January 10, 2009
Quakes In Yellowstone Stir Fear Of Eruption
A series of seismic activity events in Yellowstone National Park has sparked public concerns that the quakes could lead to a catastrophic eruption from one of the world's largest volcanoes.
Seismic activity at Yellowstone Lake in Yellowstone National Park increased in late December 2008, according to the Yellowstone Volcano Observatory (YVO), which monitors volcanic and earthquake unrest in the Yellowstone National Park region.About 900 earthquakes occurred during the period of December 26 through January 8. Five hundred of the earthquakes were reviewed by seismologists, according to YVO.
However, the seismic activity has markedly decreased since January 8, 2009. Earthquake swarms within the Yellowstone caldera are typical, with magnitudes occasionally ranging above 4.0. The largest earthquake in the recent swarm was a magnitude 3.9.
"All earthquakes with magnitudes greater than 2.0 have now been reviewed by YVO seismologists," said YVO. "It is possible that the swarm has ended, although a return of activity may occur as previous Yellowstone swarms of this size have lasted for tens of days to many weeks."
But to outside observers, the quakes are a sign of danger to come.
"To those of us who have been following these events, we know that something is brewing, especially considering that Yellowstone is over 40,000 years overdue for a major eruption," warned a posting on the online disaster forum Armageddononline.org.
Another Web site, which has been shut down, carried the U.S. Geological Survey logo and made false claims of a "Yellowstone Warning" urging people to leave the National Park for 100 miles around the volcano caldera "because of the danger in poisonous gasses that can escape from the hundreds of recent earthquakes."
Yellowstone spokesman Al Nash said the site was misleading.
"A casual observer would be led to believe that was an official source," said Nash.
In the ancient history of the park, the volcano has erupted 1,000 times more powerfully than the 1980 blast at Mount St. Helens, hurling ash as far away as Louisiana.
"Statistically, it would be surprising to see an eruption the next hundred years," said Jake Lowenstern, the Menlo Park, Calif.-based scientist in charge of YVO.
Much more likely, he said, would be a hydrothermal explosion in which underground water encounters a hot spot and blasts through the surface.
The Observatory maintains that the volcano's alert level has not changed from "normal."
On the Net:
- Yellowstone Volcano Observatory
- Recent Earthquakes in the Intermountain West
- Yellowstone National Park