Yellowstone photos (wolves and bison), plus article: "Scientists eye unusual swarm of Yellowstone quakes"... Don't forget, almost the entire park is a volcanic caldera: "One of the largest supervolcanoes in the world lies beneath Yellowestone"
Categories: International, Science, National, Environment, Photography, news
YELLOWSTONE, YELLOWSTONE WATCH!
Yellowstone - A Restless Volcanic Giant
Yellowstone has erupted roughly once in every 600,000 years.
The last eruption was 640,000+ years ago.
HERE
Yellowstone Fallout Ash Bed
Bison graze on the front lawn of Gardiner Public School just outside the north entrance to Yellowstone National Park in Gardiner, Mont. on Feb. 15, 2008.
(AP Photo / William Kronholm)
Wildlife photographers watch a herd of bison along Soda Butte Creek in the northeastern corner of Yellowstone National Park on Feb. 15, 2008. Winter is prime time for viewing wildlife in Yellowstone.
(AP Photo / William Kronholm)Scientists eye unusual swarm of Yellowstone quakes
CHEYENNE, Wyo. – Yellowstone National Park was jostled by a host of small earthquakes for a third straight day Monday, and scientists watched closely to see whether the more than 250 tremors were a sign of something bigger to come. Swarms of small earthquakes happen frequently in Yellowstone, but it's very unusual for so many earthquakes to happen over several days, said Robert Smith, a professor of geophysics at the University of Utah.
"They're certainly not normal," Smith said. "We haven't had earthquakes in this energy or extent in many years."
Smith directs the Yellowstone Seismic Network, which operates seismic stations around the park. He said the quakes have ranged in strength from barely detectable to one of magnitude 3.8 that happened Saturday. A magnitude 4 quake is capable of producing moderate damage.
"This is an active volcanic and tectonic area, and these are the kinds of things we have to pay attention to," Smith said. "We might be seeing something precursory.
"Could it develop into a bigger fault or something related to hydrothermal activity? We don't know. That's what we're there to do, to monitor it for public safety."
The strongest of dozens of tremors Monday was a magnitude 3.3 quake shortly after noon. All the quakes were centered beneath the northwest end of Yellowstone Lake.
A park ranger based at the north end of the lake reported feeling nine quakes over a 24-hour period over the weekend, according to park spokeswoman Stacy Vallie. No damage was reported.
"There doesn't seem to be anything to be alarmed about," Vallie said.
Smith said it's difficult to say what might be causing the tremors. He pointed out that Yellowstone is the caldera of a volcano that last erupted 70,000 years ago.
He said Yellowstone remains very geologically active — and its famous geysers and hot springs are a reminder that a pool of magma still exists five to 10 miles underground.
"That's just the surface manifestation of the enormous amount of heat that's being released through the system," he said.
Yellowstone has had significant earthquakes as well as minor ones in recent decades. In 1959, a magnitude 7.5 quake near Hebgen Lake just west of the park triggered a landslide that killed 28 people.
Article: HERE
This Feb. 16, 2006 photo released by the National Park Service shows a Wolf near Blacktail Pond in Yellowstone National Park.
In this Feb. 16, 2005 file photo buffalo graze in a frozen forest inside Yellowstone National Park in Wyoming.
This Jan. 9, 2003 file photo provided by the U.S. Fish and Wildlife Service shows a 130-pound gray wolf as it watches biologists in Yellowstone National Park, Wyo., after being captured and fitted with a radio collar. Record numbers of endangered gray wolves have been shot in 2008 by government wildlife agents and ranchers in the Northern Rockies, as the predators' continued attacks on livestock met with an increasingly aggressive response.
Activity discovered at Yellowstone supervolcano
Caldera bulged and deflated significantly during study period
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Wyoming's Teton Range looms behind a Global Positioning System antenna in Jackson Hole.
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Jamie Farrell, University of Utah |
By Sara Goudarzi
Staff Writer
updated 11:19 a.m. PT, Thurs., March. 15, 2007
One of the largest supervolcanoes in the world lies beneath Yellowstone National Park and scientists say activity there is increasing.
Though the Yellowstone system, which spans parts of Wyoming, Montana and Idaho, is active and expected to eventually blow its top, scientists don’t think it will erupt any time soon. Supervolcanoes can sleep for centuries or millennia before producing incredibly massive eruptions that can drop ash across an entire continent.
Yet significant activity continues beneath the surface. And the activity has been increasing lately, scientists have discovered. In addition, the nearby Teton Range, in a total surprise, is getting shorter.
The findings, reported this month in the Journal of Geophysical Research — Solid Earth, suggest that a slow and gradual movement caused by a giant hotspot of molten rock beneath a volcano can shape a landscape more than sudden ground movements caused by the volcano’s frequent earthquakes.
For the past 17 years, researchers used GPS satellites to monitor the horizontal and vertical motion of the Yellowstone caldera — a huge volcanic crater formed by a super-eruption more than 600,000 years ago.
The movement of the caldera indicates what’s going on underground where magma, or molten rock, is stored for the next eruption. When magma builds up, some of it starts to rise toward the surface, where it presses against the floor of the caldera. The pressure makes the caldera bulge, while a decrease in pressure makes it sink.
The 45-by-30-mile caldera bulged and deflated significantly during the study period.
“We think it’s a combination of magma being intruded under the caldera and hot water released from the magma being pressurized because it’s trapped,” said lead study author Robert Smith from the University of Utah. “I don’t believe this is evidence for an impending volcanic eruption, but it would be prudent to keep monitoring the volcano.”
More energy
The researchers also found that 10 times more energy goes into producing the slow and gradual ground deformations at Yellowstone than goes into ground movements released suddenly by the area’s frequent quakes.
Data shows that the caldera floor sank 4.4 inches from 1987 until 1995. From 1995 until 2000, the northwest rim of the caldera rose about 3 inches, followed by another 1.4-inch rise until 2003. Then between 2000 and 2003, the caldera floor sank a little more than an inch.
And then from 2004 to 2006 the central caldera floor rose faster than ever, springing up nearly 7 inches during the three-year span.
“The rate is unprecedented, at least in terms of what scientists have been able to observe in Yellowstone,” Smith said.
Abnormal fault
These results could explain another surprise finding: The ground along Teton fault — an active fault running 40 miles north-south along the eastern base of Teton Range in the Grand Teton National Park in Wyoming just south of Yellowstone — moves in the opposite direction compared to what’s been previously thought.
Typically, when a big earthquake takes place on a normal fault such as Teton, the ground is pulled apart. This kind of extension or stretching causes valleys to drop downward and mountains to rise upwards. Thousands of earthquakes over millions of years built the mountains that comprise the Teton Range today.
But recent measurements showed a different trend. Researchers found that just the opposite is happening with Jackson Hole — the valley below the Teton. The valley is rising up slowly and the mountains are dropping down.
What the researchers think is happening, on a short-term basis at least, is that the bulging Yellowstone hotspot north of the Tetons is pushing against the north edge of Jackson Hole and jamming it against the mountains. (This is also causing the southwest part of the Yellowstone plateau, under the hotspot, to slide downhill at a rate of one-sixth of an inch each year.).
“The textbook model for a normal fault is not what’s happening at the Teton fault,” Smith said. “The mountains are going down relative to the valley going up. That’s a total surprise.”
This motion, according to researchers, is also expected to produce bigger quakes, confusing the picture of how earthquakes occur in that area.
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Article: HERE
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