Chicagoland Quake Leaves Little Damage

By Kevin Lee

CHICAGO — A small earthquake rocked the Chicagoland area on Wednesday, awakening thousands and setting emergency response centers into action.

The 3.8 magnitude tremor left confusion, rather than destruction in its wake. No damage or injuries were reported in Illinois , nor were any emergency response teams activated as a result of the quake.

The state Department of Transportation instructed regional crews to inspect infrastructure around the epicenter of the quake, which is believed to have originated 50 miles northwest of Chicago between DeKalb and Kane counties.

“Bridge inspection crews inspected roadways and bridges in a 50-mile radius of the epicenter,” Paris Ervin of IDOT said. “Also as a proactive measure, snow plow crews were instructed to look at roadways and bridges as they plowed this morning.”

The agency has an earthquake response plan, which is activated for earthquakes with magnitudes greater than 4.5 on the Richter scale.

Ervin emphasized that the plan was not put into action. The department’s presence was more precautionary than anything else.

“We wanted to take the proper precautions to make sure our infrastructure was still intact,” she said.

The tremor was initially reported at 4.3, but was later downgraded after seismologists took a closer look at measuring instruments.

Tim Larson of the Illinois State Geological Survey says this is typical in Midwestern earthquakes.

“It’s very common in this part of the country where there are very few seismometers,” he said. “The initial report is…an approximation that is done, so we can get it out quickly — it’s in the ballpark.”

The quake was the second to hit Illinois in as many years, but what interested Larson was its location. The state’s earthquakes generally occur in southern Illinois because of their proximity to the Wabash and New Madrid fault lines.

Wednesday’s earthquake occurred in the Northern Illinois Fault Zone, which typically sees earthquakes “every five to ten years.”

Geologists are uncertain why earthquakes occur in regions lacking in seismic faults, like the Midwest. One popular theory, which Larson has studied, is the idea of “scarring” in the earth’s crust, in which weaker parts of crust buckle leading to tremors.

Larson said the depth of the earthquake makes it difficult to study. Seismologists believe the quake occurred more than two miles below ground, an area geologists have not yet been able to accurately map.

Officials from the Illinois Emergency Management Agency said the agency is prepared for major earthquakes.

“We have a very comprehensive emergency response plan that is aimed at being able to respond to all types of hazards, whether they’re tornado, flood or earthquake,” IEMA spokeswoman Patti Thompson said. “In addition, we’ve taken it a little bit further to address some of the unique aspects of an earthquake.”

The department has search-and-rescue teams throughout the state trained to work through the debris that comes with a major earthquake.

However, Larson says the state — especially its northern areas — is not too likely to get hit by a major earthquake.

According to Larson, northern Illinois has not experienced a large magnitude earthquake in a century. That 5.1 magnitude quake caused only minor damage in Aurora.