INSUBCONTINENT EXCLUSIVE:
National Park sits squarely over a giant, active volcano
This requires attention.Yellowstone has been a national park since 1872, but it was only in the 1960s that scientists realized the scale of
the volcano - it's 44 miles across - and not until the 1980s did they grasp that this thing is fully alive and still threatens to erupt
Yellowstone is capable of eruptions thousands of times more violent than the Mount St
The northern Rockies would be buried in multiple feet of ash
Ash would rain on almost everyone in the United States
Thus geologists are eager to understand what, exactly, is happening below all those volcano-fueled hot springs and geysers.Obviously they'd
like to know if and when Yellowstone will blow again, and with what level of explosiveness
A major eruption would be a low-probability, high-consequence event, a proverbial Black Swan, something that could have societal and
The problem for scientists is that these big "supervolcano" eruptions rarely happen, and the most important action is out of sight, many
miles below the surface, involving chaotic forces, complex chemistry and enigmatic geological features
One new study has offered insight on Yellowstone's hidden architecture
It modeled the way magma rises from deep in the Earth's interior and creates two large chambers of partially melted rock beneath the surface
of the national park.These two magma chambers are stacked, and separated by a layer (called a "sill," like a window sill) of non-melted rock
The magma rising from the Earth's mantle flows easily and doesn't hold much gas
It cools and solidifies as it collides with relatively cold crust, forming the sill, the top of which is about 6 miles below the surface.On
top of the sill is the upper magma chamber, with thick, sticky magma that holds a great deal of gas - which makes the magma in the upper
It's like an unopened can of soda pop that's been shaken
Geophysical Research Letters, explains how this two-tiered, geochemically diverse architecture might have come about over the course of
time."Someday we might have a model snapshot saying this is what the system looks like when there's enough melt for there to be a large
eruption," lead author Dylan Colon, an Earth Sciences doctoral candidate at the University of Oregon, told The Washington Post.The study won
praise from Michael Poland, scientist-in-charge at the U.S
Geological Survey's Yellowstone Volcano Observatory: "What's neat about their model is they can go back in time with it and see how it might
have influenced eruption rates many millions of years ago."The new study bolsters earlier research on the dual magma chambers
It used sensors arrayed around Yellowstone to record the speed at which seismic waves from small earthquakes pass through the subsurface
Such waves move more slowly through hot and/or partially melted rock formations
That data gave scientists the equivalent of an MRI showing the two magma chambers."Supervolcano," we should note, is not a technical term
The experts refer to Yellowstone as a "caldera" or a "caldera-forming volcano." Some volcanoes form conical mountains
A caldera is a volcano that creates a vast crater
These are mountain-swallowing events
Visitors to Yellowstone are given a map showing the outline of the most recent caldera, and if they go to the right vantage point it's
possible to see that the heart of the park is remarkably free of mountains
would be disruptiveThe Yellowstone region has seen three big eruptions, the first one 2.1 million years ago, the most recent 630,000 years
Contrary to Internet rumor-mongering, as well as conspiracy theories about government coverups, there's no sign that a fourth cataclysmic
event is about to happen.It's possible, in fact, that Yellowstone is getting a bit old and tired
It may be ready for a long nap rather than a major eruption.Ilya Bindeman, a University of Oregon geochemist and co-author of the new paper,
said that Yellowstone may be "approaching the end of its evolution" because so much of the material in the upper magma chamber is recycled
and remelted after previous eruptions.As Poland said: "How many times do you want to reheat your leftovers At some point you're going to say
I'm not going to reheat his
You've microwaved it six times and it's no longer food."Intellectual humility is called for here: No one can say with great confidence how
much magma it takes to trigger a caldera-forming eruption
Moreover, relatively small eruptions creating lava flows can happen within the Yellowstone system
The most recent was 70,000 years ago
The experts say one of these smaller eruptions is much more likely than a giant explosion
Speculation that Yellowstone is "due" to erupt catastrophically implies that the volcano behaves predictably, like a machine
Geologists know otherwise.Yellowstone, it should be noted, isn't the only caldera in the United States
One of the others that's worth keeping an eye on - and the U.S
Geological Survey does just that - is the Long Valley caldera in California, near the popular ski resort of Mammoth Mountain, just east of
It erupted 700,000 years ago
A major eruption is extremely unlikely, but it could produce smaller eruptions that would be highly disruptive and dangerous, said Margaret
Mangan, scientist-in-charge at the USGS California Volcano Observatory.Mangan said there are seven volcanic regions in California with zones
of molten rock beneath the surface
A volcanic eruption in California is roughly as likely as a magnitude 6 or greater earthquake on the San Andreas Fault, she said.But
Californians don't worry about volcanoes
They worry about earthquakes, tsunamis and wildfires, she said
She has tried to raise public awareness of volcano hazards but says that it is hard to get much attention."The awareness level and
preparedness level is quite low in this state," she said
"We prepare for those large earthquake events, and we need to prepare for volcanic eruptions.(Except for the headline, this story has not
been edited by staff and is published from a syndicated feed.)
