After voluntarily ceasing blasting operations following a possible blast-induced “seismic event” last November, Hanson Quarry announced that it will resume blasting this week.
Geologists and other experts are still at odds over whether the 3.2-magnitude seismic event that shook LaGrange and other Lyons Township communities on Nov. 4, 2013 was caused by an earthquake or dynamite blast.
The first blast was scheduled for around 3 p.m. on St. Patrick’s Day, but assistant village manager Andrianna Peterson said it had not yet taken place when contacted by Patch on Monday.
At approximately 12:35 p.m. Nov. 4, 2013, Hanson Material Service in neighboring McCook executed what they described as a “routine blast” well within Illinois statutory limits, company representatives said then.
About seven seconds later, a seismic event measuring 3.2 on the Richter scale. The shaking lasted about five seconds, an Oak Brook observer reported.
LaGrange and LaGrange Park residents described shaking glassware and what felt like a “truck hitting our house” in downtown LaGrange.
Residents in Hinsdale, Oak Brook, Countryside, Downs Grove and Wheaton all reported feeling the tremor. A woman said that her house “levitated” for about five seconds.
The Illinois Department of Natural Resources cleared quarry officials of any wrongdoing, stating that the company had not violated any state regulations after a two-day ground investigating in the days following the blast.
Hanson Materials spokesman Jeff Seig in Irving, TX, stated that the USGS has changed its its information several times. He said that Hanson’s own measuring devices recorded the significantly larger tremor seven seconds after the contained quarry blast.
“The USGS immediately published that it was a small earthquake, then changed it to a quarry blast, which was not correct,” Sieg said. “We went out to Denver and we showed them our data. [The USGS] agreed that it was a seismic event and not the quarry blast that was measured.”
About 100 complaints were received following last November’s seismic event. An inspection firm hired by Hanson, which specializes in vibration damage, determined that quarry blast did cause not cause any of the damages reported by residents, Sieg said..
“We’re hoping somewhere along the way we can get some kind of documentation or evidence that show these events are connected, whatever the answer,” Sieg said. “Can we do something to prevent things like this from happening again, or is it a mere coincidence.”
A statement on the the village’s website said that LaGrange officials will continue to work closely with the Lyons Township Quarry Council and Hanson Quarry to collect information regarding the source of the tremor that occurred last November the mitigation of potential future incidents.
In addition to Hanson’s own measuring tools, a more sophisticated seismograph capable of recording seismic activity 24/7 and feeding data directly to the USGS has been installed at the Hanson Quarry.
This isn’t the first time that residents have complained about Hanson’s blasting. In August 2010, LaGrange Patch reported a 2.7-magnitude tremor occurring in the area, which Hanson-hired experts explained as a “freak occurrence.”
Residents should continue to report unusual or disruptive blasting activity at Hanson and Vulcan Materials in McCook, and Reliable Materials LLC in Lyons, to the Lyons Township Quarry Council hotline at 1-866-934-3278.