... Most earthquakes in the Barnett Shale region of North Texas occur within a few miles of one or more injection wells used to dispose of wastes associated with petroleum production such as hydraulic fracturing fluids, according to new research from The University of Texas at Austin. None of the quakes identified in the two-year study were strong enough to pose a danger to the public.
The study by Cliff Frohlich, senior research scientist at the university’s Institute for Geophysics, appears this week in the journal Proceedings of the National Academy of Sciences.
"You can't prove that any one earthquake was caused by an injection well," says Frohlich. "But it's obvious that wells are enhancing the probability that earthquakes will occur."