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Sunday, 31 January 2010

Quake Swarm - 1,200 tiny quakes hit Yellowstone Park - strongest between magnitudes 3.0 and 3.8 -

Reading - Quake Swarm - 1,200 tiny quakes hit Yellowstone Park - strongest between magnitudes 3.0 and 3.8 -



CHEYENNE, Wyo. - Yellowstone National Park is shaking again, but jitters seem few so far.

Over eight days, more than 1,270 mostly tiny earthquakes have struck between Old Faithful and West Yellowstone. The strongest dozen or so have ranged between magnitudes 3.0 and 3.8.

That's strong enough to feel - barely. The vast majority have been too weak to be felt even nearby.

Likewise, online chatter about an imminent volcanic eruption in Yellowstone hasn't really picked up compared with the attention that a similar quake swarm drew just over a year ago.

"Perhaps we have done a better job in the past year or so helping the public understand that earthquake swarms are not unusual in Yellowstone," park spokesman Al Nash said Monday.

The largest quakes in the current swarm have included two of magnitude 3.1 and one of magnitude 3.0 late Sunday and early Monday, according to the University of Utah, which helps monitor seismic activity in Yellowstone.

Those who've felt some of the recent quakes include Tim Townsend, a law enforcement ranger at Old Faithful. Most haven't been alarming, he said, although one last week "had me running to cover, for sure."

One of the world's largest volcanoes slumbers at the core of Yellowstone.

The volcano last had a caldera-forming eruption 640,000 years ago and last spewed lava 70,000 years ago. Geologists say Yellowstone could erupt again, although the probability of an eruption within anyone's lifetime is extremely low.

That hasn't discouraged speculation. One Web site during last year's swarm carried a "Yellowstone Warning" urging everyone to flee the Yellowstone area, saying there was a risk of poisonous volcanic gases venting from the earth.

Others have tied the Yellowstone volcano to the end of the world in 2012, as some people fancifully interpret the ancient Mayan calendar to predict.

Relatively mundane fault slippage is believed to be causing the latest quakes, said Jamie Farrell, a researcher at the University of Utah in Salt Lake City.

Not that the swarm isn't interesting to geologists - quite the opposite.

"It gives us an opportunity to maybe get a better idea of what the processes are that are causing the earthquakes we're seeing," Farrell said. "Hopefully, each time we get one of these, we can get maybe a little better idea of what's going on down there."

Read more - http://www.missoulian.com/news/state-and-regional/article_9db5e032-0a22-11df-95bc-001cc4c002e0.html