Yellowstone Slumbering Giant

Not by Fire but by Ice


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Discover What Killed the Dinosaurs . . . and Why it Could Soon Kill Us  Updated 28 October 2006      

Yellowstone - Slumbering Giant   

Could change the world as we know it


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"When the supervolcano that lies beneath Yellowstone National Park explodes once again - as it inevitably must - it will spew out enough ash and magma to change the world as we know it."

But it is the huge lake of molten magma lying dormant five miles beneath Yellowstone that causes the greatest concern to me. Vulcanologists estimate that the volcanic chamber itself  holds 25,000 cubic kilometers of molten rock or magma.

25,000 cubic kilometers! That's 5,988 cubic miles! Can you imagine what  would happen if even a few of those cubic miles of red-hot basalt should flow into the ocean? Fish stew!

And then consider the ash. 

"An area the size of North America can be devastated," said Professor Stephen Self, a vulcanologist at the Open University. "It would dump of billions of tons of volcanic ash over huge swaths of North America … (resulting) in the devastation of world agriculture, severe disruption of food supplies and mass starvation. These effects could … threaten the fabric of civilisation." Super-eruptions are hundreds of times larger than the biggest volcanic explosions of recorded history and their effects on the global climate are much more severe.

“Few people would survive in the zone immediately around the eruption ... Those sheltering in their homes would not be safe because layers of heavy volcanic ash would eventually cause their roofs to collapse.”

The first supervolcanic eruption of Yellowstone happened 2.1 million years ago. The last supervolcanic eruption happened at Toba in Sumatra 74,000 years ago.

“Some scientists believe that the Toba eruption, which caused global climatic disturbances, may have even caused a genetic "bottleneck" in human genetic diversity following a dramatic decline in the global population. If Yellowstone were to erupt in a similar fashion the ash would cover three-quarters of North America in a layer deep enough to kill crops and other plants.”

The Toba eruption pumped some 300 times more ash into the sky than the eruption of Tambora in Indonesia in 1815 - which caused a "year without a summer" in 1816 and prompted Lord Byron to write his poem "Darkness". It dumped a layer of ash some 15 cm thick over the entire Indian subcontinent and much of southeast Asia. Southern China was also covered with several centimeters of ash.

"Many millions of lives throughout most of Asia would be threatened if Toba erupted today.  It would block out sunlight over much of the planet causing global temperatures to plummet by between 10C and 20C. The monsoon would stop, crops would fail and as many as one billion people would die through climate change and starvation. “Our world … might not even survive in its present form.”     

The Yellowstone caldera is 85km (53 miles) long and 45km (28 miles) wide - an area big enough to swallow Tokyo , the largest city in the world. 

Yellowstone is known to have erupted three times in the past 2.1 million years at a regularity of about 600,000 years. The last eruption occurred 640,000 years ago.

Condensed from an article by Steve Connor  Science Editor  The Independent – UK 3-9-5 

See also Supervolcanoes



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