eldavojohn writes "A recent peer reviewed paper and survey by Cliff Frohlich of the University of Texas' Institute for Geophysics reveals a correlation between an increase in earthquakes and the emergence of fracking sites in the Barnett Shale, Texas. To clarify, it is not the actual act of hydrofracking that induces earthquakes, but more likely the final process of injecting wastewater into the site, according to Oliver Boyd, a USGS seismologist. Boyd said, 'Most, if not all, geophysicists expect induced earthquakes to be more likely from wastewater injection rather than hydrofracking. This is because the wastewater injection tends to occur at greater depth, where earthquakes are more likely to nucleate. I also agree [with Frohlich] that induced earthquakes are likely to persist for some time (months to years) after wastewater injection has ceased.' Frohlich added, 'Faults are everywhere. A lot of them are stuck, but if you pump water in there, it reduces friction and the fault slips a little. I can't prove that that's what happened, but it's a plausible explanation.' In the U.S. alone this correlation has been noted several times."