A new report concludes that recent North Texas earthquakes were induced, likely a result of wastewater injection wells, as opposed to occurring naturally.
The report was published late last month by the journal Science Advances, and was prepared by researchers with Southern Methodist University and the United States Geological Survey (USGS).
There have been a surprising number of earthquakes in what is known as the Fort Worth Basin in recent years — as many as 1,300 since 2013, according to the new report. The vast majority of those earthquakes have been minor — between a magnitude 1 to 4 — and many would have either never or barely been felt.
The frequency of the earthquakes that have been recorded in Texas has increased dramatically in recent years. Between 1847 and 1994 — a period of 147 years — there were more than 110 recorded earthquakes of magnitude three or greater, according to the Texas State Historical Association.
Between 2008 and 2016 — a period of 8 years — there were 96 recorded earthquakes of magnitude three or greater, according to the new report.
There are ancient fault lines that run below North Texas. The researchers looked deep into the rock record to come to the conclusion that the recent round of earthquakes has been induced.
“In the Fort Worth Basin, along faults that are currently active, there is no evidence of prior motion over the past 300 million years,” SMU noted in a news release.
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“The study’s findings suggest that the recent Fort Worth Basin earthquakes, which involve swarms of activity on several faults in the region, have been induced by human activity,” noted Michael Blanpied, associate coordinator of the USGS Earthquake Hazard program.
The Texas Railroad Commission (RRC) regulates the oil and gas industry in Texas and it has consistently stopped short of recognizing wastewater injection — the process of injecting water and chemicals produced as a byproduct of oil and gas extraction into underground zones for the purpose of safely and efficiently disposing of the fluid — as a likely cause of the recent earthquake swarm.
“The Railroad Commission has long recognized the possibility of induced seismicity related to fluid injection,” noted Gaye McElwain, a spokesperson for the Texas Railroad Commission.
McElwain said that the RRC has in place “some of the most stringent rules in the nation to address the issue.”
Recently, the Environmental Protection Agency (EPA) commended the Texas RRC’s underground injection control program, according to McElwain.
“During 2016, the number of recorded seismic events in North Texas dramatically decreased. EPA highly commends the RRC for its actions to address this situation, including implementation of changes in permitting and operation requirements,” the EPA noted.