Des Moines, Iowa – A rare Midwest earthquake early Tuesday, Jan. 20, is now raising awareness across Iowa and Illinois as an intense surge of Arctic air drives temperatures sharply lower, creating conditions that could lead to frost quakes across the region.
According to the U.S. Geological Survey, a 3.5 magnitude earthquake struck central Illinois shortly before 2 a.m. Tuesday, Jan. 20, centered about 35 miles south of Springfield near Ohlman. The shallow quake was felt across much of central Illinois, with thousands reporting shaking, rumbling, and rattling windows before sunrise. No injuries or damage were reported, but earthquakes of this size are uncommon in the Midwest.
Geologists say the timing of the quake is notable as extreme cold rapidly followed, increasing the risk of frost quakes, also known as cryoseisms. These occur when moisture in the ground freezes suddenly, causing soil and rock to contract and fracture. The result can be a loud boom or brief shaking that may feel similar to a small earthquake, often occurring overnight or before dawn.
Parts of eastern Iowa and western Illinois, including Des Moines, Davenport, Bettendorf, Rock Island, Moline, Cedar Rapids, and communities along the Mississippi River, may be more susceptible as temperatures plunge following recent rain or snow. Frost quakes are shallow and localized but can crack pavement, foundations, and underground utilities, particularly near roads, older structures, and buried pipes.
Emergency officials emphasize that frost quakes are not tied to fault lines and do not signal larger earthquakes. Residents are encouraged to remain alert during the coldest hours, inspect property if shaking or loud booms are noticed, and report ground movement to local authorities or the USGS. With dangerous cold expected to persist through midweek, additional advisories or alerts may follow.
