“It’s shocking how little time is required to take a volcanic system from being quiet and sitting there to the edge of an eruption,” said Hannah Shamloo, a graduate student at Arizona State University.
When Shamloo and her colleagues studied Yellowstone’s Lava Creek Tuff — a fossilized ash deposit laid down during its last supereruption some 631,000 years ago — they found that new magma had moved into the system faster than anyone had thought possible.
“We expected that there might be processes happening over thousands of years preceding the eruption,” said geologist Christy Till, Ms. Shamloo’s dissertation adviser. Instead, the supereruption may have transpired only decades after an injection of fresh magma beneath the volcano.
During that eruption of 631,000 years ago, the Yellowstone supervolcano expelled more than 1,000 cubic km (239 cubic miles) of rock and ash.
Think about that! — 239 cubic miles of rock and ash!
Can you imagine even one cubic mile of ash and rock? I mean, that’s one mile wide, and one mile long, and one mile high, taller than many mountains. Now picture 239 cubic miles.
Manhattan covers just under 23 square miles. Meaning that that much ash would have buried more than 11 Manhattans — one mile deep.
That much ash would have blanketed most of the United States and plunged the Earth into a volcanic winter — an ice age, in other words. And not your everyday, simple run-of-the-mill ice age.
The ash would have been deeper the closer it fell to the volcano. I remember reading (I don’t remember where) that the ash from that eruption measured more than 7 feet deep in eastern Nebraska, some 800 miles away.
Imagine how much of that ash – with its fine, glassy shards – must have washed into streams, rivers and lakes, and eventually into the oceans, killing almost all of the fish.
By the way, as I mention in Not by Fire but by Ice, that eruption of 631,000 years ago occurred at a magnetic reversal—the Delta magnetic reversal.
Thanks to Gordon Broussard, Benjamin Napier and scsi_joe for this link