Minor earthquake hits Yellowstone National ParkSep 9, 2012 The Associated Press
JACKSON -- A minor earthquake has rattled Yellowstone National Park.
An expert says the strength of the magnitude 3.7 earthquake that shook Yellowstone on Wednesday afternoon puts it in the "once-a-year" category for the area.
Robert Smith, a professor of geophysics at the University of Utah, says Yellowstone experiences about 3,000 earthquakes a year. Since 1962, there have been 49 earthquakes of magnitude 3 or greater within 16 miles of the epicenter of Wednesday's quake.