A map of earthquake epicenters and known faults for the State of Ohio, issued by the Ohio Dept. of Natural Resources following earthquakes in March 2014 in the Youngstown, OH area. The ODNR says the quakes were "probably" caused by fracking in the area. If true, it would be the fourth time in recorded history (out of more than 60,000 horizontally hydraulically fractured shale wells) that fracking has caused an earthquake. To date earthquakes are usually related to injection wells and not fracking. The ODNR has instituted tight new regulations for fracking near previous seismic activity or known faults.