Dozens of Small Earthquakes Detected Near Texas Drilling Sites

A new study by researchers at the University of Texas has found that dozens of small earthquakes occurred in a shale region of north Texas within a two-year period, with many occurring close to injection wells associated with oil and gas drilling projects. In an analysis of seismic data, study author Cliff Frohlich found that 68 earthquakes had occurred between November 2009 and September 2011 — all with a relatively weak magnitude of 3 or lower — in the Barnett Shale region, a large area that covers several Texas counties and contains a geological formation increasingly targeted for extraction of oil and gas from shale formations. According to the study, published in the Proceedings of the National Academy of Sciences, 23 of those quakes occurred within two miles of high-volume injection wells that pump wastewater from controversial hydrofracturing drilling technology deep underground. “You can’t prove that any one earthquake was caused by an injection well,” Frolich said. “But it’s obvious that wells are enhancing the probability that earthquakes will occur.”