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A supervolcano is capable of eruptions thousands of times larger than normal outpouring that has had an eruption with a Volcanic Explosivity Index (VEI) of 8, the largest recorded value on the index.
This means the volume of deposits for that eruption is greater than 1,000 cubic kilometres (240 cubic miles). Explosive events of this size erupt so much magma that a circular-shaped collapse feature, called a caldera, forms above the evacuated magma storage region.
Supervolcanoes occur when magma in the mantle rises into the crust but is unable to break through it and pressure builds in a large and growing magma pool until the crust is unable to contain the pressure. This can occur at hotspots (for example, Yellowstone Caldera) or at subduction zones (for example, Toba).
Large-volume supervolcanic eruptions are also often associated with large igneous provinces, which can cover huge areas with lava and volcanic ash. These can cause long-lasting climate change (such as the triggering of a small ice age) and threaten species with extinction. The Oruanui eruption of New Zealand’s Taupo Volcano (about 26,500 years ago) was the world’s most recent VEI-8 eruption.
Most Devastating Effect Of Massive Volcano Eruption Seen In Recent Time
In 1815 the world experience the explosion of The Volcano Tambora. The year after that was called the year without a summer. Because of the super eruption global temperature suddenly reduced by 32-degree Fahrenheit, which led to a massive reduction on crops production and eventually, the human race as a whole face a massive famine.
The Year Without a Summer was an agricultural disaster. Historian John D. Post has called this “the last great subsistence crisis in the Western world”. The climatic aberrations of 1816 had the greatest effect on most of New England, Atlantic Canada, and parts of western Europe.
The Volcano Tambora has a Volcanic Explosivity Index of 7 only, then just think what Effect a Volcano of Volcanic Explosivity Index of 8 or greater could have on us.
Devastating Effects Of Supervolcano Eruption
Humans are really terrible at evaluating existential risks, in part because of their rarity. We may be afraid of terrorism or mass shootings, Even though those events are actually on a day by day base, very unlikely. Because they pop out at us, we tend to overstate the danger they pose to us.
The reverse of that is often we see with existential risks where we tend to assume they must not be possible, because they have never happened in our lifetime, that’s a mistake.
Five times over the course of the planet’s history, we’ve seen what are called major extinction events. That’s where you see something big happen that might knock out three-quarters of the life on this planet.
Obviously, the one people are most familiar with is that asteroid that collided with the Earth 66 million years ago that led to the extinction of the dinosaurs. But four out of the five mass extinction events, we believe really have some kind of volcanic cause.
Existential risk experts really believe that Toba, was the closest human beings have ever come to extinction. This was an actual supervolcano that exploded about 74 to 75,000 years ago. That’s a long time ago, but there were human beings around. It was an 8 on the Volcanic Explosivity Index.
By some climate models, it would have reduced global temperatures by 15 degrees Fahrenheit or as much as 30. The aftermath of big, supervolcanoes like Toba would be cold, dark and very hungry.
When they blow, they blow all that debris, including a lot of sulfur into the atmosphere. It can actually reduce the amount of sunlight that can come into the planet. Volcanic ash is made up of little, almost hook-like rocks that will, actually, tear human tissue. It also can contaminate crops, it can contaminate water supplies.
It’s very dense and can actually cave in roofs. We still find deposits of ash from the Toba super-eruption, thousands of miles away from the volcano. You can see it in India, you can see it in parts of Africa. You can actually trace it back to Toba.
By some estimates, it may have reduced human population to as little as 4,000 people. That shows how unbelievably powerful, how unbelievably dangerous how existential a supervolcano of that kind of scale can be.
When a supervolcano erupted 600,000 years ago in Wyoming, in what today is Yellowstone National Park, it ejected more than 1,000 cubic km of ash and lava into the atmosphere – enough to bury a large city to a depth of a few kilometres.
So How Supervolcano Explodes?
Supervolcanoes undergo a life cycle of three major stages: a surge of trapped magma, a supereruption and a resurgence.
Surge Of Trapped Magma
The first stage of a supervolcano’s life cycle involves a pocket of magma trapped under the Earth’s crust, called a hotspot. This magma reservoir is fed by a pipeline deep into Earth’s molten interior. It grows and builds pressure underground, eventually causing the crust above to be pushed upward.
The supervolcano Campi Flegrei on the west coast of Italy has pushed the ground up several times over the past few decades. At one point, within a matter of only two years, enough magma accumulated to cause the ground to swell up to six and a half feet.
The next stage of a supervolcano’s life cycle is a supereruption. At this point, the buildup of pressure in a magma reservoir hits a critical mass and then explodes, sending over 1,000 cubic kilometres of tephra or ash and rocky material, into the sky.
The most recent supereruption occurred in New Zealand approximately 26,000 years ago. The supervolcano Taupo ejected about 1,100 cubic kilometres of tephra into the air, enough material to constitute nearly half a million Great Pyramids of Giza.
After a supereruption, a supervolcano undergoes a stage called resurgence. Having dispelled its contents, a supervolcano’s magma reservoir collapses and forms a caldera.
The Yellowstone Caldera in the United States is currently in a resurgence after a supereruption occurred about 640,000 years ago.
For a long time, it was thought an external trigger, such as an earthquake, was needed to bring about a giant blast. But some recent studies suggest that the sheer volume of liquid magma is enough to cause a catastrophic super-eruption.
Can We Predict Supervolcano Eruption?
Yes. One possible mechanism was thought to be the overpressure in the magma chamber generated by differences between the less dense molten magma and more dense rock surrounding it. The effect is comparable to holding a football underwater. When you release it, the air-filled ball is forced upwards by the denser water around it.
If we measure the density difference from solid to liquid magma we can calculate the pressure needed to provoke a spontaneous eruption. A study showed that the transition from solid to liquid magma creates a pressure which can crack more than 10 kilometres of Earth’s crust above the volcano chamber.
Magma penetrating into the cracks will eventually reach the Earth’s surface. And as it rises, it will expand violently – causing an explosion.
So by calculating the density differences and geothermal activity of certain volcano we can definitely predict will it explode or not.
What Are The Known Supervolcano Eruption?
|Name||Zone||Location||Notes||Years Ago||Ejecta Bulk Volume|
|Wah Wah Springs||Indian Peak–Caliente Caldera Complex||Utah, United States||The largest of the Indian Peak-Caliente Caldera Complex eruptions, preserved as the Wah Wah Springs Tuff; includes pyroclastic flows more than 4,000 metres (13,000 ft) thick||30,600,000||5,500–5,900 km3|
|La Garita Caldera||San Juan volcanic field||Colorado, United States||Fish Canyon eruption||27,800,000||5,000 km3|
|Lake Toba||Lake Toba, North Sumatra||Sumatra, Indonesia||Produced 2200–4400 million tons of H2SO4||74,000||2,800 km3|
|Huckleberry Ridge eruption||Yellowstone hotspot||Idaho, United States||Huckleberry Ridge Tuff; consisted of three distinct eruptions separated by years to decades||2,100,000||2,450–2,500 km3|
|Taupo Nui a tia||Taupo Volcanic Zone||North Island, New Zealand||Whakamaru Ignimbrite/Mount Curl Tephra||340,000||2,000 km3|
|Heise Volcanic Field||Yellowstone hotspot||Idaho, United States||Kilgore Tuff||4,500,000||1,800 km3|
|Heise Volcanic Field||Yellowstone hotspot||Idaho, United States||Blacktail Tuff||6,000,000||1,500 km3|
|Cerro Guacha||Altiplano-Puna volcanic complex||Sur Lípez, Bolivia||Guacha ignimbrite, two smaller eruptions identified||5,700,000||1,300 km3|
|Mangakino Caldera||Taupo Volcanic Zone||North Island, New Zealand||Kidnappers eruption||1,080,000||1,200 km3|
|Oruanui eruption||Taupo Volcanic Zone||North Island, New Zealand||Taupo Volcano (Lake Taupo)||26,500||1,170 km3|
|Cerro Galán||Andes Central Volcanic Zone||Catamarca, Argentina||Consisted of three distinct eruptions, separated by 30-40 thousands of years||2,500,000||1,050 km3|
|Lava Creek eruption||Yellowstone hotspot||Idaho, Montana, and Wyoming, United States||Lava Creek Tuff; consisted of two distinct eruptions separated by years||640,000||1,000 km3|
|Bishop Tuff||Long Valley Caldera||California, United States||A single eruption completed within 6 days; volume in dense rock equivalent||760,000||600 km3|
Where Do Supervolcanoes Occur?
Supervolcanoes can occur in many situations. Some, like Yellowstone, can be due to hot spots, rising plumes of magma from deep inside Earth. Hot spots generate a trail of volcanoes as the ever-moving tectonic plates slowly march across the largely stationary plume, like the lengthy chain of volcanoes of the Hawaiian Islands.
Others, like Toba in Sumatra, Indonesia, can form along subduction zones where one tectonic plate plunges beneath another. As the descending landmass sinks deep underground, temperatures and pressures climb, forcing the water from the rocks. That water reduces the melting point of the overlying rocks, forming magma that can fuel future eruptions.
Regardless of how the magma forms, however, a volcano needs a lot of it to produce a super-eruption. As the magma builds, pressure in the underground cavity increases. A super-eruption requires tons of pressure to actually jettison the huge pockets of molten rock through the surface.
Yellowstone Supervolcano Will Erupt Or Not?
Yellowstone is now perhaps the most famous of the world’s volcanoes that have produced VEI 8 eruptions. This geologic superstar has had at least three enormous eruptions in its history: Two are super-eruptions that were VEI 8 (some 2.1 million and 640,000 years ago), and one eruption 1.3 million years ago was VEI 7, producing around 67 cubic miles of material.
The unfounded fear in a pending Yellowstone eruption has swirled for decades but studies suggest it is not going to erupt anytime soon. While an eruption in the distant future is possible, the probability of it happening in the next few thousand years is “exceedingly low.
The magma lurking in Yellowstone’s shallow reserve is between just 5 and 15% molten. An eruption usually requires at least 50% to gel in this gooey hot state. More likely than such an explosion is a lava flow—a spurt of slowly oozing molten rock.
Although a lava flow can pose hazards for communities that lie in its path or spectators attempting to approach close enough to roast a marshmallow, those dangers are much easier to predict and avoid.
Can We Survive An Supervolcano Eruption?
Most important to keep in mind that agencies around the world are keeping a close watch on supervolcanoes like Yellowstone, monitoring their every tremor and magma-laden belch.
Volcanoes provide some notice of pending eruption and modern equipment helps scientists take their pulse with more accuracy than ever before. So while a super-eruption in the near future is exceedingly unlikely, these agencies will be the first to know and alert the public if one ever becomes imminent.
Even if such a catastrophe occurs we could put food in reserve. We could actually begin to research methods of food production that don’t depend on the sun.
Ultimately, what we’re doing here is trying to preserve the future. And we can do that, but only if we take this seriously. We really have no excuse. If we go extinct now, almost certainly it’s because we did not try hard enough to keep ourselves safe.
20. There are around 20 known Super volcanoes. Names are 1.Yellowstone, USA 2. Long Valley Caldera, USA 3. Values Caldera, USA 4. Lake Toba, Indonesia 5. Taupo, New Zealand 6. Aira Caldera, Japan 7. LA Garita Caldera, USA 8. The Campi Flegrei, Italy 9. Mount Tambora, Indonesia 10. Baekdu Mountain, North Korea-China 11. Kurile Lake, Russia 12. Karymshina, Russia 13. Bennett Lake, Canada 14. Cerro Galan, Argentina 15. Pacana Caldera, Chile 16. Pastos Grandes, Bolivia 17. Mount IO, Japan 18. Kyushu, Japan
The last known supervolcano eruption, believed to have occurred around 70,000 years ago on the site of today’s Lake Toba in Sumatra, Indonesia.
No, It is very unlikely that any eruption will occur in the next thousand or even 10,000 years.