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Friday, May 29, 2015

Earthquakes in Ohio

     When they think of earthquakes in Ohio, most Ohioans think they only happen in California or some far off country, but it's not so! 
     On April 12, 2015 there was an earthquake measuring 2.3 out in the eastern end of Lake Erie some 5 miles down. The water in that area is about average for Lake Erie, slightly more than 60 feet, so the quake was way underneath the bottom of the lake. A quake of 2.5 or less is usually not felt; between 2.5–5.4 they are often felt, but only cause minor damage. 
     On May 11 there was a 2.5 quake in southern Ohio near Portsmouth on the Ohio River. And these have not been the only recent quakes. You can see a record of recent quakes HERE
     An earthquake on June 18, 1875, caused damage in western Ohio. Walls were cracked and chimneys fell in the cities of Sidney and Urbana. The shock was felt at Jeffersonville, Indiana and parts of Illinois, Indiana, Kentucky, and Missouri. 
     Slight damage was reported at Lima from a September 19, 1884, earthquake. At Columbus, chandeliers kept swinging for several minutes after the tremor. The shock was felt at Washington, D.C., by workmen on top of the then unfinished Washington Monument, about 500 feet above the ground! This earthquake was felt throughout a broad area, from Pennsylvania to Kentucky and West Virginia to Michigan. 
     Several towns in southeastern Ohio experienced moderate damage on November 5, 1926. Chimneys toppled at Keno and Pomeroy. A brief but strong shock was felt over a wide area in western Ohio on September 30, 1930 and the tremor was accompanied by a rumbling noise. Less than one year later (September 20, 1931), another damaging earthquake occurred in the same area. The strongest tremor of this series occurred at 11:45 p.m., March 8, 1937, again in Anna, where chimneys repaired after the March 2 earthquake were again toppled. Organ pipes were twisted in one church. There was also a strange phenomena common to both of these quakes: tombstones were rotated and there were changes to water wells. 
     On March 9, 1943, an earthquake centered east of Cleveland and on June 20, 1952, an early morning tremor at 3:38am awoke most of the people in the Zanesville area. 
     The one I remember happened on January 31, 1986. It was late morning and I had just walked into my boss's office which was on the second floor when the building started trembling and as I looked out the window I saw telephone poles shaking. Startled, I asked, “What's that?!” Having been originally from California, he replied that it was an earthquake. At the time, I found that hard to believe because I was unfamiliar with the fact that Ohio has earthquakes. This one caused minor property damage in several towns in northeast Ohio and northwest Pennsylvania; 17 people were injured in the epicentral area. Most of the damage to houses and commercial buildings occurred in Ashtabula, Geauga, Lake, Trumbull, and Wood Counties in Ohio and Crawford and Erie Counties in Pennsylvania. It mainly included fallen ceilings and plaster; cracked chimneys, foundations, and brick walls; and broken windows and underground pipes. Changes in the flow of water were observed in more that a dozen wells in Lake and Geauga Counties, east of Cleveland. The changes included variations in the flow of water and sediment deposits in water. In Leroy Township, a small pond was formed from the flow of a new artesian well. Another artesian well suddenly began feeding water to an old water trough. Over the next 2 months, 13 aftershocks of magnitude 0.5 to 2.4 were recorded on the area, and 13 more aftershocks of about magnitude 1.0 were detected through April 15, 1987. 
     The main earthquake was felt over a large area of the Eastern United States, covering all or parts of eight States (Illinois, Indiana, Kentucky, Michigan, New York, Ohio, Pennsylvania, West Virginia) and Ontario, Canada. It also was reported by people on the top floors of multistory buildings in Delaware, Maryland, New Jersey, Virginia, and Wisconsin, as well as Washington, D.C. 
     Although most people do not think of Ohio as an earthquake-prone state, at least 200 earthquakes with epicenters in Ohio have been felt since 1776. In addition, a number of earthquakes with origins outside Ohio have been felt in the state. At least 15 earthquakes have caused minor to moderate damage in Ohio. 
Click to enlarge
    Ohio is on the periphery of the New Madrid Seismic Zone, an area in Missouri and adjacent states that was the site of the largest earthquake sequence to occur in historical times in the continental United States. Four great earthquakes were part of a series at New Madrid in 1811 and 1812. These events were felt throughout the eastern United States and were of sufficient intensity to topple chimneys in Cincinnati. Some estimates suggest that these earthquakes were in the range of 8.0 on the Richter scale. 
     A major earthquake centered near Charleston, South Carolina, in 1886 was strongly felt in Ohio. Three areas of the state are particularly susceptible to seismic activity. Shelby County in western Ohio has experienced more than 40 felt earthquakes since 1875. Although most of these events have caused little or no damage, earthquakes in 1875, 1930, 1931, and 1937 caused minor to moderate damage. As mentioned, two earthquakes in 1937, on March 2 and March 9, caused significant damage in the Shelby County community of Anna. 

     Southeastern Ohio (Scioto Count, Meigs County and Perry County) has been the site of at least 12 felt earthquakes since 1776. The origins of Ohio earthquakes are poorly understood. Those in Ohio appear to be associated with ancient zones of weakness in the Earth's crust that formed during rifting and continental collision events about a billion years ago. These zones are characterized by deeply buried and poorly known faults, some of which serve as the sites for periodic release of strain that is constantly building up in the North American continental plate due to continuous movement of the tectonic plates that make up the Earth's crust.   
Wikipedia – Earthquakes 
Ohio Earthquakes 
Scott Sabol's Cleveland Earthquake History
Magnitude Chart 2014 
Ohio Earthquake Due to Fracking 
Fracking and Ohio Earthquakes
What is fracking and why is it controversial? BBC News

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