Supervolcanoes have repeatedly carved Earth’s landscape and bioscape over the eons. Almost two dozen of these monsters are scattered across the Earth today, recharging magma and gases, waiting to erupt again when they grow big enough. They’re sleeping giants that blow once every 100,000 years on average.
But that’s not a very precise forecast.
A study of the beautiful crystal patterns from past eruptions suggests these volcanoes will give us a warning.
Just before the magma breaches the overlying rock in an eruption, there will be an accelerating drop in pressure as dissolved gas begins escaping from the liquid magma… from the end of the chamber’s recharge period to the point of eruption, no more than a year of time passes.” iflscience.com
Imagine the US government announcing that Yellowstone will erupt within the next year. Geologists would probably offer a range of times – suppose they said that between six and eighteen months from now, hundreds of cubic miles of rock, dust, and volcanic ash will be ejected into the sky.
Imagine a circle about 500 miles (800 kilometers) across surrounding Yellowstone; studies suggest the region inside this circle might see more than 4 inches (10 centimeters) of ash… The ash would be pretty devastating for the United States, scientists predict. The fallout would include short-term destruction of Midwest agriculture, and rivers and streams would be clogged by gray muck. livescience.com
Suppose the government told everyone from the West Coast all the way east to Chicago they should get ready for ash-fall. But those aren’t the people in the greatest danger. Within that circle is a more deadly area ranging from Missoula, Montana to Denver, Colorado, including Boise, Billings, Casper, Rapid City, Cheyenne, and Salt Lake City.
Suppose the government said that, within this kill-zone, you all must leave. It’s possible you’ll never return. Your homes, businesses, and everything you leave behind will be worthless, destroyed under ash. Imagine ten or twenty million people about to join 100 million in that wider ash-fall range under many inches of ash.
Would anyone believe the predictions? Would anyone evacuate? Should people be forced to leave? Would the “safe” Atlantic Coast or northeast Canada be willing or able to absorb the refugees? What would happen as everyone sat – waiting – waiting for weeks or months – as geologists posted pressure readings? Should we spend money planning for such a cataclysmic event, and if we should, how much money should we spend?
Fortunately for America, the answer is – no, don’t worry about Yellowstone. It seems far from an eruption, and you can follow the Yellowstone supervolcano at volcanoes.usgs.gov. But the rest of the world may not be as lucky with their sleeping giants.
I’ve rhymed about supervolcanoes in one of my most popular poems – Because They’re Big. Own that