Rep. Lipinski Announces Next Step in Investigating McCook Quarry and Nov. 4 Earthquake


As part of his commitment to finding out what caused the Nov. 4 seismic event that shook several communities in his district, U.S. Rep. Dan Lipinski (IL-3) has announced that Northwestern University, in conjunction with the United States Geological Survey (USGS), has installed a seismograph at the Hanson Materials quarry in McCook. Rep. Lipinski met today with the Lyons Township Quarry Advisory Council, which is composed of local communities and McCook quarry operators, to discuss how the investigation into what may have caused the earth to shake is going to proceed.  

With the congressman’s help, the seismograph was put in place Dec. 3 by Northwestern University in order to record and upload readings to the USGS 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. This seismograph is one piece to help us solve the puzzle as to why these events have occurred and, most important, what can be done to prevent them from happening again,” Rep. 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. I am also hopeful that the 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 USGS 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. 

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