The earthquake that shook Ohio and all or portions of 13 other states and southern Canada on July 27, 1980, initiated numerous media and citizen inquiries concerning this particular earthquake and the general seismicity of Ohio. Many residents of Ohio were amazed to learn that the state had ever experienced any previous earthquakes and were startled to find out that more than 100 earthquakes have been reported from the state since 1776. The personal involvement in this event by such a large segment of the state's population effectively brought considerable attention to the geological sciences in Ohio. Division personnel answered numerous telephone inquiries and participated in a number of television, radio, and newspaper interviews. The response to a news release announcing the availability of the Survey leaflet Earthquakes in Ohio was overwhelming. Copies of this leaflet, EL 9, may be obtained free of charge from the Survey.
Preliminary information placed the epicenter of the earthquake near Sharpsburg, Bath County, Kentucky (38.19N, 83.94W), at a focal depth of 13 km. Origin time was 18:52:21 UTC (2:52 PM Eastern Daylight Time), and Richter magnitude was 5.1.
The earthquake was monitored in Ohio by the Seismological Observatory at John Carroll University in Cleveland and by the University of Michigan seismic network in western Ohio. The seismograph at Bowling Green State University in Bowling Green was turned off because of local blasting, and the Xavier University station near Cincinnati has been down for some time.
Soon after the earthquake, teams from the U.S. Geological Survey and several universities reached the epicenter area to monitor aftershock activity and to make damage assessments. At least 30 aftershocks were recorded; one on July 31 at 0:9:27 had a magnitude of 2.5.
Questionnaires were mailed to postmasters by the U.S. Geological Survey National Earthquake Information Center in Denver, Colorado, and the University of Michigan sent questionnaires to numerous newspapers to be printed, clipped out by subscribers, and returned. Isoseismal maps will be prepared from these data but are not available at this time.
Assessments of damages from the July 27 event are as yet incomplete, but from media reports and cursory sampling of Ohio communities along the Ohio River it appears that damage to property ranged from minor to moderate. Maysville, Kentucky, located about 30 miles northeast of the epicenter, was particularly hard hit. Media reports issued a week after the tremor indicated damages of more than $1 million in Maysville; 59 homes and 27 businesses sustained major damage and 210 homes and 10 businesses sustained minor damage. Few property owners carried earthquake insurance. The Ohio communities of Manchester, Aberdeen, Ripley, and West Union reported various degrees of damage. In Aberdeen several chimneys were knocked down and merchandise was toppled from store shelves. Manchester reported an undetermined number of chimneys down, one of which fell on a car . The community of West Union reported cracks in the block and concrete of the municipal building, constructed in 1974, and in Ripley the chimney was toppled on the John P. Parker house, listed on the National Register of Historic Places. Residents in Manchester and Ripley reported a roaring sound, like a strong wind, just before experiencing the vibrations from the earthquake. Media reports also indicate that Cincinnati experienced some damage, including a cornice that fell from the city halt building and crushed the steps beneath it. It is of interest to note that most cases of damage to chimneys and other masonry structures were confined to older buildings in which deterioration of the mortar had taken place.
Dr. Frederick J. Mauk of the University of Michigan Seismological Observatory reported that a focal mechanism for the July 27 earthquake indicates a thrust fault, with a large strike-slip component, striking 42°NE with a dip of 50°E. Movement was right lateral. This location and orientation places the fault in the vicinity of the Lexington fault zone, although the earthquake has not been identified with any fault mapped on the surface in this area. Mauk also noted that much of the energy released by the quake was focused northward; this northward focus accounts for the widespread alarm over most of Ohio. Further observations by Dr. Mauk suggest that many of the damaged buildings were located on alluvial terraces along the Ohio River. Maximum intensities from this earthquake were probably in the high VI to low VII range on the Modified Mercalli Scale.
The earthquake of July 27, 1980, is not without precedence in northern Kentucky, although it is the first sizeable event to be precisely located and from which a considerable amount of data has been derived. Very imprecisely located earthquakes were recorded from northern Kentucky in 1779 and in either 1791 or 1792. In 1828 four shocks, one on March 9 and three on March 10, were reported from the Maysville, Kentucky, area. These events were estimated to be in the IVV range of intensity on the Modified Mercalli Scale. On February 20, 1869, an intensity IV shock was felt at Lexington, Kentucky, and on May 28, 1933, an intensity IV event was experienced at Maysville, Kentucky. Two earthquakes have been reported just north of the Ohio River. On January 23, 1877, an intensity III shock was reported in Adams County, Ohio, and on July 23, 1957, an intensity III event was reported from Ripley, Brown County, Ohio.