Oklahoma earthquake: Small to moderate quake rattles nerves

The quake was centered eight miles southeast of Norman, south of Lake Thunderbird, near E Post Oak Road and 84th Avenue SE, Oklahoma Geological Survey research seismologist Austin Holland said. He estimated the magnitude of the 9:06 a.m. quake at 5.1 and called it a "small to moderate earthquake," while the U.S. Geological Survey put it at 4.3.

Although there were only two reported minor injuries in Oklahoma, people were caught off guard by a jolting earthquake in the land of tornadoes.

Readers of The Oklahoman reported the quake felt or sounded like "a 747 landing in the neighbors' yard," "a semi hit our house" or "my house had been hit by a trash truck." People from seven states reported to the U.S. Geological Survey that they felt the quake, including from as far away as Brentwood, Tenn.

"That sucker it rattled my whole house, it literally shook the whole thing," said Charles Parnell, who lives in east Norman near Lake Thunderbird. "The chandelier jumped up and down a little bit, but there was no damage. It just surprised the heck out of me."

Paul Earle, a seismologist and director of operations for the U.S. Geological Survey's National Earthquake Center in Golden, Colo., said the discrepancy between the earthquake magnitude estimated by his agency (4.3) and that of the Oklahoma Geological Survey (5.1) results from different methods for monitoring earthquakes. Both types of measurement are valid, he said, even though they produce different results.