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Supervolcano / Volcanos

The Yellowstone caldera.
The Yellowstone caldera.

When a volcano erupts, size matters. A small eruption might release some gas and steam before quieting down again. Larger eruptions could have lava pour out and damage areas nearby. But the largest eruptions that come from supervolcanoes are so large and disruptive; they're expected to kill tens of thousands of people if one erupted in our lifetime.

To measure how explosive a volcanic eruption is, vulcanologists use a scale known as VEI. That stands for Volcanic Explosivity Index. The smallest eruptions come in a VEI 0 classified as "Hawaiian." It typically has an outpouring of lava on the ground and a plume height under 100 meters. Eruptions of this type are happening all the time in places around the world.

Each step up the scale from VEI 2 is ten times greater than the previous one. (The first two on the scale don't fit into that quite as neatly. A VEI 0 shoots out less than ten thousand cubic meters of ejecta, and a VEI 1 kicks out more than ten thousand but less than one million cubic meters of ejecta.)

That means a VEI 2 has an ejecta volume of one million cubic meters, while a VEI 3 has an ejecta volume of ten million cubic meters. So a supervolcano would kick out a mind-boggling one trillion cubic meters of ejecta.

Within 10 miles of a supervolcano eruption, you would have ash that's tens or even hundreds of feet deep. 300 miles away, the ash would be several inches deep, suffocating plants, animals and bodies of water it fell upon.

Here's a comparison the various types of volcanoes and their effects.

DEFINITIONS:

  • Ejecta is the stuff that's kicked out of a volcano.
  • Tephra is another word for volcanic material, as scoria, dust, etc., ejected during an eruption.
  • > Means greater than.
  • < Means less than.
  • > Means greater than or equal to.

Hawaiian

VEI Classification Ejecta in Cubic Meters Plume Height in Meters Description
0 Hawaiian 10,000 or Less < 100 Effusive

Ash Thickness Ash Thickness
10 Miles 300 Miles How Frequent Are Eruptions
Nil Nil Continuous

Hawaiian
Hawaiian eruption: 1, ash plume; 2, lava fountain; 3, crater; 4, lava lake; 5, fumarole; 6, lava flow; 7, layers of lava and ash; 8, stratum; 9, sill; 10, magma conduit; 11, magma chamber; 12, dike
Image from © Sémhur / Wikimedia Commons


Strombolian

VEI Classification Ejecta in Cubic Meters Plume Height in Meters Description
1 Strombolian > 10,000 100 - 1,000 Gentle, Non-Explosive

Ash Thickness Ash Thickness
10 Miles 300 Miles How Frequent Are Eruptions
Dusting Nil Daily

Strombolian
Strombolian eruption: 1: ash plume, 2: lapilli, 3: volcanic ash fall, 4: lava fountain, 5: volcanic bomb, 6: lava flow, 7: layers of lava and ash, 8: stratum, 9: dike, 10: magma conduit, 11: magma chamber, 12: sill
Image from © Sémhur / Wikimedia Commons


Vulcanian

VEI Classification Ejecta in Cubic Meters Plume Height in Meters Description
2 Vulcanian > 1,000,000 1,000 - 5,000 Small, Explosive

Ash Thickness Ash Thickness
10 Miles 300 Miles How Frequent Are Eruptions
Fraction of an Inch Nil Weekly

Vulcanian
Vulcanian eruption: 1 ash plume, 2 lapilli, 3 lava fountain, 4 volcanic ash fall, 5 volcanic bomb, 6 lava flow, 7 layers of lava and ash, 8 stratum, 9 sill, 10 magma conduit, 11 magma chamber, 12 dike
Image from © Sémhur / Wikimedia Commons


Vulcanian / Peléan / Sub-Plinian

VEI Classification Ejecta in Cubic Meters Plume Height in Meters Description
3 Vulcanian / Peléan / Sub-Plinian > 10,000,000 3,000 - 15,000 Moderate, Catastrophic

Ash Thickness Ash Thickness
10 Miles 300 Miles How Frequent Are Eruptions
Few Inches Dusting Few Months

Vulcanian / Pelean / Sub-Plinian
Peléan eruption: 1 Ash plume, 2 Volcanic ash fall, 3 Lava dome, 4 Volcanic bomb, 5 Pyroclastic flow, 6 Layers of lava and ash, 7 Stratum, 8 Magma conduit, 9 Magma chamber, 10 Dike
Image from © Sémhur / Wikimedia Commons


Peléan / Plinian / Sub-Plinian

VEI Classification Ejecta in Cubic Meters Plume Height in Meters Description
4 Peléan / Plinian / Sub-Plinian > 100,000,000 10,000 - 25,000 Moderate to Large, Cataclysmic

Ash Thickness Ash Thickness
10 Miles 300 Miles How Frequent Are Eruptions
1 Foot 1/4 Inch > 1 Year

Plinian
Plinian eruption: 1: ash plume, 2: magma conduit, 3: volcanic ash fall, 4: layers of lava and ash, 5: stratum, 6: magma chamber.
Image from © Sémhur / Wikimedia Commons


Peléan / Plinian

VEI Classification Ejecta in Cubic Meters Plume Height in Meters Description
5 Peléan / Plinian > 1,000,000,000 20,000 - 35,000 Large, Paroxysmic

Ash Thickness Ash Thickness
10 Miles 300 Miles How Frequent Are Eruptions
2 Feet 1/2 Inch > 10 Years


Plinian / Ultra-Plinian

VEI Classification Ejecta in Cubic Meters Plume Height in Meters Description
6 Plinian / Ultra-Plinian > 10,000,000,000 > 30,000 Very Large, Colossal

Ash Thickness Ash Thickness
10 Miles 300 Miles How Frequent Are Eruptions
10 Feet 1 Inch > 100 Years


Ultra-Plinian

VEI Classification Ejecta in Cubic Meters Plume Height in Meters Description
7 Ultra-Plinian > 100,000,000,000 > 40,000 Super-colossal

Ash Thickness Ash Thickness
10 Miles 300 Miles How Frequent Are Eruptions
Tens of Feet Several Inches > 1,000 Years


Supervolcanic

VEI Classification Ejecta in Cubic Meters Plume Height in Meters Description
8 Supervolcanic > 1,000,000,000,000 > 50,000 Mega-colossal

Ash Thickness Ash Thickness
10 Miles 300 Miles How Frequent Are Eruptions
Unknown Unknown 10,000 - 50,000 Years

 

Volcano

 


Supervolcanoes 101 | National Geographic

What are supervolcanoes, and how catastrophic can they be? Learn how supervolcanoes form, where supervolcanoes are located, and how their destructive capabilities can make way for new life.

Yellowstone: Big Volcano Ready to Erupt | How the Earth Was Made (S1, E8) | Full Episode | History

Yellowstone National Park is one of the most dangerous geological features on Earth. In trying to uncover the processes behind Yellowstone's main attractions geologists came to a frightening realization, in Season 1, Episode 8, "Yellowstone." #HowTheEarthWasMade

Past and Present Threats

Supervolcanos are scary, but they're also relatively rare events. The last one to explode was at Toba in Sumatra about 71,000 years ago. Scientists discovered a genetic bottleneck in human evolution. It's thought the effects of the supervolcano on global climate killed off all but about 5,000 people. The worldwide effects of blotting out the sun's rays potentially brought humanity close to extinction.

There are still active supervolcanos, but none of them show any signs of erupting in the foreseeable future. If one did, past eruption sizes can't be used to predict how large future eruptions would be. The odds of one turning into a world-ending monster are vanishingly small. In the last 36 million years, only 42 eruptions were big enough to be classified as a VEI 8 or high 7.

While supervolcanos are rare, regular volcanos can pose a genuine threat, depending on where you live. Here are the steps you can take to protect yourself.


Preparation - Survival

Click Here for information on what to do from the United States government website, Ready.gov.

Click Here for the Red Cross Volcano Preparedness Information.

Click Here to download a PDF file with information on what to do from the United States government website, Ready.gov.

PDF Information from Ready.gov

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This information is presented to make people aware of the larger world around them. If you can prepare for something as devastating as this, you're much more likely to be ready for smaller disruptions. Be aware and prepare.

4/15/2020