Many volcanoes have captured the attention of fanatics such as us, we often pick favorites depending on our internal biases. After all volcanoes provide varieties of intrigue to curious minds, from the mechanics of explosions surpassing the greatest of bombs, million years long eruptions that cover entire regions in magma, to simpler things such as island-building, rare rocks, weather influences, even failed eruptions provide so much excitement for us. For some itis the endlessly erupting shields of Hawaii, the glacier-clad beasts of Iceland, or the sillic soldiers of South America. Amongst the topics, there is one volcano that hardly gets mentioned. Beyond it’s mundane eruptions, Klyuchevskaya stands near the pinnacle of volcanism in most areas. Surface level analysis alone gives this volcano an impressive sheet but upon deeper inspection this volcano might stand at the very top of current volcanology.
Standing 4,750 meters tall and 15 km wide, Klyuchevskaya is the highest volcano of Eurasia, and is quite voluminous despite being 7,000 years old. With an edifice volume of around 420 km3, the volcano has erupted over 0.06 km3 of magma/year. This doesn’t account for the tephra that doesn’t get incorporated into the edifice, however it is unlikely that it would make anything more than a difference of 0.01 km3/year. This volcano is responsible for ¼ of total erupted magma at Kamchatka since in it’s inception. A preposterous amount of lava erupted! Shiveluch “only” has an eruption rate of 0.015 km3/year To put this in context, this is about the long term eruptive rate all of the volcanoes of Iceland combined! It would take 22.5 Eldjas for Iceland to match this. This is even exceed the total eruptive rate of Kilauea long-term eruptive rate. Only Mauna Loa beats Klyuchevskaya in this area. It should be noted though that these rates are subject to flux and don’t account internal supply. Icelandic volcanoes store most of their supply, Kilauea, has been accelerating in it’s received rate since it’s birth. Klyuchevskaya has the same fluctuation but it’s peak erupted rate hasn’t been calculated and it’s so young that it might as well be pointless.
Funnily enough this volcano hasn’t done a single big eruption as far as we know, nothing above a VEI 4 and no extremely large lava flows like the ones seen it’s rivals in Iceland or Hawaii. It has more than enough magma for a VEI 7 and is larger than Grimsvotn. Due to it’s youth, it hasn’t constructed a strong fissure system and due to it’s frequent activity, it slowly accumulates strain. Let’s not be mistaken, the volcano recieves much more magma than it erupts and as such it is building pressure and strain for a big eruption. It’s like Hekla but way stronger. The day will come when inevitably throws a large dike intrusion and/or does a VEI 5-6. Will that happen in our lifetimes? Probably not but it would quite fun if it did! (Please God)
The magma that Klyuchevskaya erupts is also unique, having the most high-d18 O value’ basalt in conjunction with a high alumina component. It also serves as one of the few subduction zone volcanoes to erupt picro-basalt. Despite having some of the highest quality basaltic magma on the planet. As you could guess by it’s structure, the magma is not very fluid for it’s quality. Within the shallow system, basalt is crystallized, through a complex process that basically boils down to decompression and H20 degassing of ascending magma. It’s because of it’s mineral content that this volcano isn’t a shield and does basaltic plinian eruptions from time to time. The most evolved magma that you will see erupt from this volcano is andesite and unlike some of it’s siblings, it hasn’t erupted any felsic products although it might have some small amounts of dacite within it’s chamber.
More impressive still is not just what has erupted but also what hasn’t erupted. Klyuchevskaya has 2 magma chambers the top magma chamber has around 100 km3 of magma and the deeper chamber has over 650 km3 of magma, making a pretty sizable volcano! With a simple assumption that the volcano first started to erupt after accumulating 100 km3 of magma. We find that the chamber has accumulated over 0.092 km3 of magma/year! Giving this thing a total supply of 0.15 km3/yr. Impressive to say the least. And yet we can get that number even higher! Klyuchevskaya gives it’s sibling a Beziymianny, a boost from time to time giving it some of it’s magma. I don’t know the exact number but this could give the volcano an additional 0.02-0.04 km3 of magma. Giving it a maximum supply of 0.17-0.2 km3/year. The deeper chamber that feeds Klyuchevskaya, is generous enough to also feed Beziymianny as well. In a fictional volcano world, Klyuchevskaya would either be the upstart chosen one or an emerging destroyer of order. After a mere 7,000 years it stands at or near the very top of modern volcanism crushing most hotspot and rift volcanoes. How does this volcano do it? How does this volcano maintain one of the highest, if not the highest long-term supply in the Holocene? And where is this volcano headed in the distant future?
Klyuchevskaya lies in the Central Kamtchatka Depression, being the main character of the Klyuchevskaya Volcanic Group. The volcanoes of which include the aforementioned Beziymianny, Tolbachik, Bolshaya Udina, Ushovsky, Kamen, and Zimina. Despite being part of the depression Shiveluch is not part of the group. All these volcanoes share a common source but not in the form of a traditional magma chamber. The subduction of the Pacific plate beneath Okhotsk plate planted the seed of this system but the roots of this activity is far more complicated. The Okohotsk Plate is actually the remnant of a massive oceanic flood basalt event that was born from the Kula plate all the way from the jurassic period, relatively quickly after it’s formation, it would soon meet the Pacific plate. The Kula Plate is no longer with us it has been complete subducted, the very name Kula is the indigenous Tlingit Word for “All Gone”. The Sea of Okohotsk is actually the top of an ancient volcanic plateau. With this we might consider the Okohotsk plate to be psuedo-plate as flood basalts don’t make them. This is a unique volcanic setup as far as I am aware of, there isn’t similar process happening anywhere on the planet. As a psuedo-plate, the Okohotsk plate could be composed of far weaker stuff than it’s proper siblings
which might in fact lead to enhanced geological activity. As the Pacific plate goes under it, it could be more subject to breaks, which could lead to enhanced hydration, more deep quakes,and a more effective transfer of heat. All of which would lead to enhanced volcanism.
Currently the most potent volcanic group on the planet in the past 100 yrs
The Kamtchatka Peninsula lies on a Triple Junction between the Pacific, Okohotsk, and Komandorsky plates. The Pacific plate isn’t uniform in it’s subduction, as it has different speeds, angles and depth from north-south. The crust at Central Kamchatka is only 30-40 thick but the pacific plate has a depth of 170 km at the same location leading to mantle wedge. Usually massive amounts of pressure under these circumstances would limit the formation of magma but crustal pressure is bound to be low in this area due to the setup. Carl has suggested that this void is filled with magma, this I personally doubt but I am certainly in no position to contend.(gut feelings strike again). With this notion, if the void is the size of the CKD, there could be up to 512,000 km3 of magma. This magma chooses the path of least resistance and heads north, feeding the KVG. There is a large Low Velocity Layer in the area, which could be this magma body but it’s not confirmed. In any case, this setup promotes a lot of melt on top of a plate not built for this. As the Okohotsk plate breaks, and the void expands, the KVG and other volcanoes in the region grow and become beasts over time.
Klyuchevskaya is a rapidly growing volcano in a volcanic region that is also expanding, it stands to reason that the volcano might gobble up it’s siblings, Beziymianny is already becoming adirect understudy to the system. If this supply rate is not just a quick pulse of high activity but a long-term norm for the volcano then this system will become a completely different beast. The emergence of this volcano could mark the beginning of a new extreme phase in this massive complex. This process has likely already begun. The Kamen volcano has already had it’s supply cutoff thanks to the new Beziymianny cycle and is dead unless Klyuchevskaya graciously decides to send some magma their way. The massive Ushovsky compound would be the next volcano on the chopping block,unfortunately, there is no information on how expansive the magma system beneath Ushovsky is. The real juicy merger would be with Tolbachik to the south. By the time Klyuchevskaya and Tolbachik would become big enough to merge, the resulting chamber would easily exceed 10,000 km3 and would be the most productive volcano on the planet. Capable of massive mafic deluges and felsic explosions, a true supervolcano, in all categories.
If Klyuchevskaya can maintain these growth rates, it would take 50,000-100,000years before it merges with Tolbachik. Of course, the setting could change and Klyuchevskaya could wain and new volcano could receive bulk of the supply but it already has a large magma system within it and the whole system could still merge as new developing chambers absorb old, existing complexes. With the direction this complex is going, it could be one of the biggest volcanic flare ups in the current geological era. The subduction shall not end any time soon and the area is already on track tos urpass every volcanic region on the planet with only Hawaii holding firm against it. That is more than likely going to change as this complex rapidly expands and continues to intensify and with potentially over 100,000 km3 of deep magma to access. this is looking to be the biggest non-rift,non-mantle plume, zelch-hotspot volcanic region on the planet. Perhaps in the very distant future it will be the source of the next VEI 9 but that would be a story that we’ll never witness…
https://www.sciencedirect.com/science/article/abs/pii/S0377027312003216#:~:text=We%20interpret%20this%20feature%20as,pulse%20rapidly%20through%20the%20system.
https://www.researchgate.net/publication/238681861_The_evolution_of_high-alumina_basalts_of_the_Klyuchevskoy_volcano_Kamch
https://www.sciencedirect.com/science/article/abs/pii/S037702732300149X
I’ve always been fascinated by this group and have commented on it a lot over the years. In part due to how unique this volcanic system is.
I’ve wondered in part whether the klyuchevskaya volcanic group is what a pre-caldera Lake Toba would have looked like. The magmatic input is there for this to build a supervolcanic-sized chamber. After all, when you spend years of reading about large caldera systems and trying to understand what causes them to be made, you start to notice some key similarities in them. And this region does in fact have a LOT of the common characteristics you see in regions where you get huge calderas (both past and present).
– We have enormous magmatic input (possibly due to slab gap / slab rollback).
– We have evidence of volcanoes increasing in explosivity and magmatic evolution into more evolved magmas (specifically looking at the older members of the group and Shiveluch).
– We know that the tectonic region that this sits in is a zone of decompression, which is a very common component in these regions where large scale caldera volcanism occurs.
With all that said, in more recent years, I’ve come to the opinion that this isn’t likely ( at least in any geologically recent timeframe) due to some key differences in the crust environment. The main difference is that the CKD crust is oceanic, and not particularly strong due to that fact. Large-scale caldera volcanism requires both a strong lid for a large singular chamber to form, and then a mechanism for that lid to eventually get destroyed. In other regions such as the Taupo Volcanic Zone, the crust is very different being made up of hard felsic rock (greywhacke) which both forms a hard and brittle lid, but also melts and gets assimilated into the growing chambers as rhyolite. For the CKD, this assimilation process certainly occurs, but the assimilated magma would be more basaltic as opposed to the highly explosive rhyolite seen in Taupo.
Given, down a very long geologic timespan, if this group continues to see similar rates of magmatic input and the crust keeps thinning in the Central Kamchatka Depression, I *COULD* see this turn into a very large caldera system. We know there is a ton of magma down there (based on what Tallis mentioned as well as simply understanding the supply rate). But most of this is very deep and not ever a risk of erupting. It would be more of a batholith / laccolith that feeds overlying more shallow chambers.
A bit further down is the whopping Pauzhetka caldera, so large magma chambers can clearly occur here. It does have some similarities to Toba tectonically, although Toba also has the Great Sumatran Fault running through as well as the side-along extension-subduction front.
You’d need some of these shallower magma chambers to continue to grow in spite of high eruption rates, or to merge. And it hasn’t yet fractionated enough to produce the type of evolved magmas needed for a massive caldera eruption, most of the group erupts something akin to andesite. But it could do in the future.
Correct. For Toba, the Great Sumatran fault is what produces the decompression melt in the region. The fault is a strike slip fault, but strike slip faults often have regions where there is significant extension due to bending and fracturing in the fault. So while the fact that there is a strike slip fault is different from the CKD, it doesn’t change the fact that what matters is that this produces extension, decompression melt, and perhaps crustal thinning/weakness.
“You’d need some of these shallower magma chambers to continue to grow in spite of high eruption rates, or to merge”
Yeah, and that’s what I think will likely continue for a very long time. The thing is, the magma just seems to find it too easy to surface, and therefore does not seem to be growing large shallow chambers of evolved magma. That’s why you get a large cluster of mostly basaltic volcanoes. And when the edifice grows too large above and starts to actually block upward migration of magma, it just finds another path to the surface.
That type of behavior in my opinion is a good bit different from what you see in other regions where you see large calderas form. That’s not to say it can’t ever have a caldera formation, or won’t ever happen, but just that I don’t see this as a future VEI-8 candidate.