Oklahoma Earthquakes at Fracking Operations vs Wastewater Disposal Induced Earthquakes

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There is mounting evidence that fracking/injection well operations are causing instability in some regions of seismic activity, resulting in minor earthquakes. For instance, there have been multiple earthquakes this past week in Oklahoma at fracking/injection well sites. However, earthquakes that are much larger in magnitude have been caused, in Oklahoma and elsewhere, from the injection of wastewater back into the earth.

According to an article by Walter Russell Mead in The American Interest:

A team of researchers, led by Columbia University seismologist Nicholas van der Elst, found a correlation between the injection of fluids underground—a key step in the extraction of shale oil and gas (as well as the extraction of geothermal energy)—with the proliferation of thousands of relatively small-magnitude earthquakes.

Over the past 7 days Oklahoma has seen multiple earthquakes across the South, Central, and North part of the state, and they have all been at fracking/ injection well operations.

Though the quakes have been relatively minor in magnitude, they are significant, in that they point to a causal link between fracking/injection well operations.

On July 24, 2013, there was a 3.2 magnitude earthquake in north Oklahoma that occurred at a depth of 3.1 miles. Two nearby cities to the quake were Boley, Oklahoma,  from which the quake was just located 3 miles away; and, it was 27 miles from Shawnee.

Then, on July 27,  2013, a 3.1 magnitude earthquake happened in Oklahoma at a depth at 5.3 km or 5.5 miles

Nearby cities in the south of Oklahoma were Tonkawa, located just seven miles away, and Ponca City, 11 miles distant.

Finally, on July 28, at a depth of 4.8 km or three miles, a 2.8 magnitude earthquake occurred in Oklahoma. Two nearby cities to the quake were Chickasha, located just 3 km or 2 miles E of the quake, and 24 miles SSW of Mustang.

There is mounting evidence that the increasing numbers of earthquakes in Oklahoma, Arkansas, Colorado, New Mexico, and Texas are being primarily caused by injection wells along with hydrofracture (frack) well operations.

However, as bad as the practice of fracking is, wastewater disposal by injection into deep wells poses an even higher risk, because this practice can induce larger earthquakes.

For example, several of the largest earthquakes in the U.S. midcontinent in 2011 and 2012 may have been triggered by nearby disposal wells. The largest of these was a magnitude 5.6 event in central Oklahoma. That earthquake destroyed 14 homes and injured two people.

Both fracking and the disposal of wastewater are steps in the extraction of shale energy. Both carry seismic risks, but of the two, wastewater disposal is the more concerning.

Pressure builds along fault lines, which can lead to earthquakes, when wastewater is disposed of underground.

A benefit to the practice of fracking is that it has given the world access to an enormous new supply of energy. This shale oil source of energy has been particularly important to the US, which has taken the lead on its extraction.

 

Written by: Douglas Cobb

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