(KSDK) -- An aftershock originally believed to be a 4.5 magnitude earthquake, has been downgraded to a 4.0 quake.
The earthquake happened at 12:38 a.m. on Monday about five miles from Mt. Carmel, Illinois.
A much weaker 2.2 aftershock was recorded in the same area at 7:58 a.m., which was too weak to be felt in St. Louis.
There have been no reports of additional damage or injuries.
The tremor follows a weekend filled with aftershocks following a 5.2 earthquake that occurred at 4:37 a.m. Friday.
The United States Geological Survey reports 19 aftershocks between the initial quake and including this morning's two tremors.
Seismologists say aftershocks can last for a week or more following an earthquake.