Earthquakes, often associated with distant coastlines, also occur within the central United States, including Missouri. This phenomenon prompts questions about the state’s seismic history and the potential for future events. Understanding these occurrences helps residents grasp the underlying geological processes and supports preparedness efforts, ensuring communities are better equipped to respond to seismic activity.
The Most Recent Recorded Event
Missouri experiences frequent, typically small, earthquakes. The most recent recorded event occurred on August 27, 2025, with a magnitude of 2.3 in Pemiscot County, approximately 22 miles west of Dyersburg, Tennessee. Earlier, on August 4, 2025, a 3.3 magnitude earthquake was reported near Missouri. While these minor tremors are often barely felt, they serve as a reminder of the ongoing seismic processes. Missouri’s seismic network regularly detects these, indicating continuous, low-level activity.
Historical Earthquakes in Missouri
Missouri’s seismic history includes some of the most powerful earthquakes in the contiguous United States. The most notable were the New Madrid earthquakes of 1811-1812, a series of intense intraplate earthquakes and thousands of aftershocks. The main shocks, occurring between December 1811 and February 1812, had estimated magnitudes between 7.5 and 7.7. These events caused widespread devastation, notably making the Mississippi River temporarily flow backward and creating new landforms like Reelfoot Lake. The tremors were felt across vast distances, from the Gulf Coast to Quebec.
Understanding Missouri’s Seismic Activity
Missouri’s earthquakes primarily originate from the New Madrid Seismic Zone (NMSZ), an area of intraplate earthquakes in the central United States. This zone is unique as it is located within the North American plate, not at a tectonic plate boundary. The NMSZ lies above the Reelfoot Rift, an ancient failed rift system that left a deep zone of weakness within the Earth’s crust over 750 million years ago. East-west compressive forces, associated with the westward drift of the North American plate, reactivate these old faults, leading to earthquakes. The faults are often hidden beneath thick layers of river sediment, which can amplify ground motion, making earthquakes in this area potentially more damaging than those of similar magnitude in other regions.
Preparing for Future Seismic Events
Given Missouri’s seismic history, preparedness for future events is a practical consideration for residents. A widely recommended safety protocol during an earthquake is “Drop, Cover, and Hold On”. This involves dropping to your hands and knees, taking cover under sturdy furniture, and holding on until the shaking stops.
Assembling an emergency kit is also advisable, including essentials like bottled water, non-perishable food, a flashlight, and a first-aid kit, sufficient for at least three days. Developing a family communication plan, which may include designating an out-of-state contact, can help ensure connection after an event. Securing heavy furniture and appliances to walls helps prevent injuries and damage during shaking. Information and resources are available from the Missouri State Emergency Management Agency (SEMA) and through initiatives like the Great Central U.S. ShakeOut.