The biggest aftershock occurred at 10:14am CDT (15:14 UTC), on April 18; it was a magnitude 4.6, and also centered near West Salem, just north of the original quake.
The biggest aftershock occurred at 10:14am CDT (15:14 UTC),. Television reports on April 18; it was a magnitude 4.6, and also centered near West Salem, just north of the original quake.