Ohio earthquake was not a natural event, expert says - Yahoo! News CLEVELAND (Reuters) - A 4.0 magnitude earthquake in Ohio on New Year's Eve did not occur naturally and may have been caused by high-pressure liquid injection related to oil and gas exploration and production, an expert hired by the state of Ohio said on Tuesday. Ohio's Department of Natural Resources on Sunday suspended operations at five deep well sites in Youngstown, Ohio, where the injection of water was taking place, while they evaluate seismological data from a rare quake in the area. The wells are about 9,000 feet deep and are used to dispose of water from oil and gas wells. The process is related to fracking, the controversial injection of chemical-laced water and sand into rock to release oil and gas. Critics say that the high pressure injection of the liquid causes seismic activity.