Super interested in supervolcanoes?

Aerial view of the Atitlán Caldera Lake, photograph by Chensiyuan. Wikimedia Commons.

A few days ago, I wrote that we are currently living in a volcanic low period. The last significant eruption happened on the 8th of August in 1991 and the culprit was Cerro Hudson. It was a medium sized VEI-5 eruption expelling roughly 4.5 cubic kilometres of ejecta.

After that there has been a 26-year long hiatus of larger eruptions, a time span that is record breaking. And to make things even more dull, we do not even know of any upcoming events that are likely to break this dry spell.

Even the largest of the volcanoes that are showing signs of upcoming eruptions, or are currently erupting, are not likely to do something untoward. We truly live in bleak volcanic times. So, let us dream dark dreams of doom and destruction while we wait for something a bit bigger, shall we?

Below is a list of true known active supervolcanoes. I do not really like the term supervolcano, but it is now stuck in people’s daily language usage. What is a supervolcano? Quite simply, that is volcano that has had a VEI-8 eruption (1 000km3 or more), or is on good grounds believed to be able to have a VEI-8 eruption in the future.

Since supervolcanoes suffer from VEI-8 eruptions very infrequently I have decided to remove those that are known to lack eruptible magma. All supervolcanoes in this list has eruptible magma and have had eruptions in a geologically recent time, or are otherwise showing signs of activity.

Atitlán

Lake Atitlán, from Tzam Poc Hotel, near Santa Catarina Palopó. Photograph by Emilio Piovesan. Wikimedia Commons.

Atitlán in Guatemala is the oldest known supervolcano that is still active, it started to form 11 million years ago and has suffered from 3 or 4 caldera forming events. Two of those are classified as supereruptions and one was a VEI-8 eruption.

Me honeymooning at Atitlán. Photograph by Carmen Morataya de Rehnberg.

The largest of the eruptions was the Marí­a Tecún Tuff (MTT) that covered all of Central America, Mexico and Southern Continental United States. During the eruption, the ancestral Atitlán I Caldera formed as the eruption expelled 1 800 cubic kilometres of ejecta.

The other large caldera event formed the current caldera. It was the 300-cubic kilometre Los Chocoyos Tephra that left traces as far away as in Florida.

Currently there is regional uplift under the Volcán Atitlán strato-volcano tilting the entire caldera lake towards the town of Panajachel. Volcán Atitlán is believed to be located at the hypocentre of a future caldera forming event.

The risk of a caldera forming event is currently believed to be small, instead the current activity points towards a future eruption of Volcán Atitlán. It last erupted in 1853. As such, this is the longest historic pause in activity. When it erupts again it will be in the range of a VEI-2 up to a small VEI-4.

As monsters go the Atitlán caldera is beautiful, so much so that the mind can’t understand and take it in. If you ever wish to visit a supervolcano, this is the one to pick. The beauty will change you in ways you never expected. Oh, and if you wish for a volcanic honeymoon, this is definitely the spot to go.

The Taupo Volcanic Zone

Anyone surprised that Lake Taupo is also a beautiful lake? Seems to be a theme running here. Photograph by unknown. Wikimedia Commons.

If Atitlán is a majestic beauty the New Zealand volcano of Taupo is a mean drunk that will hit anyone without notice. Or just turn up unexpectedly at a party and hurl in the kid’s pool.

It is also the youngest of all the supervolcanoes with an age of 300 000 years since onset of volcanism, and it became explosive about 65 000 years ago when the magmatic composition turned into rhyolite.

26 500 years ago, the volcano entered the supervolcano range with the 1 170-cubic kilometre Oruanui Eruption. As such this is the latest of the VEI-8 eruptions on the planet. The last major eruption was the 180AD Hatepe eruption that ejected a total of 120 cubic kilometres.

This is a good bet for anyone wishing for a large eruption, only problem is that it is currently napping, but rest assured that sooner or later it will wake up, have a jug of vodka and aim for the kid’s pool again.

Toba

And yes, you guessed it correctly, more lakes that are beautiful. Photograph by Eugene T. Quah. Wikimedia Commons.

If Taupo is a mean drunk Toba is the reigning world heavy weight champion. 77 000 years ago, the current 100 by 30-kilometre caldera formed during the largest eruption in the last 25 million years. It was previously believed that the eruption produced a total of 2 800 cubic kilometres of ejecta.

But, a newly developed technique called “crystal concentration and exponential” has increased the figure to 3 200 cubic kilometres of ignimbrites and co-ignimbrites plus a further 800 cubic kilometres of distal ashes, summing it up to a grand total of 4 000 cubic kilometres of ejecta.

The Toba Caldera is filled with yet another of those ridiculously beautiful volcano lakes. Roughly in the middle of the lake there is a large island that has formed due to resurgent doming as the magma reservoir slowly refills.

The volcano has had minor volcanic activity during the last 70 000 years and it is believed that the last eruption occurred roughly 400 years ago at Tandukbenua on the northern rim of the caldera.

Toba will sooner or later produce another large eruption, but it is currently firmly in a stage of development as the magma reservoir builds back up. As such it is a bad bet for those dreaming about something really large.

Tondano

This idylic scene is from Lake Tondano situated within the 20 by 30km Tondano Caldera.

“Some volcanoes just can’t catch a break. Imagine for a little while that you are a bona fidé supervolcano. You are the largest of your type on the planet, you are highly active, and by gosh you have shown what you are capable of. In a perfect world, your 20 by 30 caldera explosion should have put the world into awe, and the 1 000-cubic kilometer of DRE you ejected in the form of pumicious tuff covers an entire sub-continent. Yepp, you really did reach the small highly exclusive club of VEI-8 volcanoes. You smirk at your little sibling Monte Sommas antics with Vesuvius. Your Vesuvius event left a 3.5 by 5 km God honest caldera on its own. To top it off you have a huge underground reservoir of liquid acid that would seriously alter the planets weather if you felt like discharging it. You are also perfectly located to have a maximum kill ratio.

So, you wake up and stretch your arms and start a double eruption from two different sub-volcanoes just to celebrate the new day. You have your largest eruption in recorded history. Then you look around to see the fearful faces of the residents as they offer up motorcycles in your name, you expect volcanologists doing somersaults as they play lip banjo, and literally thousands of blog pages glorifying your power and shear awesomeness. What do you find? Yawning people and a cockerel trying to wake up a pig sty. You find that for being an erupting supervolcano you are a massive PR failure. One single small earthquake at Yellowstone outperforms you in publicity.” (C. Rehnberg, “Did you notice the erupting Supervolcano?”)

Tondano suffered it’s VEI-8 eruption about 2.2 million years ago. It also holds the distinction of being the most active supervolcano on the planet with an estimated 300 000 eruptions since the VEI-8 eruption.

The current active volcanoes are Lokon-Empung and Soputan. The odds are very low that this volcano will produce a VEI-8 in the near geologic future. It is just too well vented by its ring fault volcanoes.

Oh, did I mention that it has a very beautiful lake inside of it? If you wish to read more about this volcano please feel free to read my original article:

https://volcanocafe.wordpress.com/2012/09/27/did-you-notice-the-erupting-supervolcano/

The Altiplano-Puna Volcanic Complex

A bit different as caldera lakes go, but still very beautiful. The Salar de Pujsa con Acamarachi at the La Pacana Caldera. Photograph by Danielle Pereira. Wikimedia Commons.

If you thought that Toba was big it is time to go totally mentally bonkers and introduce the Hypercano™. It is my own little pun on the Supervolcano term, after all, hyper comes after super. And what on earth would one call the APVC since the supervolcano term has already been used.

Regular supervolcanoes have normal stratovolcanoes as side shows, but the APVC has supervolcanoes as side shows, so let us use that ridiculous term. It will probably though drive someone crazy that I coined the term.

The heart of the beast. Shear velocity anomaly indicating the immense magma reservoir of the APVC. Image by Andrej Flis.

The APVC is a massive batholith of magma formed by the subducting Nazca-plate. Above the batholith plutonic intrusions form that in turn becomes the active supervolcanoes of Guacha Caldera, La Pacana, Pastos Grandes and Vilama Caldera. As this was not enough it also hosts the massively inflating Uturunku volcano that is believed to be a future supervolcano.

The Altiplano-Puna Hypercano™ formed about 8.5 million years ago and erupts in pulses roughly 2.1 million years apart where several of the supervolcanoes goes off in a relatively short time span. If this cyclicity holds true, we are nearing another of these pulses, and it may be that this is the reason for the massive inflation we are seeing at Uturunku.

Whereas normal supervolcanoes have magma reservoirs ranging from a few hundred cubic kilometres to a few thousand cubic kilometres, the APVC has an estimated 500 000 cubic kilometres of magma. This makes it into the largest known body of eruptible magma on the planet. I jokingly use the term hypercano™ for it, but in reallity it is not that far off the mark.

Together with Taupo this is probably the best bet for an upcoming supereruption.

Conclusion

Let us have one picture of something that is not a lake, but instead looks like a volcano. Soputan volcano inside the Tondano Caldera. Photograph by Enrico Kumesan. Wikimedia Commons.

After this little episode of dreaming dark dreams of doom and destruction we should be a little bit serious. There are currently no signs that either of these volcanoes are near an eruption. The risk of an eruption happening under our lifetime is almost infinitely small.

But, if one of them happened we would indeed be in trouble. That being said, it would not be the end of humanity, nor would it be the end of human civilization. The bad news is that at least 1 billion humans would most likely die in famine and ensuing pandemics. It would probably take at least a decade before the world economy was back on its feet.

That is the thing most people forget as they dream dark dreams of doom and destruction, events like that kill people. A lot of people.

Now a word for those who will start yammering about me excluding Yellowstone. Face the music, it lacks enough eruptible magma to be able to erupt. It has passed, it is an ex parrot, and it is currently pining for the fiords. Don’t argue with me about it, take your argument and go try to impress Yogi the Bear with it.

CARL REHNBERG

57 thoughts on “Super interested in supervolcanoes?

  1. What surprised me was that I could only come up with 8 Active supervolcanoes around the World. And that 4 of them would be in the same spot. Remarkable in an odd way.

    • Since Campi Flegrei has not had a VEI-8 eruption it is not on the list, nor can it have one. Laacher See is way piddlier than Campi Flegrei so it will not even get a sidenote.

  2. Totally agree about the majestic beauty of Lake Atitlán.

    However, if you intend to visit it for scenic views, the month of May though dry, would be a bad choice because usually there’s a haze then above the lake and the volcanoes often will be invisible.

    Maybe on Antarctica more supervolcanoes could exist under the ice? Could a (super)volcano erupt through km’s of ice? Given enough time I guess so but how big should it be? (Just wondering out loud)

    • It took Grimsvötn about 20 seconds to blast through 500 meters of water and 700 meters of ice in 2011. A supereruption would do it in something like a tenth of a second. It would just lift it all up and hurl it to the side.
      That being said, there is a very low probability for a hidden supervolcano there since there is no subductive zone there.

  3. Good recap Carl.

    Personally, I think one of the issues with supervolcanoes is that people tend to look towards the past too much. At some point in time, Taupo had never erupted a VEI-8, nor had Toba, Yellowstone, the Altiplano Puna Complex, or any of these other volcanoes. If we were to go back in time, there were likely signs and symptoms ahead of time that would have indicated potential for a very large eruption was possible even before the actual event occurred.

    My biggest interest is identifying the preliminary conditions that lead to the next supereruptor.

    On a separate note, there may be a few active supereruptors out there that we simply don’t know enough about in terms of their past, or whether they’re capable of producing a VEI-8 at any point again in their geological future. I know of a few good candidates in the Andes range that are not a part of the Altiplano Puna volcanic complex.

    • On a slightly separate note, VEI-8 eruptions are extremely rare events that definitely have far-reaching consequences. But they’re so uncommon they simply aren’t worth worrying about.

      VEI-7 eruptions are what worry me, especially in a populated country. They’re not super common, but they happen frequent enough that there is actually a reasonable chance of living through one given a lifespan of roughly 90 years. Based on rough calculations, I estimate that a VEI-7 eruption occurs approximately every 350 (+/- 50) years in the Holocene period. That gives roughly a 25% chance of experiencing one if you were to live to be 90 years old.

      Having an eruption like Kikai occur again would be a disaster on a scale that the world has never seen.

  4. “…is almost infinitely small.” So it is a bit larger than infinitely small? Or how should I read this.

    • And there is the realm of the Law of Large numbers. If enough days go by, eventually the condition being tested for will happen. (considering each day as a Bernoulli test for being in eruption or not) Carl is the one who introduced me to the concept, but if you consider the probability density function as being an infinite series, the areas outside the peak area will in total, far exceed the area under the the curve near the mean. If you think about it, that means that the ultra rare event HAS to happen… eventually. Where the victims of the gamblers fallacy fall prey, is in the idea that if they can play long enough, they can hit that return to calculated average odds. There is an infinite amount of time for that to play out, gamblers don’t have that luxury. The same thing applies to watching volcanoes. Eventually one of em is gonna do something stupendously awful. But we may not be around to see it. (which also means that we won’t have to deal with it)

      Along this same line of thinking, Wikipedia states “The volcano is thought to be related to Katla geologically, in that eruptions of Eyjafjallajökull have generally been followed by eruptions of Katla.” This is a perceptual error. With Katla’s normal frequency of eruption, whenever Eyjafjallajökull goes off, Katla has either just completed a cycle or is well on it’s way to starting one. It’s like walking outside and seeing a bus at the bus stop on a couple of Fridays. The bus didn’t show up because you came outside. It’s always stopping there but you just never saw it. The bus is Katla, and you are Eyjafjallajökull.

    • Not to belittle Kilauea, but on the VEI-scale it is coming as a VEI-2.
      And even compared to some effusive eruptions it is not that big.
      During the same time it has been in eruptive amounts been outpaced quite liberaly by Grimsvötn for instance.
      No, we do live in quiet times. And I Think we should be happy about it.

      • Didn’t Grimsvötn outpace Eyjafjallajökull’s entire eruption in about 4 hours?

        • Yupp. It is the closest thing we have to a significant eruption since Mount Hudson. It was borderline to VEI-5.

      • Since 1983 Kilauea has erupted something like 4 km3 of lava. That makes it a VEI5. One can argue about the explosivity part of the VEI scale, of course, and perhaps there should be a time limit on eruptions. The VEI-8 eruptions we discuss are also partly or largely effusive (there was little explosive activity in the enormous Toba eruption, but it was a bit faster than Kilauea, taking only nine days). On the other hand, an explosion artificially enhances its volume, first by blowing out rock rather than lava, and second by forming ash which takes up a lot more space. For effusive eruption, what you see is what you get.

        It is a bit strange to measure explosions by volume.

        • Regardless of the debate that the VEI-scale is not applicable on Kilauea, it still leaves the time thing.
          0,11km3 per year in slow constant oozing just do not cut it.
          Now compare that to for instance Grimsvötn that has coughed since 1983 roughly 4.5km3 during 32 days of eruption in combined ejecta. And those 5 eruptions are not considered significant (even though 2011 is a borderline).

          Kilauea is a slowly dripping wound from a fingertip compared to what a significant eruption does in hours, like Mount Hudsons 4.6km3 in 2 months. 40 percent of the ejecta was in 1 hour. Comparatively Mount Hudson was a ruptured aorta.

          • Sure, but you do need a definition on what counts and what doesn’t! It may be reasonable to discount Kilauea, but it is still arbitrary. And you did assign it a VEI2, presumably based on annual output, but why pick a year? Two tacks you could take: a VEI should involve an explosion, and only the explosive part counts (which would make Toba more run-of-the-mill), or you can say that the eruption should come from a static magma reservoir – no refilling during the eruption is allowed. Kilauea is fed from a continuous magma flow, so in theory it could go on forever. That is unfair competition. The fundamental problem is that the explosivity index does not actually require an explosion: the definition has an error fault uncertainty. Explosions should be measured by energy rather than volume.

          • Nope, the VEI-2 is even a bit of stretch.
            According to the HVO the entire eruption from 1983 to this date is counted as a VEI-1 based on ejected ashes.
            There is nothing arbitrary for it, the VEI-scale is based on explosivity.

            If we instead would agree that Veidivötn 1477s output of 5km3 of lava as being significant due to speed of the effusive eruption and the volume of effused lava, then we have a benchmark. And Kilauea is nowhere near that on the speed front.

          • Going back to the original paper where VEI was defined, they use a variety of aspects but only the ejecta volume is easily measurable. Although the text mentions that the ejecta re for tephra, the table only lists ‘ejecta volume’. They do indicate that the eruption normally occurs within at most 12 hour. The height of the eruption column is also used.

            Going back to Toba (which I know best), you assign it VEI8. Most people would agree. But the eruption lasted nine days, so over 12 hours it ‘only’ erupted 200km3 which makes it a VEI7. And the ash column did not reach much over 10km, insofar as this is known of course, which is VEI4. (The ash was mainly generated and lifted by the heat.) You can see why these additional criteria are not often used!

            Reading their paper, they clearly did not mean their scale to be used for effusive eruptions. Perhaps they wanted to exclude lava from the ejecta volume but the paper doesn’t say so.

            Since Bardarbunga, we know that you don’t always need an explosion to get a caldera.

          • And that would make Eyja a VEI-2 at best.
            The 12 hour provisa was partially abandoned since it gave weird numbers for the slightly slower eruptions.

      • Although you could say there was a mini-uptick between 2008-11, with 9 VEI-4s including two 4+’s a few weeks apart. And a mega-lull between 1995-99 when no VEI-4s happened at all! Anyway, I think there’s a good chance that Katla could be the one to break the VEI-5less streak fairly soon. Is it just me or did 2011 Grimsvotn not really seem that large even though it was two-thirds of St Helens?

        • There is a bit of a confusion here…
          VEI = volcanic EXPLOSIVITY index. So effusives are not counted in it.
          And even regardless of that, effusive eruptions can be fairly large.
          But to be significant they would need to cough up around 5km3 in a short time period. So, Holuhráun that was 2km3 in about 6 months does not qualify.

  5. So, let us ponder EVI = Effusive Volcanic Index…
    Let us for the sake of it say that it Counts on an annual basis since effusive eruptions can be long lasting.
    All effused lava in a year counting from start date of the eruption is counted. Over a long eruption you even it out the mean number.
    EVI-1 = 0,0001km3
    EVI-2 = 0,001km3
    EVI-3 = 0,01km3
    EVI-4 = 0,1km3
    EVI-5 = 1km3
    and so on.
    In this case Kilauea would even out as a EVI-4. Thusly not significant.

    Problem is that by no means was Holuhráun significant, and on this EVI-scale it would be a EVI-5. It would probably need some tinkering to hold up to scrutiny.

    • Maybe lower the number for each one, so that EVI-4 is 1km3 and 5 is 10km3?

      • Problem is that I Think most people would Award Laki an EVI-6 due to the climate impact.

        I will return soon to a potential EVI-scale. I just need to ponder stuff a bit. I have a pretty good definition to come (I Think).

    • First, thank you for all the articles so far: As a common lurker I really enjoy all of them!

      Two questions:
      Why is Iwo Jima excluded from the list?
      How much was erupted from Kilauea so far?

      Oh and as a bit of an impulse: An article about the current eruption of Erta Ale would be really interesting – it is having one of the most significant eruptions in recorded history right now!

      • And two answers coming up 🙂

        Iwo Jima has never suffered from a VEI-8 eruption, nor is there any evidence that it ever will. Iwo Jima ended up on our rather famous list for other reasons than brute force eruptions. It is though of a size implying that a medium sized VEI-7 can occur.

        During this eruption it is 4km3 so far. The total number is something like 80 000km3 if memory serves throughout the volcanoes lifetime.

        • If i may ask, Valles Caldera is only capable of VEI 7 if it’s even still alive, correct? The Aira and Aso calderas are also only capable of vei7, if i’m correct, Same with the Amatitlan caldera. It’s already been stated that they have gone seven, but could any of them pull of a VEI 8 at some point in the future?

          And if we’re looking for possible future super erupters, I feel the best places to look would be South America, Indonesia, and maybe Japan or Alaska.

          Held by aksimet for approval. Further comments should appear without delay -admin

    • The volcanic explosive index must be in m^3/s, where time is small. seconds to days.
      EVI can be in m^3 without time. just the total effussive amount over months or years.

  6. Puyehue-Cordón Caulle, Chile, 2011, is variously categorised as a large VEI4 or a small VEI 5, with a volume around 1 km3, so very similar to Grimvotn in the same year.

    • Grimsvötn is further misleading. The 0.8km3 is the ash, there was also 1km3 of lava embedded on the bottom of the lake. And together with the very high ash column in would at any other Place have been put as a VEI-5, but the IMO are made of Sterner stuff and has decided that 1km3 DRE is the tipping Point 🙂

      • Well the 1km3 lava emplacement obviously isn’t included in the bulk tephra deposit (and DRE isn’t a factor in the scale), and the use of ash column height in assigning VEI isn’t really done anymore, so even though it had the “power” of a VEI-5, it didn’t have enough “fuel” to push it over that line, hence the application of a + sign when an eruption is at or above 70% of the minimum requirement for next VEI number (4+ at 0.7km3, 5+ at 7 etc.), as in this case. This is related to the eruption magnitude scale, much less commonly used, but does round up Grimsvotn to M5.0 (actual number being 4.9-something-above-5), using the DRE volume of bulk ash (generally given as 40% of bulk when exact details are unknown). The 0.8km3 figure is also at the maximum value within the margin of error given in the reports, so there is no reason to apply the VEI-5 figure here. Same goes for PCC too.

        On another note which I slightly alluded to earlier, the eruption magnitude scale places the largest ever known eruption (Wah-Wah Springs, bulk deposit 5,500km3) at M8.8, which if you notice is almost exactly one degree of magnitude lower than that of the largest possible tectonic earthquakes (M9.7).

        Considering this scale was designed to be analogous to the moment magnitude scale, and that the formula used to calculate ((log DRE volume*density)-7) was formatted to match with the VEI scale, and that the VEI scale jumps up a factor between 1 and 2, due to explosive eruptions between 1,000-10,000m3 being counted as VEI-0, because even though explosive, register between M0.0 and 0.9, a reasonable argument can be made that the VEI scale numbers should be raised by one, and the magnitude calculation changed to -6 instead of -7, so that both eruption scales match up better with the equivalent earthquake scale, so the largest of large eruptions has a matching magnitude value to those of the largest earthquakes. Basically, eliminating the need for the gap between VEI-1 and 2, and raising the 1km3 boundary to VEI-6. If this was the case, the eruption magnitude could be adapted to effusive eruptions (examples, maybe a slightly different formula or maybe accounting for sulphur emissions, a comparison of average rates of eruption (“power”)), allowing a more accurate comparison between relative “sizes” of explosive and effusive eruptions. I think all of that would help to reduce some of the ambiguity of the current system.

        Or, alternatively, a brand new system that combines intensity and volume, again something similar to the moment magnitude scale. Or, simply introduce a formula into the VEI system that sub-divides it into tenths-of-a-magnitude, once again, like earthquake calculations. Aside from that, the current system isn’t quite as flawed as some say it is, I think. At the end of the day, the size of an eruption on its own doesn’t necessarily translate to the effects of eruptions in the long run, and the scale does do its job, as long as there is a reasonably-small margin of error, which is partly accounted for, as I said earlier, with the usage of the + sign in high-end magnitude eruptions, like Grimsvotn.

        *Tangent over :D*

        • Yeah, it is the Icelanders. They seem to think that DRE is the cool way to Count things and that non-DRE is slightly on the whimpy side. 😉

          • in my head (not currently quite right clearly) I kind of have DRE as total size of eruption, with VEI (in my head) being tied to total tephra as a proportion of DRE (ie how explosive it was,not just how big it was) – and that would be the reciprocal of EVI (how effusive it was) ie. the non tephra as proportion of DRE

            but I think the real question is the rate of eruption over geological timescales

            so my new measurement scale might be
            VRI (volcanic rate/repose index) DRE from this eruption/(time between eruptions)

            giving change of VRI over time as the indicator of decreased/increased magma output in an area

            repeat eruptions in one spot could give high VRI and either high EVI or VEI (but not both)

            so traditionally dangerous volcanoes would have
            high VRI high VEI (big/frequent largely tephra)
            other volcanoes of interest would be high VRI (big/frequent effusive eruptions)

            and increasing VRI might be of interest once it passes a significant volume DRE per eruption

            hmm, mono genetic cones would start with a high VRI (time between eruptions being 0 initially) – or I suppose you might use the geological age of the bedrock – so the correct formula for ‘time between eruptions’ is probably going to need some fiddly maths or a bit more thinking.

            anyway that’s my 2d 🙂

          • just realised I should have used a new name (rather than vei or evi) for my imagined measures above to avoid confusion

            VER Volcanic Explosivity Ratio would be the reciprocal of EVR the Effusivity Volcanic Ratio

            so volcanoes would have
            DRE for size of eruption
            VRI for rate of magma production over time (cubic km/years)
            and VER or EVR for how explosive/effusive they are

  7. Note for the readers passing through. The VEI scale and criteria is generally hated by most volcanologists for the reasons Carl an Albert are discussing. In my opinion, Carl may be on a fast track to come up with an alternate scale to deal with the less energetic/non explosive events. I think where the problem is at now, is getting EVI numbers to equate with the severity of the various VEI levels.

    That’s gonna be a tough nut to crack. Base it around mortality rates? Or local/regional climatic effects?

      • Given the location, that seems plausible. The seismographs seem to have all saturated.

        Bit of a nuisance (to me) that HVO now gives the depth in miles.. (is that caused by pulling out of Paris?) Luckily the main plots are still metric.

        • Rely depends on who the target audience is. Mentally, it’s easier for me to visualize stuff in miles since I do it every day. I’m okay with km depths, but I still have to rough out an estimate in miles to appreciate it.

        • It’s also how we,are so adept at driving hyper expensive spacecraft into a planet while trying to establish an orbit.

    • After the quake, the tilt meter has changed by a fair amount. Slumped, probably.

        • The one that shows the change is at Pu’o’o. Two other tilt meters in that area, near the top of the cliff above the coastal plain, also show this. Ones on the coastal plain do not. Kilauea itself is not affected. The quake gave huge tilt excursions for tilt meters along the crater road, but they returned to the original levels.

          The new HVO site has a wealth of information

          • The change is in Micro-radians, so it is not an enormous change per see. But it is very clear, so we can state that it is slumping involved.

          • True – it nothing like an eruption when the change will be 10 times larger. It is still significant, though.

  8. So Bogoslof finally has a new lava dome!

    I’ve noticed there have been a few repetitive earthquakes just west of Pretahnukur, anything happening there?

    • It’s something we’ve been discussing in the back channel, Carl wondered if it was slow rifting. It’s an area we’re keeping an eye on along with the recent deep quakes at trolladyngja.

      • The earthquakes at Trölladyngja was magma coming up from below. Seems like it is magma pulse time again from the plume. It is reminiscent of the situation in the months prior to Bárdarbunga.

    • Tectonic earthquakes at a set of sprungur. It was quite clear on one of the sets of maps that Andrej made.

  9. For those who are interested in the EVI concept I will present it on Monday, today there will be an archived piece from the wayback machine.

Comments are closed.