Another study, this one at the University of Texas at Austin, says small earthquakes appear to be associated with some high-volume wastewater disposal wells, but not all of them. Using seismographs placed around the Barnett Shale, the study by Cliff Frohlich at UT's Institute for Geophysics also found many more small quakes than previously reported, suggesting the phenomenon is more common than supposed. The UT report echos a similar report by the National Research Council in June that also linked seismic activity with high-volume injection wells. Frohlich found that quakes occurred near nine of 27 high-volume disposal wells he studied in Johnson County, while there were few quakes near similar wells in Wise County. "A plausible hypothesis to explain these observations is that injection only triggers earthquakes if injected fluids reach and relieve friction on a suitably oriented, nearby fault that is experiencing regional tectonic stress," Frohlich wrote, adding that the theory would need more study to be proved. The Star-Telegram's report is here.
-- Jim Fuquay