MT. VERNON, Ill. (WJPF) – A small earthquake was detected Monday near Mt. Vernon.

The 2.3 magnitude quake hit at about 6:30 p.m. and was centered 4.3 miles northwest of the city at a depth of about 9.6 miles. 

Earthquakes registering a 2.5 or less on the Richter scale are usually not felt, but can be detected by scientific instruments.