Black Swans and Iceland

The initial eruption at Fimmvörduhals next to Eyjafjallajökull in march 2010. Photograph by Boaworm.

Two weeks ago I wrote about statistics and the possibility to predict volcanoes in any way by using statistics. I think that the point was a bit lost, my entire point was to show that it was impossible to in any useful manner predict when an eruption would occur, and also that it is impossible to use statistics to show how the volcano will erupt when it does erupt. I also tried to prove that in the end a volcano is more likely to do something statistically unexpected, than the expected.

To accurately forecast a volcano, you are far better off if you study the volcano at question well, and then put a lot of equipment on top of it and then interpret the data. If you are an expert you are quite likely to see if the volcano is about to erupt, and sometimes even say something about how it is likely to erupt.

After that I ventured into Adamsian Improbabilistics and pointed towards it perhaps being a useful tool to say something about eruptions of a particular volcano that is out of the ordinary. The reason for this possibility is that there are so many improbable things that can happen around volcanoes as they erupt that it is interesting to study what is hiding out in the land of improbable.

Albert asked if it would be possible to use Improbabilistics on a particular volcano, Hekla, to see what would could be lurking “out there”. Problem is just that Improbability theory is not yet advanced enough to do that.

So, I thought we should start with looking at a few historical eruptions, just to get a feel for what is improbable (out of the ordinary) around Icelandic volcanoes. After that it is time to look at Hekla from a historic standpoint and see what we can find that is out of the ordinary there.

So, let us take good look at what is hiding among the statistical outliers from the statistical models of our favourite volcanoes. Just to keep it short I will briefly venture out into the 3 last eruptions on Iceland and see if they fall into the statistically probable, or if they indeed where cases that are improbable.

Eyjafjallajökull 2010

The main eruptions from a distance. Photograph by David Karnå.

Before the eruption started there had been 3 different episodes of inflation in the volcano. So, it was not unexpected when the final earthquake swarm started that an eruption would follow. In other words, due to instrumentations and interpretation of data the eruption was accurately forecasted, and it is possible that this saved lives.

This is though the end of the good news. Everything else that was expected from statistical analysis was promptly falsified.

The first thing that was falsified was the statistical assumption that this volcano suffers from mild eruptions ranging between a small VEI-2 to a small VEI-3. In the end the eruption turned out to be 10 times more powerful than anything known from historical records.

The next thing that we “knew” about this volcano is that there was supposedly some function that caused nearby Katla to erupt almost directly after Eyjafjallajökull. This sent a lot of doomsayers into playing lip banjo out of joy since Katla would blow the world up.

And, obviously a lot of nothing happened at Katla and it turned out that this mystic connection was just a simple statistic anomaly caused by the normally frequent eruptions of Katla.

Prior to this eruption it was a mantra in volcanology that what comes out of a volcano has entered the same volcano. Or in other words, volcanoes do not swap or inject magma into each other’s magma reservoirs. Even hinting at anything like that was seen as perverse.

In the end we could track 3 individual magma paths from depth. First, we had the known conduit of Eyjafjallajökull itself that had received fresh magma from depth. Secondly, we had a completely unknown conduit that went up to Fimmvörduhals (where the initial eruption started), that conduit later took a sideways walk and connected with the one at Eyjafjallajökull. The third conduit is the one reaching up to Godabunga. There are haunting trails of earthquakes reaching from Godabunga towards Fimmvörduhals prior and during the eruption there. As such Fimmvörduhals could have been the first eruption of Godabunga.

In other words, even though this eruption was expected from seismic data over two decades, it turned out to be a fairly improbable.

Grimsvötn

The aftermath of Grimsvötn 2011. Photograph by Boaworm.

If we fast-forward a year we get to the largest explosive eruption since Cerro Hudson vent boom in august of 1991. In 1996 Grimsvötn had thrown us a true black swan as an earthquake at Bárdarbunga set off a radial fissure eruption of Grimsvötn at Gjálp.

Before the VEI-3 of Gjálp it had mainly produced numerous weak eruptions for more than a century. Gjálp at VEI-3 was the largest since 1873 (minor VEI-4), it was also producing quite a bit of lava. This lead most people to believe that the next eruption would take a while or, be a regular small VEI-2.

But, alas, as soon as 1998 came another VEI-3, this time at the south caldera wall. And once more statistics came into play and everyone said that it would either take time to the next eruption, or it would be a VEI-2. Rinse repeat in 2004.

By now people had come to the conclusion that Grimsvötns pattern had changed a bit and that VEI-3s a few years apart might be the new thing for the volcano.

As earthquakes picked up in late 2010 everyone was expecting a mild VEI-3 to follow. Instead we got ashmageddon and an eruption that was an inch of a VEI-5. Another way to put it, the eruption turned out to be about 80 times bigger than expected.

Once more it was back to basic research. In the following years we understood that the deep reservoir of Grimsvötn had been depleted during Lakí in 1783, and that it was not until now that it had been fully replenished.

We also learned that Grimsvötn has 3 different shallow magma chambers, and that all of them had been almost completely destroyed in a series of VEI-6 eruptions known as the Saksunarvatn tephra’s.

If we had known all of that in 2011 we would not have been as surprised. But back then it was seen as a full on black swan, but in reality, it was just our ordinary day improbable grey swan.

Holuhraun

In 2014 we got a true black swan as a large amount of magma entered the relatively unknown volcano of Kistufell. Such intrusions are not uncommon in Iceland, most often nothing happens, and the magma just remain in the magma chamber.

This time there was just too much of it, so it first tried to hammer its way straight up, but the lid was stronger than the side of the chamber and the magma started to move towards Bárdarbunga and succeeded with entering that magma chamber.

Once more the lid was stronger than the sides of the magma chamber and the magma from two volcanoes started to progress towards the fissure swarm of Grimsvötn. As the magma arrived there it rebounded against yet another volcanic intrusion hotspot that we have named Greip. It has been suggested that the magma flow here connected with the magma conduits of Greip and that the flow was now powered by 3 separate deep conduits in a perfect threesome of magma-swapping.

The magma then travelled up to a previous eruptive zone known as Holuhraun where it popped up in a rather massive way. Incidentally every text book before 2014 said that Holuhraun was erupted in 1797 by Askja, not Bárdarbunga. Well, we learn something new every day.

It is not that Bárdarbunga erupted that is a black swan, and it is not the size. Bárdarbunga has produced far larger eruptions in it’s lifetime. What comprised a black swan here was that prior to the eruption we did not know that different volcanoes could play magmatic snooker with each other exchanging wads of magma with each other and bouncing that magma around a sizeable portion of Iceland. Seems that we did not learn the lesson from Eyjafjallajökull that well.

Conclusion so far

The only conclusion we can draw with such a small sample of eruptions is that improbable eruptions seems to occur improbably often. We could probably make a list of how big a percentage of Icelandic eruptions are unexpected and improbable in one way or another, but I think we will find that it is more common with the uncommon than we expected.

And now it is time for the mother-factory of black swans. The swaniest and blackest of them all.

Hekla

It was an improbably nice Icelandic morning in May 5152BC as a bowl of petunias materialized on the plains northwest of Hella. It looked around and said to itself; “Oh no, not again!”.

Quickly a series of powerful earthquakes ripped open a 6.5 kilometres long fissure at a with of about 50 metres. Out of the fissure roared ash and pumice towards the sky as the bowl of petunias was shattered.

Within an hour or two 5 cubic kilometres of ash, pumice and tephra was ejected. After that, as if someone had pushed a button, the eruption changed, and 1200-metre-high lava fountains fountained out along the length of the fissure.

After a couple of weeks, the eruption was over, leaving a fresh plain of still molten lava. The only remnants were a series of low spatter cones left behind. Hekla had been born unto us.

Compared to any other volcano, and the birth of any other volcano, this was the black swan of all volcanic births. The paradigm of volcanoes is that they are born relatively calmly with frequent small eruptions as they are young, and that as they mature they will have fewer eruptions that are larger due to the development of their magma reservoirs. Hekla did it in reverse order.

Hekla then continued to have large (VEI-5) eruptions far apart in 4700BC, 4110BC, 2310BC, 1550BC, 1100BC and 1104AD. Seven eruptions in 6000 years might not seem a lot, but if all of them follow the brutal pattern of Hekla, it will still construct a mountain.

We do know that Hekla looked different prior to the 1104 Seslund Pumice, and also that it was significantly lower compared to today. The eruptions up to and including 1104 was just to brutal to be good at constructing a majestic edifice.

In this series of 7 eruptions only 2 can be seen as black swans. The first one is obviously one. The second one is also one since large fissure eruptions rarely happen at the same place. Iceland is filled with one hit wonders that have left a fissure row behind as it’s only legacy.

After 1104 something changed, and we do not know what. The style of the eruptions stayed the same with an initial short brutally explosive phase, followed by lava pouring out. After 1104 Hekla erupted roughly every 50 years six times in a row, ranging from VEI-2 to VEI-4.

Then it calmed down and started to pace itself slightly better with inter-eruptive periods ranging from 50 to 150 years. These can be called the classical years of Hekla. It had by now a tremendous reputation as the gateway to hell.

But, once more Hekla felt the need to change things, and in 1947 it started the modern age of Hekla with far more frequent eruptions ranging between 1 and 27 years. The eruptions once again diminished in size a bit.

In a sense of it Hekla is becoming younger as it is aging. It started big, and then as time went by it started to erupt more often and smaller instead of going the other way.

In a way Hekla is that Rockstar that everyone loves, a volcanic badgirl. Living life to hard, using to much drugs, and we just know it will end badly and after a short lifespan.

Question is more how Hekla will end. Will it erupt so often and so hard that in the end the edifice becomes to heavy and it all drops down and form a caldera. Will it sputter out, forgotten on a wayside roadhouse of volcanic music drowning in its own vomit. Or, will it go dormant and make a comeback in a thousand years with a final cataclysmic VEI-6 concert that kills it on stage?

Personally, I favour the version where the edifice becomes to heavy and it drops down into the wedge-shaped magma reservoir under it as a flood of lava pours out to cover any trace that this improbable volcano ever existed.

In the end, the only true black swan left in regards of Hekla is if another Hekla happens. Today it is unique, so much so that it is a class of volcanoes unlike any other on the planet. And it is a class of one. As such, another would be the true black swan. And since it is so improbable it will probably happen quite soon.

CARL REHNBERG

104 thoughts on “Black Swans and Iceland

  1. Excellent! Almost poetic. LOL magmatic snooker 😀
    According to the futurevolc project, Hekla has a Pleistocene history, or do they mean Vatnafjoll? I wonder what effect a new Vatnafjoll eruption would have on Hekla… Plus, they say the H3 and H4 eruptions were VEI-6.
    Oh, and in other news, there’s a new report out about how the Eldgja eruption may have triggered the conversion of religions. Anyway, it mentioned that the eruption lasted from early 939 to late 940, so I guess we have some degree of confirmation to our articles from a while back!

  2. One more fantabulous (?) article.

    There’s one catch with Hekla…. Historical monitoring didn’t exist in 1104AD and before, so it could well have thrown some 1991-sized “little” eruptions at regular pace before the big one came and obliterated everything.

    And I think it’s gonna keep on doing the same throughout our lifetimes, one every 20ish year…. then go silent for a few centuries while whipping up some rhyolite…. and no, the VEI6 that will ensue, won’t kill her, but start her afresh (and probably give it a good facelift which will wipe all evidence of the long-gone trail of eruptions before).

    Another true Icelandic hyper-black swan was the eruption of Eldfell in 1973. I wouldn’t have bet half a cent on Heymaey (orth?) going off ever ever again. That strombolian cone came out of the blue. Maybe there was the smallest hint a few years before, when Surtsey broke out of the water not too far away, that the old Westmann volcanic complex had some life left in it, and that more could be expected. More did come.

    • Eldfell can’t be a black swan. The Westman Islands are the tip of a propagating rift zone being born and extending southwest. In the future it will become part of the mainland and connect to Reykjanes. I expect more in centuries aheaf, even perhaps in the near future!

      • Whoa didn’t know that. Thought it was a far-away satellite of the main Icelandic plume, that happened to be there only by luck, as the mid-ocean ridge had created some kind of weakness through which stray magma from the mainland tectonic system could seep out.
        So this is a new bit of Iceland building right in front of us. Fascinating.

        I expected these islands to behave like Bogoslov or Nishino Jima, popping out of the water, and being eroded away by wave action, only to break out of water again if activity resumed…

        • Well nishinoshima is probably going to be permanent with how much lava it erupted, and that it has already erupted once again (2017) since its island forming eruption (2013-2015). It might actually be the first volcanic island formed in historic time that will persist long enough for another eruption to happen there before the central vent ends up underwater again.
          Surtsey was probably a one off eruption and no eruption will happen there exactly ever again, and bogoslof is still in a bit of a grey area in terms of wether it will actually survive as a permanent island, especially with the huge explosive eruptions it did in its last eruption basically destroying most of the old island. But nishinoshima is probably destined to end up like the other subaerial volcanoes in the area, maybe something like izu oshima volcano just south of Tokyo.

      • Did Surtsey and Heimaey receive their magma supply from the magma source below the Eyjafjallajökull central volcano? I am thinking about a long dike extending from Eyjafjallajökull all the way to Surtsey. Another view could be that Heimaey is a central volcano with its own magma chamber which supplied Surtsey.

        • Surtsey was plain-label, Icelandic basalt. Heimaey was hawaiite at first, Icelandic Alkali Basalt™ later. also, the fissure trend at Surtsey was the same as the regional fracture zone, while Heimaey’s fissure was oblique to it.

        • My first decent plotted quake stack was for Eyjafjallajökull. Though some parts seemed odd (helical? Wtf?) Down to the Moho. I saw no indication of a dyke pointed lateral to the stack… except for the quick quake shot from Fimmvörðuháls over to Eyjafjallajökull.

          Your mileage may vary…

  3. I know I’m talking too much 😉

    Your reference to Cerro Hudson’s eruption in 1991, is quite fascinating, because it’s almost an exact replica of a Katla erupting in a 2-staged Eyjafjallajokull way.

    Cerro Hudson is a Chilean Icelandic replica. It’s a large glaciated caldera far far south of the Andes, looking very similar to what anything with a name ending in “jokull” would look like.

    Here’s how things went.

    First stage: basaltic intrusion rips through the andesitic magma sitting beneath the glaciated caldera, and erupts in a phreatomagmatic fire-show… Lava flows, heavy ash, glacial floods, all was there.

    Meanwhile, down under,a good part of the basaltic intrusion started mixing into the existing andesitic magma, diluting it down to basaltic andesite, but most importantly supercharging it with gas and heat to make it eruptible again.

    Second stage: the now very angry fresh basaltic andesite pops right through the lid of the caldera, and the whole thing goes off in the same way Katla did in 1918 (or a bigger Grimsvotn 2011 event). Ash ash ash, and glacial floods to no end. It ended up being a very large VEI5, almost a 6.

    • Hudson was almost 10 times larger than Grims 2011 and Katla 1918 and a bit over half of Pinatubo, best estimate is 6km3.

      • Pfew…. Didn’t realize it was THAT big…….. Thanks for correcting…

        How is it possible it didn’t go full-on caldera again? 6km3 is a heck of a lot of material to blow in one go…

        • Well, it’s 6km3 in bulk deposit, the actual amount of magma emptied from the chamber was about 2.5km3. Most of the time, an explosive eruption needs to reach the VEI-6 mark (10km3 bulk, 4km3 magma) to form a caldera- even Pinatubo’s 1991 caldera is pretty much as small as they get, and that’s with 5km3 being emptied out of the chamber. Some relatively rare exceptions are the Askja 1875 eruption, which formed a caldera even with just 1.8km3 bulk (1.5 times St. Helens 1980), and Fernandina 1968 (Galapagos) which formed from a 0.4km3 eruption (less than Chaiten!). On the other end of the scale, the ~1800BC eruption of St. Helens was a third larger than Pinatubo 1991, with a bulk deposit of 15km3, but did not form a caldera, and most remarkably of all, the 1600 eruption of Huaynaputina in Peru was 30km3 bulk, or around 12km3 of magma (just bigger than Novarupta 1912), but again, no caldera! For reference to all of this, if the Holuhraun eruption had been explosive, it would have been approximately 4km3 bulk, or two-thirds of Hudson. So 6km3 sounds like a lot, and it is by our standards, but in the bigger picture, it wasn’t that remarkable, after all some explosive eruptions have been 5000 times larger than Pinatubo!

          • Sitting on my chair now…. Mt Saint Helens capable of THAT????? And I knew that eruption in Peru was a big one, but didn’t expect anything that big.

            There’s also another one I think about, Santa Maria/Santiaguito in 1902, which was also in the several cubic Km range… Again no caldera, but a nice explosion crater on the flank of the mountain, through which Santiaguito developped later.

            The Chilean Cerro Azul-Quizapu eruption of 1932 was also a biggie, no caldera, and the most unexpected sequence of events…. First of all, high volume dacitic lava flows (???) in the several km3 range, then sustained strombolian activity building a new cone, and in 1932, a Pinatubo-sized explosion, all from the same magma.

          • Don’t forget Katmai. Made a caldera without erupting. (Nearby Noverupta emptied the Katmai chamber)

          • Novarupta / Katmai are essentially the same thing Lurk (I know you’re aware of that of course).

            @Alcide Cloridrix , one thing to keep in mind in terms of caldera creation is that the strength of the overlying “lid” plays a big role here. If a volcano’s magma chamber sits 10km below the surface, chances are, a VEI-6 eruption won’t collapse the roof. On the other end of the spectrum, you get volcanoes like those that we see in Iceland, which tend to have pretty shallow magma chambers. Those typically do not require as large of an eruption to create a caldera.

            Finally, for volcanoes that already have a caldera (take Bardarbunga, fernandinha, for instance), the weakness and ring faults are already built in, so a new drop or nested caldera is much easier to produce.

  4. Thanks, Carl, that explains why everyone talks about Hekla. i didn’t realize her history.

  5. This is old info and an old plot from some time back.

    As a general rule, a human being can not detect very small earthquakes without some sort of instrumentation that has the sensitivity to see them. If you are standing around somewhere, and an earthquake less than Mag 1.2 or so happens, you will not know it from what you can feel. (feet, vestibular system etc). The actual distance to the quake plays a large role in this. The reason why I count Hekla as a true ninja of a volcano, is that in it’s last significant action, had you been standing on the top of the edifice, you would not have known that you were in danger, until about 15 minutes before all hell broke loose. Though the quakes started about an hour before show time, without some other instrumented warning system, you would have been doomed.

    In essence, what you got was “Hi! I’m Hekla, you really should be running! 😀 “

  6. I often wonder if Hekla is nothing more than the common birth of an Icelandic caldera volcano. Perhaps Katla, Bardarbunga, Askja, all started likewise. A few millennia with big fissure eruptions, then eventually a caldera in the near geological future, then what we already know if typical from other Icelandic caldera volcanoes.

    Such a first caldera event would indeed wipe out the signs if it’s birth.

    All other Icelandic calderas are older. At least 1 Milllion years. I know that Katla, Hofsjokull, Krafla and Oraefajokull reasonably old. Which is the youngest one? Grimsvotn? Askja?

    • May be Askja, seems to have ended its caldera forming stage in the 1875 Viti eruption. Grimsvotn is also quite young, might have formed in the super-big-one whose name I won’t dare to write down described in the article. That VEI6.

    • Since I found maps of the volcanic areas of iceland, I have noticed that hekla has a rift zone extend mostly north but also south of the existing mountain. It looks like it is developing a fissure swarm parallel to veidivotn and as such there is a pretty good chance of it having similar eruption style. I think I have said in comments before that I think helka is probably only at the very start of a long and productive history. Maybe vatnafjoll and hekla are the same system but hekla is where there is a magma chamber so more evolved magma can form, while the eruptions directly at vantafjoll to the east are direct mantle fed with little residence time in the crust, and hence also a different magma composition. This would also explain why no large eruptions have happened east of hekla since around the time hekla started erupting more often, all the available magma is going to hekla proper. Judging from the size of some of the vatnafjoll eruptions, we probably havent seen heklas full fury yet…

      • Heklas rift orientation is likely due to it forming on a riedel shear structure above the underlying transform fault. The sprungur (sp?) to the west are similar features. At depth, the fault plane rotates to match the transform.

    • “I often wonder if Hekla is nothing more than the common birth of an Icelandic caldera volcano. ”

      I think this has a LOT of merit. Askja is just a few steps further along the growth cycle, and the Bardarbunga /Grimsvotn complex are in the more mature stages of growth.

  7. Holuhraun as a black swan.

    Before it, it was known fact that magma from.Bardarbunga triggered co-eruptions at Torfajokull, linked by Veidivotn, at least 5 times in the Holocene.

    Magma linking between volcanoes seems common in Iceland.

    I wouldn’t be also surprised if Hekla was born of one such long Bardarbunga dikes.

    • In Iceland, the same rift can hold magma from different volcanoes. That is clear for instance in the Dead Zone where Eldgja and Laki erupted in the same region (not the same dike) with magma coming from opposite directions. However, pushing magma into someone else’s reservoir is a different problem. It can’t happen between similar upper chambers of different volcanoes because it would require magma to flow uphill. Holuhraun’s dike stopped at the position where Askja began and the land started to rise. It could only happen at great depth.

      The lines of earthquakes show connections, with a dike forming between deep chambers. But they do not proof that magma flows through the dike from one chamber into another, or the direction of such a flow. Flowing magma does not give earthquakes: it can only be traced by patterns of inflation/deflation.

      There was a case in Ethiopia where a long dike formed similar to Holuraun, and a volcano halfway on the dike erupted. This was attributed to heat from the dike remobilising the cooling magma chamber, and is probably the best case for such a case. An old magma chamber is not overpressured (neither from the cold magma itself nor from the weight of the eroded mountain above) and so is easier to penetrate by the new magma.

  8. Carl, maybe if you write this same (fabulous) article one year from now, you will have another Icelandic black swan. Either Oraefajokull or a Surtsey-like event in Tjornes.

    • Or something even more outlandish. Improbable things crop up where nobody’s looking, wait for nobody to be around, and do the most unexpected thing at the most unexpected time.

      What about the birth of a new central volcano, one that’s built to last and grow into it’s own Jokull…

      • Technically there would be no way to tell if an eruption would create a new central volcano, when hekla first erupted there was probably nothing different about that eruption and the eruptions at vatnafjoll to the east, except maybe for explosivity which could have been due to groundwater. It was only a few thousand years later when other eruptions had occurred on the same fissure that it became notable, as is said in the post.
        Maybe greip to the north of grimsvotn is a forming central volcano, as is godabunga between katla and eyafjallajokull. Both of these started forming within very recent history and particularly in the case of greip, have a pretty robust magma supply. But until an eruption happens it doesn’t mean much.

        Come to think of it, are there any true polygenetic stratovolcanoes that have formed in historical time? The only thing that comes to mind is that cerro negro in Nicaragua might be a stratovolcano at the start of formation, and that momotombo nearby is at a slightly later stage. But the line between stratovolcanoes and cinder cones is blurry at that early stage so it’s hard to tell.

        • The stratocone of St Helens must have grown in part since the major eruption of around 1400 AD. Any smooth-looking cone must be young in part, perhaps resurfaced, perhaps with re-flation after the last event.

          If Hekla is less than 10,000 years old, it must have been growing at 10-20 cm per year. It isn’t doing that now, so it must have grown faster at times to compensate. Much of that growth would have been caused by the development of its magma chamber . The growth rate is not extreme: Anak Krakatoa has grown by an average of 1 meter per year since it formed. Perhaps Iwo Jima is in this phase as well – the jury is out.

          • The average is indeed roughly 20cm per year.
            But the growth rate lately has been far larger.
            Just 1947-48 raised the height with 50 meters.
            Slow pouring from the top is really the best way to build a mountain. Large eruptions just rip things apart.
            Another long topgigur eruption would probably do the same type of increase.

            And in regards of Cerro Negro, it is normally said to be the youngest stratovolcano.

        • Izalco is probably the best case in historical time, we observed that grow from a cinder cone to a fully fledged stratovolcano. Although built partly on Santa Ana, it’s lavas have a different geochemistry than those of the Santa Ana complex

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        • I would put in a claim for Izalco in El Salvador as having -slightly- better credentials as the world’s youngest stratovolcano On the grounds that Cerro Negro is just the latest in a chain of cinder cones stretching NW from the (still nominally active) Las Pilas,and only about 5km from it While Izalco is likewise within a chain of cinder cones related to an existing centre (Santa Ana), the key point is that its lavas, for most of its history, have been chemically distinct from those of the neighbour. Both of them are more-or-less on Carl’s home turf, maybe he could adjudicate?

          • The youngest volcanic centre of any type is Ukinrek Maars in Alaska, the location of the eruption of 1977 was in an area where lava had never reached the surface before.

          • Can we count post-caldera cones in it? If so, there’s Anak Krakatau, which is becoming respectable post-caldera stratovolcano. Baru Jari in Rinjani’s caldera is the same thing at a later stage.

          • Acide – also Nea Kameni, it’s bigger than it was when I was a kid.

        • Cerro Negro, good candidate. Also Izalco in Salvador, but it’s in a quiescent stage now.

          A stratovolcano is basically a cinder cone that makes it. Even Klyuchevskoy, that 6000-year old Russian giant, has started its life as a cinder cone on the flanks of Kamen.

  9. The biggest black swan would be if all of Iceland’s volcanoes went on holiday and no eruption happened for a century 😀

  10. It is possible that a breakout has started on pu’u o’o, heres the deformation reading showing very recently started (probably within the last hour) sharp deflation. Theres nothing on the webcams but if the breakout happened on the northwest side of the cone it would be out of view of all the webcams. There is a strong glow from the small lava pond in the crater though.

    • If this is a break-out it would be a very small one, bottoming at -1 microrad rather 50 or 100. The signal, an increase followed by a steep drop with a ‘U’-shaped profile looks like a mini-DI event, as is seen in Kilauea. My guess is a burp in the lava pond. It will be interesting to see what happens next.

      • You are probably right but looking at the 5 year deformation graph it looks like the last 3-4 years have been relatively high pressure compared to before, so a total drain out like in 2011 would lead to a pretty big flow. As stated in a comment on the last post, the ‘magma chamber’ under pu’u o’o is very shallow (less than 300 meters) and the roof is basically gravel, so unlike a bigger volcano most of the inflation just pushes up the floor of the crater without pushing out the side sat all. There was visible inflation in the webcams of the crater floor preceding the 61g flow, and considering the size of the crater that inflation was probably on the scale of meters. The data shows only a small inflation similar to the current one though.

        I do agree that something happened at the lava pond though, it looks like a significant collapse, which would be appropriate if magma was draining out somewhere at a significantly higher rate than before.

        • It is beginning to look that the rapid inflation is resuming. Which would make this a hick-up.

        • Actually, it looks more like a lava flow on the thermal camera now that the image is more clear, so I guess the lava level is high enough to overflow the small pit in the west half of the crater. I wonder if HVO will do an overflight tomorrow to investigate. Still, if this pit is overflowing then the lava level is very high and so the possibility of a new breakout is also very high and gets higher the longer this inflation continues.

          • It was apparently one of the small vents inside the main crater, one of which has been there since august 2011, but only glow except when inflation happens preceding a new breakout. These same vents overflowed frequently in the week before the 61f/g breakouts in May 2016. So it might not be that long before something happens at this rate. The only danger is that there is a decent chance of lava breaking out into a drainage that flows directly north into inhabited areas, and unlike in 2014 it doesn’t have to flow 20+ km to get there so this next flow could be quite destructive.
            Or maybe a 2011 type event will happen with halemaumau draining out and a new fissure eruption somewhere up rift of pu’u o’o or somewhere else. Kilauea has been inflating pretty steadily for a long time and it has to end somewhere

  11. Actually, the biggest black swan event would be if yellowstone actually did erupt within the next 100 years. Im not convinced it is completely dead, as it still sits roughly over the hotspot and its last magmatic eruptions were ‘only’ 70,000 years ago or less which is not that long for supervolcanoes. But rather than a new VEI 7 or 8 it would probably be a long lived and very voluminous rhyolite lava flow that would erupt from a ring fault. This would probably be a major tourist attraction though rather than a national catastrophe… I mean who wouldn’t want to see an entire mountain that is literally younger than you. It would probably be extremely noticeable before it happened though, and climbing it would be a darwin award contest where everyone ‘wins’ and no-one actually wins…

    https://volcanoes.usgs.gov/volcanoes/yellowstone/yellowstone_hazard_44.html

    • Infill events are the most likely Yellowstone activity. Along with that scenario, Maar events are also quite possible… long before anything stupid big is gonna occur.

      Failing that, geothermal activity will have to do.

    • Offcource seeing how hyped the supereruption scenario is in the media. Even minor explosions could set off a scare driven period of economic and social upheaval.

  12. OT… please have pity on a cabin fevered brain of 70+ years who has the constant companionship of her retired husband (who has Parkinson’s but it doing pretty well with it) so to the point…. does anyone remember a recent movie of an Indian engineer who had come to the US and wanted to do well but no one would give him credit and he lived in a house with 12 other young men who banded together to help each other and they invented a convection microwave that would heat stuff all the way thu without burning or leaving it frozen. Have tried to find it for 3 weeks but ………. Please help….. and i’m sorry to be such a burden to such a field of intelligent people. Consider it a favor to the universe. Thanks! Best!motsfo

      • THAT”S IT!!!!!! Thanks! people with parkinson’s can’t let stuff go so You have saved the day!!!! There will be peace tonight…. Deeply…. Thank You!
        Best!motsfo

        • I just did a Gurgle search for “Indian engineer microwave” and that was the top result! 🙂

          • Your Gurgle is better than mine….. all that came up was the real inventor and Spiderman quotes, repeatedly….. for days! i was desperate, Again, Thank You so much… Roses for You! Best!motsfo

          • Spiderman quotes? I couldn’t think of anything worse! I’ve never been a fan of the superhero genre. I prefer my films dark, bleak, soul destroying and disturbing. A bit stereotyped for a belligerent British guy I know… I know I’m going a bit OT here, but I really liked the ending of the film version of Stephen King’s ‘The Mist’. Even Stephen King liked it and that’s saying something for film adaptations.

    • Glad to hear your husband is managing the Parkinsons. I have two close relatives with Parkinsons. It can be challenging for them and for those around them. The new medicines are great.

  13. Surely, it must be a black swan that it’s been 12h and still nobody has mentioned this green star at Tjörnes 😉

    Þriðjudagur
    27.03.2018 02:33:16 66,283 -18,670 10,6 km 3,0 99,0 19,9 km NA af Siglufirði

  14. You know, Given that this post is about volcanoes in Iceland, and in particular about hekla, Ive got a question about that sort of stuff. On some maps I have seen, hekla itself is entirely holocene (actually entirely covered in historical lava flows), but a number of mountains all around it are subglacial formations from the last ice age, so is the existing mountain just the most recent thing to form in the system and that the system itself is older. And following on from that, is it possible that the actual hekla mountain is just a very recently formed central volcano on that system which also includes vatnafjoll to the east and some other structures to the north and south, and that the localisation of eruptions to hekla after 1104 is a result of the formation of a larger magma chamber which directs all the magma towards the mountain and away from other parts of the fissure swarm. It is then that the top of this magma chamber evolves and the eruptions tap into the evolved magma and leave the basalt behind? This would also expain why eruptions along other parts of the fissure swarm erupt normal basalt instead of basaltic andesite or rhyolite. It would also mean the big fissure eruptions at vatnafjoll stopped now that a more direct outlet has formed, and with all that magma the eruption frequency has increased significantly. In the future it could be expected for larger distal fissure eruptions to start again as the magma chamber becomes too large to empty through the main hekla fissure anymore.

    I think I asked this in a comment above but it got skimmed over when I commented on the stuff in hawaii.
    This might be a question best answered by Carl, seeing as he has a lot of experience with this area and wrote this actual post 😉

    • This could be expanded into an entire article.
      But I will have to keep it short.

      Hekla resides in the area where the SIFZ (South Icelandic Fracture Zone) joins the southern part of the main volcanic belt.
      This means that you have one hit wonders erupting directly up from the MOHO due to decompression melt as a larger than usual Sprungur forms. There are the ice age mountains you are referring to up above. These erupt unadulterated MORB (Mid Ocean Ridge Basalts).
      Vatnafjöll on the other hand is indeed reminding of Hekla, but the magma is not the same, and does not share the same origin. Here we are talking about more ordinary Icelandic Basalt, same type as at Eyjafjallajökull and Katla. It is more possible that the very large eruption of Eldgjá put a stopper into this volcano. But, it is very active and is known to have had magma-tectonic earthquakes above M4 in fairly recent times. It is though in no way related to Hekla.

      In the end it is just not possible for these volcanoes to have the same origin. Going from MORB or Icelandic type basalt to Hekla extremely volatile rich and explosive alkali-andesite is just not possible with that. And the volatiles and trace-minerals are also very different compared to it’s neighbours.
      The eminent Professor Erik Sturkell has most resoundingly killed that debate off in a couple of papers. If you google VC you will find that I have written about the papers he has written.

      The problem is though that we do not understand how that ultraweird origin basalt is coming into existence. The rapid evolvement to andesite is easier to explain, that is due to the wedge-shaped magma-reservoir working as a heat inducted refinery-column.

      • I just reread that article. It needs to be rewritten.
        Here are the original sources.

        Sources
        Sturkells online notes;
        http://www.earth.geo.su.se/geology/swedish9.html
        http://www.geo.mtu.edu/~raman/papers2/MouneHeklaEPSL07.pdf
        http://www.surtsey.is/SRS_publ/1968-IV/1968_IV_3_02.pdf
        And of course Carmichaels groundbreaking work on Icelandic intermediary magmas. Good read for anyone who has been wondering what Thingmuli is about. http://www.minsocam.org/ammin/AM52/AM52_1815.pdf

          • Hekla really is a weird volcano then, right next to a basalt center but not connected to it. I still think there is some sort of connection seeing as hekla became much more active only after larger eruptions at vatnafjoll stopped.

            It would be really useful if there was more information out there about vatnafjoll, but most sources I find, including GVP, classify it as a part of hekla and as such give little notice to it. Most of what i know about it I actually found on this site, and it sounds like a monster of a volcano if it can manage 24 >holuhraun sized flood basalts in 9000 years or something like that. Maybe that is a glimpse of heklas future, once it has matured a bit more.

            (also the first link doesnt work for me, might be a regional thing)

          • If you look at an inverted plot of the moho there, Hekla lies at the far end of a “valley” made up of the dead zone, magma from the hotspot flows “downhill” towards the west.

      • I wonder whether Torfajökull is a Hekla precursor. It is also located at the intersection of the SISZ and the volcanic belt

          • With precursor, I meant by 100,000 years. I cold have phrased this more clearly..

          • Over the years of lurking I know when Carl troughs out a short comment like above there is some science behind the statement, aka 2015 run up to holuhraun’s fun and games

    • Turtle man, I like your theory. It’s a possibility.
      Hekla is just the youngest Icelandic volcano.

  15. Regarding the Chinese space station, the ESA office for space debris is reporting that “the current estimated reentry window runs from the morning of 31 March to the afternoon of 1 April (in UTC time); this is highly variable.” The Easter bunny may need a hard hat to protect against a big egg . (And that sentence makes no sense in any language or cultural tradition.)

  16. Your reasoning has great merit Albert. 70000 years ago Torfajokull might have been similar to Hekla and suffered a massive ring fault rhyolite eruption, around 30+km3. Must have been huge!!!

    In the future, Hekla will matured then form a caldera too. After a massive eruption.

    • This is just an example of typical money fishing in an dysfunctional law system. Many large epidemical studies show that coffee and tea consumers actually get less cancers than non consumers. Acrylamid is produced as soon as you heat up foodstuff of various kinds. We, our bodies, are adapted to handle that up to much higher levels than found in coffee… The bad thing is that this makes many people anxious for no reason…

    • Have the coffee and die happy; beats not having coffee and being miserable for any length of time…. 😉

    • Pay a consultant/think tank enough, they’ll come up with the conclusion you want them to…

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