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  • The Earth is a gigantic ball of semi-molten rockwith a heart of iron as hot as the surface of the  

  • Sun. Titanic amounts of heat left over from its  birth and the radioactive decay of trillions of  

  • tons of radioactive elements find no escape  but up. Currents of rock spanning thousands  

  • of kilometers carry this energy to the surfaceEarth’s crust is the only thing in their way.  

  • It feels solid to us, but it is only a fragile  barrier, an apple skin around a flaming behemoth.  

  • True apocalypses can break through  and unleash eruptions tens of times  

  • more powerful than all of our nuclear weapons  combined, subjecting the climate to centuries  

  • worth of change in a single year, while  drowning continents in toxic ash and gases:  

  • supervolcanoes. How big can they getAnd will they put an end to humanity?

  • Volcanoes

  • There are many types of volcanosfrom towering mountains to lava domes,  

  • but they have two main sources:

  • The first is at the boundaries between tectonic  plates, the pieces of the crust that cover the  

  • Earth like a giant jigsaw puzzle. There are seven  major tectonic plates and dozens of smaller ones,  

  • drifting against each other at up  to 15 cm per year. This sounds slow,  

  • but on geological timescales it istitanic struggle over who gets to stay  

  • on the surface. The winning plate crumples  into a new mountain range while the loser  

  • is shoved underneath, into an ocean of  hot rock at1300°Ct: The asthenosphere.

  • The temperature here is enough  to melt rock into a liquid,  

  • but the insane pressures of all that  mass keep it a superheated solid.

  • Tectonic plates are usually in contact  with water for thousands of years and  

  • absorb some of it. When they are  submerged into the hot underworld,  

  • this water triggers chemical transformations  that allow tiny portions to melt into magma.  

  • Liquid magma is less dense than solid rockso it rises to the surface in furious bubbles  

  • that accumulate in sponge-like reservoirs right  under the crust. If enough magma accumulates,  

  • it becomes powerful enough to pierce through the  crustwhich we experience as volcanoes. This  

  • happens under the winning plate, like a revenge  attack by the loser before it is erased forever.

  • The second main source of volcanoes are thought to  be mantle plumes. These are columns of abnormally  

  • hot rock that rise all the way from the planet’s  core-mantle boundary to the surface. Much less is  

  • known about them, but in a way it is as if the  Earth’s mantle has weather patterns and mantle  

  • plumes are a little like hot air rising to form  storm clouds. Storms hundreds of millions of  

  • years old, made of rock circulating at  a rate of a few millimetres per month.  

  • They don’t care about the motion of tectonic  plates, so they can break the crust to create  

  • volcanoes in the middle of nowhere that stubbornly  stay active as the crust shifts around them.

  • The volcanic boom-meter

  • Scientists love to put big booms onscale and came up with a logarithmic  

  • scale that measures the volume ejected during  an eruption: The Volcanic Explosivity Index,  

  • or VEI. Simply put, it starts really  small and gets very big very quickly.

  • A VEI 2 eruption would fill four hundred  full Olympic swimming pools with lava.  

  • We have around 10 of these per year.

  • At VEI 3 we already see devastating effects,  

  • like the eruption of the Semeru volcano in 2021  that destroyed thousands of homes in Indonesia.

  • At VEI 5, we see catastrophic amounts of  materials, cubic kilometers of debris, equivalent  

  • to an entire lake of molten rock blasted into  the air. Like the 2022 Hunga Tonga-Hunga Haapai  

  • eruption that sent a shockwave around the globe  many times and created ocean-wide tsunamis.

  • At a VEI of 6, an eruption can change the worldIn 1883, the Indonesian island volcano Krakatoa  

  • erupted nearly continuously over the course of  5 months. One of those eruptions blew it apart,  

  • producing the loudest sound recorded in history,  

  • 10 trillion times louder than a rocket  taking off, heard halfway around the world.  

  • 30m high tsunamis swept away nearby populations  and so much gas and ash were released that  

  • global temperatures cooled by nearly 0.5°C.  Red dusty sunsets followed for many years.

  • At VEI 7, we get Super-Colossal  eruptions, millennium-defining  

  • events that human civilization has  only encountered a handful of times.  

  • Mount Tambora was a 4300m high mountain  until it exploded in 1815 and released 400  

  • times more energy than the Tsar Bomba.  140 billion tons of ash and dust were  

  • shot halfway to space before smothering the  world’s skies, turning them a sickly yellow.  

  • There was no summer the following year, crops  died and over a hundred thousand people perished.

  • This is the dreadful potential of volcanic  eruptions, with famines across the other  

  • side of the world and even centuries-long  cold periods being attributed to them.

  • Ok. But what is a supervolcano?

  • The termSuper volcanois a media invention  and not a scientific term. The main issue with  

  • them is that not every eruption from  a supervolcano is a super eruption.

  • What makes super volcanoes special is that  they have been waiting to erupt for hundreds  

  • of thousands of years. Pressure builds up in  colossal magma reservoirs several kilometers deep,  

  • until it becomes strong enough to lift  the rock above it by several meters.  

  • Rocks crack under the pressure, until they finally  give way and billions of tons of gas and ash blast  

  • out at supersonic speed. An insane explosion  of at least a thousand cubic kilometers that  

  • impacts every corner of the globe. And yet, that  is only a small portion of the magma reservoir.

  • Super eruptions are like a boiling pot of water  popping its lid off and spilling a bit off the  

  • top. Afterwards the ground collapses into  the void left behind, forming a hole called  

  • a caldera. Under this caldera, pressure starts  building again until the volcano gathers enough  

  • energy for another supereruptionbut this  could take hundreds of thousands of years.

  • It is estimated that one of the few  volcanoes capable of supereruptions  

  • on Earth could cause a catastrophic eruption every  

  • 17,000 years on average. That would make them far  more frequent than comparable asteroid impacts..

  • The most recent super-eruption is the Oruanui  eruption 26,500 years ago in New Zealand.  

  • With the force of dozens of billions of tons of  TNT, a Mount Everest- sized pile of explosives,  

  • a huge portion of the landscape was  scooped out and thrown into the atmosphere.  

  • It left behind a caldera spanning 20km and  it caused the entire Southern Hemisphere  

  • to undergo a period of abrupt cooling. Though  among super-eruptions, it is a mere firework.

  • The Lake Toba eruption of 74,000 years ago  was a much more significant turning point  

  • in history. It released a gargantuan 5300 cubic  kilometers of material, enough to blanket parts  

  • of South Asia in 15 cm of ash and trigger  a rapid 4°C drop in global temperatures.  

  • It’s possible that the volcanic winter lasted  ten years, followed by worldwide droughts for  

  • centuries. Earth’s climate might have  not recovered for a thousand years.

  • The largest volcanic events we know  of were not really huge explosions,  

  • but floods of millions of cubic kilometers of  lava. The grand finale were the Siberian Traps  

  • around 250 million years ago, a continuous  release of lava for two million years.  

  • They raised the ocean temperatures to over 40°C,  which caused the PermianTriassic extinction,  

  • killing over 90% of all species. Earth’s surface  needed 9 million years to recover. These sorts  

  • of eruptions don’t change the climatethey are the climate. But thankfully,  

  • we haven’t seen anything even remotely close  to that scale in many millions of years.

  • So. Should you be scared of super-volcanoesDefinitely not. Theyve been used to frighten  

  • many people and are overhyped as an unavoidable  apocalypse. The most famous one, Yellowstone,  

  • will erupt again, but they will  be relatively small eruptions.  

  • Natural disasters for sure, but not enough to  devastate the US or come close to ending humanity.

  • The chance of a VEI 8 eruption in the  next few hundred years is less than 2%  

  • and more importantly, it would  not come as a sudden surprise.  

  • However, less powerful but more  frequent eruptions can also do  

  • serious damage to our civilizations and  are in many ways a much greater concern.

  • So we must watch for slow changes in  magma reservoirs, like ground swelling  

  • and temperature increases, to get an early  warning that can save the lives of people  

  • living the closest to a volcano. And there’s time  to develop solutions that can remove sulfur and  

  • ash from the stratosphere to eliminate the root  cause of the climate disruption weve seen from  

  • previous eruptions. Who knows, maybe well even  be able to turn this force of destruction into  

  • an agent for good by exploiting the geothermal  energy held in their giant magma reservoirs.

  • Weve done this work for so many other disasters  and we are already doing things we could only  

  • have dreamed about decades ago, like sendingprobe to perform our first asteroid redirection  

  • test. With determination, humanity really  can solve anything. So while deep below us  

  • an angry hell is churning and waiting for  its moment, you can sleep well tonight.

  • Learning how we can get ahead of catastrophes like  climate change and supervolcanoes is interesting,  

  • but can also be challenging. Maybe you still  feel like you don’t really understand how  

  • most of the science behind it works. And on  your own it seems too hard to dig deeper.

  • To solve this, weve collaborated with our  friends from Brilliant to create a series of  

  • lessons to build your understanding of fundamental  scienceby exploring fascinating insights from  

  • our most popular videos, on topics like black  holes, the size of life, and climate change.

  • Brilliant is an interactive learning  tool that makes science accessible with  

  • a hands-on approach. Because we know that  to really learn something, youve got to do  

  • it. Think of each lesson as a one-on-one  deep-dive version of a Kurzgesagt video.

  • In our latest lessons, youll discover the  mechanisms that drive climate change and  

  • use them to understand the impact of  supervolcanoes on our global climate.

  • Beyond new Kurzgesagt lessons regularly released,  

  • Brilliant has thousands of lessons for members  to explorefrom math-based topics like algebra  

  • and probability to the concepts behind  machine learning and quantum computing.  

  • With new releases each month, youll  always find something fascinating to learn.

  • To get hands-on with Kurzgesagt lessons now, go  to Brilliant.org/nutshell and sign up for free.  

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The Earth is a gigantic ball of semi-molten rockwith a heart of iron as hot as the surface of the  

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