Ohio is not known for its seismic activity, but the state has experienced some notable earthquakes in its history. The biggest earthquake to ever shake Ohio occurred on March 9, 1937, near the town of Anna in western Ohio. The quake had a magnitude of 5.4 and was felt over a large area of the Midwest and the East Coast. It caused damage to buildings, roads, and bridges, and was followed by several aftershocks. The quake was also felt in Canada and as far away as New York City.
What Caused the 1937 Ohio Earthquake?
The 1937 Ohio earthquake was caused by the movement of ancient faults in the basement rocks of the region. These faults are part of the New Madrid Seismic Zone, a complex system of faults that extends from southern Illinois to northeastern Arkansas. The New Madrid Seismic Zone is responsible for some of the largest earthquakes in North America, including the series of quakes that occurred in 1811 and 1812, which had magnitudes of up to 7.5.
The 1937 Ohio earthquake was triggered by the stress buildup in the crust due to the glacial rebound effect. This is the process of the land rising after being depressed by the weight of ice sheets during the last ice age. The glacial rebound effect causes the crust to adjust and crack, creating or reactivating faults. The 1937 Ohio earthquake was one of the largest examples of an intraplate earthquake, which occurs within a tectonic plate rather than at a plate boundary.
How Often Do Earthquakes Occur in Ohio?
Earthquakes are relatively rare in Ohio, but they are not unheard of. According to the U.S. Geological Survey, more than 200 earthquakes have been recorded in Ohio since 1900, although some of them were centered in Lake Erie or surrounding states. Most of these quakes were minor, with magnitudes below 3.0, and did not cause any significant damage or injuries. However, there have been a few exceptions, such as the 1986 Chardon earthquake, which had a magnitude of 5.0 and caused some structural damage in northeastern Ohio.
The frequency and intensity of earthquakes in Ohio depend on several factors, such as the location, depth, and orientation of the faults, the stress level in the crust, and the geological history of the region. Earthquakes in Ohio tend to occur in clusters or swarms, which may indicate a period of increased seismic activity or a release of accumulated stress. Some of the most seismically active areas in Ohio include the western and northeastern parts of the state, where the faults are more numerous and active.
What Is the Future of Earthquakes in Ohio?
The future of earthquakes in Ohio is uncertain, but experts agree that the state is not immune to the possibility of another large quake. The 1937 Ohio earthquake demonstrated that the state has the potential to experience a damaging earthquake, even if the probability is low. The USGS estimates that there is a 1% chance of a magnitude 6.0 or greater earthquake occurring in Ohio in the next 50 years, and a 5% chance of a magnitude 5.0 or greater earthquake.
The risk of earthquakes in Ohio may also be influenced by human activities, such as oil and gas extraction, mining, and wastewater injection. These activities can alter the stress and pressure in the subsurface, which may trigger or enhance earthquakes along existing or new faults. Several studies have linked some of the recent earthquakes in Ohio to these activities, especially in the eastern part of the state, where the Utica Shale formation is being exploited for natural gas.
Conclusion
The 1937 Ohio earthquake was the biggest earthquake to ever shake Ohio, and one of the largest intraplate earthquakes in North America. It was caused by the movement of ancient faults in the basement rocks, which were influenced by the glacial rebound effect. The quake caused damage to buildings, roads, and bridges, and was felt over a large area of the Midwest and the East Coast.
Earthquakes are rare in Ohio, but they do occur from time to time, mostly in the western and northeastern parts of the state. The future of earthquakes in Ohio is uncertain, but the state may face a higher risk of seismic activity due to natural and human factors. Ohioans should be aware of the earthquake hazard and prepared for the possibility of another big quake.