Yellowstone 'super-eruption' less super, more frequent than thought

Apr 30, 2012

The Yellowstone "super-volcano" is a little less super—but more active—than previously thought.

Researchers at Washington State University and the Scottish Universities Environmental Research Centre say the biggest Yellowstone eruption, which created the 2 million year old Huckleberry Ridge deposit, was actually two different eruptions at least 6,000 years apart.

Their results paint a new picture of a more active volcano than previously thought and can help recalibrate the likelihood of another big eruption in the future. Before the researchers split the one eruption into two, it was the fourth largest known to science.

"The Yellowstone volcano's previous behavior is the best guide of what it will do in the future," says Ben Ellis, co-author and post-doctoral researcher at Washington State University's School of the Environment. "This research suggests explosive volcanism from Yellowstone is more frequent than previously thought."

The new ages for each Huckleberry Ridge eruption reduce the volume of the first event to 2,200 cubic kilometers, roughly 12 percent less than previously thought. A second eruption of 290 cubic kilometers took place more than 6,000 years later.

That first eruption still deserves to be called "super," as it is one of the largest known to have occurred on Earth and darkened the skies with ash from southern California to the Mississippi River. By comparison, the 1980 eruption of Mount St. Helens produced 1 cubic kilometer of ash. The larger blast of Oregon's Mount Mazama 6,850 years ago produced 116 cubic kilometers of ash.

The study, funded by the National Science Foundation and published in the June issue of the Quaternary Geochronology, used high-precision argon isotope dating to make the new calculations. The radioactive decay rate from potassium 40 to argon 40 serves as a "rock clock" for dating samples and has a precision of .2 percent. Darren Mark, co-author and a post-doctoral research fellow at the SUERC, recently helped fine tune the technique and improve it by 1.2 percent—a small-sounding difference that can become huge across geologic time.

"Improved precision for greater temporal resolution is not just about adding another decimal place to a number, says Mark. "It's far more exciting. It's like getting a sharper lens on a camera. It allows us to see the world more clearly."

The project asks the question: Might super-eruptions actually be products of multiple, closely spaced eruptions through time? With improved temporal resolution, in times to come, maybe super-eruptions will be not quite so super.

Explore further: Tropical Storm Marie forms in Pacific off Mexico

More information: doi:10.1016/j.quageo.2012.01.006

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Origin
1 / 5 (5) Apr 30, 2012
Yellowstone caldera is rising with increased rate. The rising of central area of caldera is followed with lateral motion, which would indicate the bulge of magma is raising towards the surface (magmatic intrusion). Because the upper boundary of magmatic bulge becomes thinner, it exhibits less intensive but more frequent seismic and volcanic activity. IMO this behaviour fits my theory of geothermal origin of global warming and shift of magnetic poles, induced with accelerated decay of radioactive elements inside of oceans and Earth core inside of dark matter cloud, passing through solar system at the galactic plane.
wttmartin9
not rated yet Apr 30, 2012
In actual fact the caldera has been sinking since some time in 2010. In the past and with most cladera the huge erruptions are associated with a huge collapes of the volcanic mountain in to the magma chamber below. With no mountain there to collapse in the likely hood of a huge mega volcano is all just media hype. No one is really looking at the facts.
Terriva
1 / 5 (1) Apr 30, 2012
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. Between 2007 and 2010, the rate slowed to no more than a centimeter a year. But since it started swelling there are ground levels over the volcano that have risen up to 10 inches in places. http://www.myfoxm...11620637
Caliban
not rated yet Apr 30, 2012
In actual fact the caldera has been sinking since some time in 2010.


These sorts of "pulsations" aren't unusual, although I wasn't aware of any check in the uplifting.

In the past and with most cladera the huge erruptions are associated with a huge collapes of the volcanic mountain in to the magma chamber below.


That's the "volcanic mountain" collapsing into the hole left by the erupted magma/ash/gas.

With no mountain there to collapse in the likely hood of a huge mega volcano is all just media hype.


The collapsing overburden isn't what defines a supervolcano -it's the sudden, catastrophic venting of HUNDREDS of CUBIC Km/Mi of magma/ash/gas.

No one is really looking at the facts.


You've got the mechanics of the thing all confused. Have another look.

Terriva
1 / 5 (1) May 01, 2012
Might super-eruptions actually be products of multiple, closely spaced eruptions through time?
I presume, it's already known at the case of Yellowstone caldera. Check the Flash graphics here