The quake came at 6:25 a.m., centered two miles southeast of Valley Park, according to Jessica Sigala, a geophysicist with the U.S. Geological Survey's National Earthquake Information Center based in Colorado.
Sigala said it doesn't appear that this morning's quake is connected to the 5.2 magnitude quake that struck at 4:37 a.m. on April 18 in the Wabash Valley Seismic Zone.
"It's about 140 miles away" from the epicenter of that April 18 quake in the Wabash zone, she said.
When this morning's quake hit, an officer with St. Louis County police in the Affton precinct said he felt the ground shaking for perhaps five seconds and the roof moving, "like someone was moving something around." Police had no reports of damage or injuries.
"One thing we have to be kind of worried about is that earthquakes like this have the potential to shake up loose sand .... and some of the levees saturated with water right now might collapse," said Timothy M. Kusky, director of the Center for Environmental Sciences at St. Louis University.