A 4.0 magnitude earthquake that struck northeastern Ohio on Saturday might have occurred due to manmade causes. According to a CNN report, officials in Ohio have prohibited the opening of four new natural gas fluid-injection wells following the quake as there is concern that fracking to release the natural gas from pockets underground may be related to the increased seismic activity in the area.
One well was prohibited from opening after a 2.7 magnitude quake that occurred on Dec. 24 in the area, but Saturday's 4.0 temblor prompted officials to prohibit the planned opening of four other wells that are situated within a five-mile radius of the epicentral location.
What is fracking?
Fracking is a slang term for fracturing, a method of injecting fluid (usually saltwater) into the ground to fracture the earth and release natural gas deposits. The process of injecting the brine breaks up the hard shale rock and allows the natural gas to be collected.
Does fracking cause earthquakes?
While fracking is not believed to be the issue that triggers seismic activity, the wastewater used for fracking is disposed of via injection wells. The water is pressurized, then injected deep into Earth and it is this process that is believed to be able to trigger normally silent faults to rumble. According to the U.S. Geological Survey, minor seismic activity caused by wastewater injection has been documented in Japan, Canada and the United States.
Ohio quake preceded by smaller quakes
The 4.0 magnitude quake in Ohio was minor as far as seismic activity go. Leading up to that quake, the area around Youngstown saw several small temblors during 2011. According to the Ohio Geological Survey website, 10 small earthquakes occurred in the same area between March 17 and December 24. Those quakes ranged in magnitude from 2.1 to 2.7.
Historic seismicity of area
The largest earthquake registered in northeastern Ohio occurred in 1986 when a 5.0 magnitude quake struck rattled northeastern Ohio and northwestern Pennsylvania. This quake occurred on Jan. 31 and caused 17 injuries near the epicenter as well as property damage to homes and businesses.
Tammy Lee Morris is certified as a Community Emergency Response Team (CERT) member and is a trained Skywarn Stormspotter through the National Weather Service. She has received interpretive training regarding the New Madrid Seismic Zone through EarthScope -- a program of the National Science Foundation. She researches and writes about earthquakes, volcanoes, tornadoes, weather and other natural phenomena.