A magnitude 4.3 earthquake struck central Oklahoma on Wednesday morning, the U.S. Geological Survey reported, but officials said no significant damage or injuries had been reported.
"At first I thought it could be an explosion," said Capt. Tom Easley, of the Norman, Oklahoma, police. "You think of the worst possible scenario."
Posters on the website of CNN affiliate KOCO in Oklahoma City reported feeling the temblor in numerous locations.
"Our office building shook for nearly 30 seconds," one poster wrote. "I heard it and felt it. I watched the drink on my desk shake and the liquid slosh around in my cup."
Another said the wall of his home had minor damage.
The USGS initially classified the quake as a magnitude 4.5 but later downgraded it to 4.3. It struck at 9:06 a.m. (10:06 a.m. ET) and was centered five miles east of Norman and 20 miles south-southeast of Oklahoma City, USGS said. The quake was relatively shallow, at 3.1 miles deep.