Fracking Fears Grow: Oklahoma Now Experiences More Earthquakes Than California -- July 8, 2014

Bloomberg is reporting:

So far this year, Oklahoma has had more than twice the number of earthquakes as California, making it the most seismically active state in the continental U.S. As recently as 2003, Oklahoma was ranked 17th for earthquakes. That shift has given rise to concern among communities and environmentalists that injecting vast amounts of wastewater back into the ground is contributing to the rise in Oklahoma's quakes. The state pumps about 350,000 barrels of oil a day, making it the fifth largest producer in the U.S.

The rise in earthquakes isn't just happening in Oklahoma, challenging scientists and regulators across the country. The growth of seismic activity alongside oil production in fracking states from Colorado to Ohio has sparked a series of studies tying the temblors to drilling activity. Most seismologists around the country are convinced that wastewater injected back into the ground is jolting fault lines and triggering earthquakes. Between 2006 and 2012, the amount of wastewater disposed in Oklahoma wells jumped 24 percent, to more than 1 billion barrels annually, according to the Oklahoma Corporation Commission, which regulates the industry. 

Guilt by association. It's not fracking per se that is associated with earthquakes; it is wastewater injected back into the ground. This has been discussed before.