
      However, even the un-de-tided (sounds nasty) data looks like a drop.

      • I looked at the original data first, with the tide left in (I don’t trust algorithms). It is very clear in there as well. Of course anything can have happened – the gauge may have been knocked. But it is not impossible that the land was pushed up.

  30. The gauge will have moved. Here’s the GPS-measured ground movement from the quake from a station North of Kaikoura.

    Trivial fact – “Kaikoura” mens “To eat crayfish” in Maori.

    Two confirmed deaths sadly, there are however isolated communities, farmhouses etc in the affected area which haven’t been able to be contacted yet. Some roads are impassable. Helicopters etc have been mobilised.

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