Posted by Jeff Tollefson
...Cliff Frohlich, a seismologist at the University of Texas at Austin, used highly sensitive data from the seismic component of the National Science Foundation’s EarthScope initiative to investigate the impact of hydraulic fracturing operations tapping into the Barnett Shale. Operating across a 70-kilometre grid, Frohlich identified 67 tremors with magnitudes as small as 1.5 from November 2009 and September 2011, according to the study, published today in the Proceedings of the National Academy of Sciences. All of the 24 earthquakes for which the epicentre could be reliably located were within 3.2 kilometres of at least one injection well....
