Ohio does experience earthquakes, which may surprise residents who associate seismic activity with the western coast of the United States. While the state is far from tectonic plate boundaries, it is an area of persistent, low seismic activity. Most tremors are mild and go unnoticed, but the historical record includes events strong enough to cause damage. Ohio’s seismic status is defined by the occasional release of deep-seated geological stress.
Historical Record of Earthquakes in Ohio
Ohio has recorded over 160 felt earthquakes since documentation began in 1776, though most events are below magnitude 3.0. The largest and most damaging event occurred in western Ohio on March 9, 1937, near the village of Anna in Shelby County. This earthquake registered an estimated magnitude of 5.4, causing significant damage, including toppled chimneys and the eventual demolition of the local high school.
A more recent, widely felt event was the magnitude 5.0 quake near Painesville in Lake County on January 31, 1986. This tremor was felt across 11 states and parts of Canada, resulting in minor property damage in the epicentral area. Historical data confirms the state is capable of producing moderate-sized events.
The Geological Mechanism of Intraplate Quakes
Earthquakes in Ohio are classified as intraplate seismicity, meaning they occur far from any active plate boundary. The North American continent is subjected to immense, continuous stress transmitted from the edges of the plate. This stress originates primarily from the “ridge push” at the Mid-Atlantic Ridge and resistance from subduction zones to the west.
This regional stress field reactivates ancient zones of weakness deep within the continental crust, specifically in the Precambrian basement rock. These billion-year-old fault lines are buried under layers of younger sedimentary rock. When accumulated tectonic strain overcomes the friction along one of these deeply buried faults, the stored energy is suddenly released as an earthquake.
Specific High-Activity Seismic Areas
Seismic activity is not uniformly distributed across Ohio, but is concentrated in distinct zones where ancient faults are susceptible to the current stress field. The most historically active region is the Western Ohio Seismic Zone, centered around Shelby and Auglaize Counties, including the town of Anna. This area is associated with the Fort Wayne Rift complex, a failed rift system characterized by ancient faults.
Another significant area of activity is the northeastern part of the state, particularly along the Lake Erie shore near Cleveland and Painesville. This region has experienced several clusters of earthquakes, including the 1986 event. Geologists suggest some of this activity may be related to the Akron magnetic boundary, an extensive north-south linear feature in the basement rock.
Earthquakes Caused by Human Activity
In addition to natural tectonic stress, Ohio has experienced earthquakes directly caused by human industrial operations, known as induced seismicity. This occurs when fluid injection activities increase the pore pressure in the subsurface, effectively lubricating a pre-existing fault and allowing it to slip. The primary cause of concern has been deep wastewater injection wells, which dispose of large volumes of brine produced during oil and gas extraction.
A notable series of induced earthquakes occurred in the Youngstown area between 2010 and 2012. A single deep injection well, the Northstar 1, was linked to this cluster of seismic events. The largest was a magnitude 4.0 earthquake on New Year’s Eve 2011, which led the state to order the immediate shutdown of the well. Modern regulations now require more stringent monitoring and permitting for these wells, especially near known fault lines.