Oklahoma may be known for its wind swept plains, but the state’s current claim to fame is the recent spate of earthquakes across its central region. In 2010, the United States Geological Service (USGS) partnered with the Oklahoma Geological Survey (OGS) and installed 12 extra temporary seismic stations throughout Oklahoma and neighboring states to investigate what they believed was an increase in earthquakes. In the resulting study published in February, the USGS states that Oklahoma has experienced an increase in the rate of earthquakes over a 3.0 magnitude by almost 300 times.
One aspect noted by the researchers is that they believe there are fault lines, similar in origin to the Ouachita one underlying the DFW area, which intersect like a “V” under central Oklahoma. This style of formation leads to an increased risk of plate slipping and a greater likelihood of experiencing higher magnitude and more frequent earthquakes. Unfortunately, this study is misleading on other points.
Citing a 2011 earthquake with a 5.6 magnitude, the USGS researchers point at fracking as the cause of the largest quake in Oklahoma’s history. What they fail to mention is that the 2011 quake is the largest by .1 – and the next to largest occurred in 1952.
In a brief research study released last October, the OGS notes many scientists believe wastewater disposal wells are to blame for the increase in earthquakes. However, in Oklahoma, the largest increase in earthquakes over the last 5 years has occurred over an area totaling around 15 percent of the state. Over 3,000 disposal wells of varying depths are active across the entire state. Due to the relative dispersion of wells and earthquakes, there is no easy way to track, or say definitively, that the increase in earthquakes is man-made.
Although rare, Oklahoma has recorded at least one other earthquake over 5.0 magnitude and 30 others over 4.0 since the OGS began recording earthquakes in 1882. Notably, several of these major earthquakes occurred before fracking had been invented and many more occurred before it was in widespread use. While the USGS has been quick to blame fracking, the truth is, the science is not settled.