The Monday morning aftershock was at least the 15th since Friday's quake.
Strong aftershock reported Monday in Illinois
WEST SALEM, Ill.
Geologists say the temblor just before 12:40 a.m. Monday registered at 4.5 magnitude at its epicenter about 5 miles northwest of Mount Carmel. The location is in the same area as Friday's early-morning 5.2-magnitude earthquake, which was followed by a 4.5 magnitude aftershock about 5 1/2 hours later.
