Concord, New Hampshire – A rare Midwest earthquake early Tuesday is now drawing attention across New Hampshire as a powerful surge of Arctic air drives temperatures sharply lower, creating conditions that could lead to frost quakes during the coldest overnight hours.
According to the U.S. Geological Survey, a 3.5 magnitude earthquake struck central Illinois shortly before 2 a.m. Tuesday, centered about 35 miles south of Springfield. The shallow quake was felt across a wide portion of Illinois, with thousands reporting shaking and loud rumbles before sunrise. While no damage was reported, seismic events of this size are uncommon in the Midwest, making the timing notable as extreme cold spreads into New England.
As the deep freeze grips New Hampshire, geologists say rapid temperature drops 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. The result can be a sharp boom or brief shaking that may rattle homes, vehicles, and outbuildings, often overnight or before dawn.
Interior and northern New Hampshire, including Concord, Laconia, Lebanon, Littleton, and the White Mountains region, may be especially susceptible as temperatures plunge well below normal following recent snow and moisture. Frost quakes are shallow and localized but can crack pavement, foundations, and underground utilities.
State emergency officials emphasize that frost quakes are not related 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 unusual ground movement to local authorities or the USGS. With dangerous cold expected to persist through midweek, additional advisories or alerts may be issued as conditions continue to evolve.
