Yellowstone is well known for its “Old Faithful” geyser and its stunning wildlife.
But the national park also sits atop a supervolcano, simmering just under the surface. You can see some of the evidence of its active state in the hydrothermal activity that bubbles up, including the Old Faithful geyser that shoots up water every few hours.
Supervolcanos are characterized as volcanic centers that have had eruptions that covered more than 240 cubic miles. The US has two: Yellowstone, and another at Long Valley in California.
So what would happen if it were to erupt again?
If it did erupt, it could have some pretty extreme effects on the surrounding areas.
For starters, the eruption could emit ash that would expand over a 500-mile area. For comparison, this map shows the area that the Mount St. Helens 1980 eruption ash reached.
Molten lava over 1,000 degrees oozing out from an eruption might be less of a concern than the ash. The eruption would likely cover the ground with as much as 4 inches of gray ash, which could be detrimental to the crops growing in the Midwest.
Along with the ash, the supervolcano would spew out a whole bunch of gasses, including sulfur dioxide, a gas that can lead to acid rain, as well as global cooling as it reflects the sun away from the Earth.
The explosion likely won’t wipe out human life, but it certainly would be destructive, especially to the western half of the US.
