Rare 2.9 Magnitude Earthquake Strikes Lake Michigan, Felt Widely Across North Shore Suburbs

USGS placed the epicenter about 10 miles off the shore from Highland Park, near Kenilworth, Wilmette and Evanston, at a depth of roughly 3 miles beneath Lake Michigan.
The quake was felt as far west as Elgin and as far north as the Wisconsin border, with Madison about 114 miles away from the epicenter.
CBS News Chicago notes this event may be one of only two Lake Michigan earthquakes recorded in the last 100 years.
This earthquake is described as the second Illinois quake in the past 30 days, following a 3.5-magnitude event near West Salem on June 29.
Depth reporting varies slightly, with some sources listing 3.1 miles depth (Patch), while USGS reports about 3 miles.
A 2.9-magnitude earthquake struck beneath Lake Michigan on Monday afternoon, rattling North Shore suburbs and sending shockwaves as far as the Wisconsin border. Daily Herald reported the quake hit at 2:38 p.m., with the epicenter sitting about 10 miles off the shore near Highland Park — close to Kenilworth, Wilmette, Winnetka, and Evanston.
No injuries or damage were reported. But the event turned heads for a simple reason: according to CBS News, this may be only one of two Lake Michigan earthquakes recorded in the last 100 years.
The U.S. Geological Survey placed the quake's depth at roughly 3 miles beneath Lake Michigan's surface. Patch listed the depth at 3.1 miles. The epicenter was about 13.8 miles southwest of Evanston and roughly 114 miles from Madison, Wisconsin. At that shallow depth, even a minor quake can be widely felt at the surface.
Chicago Tribune reported the quake stretched across a wide area of northern suburbs. Residents in Evanston, Kenilworth, Wilmette, Winnetka, and Deerfield all felt the shaking. Reports also came in from as far west as Elgin and as far north as the Wisconsin border.
The reach of a 2.9-magnitude quake is usually limited. This one was different. Shaking was reported about 114 miles away in Madison, Wisconsin — a surprisingly wide area for a quake this size. The shallow depth of about 3 miles likely helped the tremors travel farther than usual.
Head Topics noted the epicenter was southwest of Evanston, near the Illinois-Wisconsin border region. The USGS has not disclosed what caused the quake. Officials say they are still gathering details on the event.
This was not Illinois's first recent quake. A 3.5-magnitude earthquake hit near West Salem, Illinois, on June 29 — just 30 days before this Lake Michigan event. Two quakes in a month is unusual for the region, though seismologists have not linked the two events.
CBS News brought in an earth scientist to explain the Lake Michigan quake. Experts describe the region as seismically quiet. That makes Monday's event stand out even more. Authorities and seismologists are still monitoring the situation and have not named a cause.
Despite the wide reach, there were no reports of damage or injuries. A 2.9-magnitude quake sits in the "minor" range on the scale used by seismologists. It is strong enough to feel but rarely strong enough to cause harm. Still, the rarity of a Lake Michigan quake made it big news across the region.
Daily Herald said the quake rattled suburbs across eastern Cook and Lake counties. For most residents, it was a brief and surprising jolt. For scientists, it is a rare data point from one of the quietest seismic zones in the country.
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