Someone told me that a big fault, running from Missouri to the St. Lawrence River runs near my town in Ohio. How do I find out where this, or other, faults are in Ohio?
It is a myth that a great, multistate fault cuts across Ohio. However, Ohio is certainly not "faultless." However, very few faults are visible in surface rocks in Ohio. In large part, this is because a thick blanket of sediment deposited by glaciers of the Pleistocene Ice Age covers bedrock in about two-thirds of the state (all but southeastern Ohio) and thick vegetation obscures other exposures of bedrock. Most known faults in the state originate in crystalline Precambrian rocks that lie deep beneath the sedimentary bedrock. Many of these deep faults are suspected to be blind faults; that is, they do not reach the surface. These deep faults have been discovered primarily through deep drilling for oil and gas and remote-imaging techniques such as seismic reflection, and gravity and magnetic surveys. Some of these faults appear to be seismogenic (earthquake generating) whereas others seem to be inactive, at least during the short span of time that earthquakes have been recorded in Ohio. It is probable that there are many more faults in the basement rocks of Ohio than the few that have been mapped. The map of deep structures in Ohioshows the distribution of these known faults. One objective of the Ohio Seismic Network is to detect and precisely locate earthquakes in the state so that seismogenic faults can be identified.
Last update July 20, 2005