UPDATED: 11/4/2013 4:10 p.m.
INDIAN HEAD PARK, Ill. (CBS) — Residents in the western suburbs felt tremors early Monday afternoon, and federal officials believe the shaking was from a quarry blast and not a natural earthquake.
The Hanson Material Service quarry acknowledged it was performing routine blasting operations in McCook, not far from the epicenter of the event.
However, spokesman Jeff Seig said “we have no reason to believe that there is a connection between our routine blast and this seismic event.”
About seven seconds after a blast around 12:35 p.m. a “separate seismic event was recorded,” Seig said.
He said the company was reviewing the data to better understand what may have occurred, adding the seismic readings were below regulatory limits.