Oklahoma earthquakes raise more questions about hydrofracking, injection wells

By David O. Williams
Monday, November 07, 2011
The Colorado Independent

A holding pond for fracking fluids in Texas.

Another swarm of earthquakes in an unusual part of the country has generated aftershocks of debate about whether the oil and gas drilling process called hydraulic fracturing, or fracking, is to blame.

The early returns in Oklahoma, where a 5.6-magnitude earthquake near Sparks damaged buildings and rattled nerves on Saturday, are inconclusive. Much as scientists said there just isn’t enough evidence to link earthquakes this summer in Virginia and Colorado to fracking, officials over the weekend declined to connect the Oklahoma quake to the common drilling practice.

The process of fracking involves the high-pressure injection of water, sand and chemicals into oil and gas wells to break up tight rock and sand and free up more hydrocarbons. The fracking fluids are then stored for later use, recycled or disposed of in injection wells.

According to the Associated Press, there are 181 such injection wells in the vicinity of Saturday’s Oklahoma quake and Sunday’s aftershocks. AP also reported Oklahoma typically only experienced about 50 earthquakes a year until 2009 when that number spiked dramatically. Last year there were 1,047 small quakes in the area, prompting the installation of seismographs.


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