Jan 2, 2009 3:00 am US/Eastern
Imminent Yellowstone 'Supervolcano' Now 'Unlikely'
NEW YORK (CBS) ―
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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. (File)
CBS
The recent "swarm" of small earthquake tremors happening in Yellowstone National Park are not likely to be a sign of a pending "supervolcano" eruption as some fear, according to a top scientist at the Yellowstone Volcano Observatory.
Dr. Jacob Lowenstern of the U.S. Geological Survey said Monday that the earthquake activity in Yellowstone most likely will continue for weeks, "and then will end without any other related activity."
Lowenstern's comments were reported by money and politics blogger
James Pethokoukis of U.S. News & World Report,
who chatted with the scientist via e-mail.
Yellowstone National Park was jostled by a host of small earthquakes this week, and scientists watched closely to see whether the more than 250 tremors were a sign of something bigger to come.
"There have been 80 volcanic eruptions at Yellowstone since the last 'supervolcano' eruption 640,000 years ago and hundreds of large steam explosions," said Lowenstern. "The last time a volcanic eruption occurred at Yellowstone was 70,000 years ago."
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 interviewed by the Associated Press.
"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.
Some have predicted a doomsday scenario for North America should the energy beneath the national park release all at once, creating an eruption which would darken skies over the Midwest and alert global weather patterns for decades.
"There is this huge volcano underneath Yellowstone National Park," said Greg Breining, a writer from St. Paul, Minn.
Breining spent time studying the geology and enjoying the natural wonders of Yellowstone before writing "Super Volcano: The Ticking Time Bomb Beneath Yellowstone National Park."
"There is this huge reservoir of magma just three or four miles beneath the surface of the park, and it is that magma -- this is still an active volcano -- that creates the geysers, the mudpots, the hot springs, all the other features for which Yellowstone is famous," 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.
(© 2009 CBS Broadcasting Inc. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. The Associated Press contributed to this report.)
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