Northwestern University has installed a seismograph at the Hanson Materials quarry in McCook, an effort in conjunction with the U.S. Geological Survey to determine the cause of a Nov. 4 tremor that shook several area communities.
U.S. Rep. Dan Lipinski, D-3rd of Western Springs and one of those who felt the tremor, announced the effort after meeting Tuesday with the Lyons Township Quarry Advisory Council. The council is composed of local communities and McCook quarry operators.
The seismograph was put in place Dec. 3 by Northwestern University in order to record and upload readings to the geological survey around the clock. This will provide the first comprehensive information on seismic activity in the area. Prior to the Nov. 4 event, the only seismic activity at the quarry being recorded was limited and performed by Hanson Materials immediately before, during and after scheduled blastings.
“More than a month after the event that alarmed so many throughout our communities, it is clear that the answers to some of the key questions will take time and significant study,” Lipinski said. “I am committed to continuing to work with our communities, Hanson Materials, and the relevant federal agencies to learn as much as we can about what exactly happened so we can protect homeowners and businesses.”
Lipinski also said he would hope state agencies responsible for granting permits and overseeing quarries and mines in Illinois will begin to take a closer look at what has happened.
The 3.2 magnitude tremor was recorded at a seismograph in Lake County seven seconds after a much smaller blast at the McCook quarry. It ultimately was determined by the geological survey to be an earthquake likely caused by normal, legal activities at the quarry. A similar event also occurred in 2010.
Hanson Materials has not performed blasting since the incident and does not anticipate resuming until spring. The company has promised the neighboring communities that it will inform them if and when blasting does resume.