Litigation brought over hydraulic fracturing—fracking—is looking at the connection between fracking wastewater and increased seismic activity and earthquakes.
For example, in 2010 and 2011, the town of Greenbrier, Arkansas experienced more than 1,000 minor earthquakes; the largest was a magnitude 4.7, according to Reuters. University of Memphis and Arkansas Geological Survey scientists said the activity was most probably triggered by fracking wastewater disposal, prompting regulators from the Arkansas Oil and Gas Commission to call for the shut down of a number of area wells.
The earthquakes stopped and more than a dozen residents filed five lawsuits in federal court naming Chesapeake Operating Inc. as the defendant. The defendant owns—as of 2010—two injection wells; BHP Billiton purchased Chesapeake’s shale gas assets in 2011, Reuters reported. Clarita Operating LLC owned a third well that was shut down. That company declared bankruptcy and was dropped from the lawsuit in 2011.
The litigation is the first legal effort that ties earthquakes to wastewater injection wells, as well as the first attempt to win compensation from drilling companies for earthquake damage, noted Reuters. The wells are not just used in fracking; they are employed in other oil and gas drilling, as well as in geothermal energy production. The first lawsuit, filed in U.S. District Court in Eastern Arkansas, is scheduled for trial next March, Reuters reported.
Steve Horton from the University of Memphis Center for Earthquake Research and Information installed seismic monitors around eight disposal wells and found that 98 percent of 2010-11’s earthquakes occurred within 3.7 miles of two wells. “Given the strong spatial and temporal correlation between the two wells and seismic activity on the fault,” Horton wrote in a study published in Seismological Research Letters in 2012. “It would be an extraordinary coincidence if the recent earthquakes were not triggered by the fluid injection. For these reasons, I conclude that fluid injection triggered the recent seismicity,” he added, according to Reuters.
We recently wrote that fracking has been tied in recent research to a significant association with increased seismic activity in Ohio. Records going as far back as 1776 indicate that Youngstown, Ohio has never experienced an earthquake; however, since January 2011, 109 tremors were recorded, according to The Institute of Engineering and Technology’s E&T Magazine. Emerging research from Geophysical Research-Solid Earth indicates that the increased seismic activity is probably due to area fracking facility activity.
“In recent years, waste fluid generated during the shale gas production—hydraulic fracturing, had been increasing steadily in US. Earthquakes were triggered by these waste fluid injections at a deep well in Youngstown, Ohio during January 2011 to February 2012. We found that the onset of earthquakes and cessation were tied to the activity at the Northstar 1 deep injection well,” said Dr. Won-Young Kim.
We previously wrote that other researchers found that the disposing of fracking wastewater might be associated with an increase in earthquakes. Researchers from Columbia University and the University of Oklahoma found what they described as a “profound” increase in the number of earthquakes at three different sites in which fracking wastewater was injected into the ground, said the study’s lead author, Nicholas van der Elst, a scientist at Columbia’s Lamont-Doherty Earth Observatory in Palisades, New York, according to a prior Bloomberg News report. van der Elst’s article on the research appeared in Science.
The researchers found that fracking wastewater disposal might impact fault zones, making them more prone to earthquakes. As subsurface rocks become saturated with fracking fluids, area fault lines, in turn, may become less stable, van der Elst said, according to Bloomberg News. “This study helps show the link between the pumping and the earthquakes,” van der Elst said in an interview. The report indicated that “significant seismic activity” taking place in other locations on earth—even as far away as on other continents—might “induce” an earthquake in a fracking injection zone days, even hours, following injection. “Seismic waves from the distant earthquake can squeeze the rock like a sponge,” van der Elst told Bloomberg News.
Fracking drilling involves horizontally injecting tons of silica sand, a massive mix of more than 600 chemicals, and water at least one mile underground via a drill into a concrete well that extends to a bed of shale rock deep beneath the earth’s surface. When this combination reaches the rock, it is blasted apart and natural gas is released and supposed to be returned to the surface and captured; most of the water remains underground.