Steamboat Geyser at Yellowstone Keeps Erupting, But What Would Happen If the Supervolcano Erupted?

Steamboat Geyser at Yellowstone National Park keeps erupting. In fact, it just erupted for the ninth time in the space of a few months. It’s the world’s tallest geyser, and it’s far more powerful than Old Faithful. And another disconcerting fact? Steamboat Geyser — and the entire geyser field at Yellowstone — sits on top of an active volcano. And wherever there’s an active volcano, people wonder: What if it erupts?

Thankfully, the odds of that are pretty low. (Don’t start panicking!) But what would happen if the supervolcano underneath Steamboat Geyser were to erupt? We have the answers to all your questions ahead.

Steamboat Geyser at Norris geyser basin in Yellowstone National Park, USA

Steamboat Geyser at Yellowstone National Park | Byelikova_Oksana / iStock / Getty Images Plus

Why does Steamboat Geyser keep erupting?

  • The answer: Scientists haven’t come to a consensus.

Mental Floss reports that Steamboat Geyser keeps erupting, but scientists aren’t quite sure why. Geysers occur when magma heats up the water and gases trapped under the ground. If enough pressure builds, the steam and boiling water escape through cracks in the earth and shoot up past the surface. The reservoir beneath Old Faithful is simple, which explains that geyser’s regular eruptions. But the structure beneath Steamboat Geyser is probably more complicated. As Mental Floss notes, that means that its eruptions result from a combination of hard-to-predict factors.

Do scientists have any guesses?

  • The answer: Geologists have come up with a few possible explanations.

Mental Floss reports that though they don’t know for sure, geologists have put forward a few possible explanations for the recent spate of eruptions. Some think thermal activity in the Norris Geyser Basin causes these eruptions. Others hypothesize that Steamboat Geyser is having smaller eruptions closer together instead of one larger eruption. Experts haven’t come to a consensus as to the cause.

Does it mean that the volcano will erupt?

  • The answer: Experts don’t think so.

The sudden and literal burst of activity at Steamboat Geyser has experts stumped. But they don’t think that it’s any indication that we should expect a catastrophic volcanic event at Yellowstone anytime soon. The last volcanic eruption on the park’s land took place about 70,000 years ago. And scientists haven’t observed any signs that another eruption could happen anytime soon. However, there is a five-mile-deep reservoir of hot magma beneath Yellowstone, fed by a plume of molten rock welling up from hundreds of miles below that, according to Vox. On rare occasions throughout history, that magma has erupted. And it’s possible — though unlikely — that it could erupt again in the future.

OK, but what would happen if it did erupt?

  • The answer: You would probably see the ash cloud in Chicago and Los Angeles.

If the volcano did erupt, the lava flows would stay within a relatively small radius in the park. Ash would cause the bulk of the damage. You would probably be able to see the ash cloud from as far away as Chicago and Los Angeles. Vox reports that the supervolcano would spew ash for thousands of miles across the United States, damaging buildings, smothering crops and shutting down power plants. As Vox notes, an eruption would constitute “a huge disaster.” (That’s probably one of the reasons why scientists keep clarifying that they don’t expect an event anytime soon.)

How much ash would we see?

  • The answer: Some states could get blanketed with as much as three feet of ash.

Vox reports that a Yellowstone super-eruption could have a devastating effect on nearby states, according to researchers. (A super-eruption ejects at least 1,000 cubic kilometers or 240 cubic miles of material.) It could bury states including Wyoming, Montana, Idaho, and Colorado in three feet of harmful volcanic ash. Ash would also blanket the Midwest. Volcanic ash consists of splintered rock and glass. And those amounts of ash could kill people, animals, and plants; clog roadways and crush roofs; block sewer lines and even short out electrical equipment. It would also shut down air travel across much of North America.

How many times has the volcano erupted?

  • The answer: It has only had three super-eruptions.

Vox reports that the Yellowstone supervolcano — which is thousands of times more powerful than a regular volcano — has only had three “truly enormous” super-eruptions in its history. One of those super-eruptions occurred 2.1 million years ago. Another happened 1.3 million years ago. And the most recent one occurred 664,000 years ago. As Vox explains, it’s possible that Yellowstone may never see another eruption that big again. Even if Yellowstone did erupt, it would be much more likely that a small eruption would occur.

Would there be any warning signs?

  • The answer: Most likely.

The odds of any Yellowstone eruption, big or small, remain low. But either way, scientists would likely see some warning signs ahead of time. Vox reports that a swarm of earthquakes in a specific region of the park could warn scientists about a smaller eruption, as magma makes it way to the surface. They would see more dramatic warning signs ahead of a bigger eruption. They could track intense seismic activity across Yellowstone, and it would take weeks or months for those earthquakes to break up the rocks above the magma for an eruption.

Tell me again what the odds of an eruption are?

  • The answer: Very low. Only 0.00014% in a given year.

Vox reports that the odds of Yellowstone erupting in any given year — if you look at the last three eruptions — are 0.00014%. That’s lower than the odds of getting hit by a civilization-destroying asteroid, the publication reports. However, it’s entirely possible that Yellowstone will never erupt again. Volcanoes do die out. And the magma chamber beneath the park could eventually solidify. Plus, the hotspot is slowly moving out from under Yellowstone, and another supervolcano could take a million years or longer to heat up and melt the crust.

Read more: 7 Fascinating Yellowstone National Park Facts Donald Trump Should Appreciate More

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