Small but rare earthquake shakes Chicago area

A small but rare magnitude 2.9 earthquake shook the Chicago area, with weak shaking reported across parts of northeastern Illinois, according to the U.S. Geological Survey (USGS).

The magnitude 2.9 earthquake struck at 2:38 p.m. in Lake Michigan, about 12 miles east-northeast of Kenilworth in Cook County and 22 miles northeast of downtown Chicago, according to USGS data. It had a depth of 3 miles.

More than 300 people submitted felt reports to the USGS, most of them indicating weak shaking. Reports came from as far north as North Chicago, south to Palos Heights and west to Glen Ellyn.

Earthquakes are uncommon in the Chicago area. According to USGS data dating back to 1900, Wednesday’s quake is the only earthquake above magnitude 2.5 recorded in the immediate area.

Nearby earthquakes have included a magnitude 3.2 near Lyons in 2013 and an estimated magnitude 5.0 near Aurora in 1909.

Earthquakes east of the Rocky Mountains are often felt over a wider area than similar quakes in the West because older, harder bedrock transmits seismic waves more efficiently, according to the USGS. As a result, even small earthquakes in the Midwest can be felt across a broader region.