When I first heard about "fracking causes earthquakes" a few years ago, I put it in the same category as burning tapwater and forgot it. Apparently I was wrong: it's wastewater disposal, not fracking, and it's now officially a fact in Oklahoma, but not in Texas:
http://www.scientificamerican.com/artic ... rthquakes/
"To many Oklahomans, it is clear that that risk has risen sharply. Data backs up their experiences. The earthquake rate in the state has grown at an astounding pace. In 2013 the state recorded 109 quakes of magnitude 3 and greater. The following year the number jumped to 585, and in 2015 it reached 890.
The escalation prompted two unusual warnings jointly issued by the USGS and the OGS in October 2013 and May 2014. Seismologists stated that Oklahoma had a significantly increased chance of seeing a damaging magnitude 5.5 temblor. “It was the first time I think we’d ever issued an earthquake advisory east of the Rockies,” says Robert Williams, the USGS central and eastern U.S. coordinator for earthquake hazards."