Thursday, January 01, 2009

Quakes Swarm Yellowstone Supervolcano

Helena, Montana — Scientists are alarmed and concerned after the majestic Yellowstone National Park was shaken up by a flurry of small earthquakes for a third straight day Monday. They will continue to closely observe the park to find out whether the over 250 tremors was an indicator of something bigger on the horizon.

Groups of miniature earthquakes are a frequent occurrence in Yellowstone, but it’s extremely 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 heads the Yellowstone Seismic Network, which manages seismic stations around Yellowstone. He reported the quakes ranged in strength from hardly detectable to a sizable magnitude 3.8 which hit on Saturday. A magnitude 4 quake typically produces 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.”

All of the earthquakes were concentrated beneath the northwest end of Yellowstone Lake. Smith continued that it is hard to pinpoint what may be causing the quakes and noted that Yellowstone is the caldera of a volcano that last erupted 70,000 years ago. Unusual Yellowstone Quakes

Keywords: Hundreds of Earthquakes - Earthquake Swarm - Unusual Earthquakes