Big volcanoes look like this
(Mount Rainier, Washington)
The BIGGEST volcanoes look like this
Or this
Notice how they don’t have that nice big pretty volcano cone shape? It just looks like some drunk geologists scribbled on a map and drew circles around a low lying area with a lake or two in it and called it a “volcano” or a “volcanic zone”.
The reason though is that the BIGGEST and most destructive volcanic eruptions tend to happen with lava/magma that doesn’t flow very well and like when you get a stuffed nose, everything gets blocked up. Like many of us, these volcanos don’t solve the problem and go take a decongestant or blow their nose, they just sit there sniveling and stewing, failing to release the pressure that keeps building and building and building.
These eruptions are called felsic eruptions (the opposite of mafic, goopy eruptions you have seen footage of from Hawaii where the lava comes out like a fluid). An immense amount of gas is released by magma as it becomes exposed to the surface (which then we call it “lava”) as the gas is no longer kept in the magma at immense pressures. The magma can’t flow and “pass the gas” so to speak so a plug forms and what you get is a terrifyingly big pressure cooker that just builds and builds like that person on the plane next to you that just keeps sniffing and sniffing and never blowing their nose.
When the built up pressure finally overcomes the plug, the resulting explosion is so catastrophic it doesn’t leave a clean volcano shape. What you are left with is an uneven low topography dotted with lakes that marks the site of an incomprehensibly large explosion, hence the topography of Yellowstone, Wyoming and the Taupo Volcanic Zone on the North Island of New Zealand.
TIME FOR SOME STATS THAT WILL BREAK YOUR BRAIN
"The Taupō Volcanic Zone has produced in the last 350,000 years over 3,900 cubic kilometres (940 cu mi) material, more than anywhere else on Earth, from over 300 silicic eruptions [my edit: “Felsic” means “has lots of silica/silicic (silicic? seriously wikipedia?) and wants to form minerals high in silica like quartz and feldspar”], with 12 of these eruptions being caldera-forming. Detailed stratigraphy in the zone is only available from the Ōkataina Rotoiti eruption but including this event, the zone has been more productive than any other rhyolite predominant volcanic area [my edit: Rhyolite is a record of catastrophe, it is a Felsic, silica-rich igneous rock like Granite except it cooled FAST at the surface instead of in big underground “batholiths” (that make up a good portion of the Canadian Shield and the NE of the US among other places) where the minerals had time to grow into big pretty crystals, same ingredients as Granite but with much more exciting baking instructions] over the last 50,000 odd years at 12.8 km3 (3.1 cu mi) per thousand years. Comparison of large events in the Taupō volcanic zone over the last 1.6 million years at 3.8 km3 (0.91 cu mi) per thousand years versus with Yellowstone Caldera’s 2.1 million year productivity at 3.0 km3 (0.72 cu mi) per thousand years favours Taupo…
…The last major eruption from Lake Taupō, the Hatepe eruption, occurred in 232 CE. It is believed to have first emptied the lake, then followed that feat with a pyroclastic flow that covered about 20,000 km2 (7,700 sq mi) of land with volcanic ash. A total of 120 km3 (29 cu mi) of material expressed as dense-rock equivalent (DRE) is believed to have been ejected, and over 30 km3 (7.2 cu mi) of material is estimated to have been ejected in just a few minutes."…
^https://en.wikipedia.org/wiki/Taupō_Volcanic_Zone
…“The main extremely violent pyroclastic flow travelled at close to the speed of sound and devastated the surrounding area, climbing over 1,500 m (4,900 ft) to overtop the nearby Kaimanawa Ranges and Mount Tongariro, and covering the land within 80 km (50 mi) with ignimbrite [my edit: the name for pyroclastic flow deposits, i.e. pumice and ash, that kind of thing]. Only Ruapehu was high enough to divert the flow. The power of the pyroclastic flow was so strong that in some places it eroded more material off the ground surface than it replaced with ignimbrite. There is evidence that it occurred on an autumn afternoon and its energy release was about 150 megatons of TNT equivalent. The eruption column penetrated the stratosphere as revealed by deposits in ice core samples in Greenland and Antarctica.”
^https://en.wikipedia.org/wiki/Taupō_Volcanic_Zone
why the did I make this stupid meme in feet instead of metric, I am such an asshole -facepalm
IIRC when Mount Saint Helens erupted in the 80s it blew the top half of the volcano off.
Yeah and slightly off topic wasn’t the pic of Helens blowing its top taken by a man who knew in advance the explosion would kill him and protected his film? Am i thinking of the right story?
Yes. Heroic deed it was.
That’s Robert Landsburg although I don’t think his photos are very famous.
The series of photos that were turned into a video were taken by Gary Rosenquist, who survived the eruption.
So much awesome power in that eruption (with non-awesome human and nature/animal consequences).
http://mountsthelens.com/history-1.html
This article is a good play-by-play of how the eruption physically progressed, I particularly like this illustration.
So you’re saying we need to cover Wyoming in cement. Gotcha.
Seriously though, cool info!
So you’re saying we need to cover Wyoming in cement. Gotcha.
I am sure if you sold it to Wyoming voters as a way to hurt trans people AND immigrants at the same time they would happily vote for it and drown themselves alive in a sea of concrete.
Made me whip out my geology notes I took a few semesters ago, thanks for the fun explanation
Thank you, kind geology enthusiast.
Really barely comprehensible how immense those volcanic activities are.
On a side note, you’ve listed insane unit after insane unit of death and destruction. And then there is this sentence:
There is evidence that it occurred on an autumn afternoon
That was a cute turn and I laughed. :D
Ohhh, I had no idea there were different kinds of volcanoes but it does make sense in hindsight.
Well, I guess this might have been covered in primary or secondary education at some point but it’s been about 3000 years since my last geography class
yo geolooggggyyyyyyy (lots of good brain food I promise)
There is a wonderful diverse world of volcanic eruptions! One thing you might not have thought about is how glaciers often form at the top of large cone volcanoes and the way the lava erupting interacts with a large volume of ice can shape the eruption significantly. One of the biggest results are lahars, like muddy, liquidy avalanches but even faster and deadlier.
https://www.usgs.gov/programs/VHP/lahars-move-rapidly-down-valleys-rivers-concrete
To give you a good point of reference though, one thing that links all volcanic eruptions and is a good axis for comparison between different eruptions and volcanoes is that all magma pretty much comes up from the interior of the earth to the near surface starting at the same chemical composition (called “mafic” it sounds like “basic”). Mafic minerals are heavy, dense and tend to be dark colored when viewed in a hand specimen, a common mafic rock is Basalt. Most of the oceanic crust is basalt.
Available Wherever You Get Your Bottoms Of Oceans
Felsic minerals tend to be light both in mass and in coloring, a comon felsic rock is Granite.
Looks like your mom’s countertop, I remember it well how perfectly the skin of her naked legs complemented the gorgeously polished crystal textures of quartz, potassium feldspar (K-feldspar), sodic plagioclase feldspar, hornblende amphibole, and mica
This is a graph of Viscosity, the more Viscous the Magma the less ability it has to flow like a liquid (and thus the more likely a plug is likely to form inside a volcano). It is also more difficult for lower temperature magma to flow, and Felsic lava is almost always lower temperature (cooling had to occur to become Felsic in the first place so).
https://en.wikipedia.org/wiki/Magma
Here is something to ground these two ends of what probably seems like an arbitrary spectrum to focus on, the Oceanic Crust (i.e. the bottom of the ocean) on this planet is overwhelmingly made up of mafic rocks (i.e. Basalt) and large amounts of felsic rocks only really form on continental plates where there is the space and depth of rock to house massive chambers of magma, especially since Oceanic Plates are always getting subducted and recycled unlike Continental Plates (and thus the magma might be subducted & recycled before it could even begin the process of becoming significantly felsic). This axis of chemistry is critical to Geologists because it points directly to some of the biggest trends of geology on the planet and a related fact I might as well drop here is that because of these dynamics Continental Plates (i.e. basically the continents) can be orders of magnitude older (on the order of 1 billion years or older, the earth is only 4 or so billion years old) than oceanic crust which tends to be younger than 200 million years old (and often is much younger).
On Continental Plates if magma feeds into large underground chambers (batholiths) and is allowed to cool slowly then certain minerals will begin to form and precipitate out like snow that layers up on the bottom of the chamber. The specifics of what minerals these are depends on how long, how hot, how much pressure and other factors but you can vaguely think of it as a process of distillation where magma progresses from the original “mafic” composition to a “felsic” one as the high temperature mafic minerals crystallize out leaving behind a progressively more felsic magma mixture. The felsic minerals don’t crystallize out until the magma has significantly cooled and thus if the magma chamber undergoing this process is integrated into an eruption, it can become extremely explosive and destructive.
https://opentextbc.ca/geology/chapter/4-2-magma-composition-and-eruption-style/
Half Dome in Yosemite California is such a trip because it is so clearly what we imagine in geology when we talk about a really big underground chamber of magma (after it has cooled into rock obv), Half Dome just looks like exactly how you would imagine it if you dug up an old magma chamber and cracked in half with a suitably large hammer
Except Vesuvius, which looks like a volcano, but in 79CE erupted violently sending lave, magma and molten rocks several kilometers away, exactly like the stuffy nose you described. It completely destroyed Pompeii and Herculaneum, burying them for thousands of years.
Still nothing when compared to the destruction that the “Campi Flegrei” volcano brought 37’000 years ago, completely burying a huge section of the Campanian coastline.
Super cool!!
Aain I love how it looks like a drunk geologist made a big scribble on a map and said before passing out “that Campi Flegrei, that’s a BIG one right there!” and you are just left looking at the map being like… what… are you sure that just looks like you randomly circled a huge part of the landscape?..like… really the whole bay?
Yeah, it pretty much blew out that whole section of coastline, that big hole is called a “caldera”. It’s still active btw, you can go and check it out if you want. Look for Solfatara di Pozzuoli.
You can also look at the Greek island of Santorini, where the whole western and central part of the island was blown off during the bronze age iirc. Historians speculate the eruption, earthquake and tsunamis caused by the event could have partially influenced the collapse of the Minoan civilization, the rise of the Mycenaeans, turmoil in Egypt and possibly even the fall of the Chinese empire due to a global winter. Crazy stuff
Thank you that was super informative. Is there anything that can be done to mitigate an impending eruption? Ive always heard that if one of the big super volcanoes goes it could be quite catastrophic for the entire world. Surely theres been some research into like pressure relief holes or something…antacid tabs?
Surely theres been some research into like pressure relief holes or something…antacid tabs?
I am sure there are lots of geologists who have thought of it, it makes sense right?
The problem is that nobody gives a shit about listening to geologists unless they are talking about where to find oil. Even if a geoengineering project of this scale and magnitude (with such catastrophic consequences if it goes wrong) where possible with near current geological science and hardware this degree of interest and investment of society is only ever committed to visions techbros provide and I don’t think a single techbro has ever taken a geology class and actually remotely paid attention.
It was geologists in the 1970s who first pointed out the obvious connection between human released CO2 emissions and global warming.
Nobody gave a shit :)
(plenty of complicit geologists who made a veryyyyy good living too don’t get me wrong)
We are just weirdos going on about rocks except when those rocks are really valuable and provide the capacity to create empires but even in those cases we are never really part of that, we are always still the weirdos going on about rocks who everybody is like “ok but can you shut up now and point to the gold on the map?”.
I know it is a weird example but look at the landscapes of virtual environments, video game developers have been trying to craft evocative landscapes since the beginning of video games even before 3D engines, you would think that some of them might have been interested to find inspiration for world design from the dizzying variety of landforms and stories described in geology (that are perfect to engage a player with because geological landscapes are layered stories first and foremost).
From the perspective of a geologist, it is obvious for game developers to make world building tools that allow molding an entire mountain range for an open world rpg by first starting with two continents and smashing them together with your mouse over and over again until it made a compelling starting point (instead of just making every damn mountain by hand or just writing a dumb algorithm to randomly generate mountains) and then running a massive river through the mountains for 10 million years to create the main valley for the game.
Todd Howard released a screenshot of the next Elder Scrolls Game
the story here was there was a river and then a mountain range came in (some new kid named Appalachians) and was like “sorry dude” but then the Delaware River was like “I am literally going nowhere bro, put your silly mountains wherever you want and I will cut you down when you get in my way”. This friendly conversation has been going on for 400-500 million years, which is about 1/8 of the earth’s history (the earth was a hot mess for the 1st billion so that barely counts). A lot of rivers are pretty lazy, but not the Delaware River, you gotta give it credit.
A geological sandbox for large scale world design that allowed game developers to quickly and intuitively create landscapes with layered pasts and local variety that perennially inspired curiosity from players seems so obvious to me it is painful. (Also as a fun toy for its own sake).
Like damn… video games barely know how to make a rock outcrop look natural and it is 2024… ——
All that being said to point out that your vision of a cool geo-engineering project is mostly unrealistic because of humans not even bringing geology into the picture. Part of the globalized contagion of late-stage capitalism is VERY crucially a collective forgetting of the stories in the landscapes around us. We have been taught to see the landscape around us as a background for our genius, not the primary gift passed down by our ancestors, the foundation of all the beauty in our lives and a fascinating machine of anarchy that creates endless forms of order.
Everywhere all over the world people are extracting groundwater at a ridiculously unsustainable rate (the fucking AXIS EARTH IS TILTED ON has changed because so much groundwater has been extracted) even while geologists try to point out there is going to be no clean water left???, the dysfunction of our thinking with respect to land goes very deep unfortunately.
Instead we are left with this trash Elon Musk-esque obsession with spiritually disconnecting ourselves from Earth and leaving for Mars as if the idea of separating us from the landscape (and natural systems/biosphere) we evolved in makes any sense at a basic level of our body maintaining homeostasis effectively or is something we would even desire to do (thanks for that one, sci-fi shows and books!). It is like plucking an ant from an ant colony, carefully placing it into the ocean and whispering “now you can start a new life here”…… It makes no sense.
On the game side of things, while i agree more realistic landscapes would be awesome, making games is really hard work and you need to be careful where you’ll invest your time in if you want to actually get anything finished. The truth is most people who are not geologists can’t tell the difference between a realistic landscape and an unrealistic one.
We have some tools for world generation, though i’m not sure how realistic they are. Mostly a mix of noise functions (Simplex, Perlin, etc) and erosion simulation. But i barely understand how that works, so your “geological sandbox” seems a lot less obvious to me.
Another thing to consider is that in game design, realism will always take a backseat for good gameplay. A map that naturally guides the players where they need to go is usually much more desirable than one that is realistic but unintuitive. Plus when you add magic, gods, or even enough sci-fi, the bar for what counts as a realistic landscape really goes out the window anyway.
