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News Release
FOR IMMEDIATE RELEASE
September 18, 2007
Click here to download a page-sized version
OHIO EARTHQUAKE MAP UPDATED TO REFLECT LATEST SEISMIC ACTIVITY
COLUMBUS, OH - Its hard to believe that more than 30 earthquakes have occurred in the Ohio region since 2002. The Ohio Department of Natural Resources, Division of Geological Survey has revised and updated their Earthquake Epicenters in Ohio and Adjacent Areas map with the location and approximate magnitude of these new earthquakes, as well as information about historic earthquakes that has been gained since the map was originally released in 2002.
More than 200 earthquakes with a magnitude of 2.0 or greater have occurred in the Ohio region since 1776. While it may seem like earthquakes are occurring more frequently in recent years, the Ohio Seismic Network attributes this perceived change to improved technology and communication among a larger population of people who are exposed to seismic activity. The new map, which includes all of Ohio's recorded earthquakes, shows a concentration of earthquake epicenters in two areas of the state: western Ohio in the vicinity of Shelby County, and along the Lake Erie coast in Lake County at Painesville. Map users can apply this information to earthquake insurance rate determinations, construction strength determinations for bridges and buildings, and research on deep-earth structures such as hidden faults.
Michael C. Hansen, coordinator of the Ohio Seismic Network, found several previously unknown historic earthquakes to add to the new map from an extensive collection of earthquake catalogs, accounts of earthquakes in historic newspapers, and information in the files of the Division of Geological Survey. From this information he also found several non-seismic historic events (e.g., explosions, atmospheric phenomena, and rockfalls) that had been mapped as earthquakes on the 2002 map; these false earthquakes were removed from the 2007 map. Earthquakes recorded only by reports from the public often less accurate than seismic station reports available after 1970are depicted by a different color symbol on the new map than post-1970 earthquakes.
The 2007 map has an explanatory text and chronological table listing exact coordinates and other details for each Ohio earthquake, such as earthquake event time, depth, felt-area size, and information source. Epicenters are plotted on a base map that corresponds different shades of color with Ohio's various elevation levels. County boundaries and county seats, latitude and longitude, and known faults deep below the surface are also depicted on the map to help map users relate points of interest with earthquake information.
The wall-size Earthquake epicenters in Ohio and adjacent areas (map EG-2) measures 50 X 35 inches and is available for $10.00 (plus tax and mailing) from the Division of Geological Surveys Geologic Records Center, which can be contacted by phone 614-265-6576 or e-mail geo.survey@dnr.state.oh.us. A free page-size version of the map and chronological listing of earthquake epicenters is available on the Ohio Seismic Networks website: www.ohiodnr.com/OhioSeis.
Department of Natural Resources
Division of Geological Survey
2045 Morse Rd. Columbus, OH 43229-6693
Phone: 614-265-6576
email: geo.survey@dnr.state.oh.us
web: www.dnr.state.oh.us/geosurvey
Geologic Records Sales Office hours:
Monday - Friday, 8:00 A.M. to 4:30 P.M. EST
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Michael C. Hansen, Ohio Earthquake Information Center
(740) 548-5979
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