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 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.
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
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.
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.
“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:
The Altiplano-Puna Volcanic Complex
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 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.
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.