A hydraulic fracturing, or fracking, well in Ohio triggered scores of small earthquakes in March 2014, including one large enough to be felt in nearby towns, a new study confirms. The biggest quake, a magnitude 3, was one of the largest ever caused by fracking. State officials shut down the well two days after the earthquake hit.
Fracking involves the high-pressure injection of water, sand and chemicals into rock to break it up and release trapped oil and gas. In Ohio, fracking triggered earthquakes on a hidden fault in ancient crystalline rock beneath a natural gas well in the Utica Shale, according to the study, published today (Jan. 5) in the Bulletin of the Seismological Society of America.
No earthquakes were ever recorded in this region of Ohio before fracking started, and the shaking stopped after the well was shut down, said lead study author Robert Skoumal, a graduate student in seismology at Miami University in Ohio. Skoumal and other Miami University researchers identified 77 earthquakes with magnitudes ranging from 1 to 3 that occurred from March 4 to 12. [Top 10 Ways to Destroy Earth]
"The company happened to be unlucky because they were hydraulic fracturing near an unknown fault," Skoumal said.
The largest earthquake rattled nerves in eastern Ohio but did not cause any damage. "It could be felt, but this is a very small event," Skoumal said. "It did not pose any risk."
It's rare for fracking to cause earthquakes that people can feel. This is the fifth reported case tying fracking to felt earthquakes, and the second instance in Ohio. Fracking typically causes tiny tremors that are too small to be felt by people, usually smaller than about magnitude 1.