St. Louis, Missouri – A rare Midwest earthquake early Tuesday, Jan. 20, is now heightening awareness across Missouri 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 a wide portion of Illinois, including Springfield and the Metro East, with thousands reporting shaking, rumbling, and rattling windows before sunrise. No damage or injuries were reported.
While earthquakes of this size are uncommon in the Midwest, the timing is notable as extreme cold rapidly followed the seismic event. Geologists say sharp temperature drops associated with this Arctic outbreak can trigger frost quakes, also known as cryoseisms. These occur when moisture in the ground freezes suddenly, causing soil and rock to contract and fracture, producing a loud boom or brief shaking that can feel similar to a small earthquake.
Parts of Missouri and Illinois, including St. Louis, Columbia, Jefferson City, Quincy, Springfield, and communities along the Mississippi and Missouri rivers, 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, especially near roads, older structures, and buried pipes.
Emergency officials stress that frost quakes are not tied to fault lines and do not signal larger earthquakes. Residents are encouraged to remain alert during the coldest overnight 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.
