ST. LOUIS COUNTY, Mo. — A magnitude 2.8 earthquake struck Friday about 1 mile southwest of Interstate 44 and Highway 141 in Valley Park, according to the U.S. Geological Survey.
According to the USGS, the earthquake happened at 5:30 p.m. and was at a depth of about 4.9 miles (7.9 km).
Numerous calls came into the 5 On Your Side newsroom describing shaking and loud explosion noises.
By 8:50 p.m., about 3,138 people from Affton, Fenton, Kirkwood, Ballwin, south St. Louis and elsewhere across the region had reported feeling the earthquake to the USGS.
"This one was a little unusual because it was right underneath the metro area. ... More often earthquakes will be where people aren't living just by random chance, but this one happened to be under just south of Valley Park so we all felt it," said Dr. Douglas Wiens, a professor of Earth and planetary sciences at Washington University.
The St. Louis County dispatch center reported a large number of emergency calls immediately after the quake, prompting a request by the St. Louis County Office of Emergency Management for people to only use 911 for an emergency situation.
There were no immediate reports of damage.
St. Louis is in the Illinois basin-Ozark dome region of the country's tectonic map. The region borders the New Madrid seismic zone to the north and west.
Moderately damaging earthquakes strike somewhere in the region each decade or two, and smaller earthquakes are felt about once or twice a year.
The USGS initially reported Friday's earthquake as a magnitude 2.5 with a depth of about a 1/2 mile (1 km).
Experts warn that hazards like building damage, leaking gas and water lines can occur after earthquakes.
5 On Your Side's Allie Corey felt the shaking.
5 On Your Side contributor Dan Buffa tweeted about the shakes as well.
Did you feel the earthquake? Let us know on social media.