Oklahoma Earthquake Unusual But Not Really Rare
An Oklahoma earthquake racked up a 5.1 magnitude and a whole lot of surprise on Wednesday, but the state is no stranger to tremors.
About 2,000 earthquakes have rattled the state since 1950, including about 200 this year alone, according to data from the Oklahoma Geological Survey.
Wednesday's quake, however, was the second-strongest ever recorded in Oklahoma. Only the April 9, 1952, magnitude 5.5 earthquake registered higher on the Richter scale.
"There's just not that many that have been reported in that range," said Bryan Tapp, chairman of the University of Tulsa's Geosciences Department in the College of Engineering and Natural Sciences.
Between 1950 and 2008 -- the last year complete data were available -- only nine Oklahoma quakes reached a 4.0 or higher, data show. None had an epicenter in Tulsa County.
Like the 1952 earthquake, which was felt in six Midwestern states, Wednesday's quake shook parts of Texas and Kansas, as well. There have even been reports that folks in Kansas City and south of Dallas felt the tremors, Tapp said.
He said it's not uncommon for Oklahoma earthquakes to travel great distances, thanks in part to the old rock that rests under the state.
"You get older and older rocks that have had time to become really quite hard, so the harder the rock, the greater the ability to transmit seismic energy," Tapp said.