Earthquake shakes U.S. Midwest from Oklahoma to Missouri

An earthquake rattled a swath of the Great Plains, from Kansas City, Missouri, to central Oklahoma on Saturday, damaging buildings and injuring at least one person.

The 5.6 magnitude quake was centred 14 kilometres northwest of Pawnee, Oklahoma — a town of about 2,200 about 110 kilometres northeast of Oklahoma City — the U.S. Geological Survey said.

People in Kansas City, Missouri, Fayetteville, Arkansas, and Norman, Oklahoma, all reported feeling the earthquake at 7:02 a.m. local time.

The USGS reported a 3.6 magnitude aftershock at 7:58 a.m.

Oklahoma Gov. Mary Fallin later declared a state of emergency in Pawnee County, which allows state agencies to make emergency purchases for disaster relief and is also the first step toward asking for federal assistance, if necessary. The state of emergency lasts for 30 days and additional counties may be added.

So far, however, only one minor injury has been reported because of the initial quake. Pawnee County Sheriff Mike Waters told the CBS affiliate in Tulsa that falling bricks from a crumbling chimney landed on a man's head as he was protecting his child.

A Pawnee business owner said the quake shook his house "like a rubber band" and knocked items off cabinets and broke glass.

Furniture store owner Lee Wills said he was awake when the quake struck and first thought it was a thunderstorm. But then his home, which is about four kilometres outside town, started shaking.

Wills said buildings in the downtown area are cracked and sandstone facing on some buildings fell and described the scene as "a mess."

Some of the city buildings that were left with cracks date back more than 100 years.

The quake was felt as far away as Minnesota and Nebraska, but did not cause significant damage, partly because of the type of rock beneath the region.

Geophysicist Jefferson Chang with the Oklahoma Geological Survey said a hard, or competent, bedrock crosses north-central Oklahoma while the subsurface around Prague is softer. Chang said the harder rock absorbs more of an earthquake's energy, reducing potential damage.

Emergency officials say the Saturday morning quake northwest of Pawnee led to sandstone facings of some buildings falling, but that no buildings collapsed.

The quake is the same magnitude and approximately the same depth as a 2011 earthquake near Prague, about 95 kilometres to the south. In that quake, two towers collapsed at a university in nearby Shawnee. It was the strongest recorded in Oklahoma history.
 
Fallin said crews were checking bridges and structures for damage. She also said in a statement that information is still being gathered and will be reviewed by her co-ordinating council on seismic activity.