Drop In Oklahoma Earthquakes -- SWD Well Management Cited As Reason -- July 1, 2016

In The Wall Street Journal today: Oklahoma Quakes Decline Amid Curbs on Energy Industry’s Disposal Wells. Drop attributed to restrictions on oil and gas companies’ pumping of wastewater from underground operations.

The number of earthquakes in Oklahoma has fallen 25% in 2016 compared with a year earlier, a decline attributed in part to actions by state regulators to police the oil and gas industry’s practice of pumping wastewater from its operations deep underground.

The Oklahoma Corporation Commission, which oversees the state’s oil and gas industry, earlier this year stepped up efforts to get companies to reduce the amount of wastewater they inject into hundreds of disposal wells, which have been blamed for a surge in earthquake activity in the state over the past decade.

More than 2,700 temblors of magnitude 2.5 or higher occurred in Oklahoma last year, up from 3 in 2005, according to data from the U.S. Geological Survey. So far this year, Oklahoma has had 1,098 quakes of that magnitude—strong enough to be felt by humans— down from about 1,400 over the same period in 2015.

It's a fine distinction, but an important distinction, it's not fracking per se that has been associated with earthquakes. It is the disposal of "salt water" that is associated with earthquakes.