Earthquakes, the shaking of Earth’s surface caused by a sudden release of energy in the lithosphere, are often associated with distant, highly seismic regions. While not considered a major hazard, earthquakes do occur in Ohio. These events are less frequent and powerful compared to those in active seismic zones, but they are a documented part of the state’s geological activity.
Ohio’s Seismic Activity
Ohio experiences a consistent, minor level of seismic activity. The state records about 20 earthquakes per year. Most events are small, often below magnitude 3, too weak to be felt. Modern monitoring equipment has improved detection of smaller tremors, leading to an apparent increase in reported events.
Most Ohio earthquakes fall within the magnitude 2 to 3 range. Larger events are less common: magnitude 4 or higher occur roughly once every three years, and magnitude 5 or higher, once every 22 years. Seismic activity is not evenly distributed across the state. Western Ohio, particularly around Shelby County, has historically been the most active region, with more felt earthquakes than any other part of the state. Northeastern Ohio, near Cleveland and Akron, also shows consistent activity; central Ohio appears largely without seismic events.
Geological Explanations
Earthquakes in Ohio, and throughout the eastern United States, are examples of intraplate seismicity, occurring within the interior of a tectonic plate rather than at its boundaries. The North American continental plate constantly moves, creating stress that builds in the crust. This stress releases along ancient zones of weakness.
These zones feature deeply buried fault lines formed during continental rifting and collision events approximately a billion years ago. These faults are generally not visible at the surface and poorly understood, but serve as points where accumulated strain can be periodically released. Brittle, flat-lying sedimentary rocks allow seismic waves to travel long distances, meaning even moderate earthquakes can be felt across a wide area.
Notable Past Events
Ohio’s seismic history includes several notable earthquakes causing minor to moderate damage. One significant event occurred on March 9, 1937: a 5.4 magnitude earthquake near Anna in western Ohio. This quake caused considerable damage, including widespread chimney collapses and structural issues leading to the condemnation and demolition of the local school building.
Another prominent earthquake took place January 31, 1986, near Lake County in northeastern Ohio. This 5.0 magnitude event was felt across 10 other states and southern Canada, resulting in minor to moderate damage like broken windows and cracked plaster in the epicentral area. Ohio also felt a 5.3 magnitude earthquake centered in Kentucky in 1980, causing moderate damage in communities along the Ohio River. Powerful New Madrid Seismic Zone earthquakes of 1811 and 1812 also affected the state, strong enough to topple chimneys in Cincinnati.
What to Do During an Earthquake
Knowing how to react during an earthquake reduces injury risk. The widely recommended procedure during ground shaking is “Drop, Cover, and Hold On.” This involves immediately dropping to your hands and knees to prevent being knocked over. Next, take cover under sturdy furniture, such as a desk or table, to protect from falling debris. If no sturdy shelter is available, crouch against an interior wall, covering your head and neck with your arms.
Hold on to your shelter, or your head and neck if no shelter is present, until shaking stops. Remain in place until shaking subsides, as moving during an earthquake increases injury risk from falling objects. Preparing an emergency kit is also beneficial. Securing heavy furniture and appliances to walls further reduces home hazards.
An emergency kit should include:
- Water
- Non-perishable food
- A first-aid kit
- Flashlights
- A battery-powered radio