Seismologists tie well to DFW earthquakes

IRVING, Texas, March 11 (UPI) -- A well used to get rid of wastewater from natural gas drilling may have caused small earthquakes at Dallas/Fort Worth airport, university researchers say.

The injection well -- which disposed of water contaminated with salt, chemicals and crude oil by forcing it deep into the ground under high pressure -- was a "plausible cause" of the earthquakes, four Southern Methodist University and University of Texas at Austin researchers contend in a paper published in the Society of Exploration Geophysicists' journal, The Leading Edge.

The quakes started seven weeks after the well began operating in 2008 and stopped when the well was closed last year, the researchers observe.

A spokesman for Oklahoma City's Chesapeake Energy Corp., which owns the well in question, disputed the researchers' conclusion, telling the Star-Telegram of Fort Worth, Texas, "a direct, causal relationship between saltwater disposal wells and seismic activity" in the area of Dallas/Fort Worth International Airport had "not been scientifically proven."

SMU seismologist Brian Stump told the newspaper the researchers didn't suggest that they had definite proof, but that they'd found "a plausible cause."

"All of us would like to do more research," he said.

The researchers discovered the earthquakes, which shook walls and furniture but caused no damage on the surface, were centered on a fault line that runs close to the injection well at the south end of the airport, Stump said.

The quakes also occurred at the same depth as that of the injection well, about 2.7 to 3 miles underground, the researchers said.

"There needs to be collaboration between universities, the state of Texas, local government, the energy industry and possibly the federal government for study of this complicated question of induced seismicity," Stump told the newspaper.