No, The Yellowstone Supervolcano Is Actually Not Overdue For An Eruption
Updated: May 21, 2019
By Eric Mack:
It's a favorite worry of the apocalyptically-minded: The huge supervolcano centered below Yellowstone National Park hasn't erupted in hundreds of thousands of years, so obviously it could blow at any minute, right?
"In a word, no. In two words, no way. In three words, not even close. Yellowstone doesn't work that way," writes Michael Poland, Scientist-in-Charge of the Yellowstone Volcano Observatory, in a new blog post for the U.S. Geological Survey.
Poland goes on to challenge the basic numbers that lots of the recent tabloid stories warning of an "overdue" eruption are based on.
"In terms of large explosions, Yellowstone has experienced three -- at 2.08, 1.3, and 0.631 million years ago. This comes out to an average of about 725,000 years between eruptions. That being the case, we still have about 100,000 years to go, but this number is based on very little data and so is basically meaningless (would you base any conclusion on the average of just two numbers?)."
But even if Yellowstone is still on schedule for its next eruption to take place in the distant future by the numbers, it's a moot point because volcanoes don't keep schedules.
The idea of being overdue for a natural disaster might come from the way we think about earthquakes, which are caused by consistently building pressure on a fault that eventually snaps.
But, as Poland points out, most volcanoes don't work the same way. They don't necessarily accumulate magma at a constant rate until an inevitable eruption occurs. Even the small eruptions of lava flows at Yellowstone have been fairly irregular over the eons - the most recent one erupted 70,000 years ago and going further back similar eruptions have been separated by hundreds of thousands of years or have come in relatively quick succession.
HOW DO WE KNOW...
"This is because the Yellowstone magma reservoir system receives new magma only in discontinuous batches, causing several eruptions in a short period of time with long periods of quiet in between these episodes," Poland explains.
While the Yellowstone caldera is the subject of lots of scare-mongering, conspiracy theories and rather obvious falsehoods, there is reason for some of the confusion and concern. For example, one widely publicized 2017 study finds that we may only have a few decades warning prior to a major eruption.
There's also been lots of geyser activity at Yellowstone over the last year that breaks with the pattern of recent decades, especially a new period of heightened activity for Steamboat Geyser, which is the world's tallest.
But the fact remains that none of these actual facts point to an imminent threat of eruption for the Yellowstone Supervolcano or support the notion that one is "overdue."
"Not even close," concludes Poland.
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