The Yellowstone Super Volcano last erupted 640,000 years ago. What are the odds it will erupt in our lifetime? Virtually zero. But it will erupt someday.
The volcanic eruptions, as well as the continuing geothermal activity, are a result of a great cove of magma located below the caldera’s surface. The magma in this cove contains gases that are kept dissolved only by the immense pressure that the magma is under. If the pressure is released to a sufficient degree by some geological shift, then some of the gases bubble out and cause the magma to expand. This can cause a runaway reaction. If the expansion results in further relief of pressure, for example, by blowing crust material off the top of the chamber, the result is a very large gas explosion. According to the analysis of earthquake data in 2013, the magma chamber is 80 km (50 mi) long and 20 km (12 mi) wide, and is shaped like 4,000 km3 (960 cu mi) underground mass, of which 6–8% is filled with molten rock. This is about 2.5 times bigger than scientists had previously imagined it to be.
The last full-scale eruption of the Yellowstone Supervolcano, the Lava Creek eruption which happened nearly 640,000 years ago, ejected approximately 240 cubic miles (1,000 km3) of rock, dust and volcanic ash into the sky.Geologists are closely monitoring the rise and fall of the Yellowstone Plateau, which measures on average 0.6 inches (1.5 cm) yearly, as an indication of changes in magma chamber pressure. The upward movement of the Yellowstone caldera floor between 2004 and 2008 — almost 3 inches (7.6 cm) each year — was more than three times greater than ever observed since such measurements began in 1923. From mid-summer 2004 through mid-summer 2008, the land surface within the caldera moved upward as much as 8 inches (20 cm) at the White Lake GPS station.
Supervolcanoes represent the second most globally cataclysmic event – next to an asteroid strike – and they have been responsible in the past for mass extinctions, long-term changes to the climate and shorter-term “volcanic winters” caused by volcanic ash cutting out the sunlight. The last known supervolcanic eruption was believed to have occurred about 70,000 years ago at the site today of Lake Toba in Sumatra, Indonesia. It caused a volcanic winter that blocked out the sun for between six to eight years, and resulted in a period of global cooling lasting a thousand years.
So the good news is that a Yellowstone super volcano eruption would solve our global warming problem. The bad news is we would no longer have comments from Wyoming Mike. If the pressure keeps building I suggest exiting stage left.
Scientists dismiss claims that Yellowstone volcano about to erupt
By Laura Zuckerman
(Reuters) – Yellowstone National Park assured guests and the public on Thursday that a super-volcano under the park was not expected to erupt anytime soon, despite an alarmist video that claimed bison had been seen fleeing to avoid such a calamity.
Yellowstone officials, who fielded dozens of calls and emails since the video went viral this week following an earthquake in the park, said the video actually shows bison galloping down a paved road that leads deeper into the park. (To see the video, click here)
“It was a spring-like day and they were frisky. Contrary to online reports, it’s a natural occurrence and not the end of the world,” park spokeswoman Amy Bartlett said.
Assurances by Yellowstone officials and government geologists that the ancient super-volcano beneath the park is not due to explode for eons have apparently done little to quell fears among the thousands who have viewed recent video postings of the thundering herd.
Commentary with one of the clips by a self-described survivalist wearing camouflage, dark sunglasses and a black watch cap suggests the wildlife exodus may be tied to “an imminent eruption here at Yellowstone.”
The 4.8 magnitude earthquake that struck early Sunday near the Norris Geyser Basin in the northwest section of Yellowstone, which spans 3,472 square miles of Wyoming, Montana and Idaho, caused no injuries or damages and did not make any noticeable alterations to the landscape, geologists said.
Though benign by seismic standards, it was the largest to rattle Yellowstone since a 4.8 quake in February 1980 and it occurred near an area of ground uplift tied to the upward movement of molten rock in the super-volcano, whose mouth, or caldera, is 50 miles long and 30 miles wide.
But neither the quake, the largest among hundreds that have struck near the geyser basin in the last seven months, nor the uplift suggest an eruption sooner than tens of thousands of years, said Peter Cervelli, associate director for science and technology at the U.S. Geological Survey’s Volcano Science Center in California.
“The chance of that happening in our lifetimes is exceedingly insignificant,” said Cervelli, a scientist with the Yellowstone Volcano Observatory.
Cervelli said the area of uplift that scientists have been tracking since August is rising at a rate of between 10 centimeters (4 inches) and 15 centimeters a year. Geologists who tracked uplift in the same area from 1996 to 2003 also saw elevated seismic activity, he said.
(Editing by Dan Whitcomb and Steve Orlofsky)
