By CHRISTIN COYNE
Scientists have known for some 50 years that injection can lead to seismic activity, according to one researcher studying the Azle earthquakes.
However, it’s not always an easy thing to determine whether a particular injection well is or isn’t causing earthquakes and USGS researcher William Ellsworth, a geophysicist working with a research team from SMU and other colleagues to study the dozens of recent small earthquakes near Azle, isn’t making any promises.
“The scientific evidence has really been very conclusive since the 1960s about how injection can induce earthquakes,” Ellsworth said. “It doesn’t prove that any particular well is responsible but the mechanism is well understood. And often what we lack is enough information to really tie pieces together to associate activity with a particular well or to rule out an association.”
Researchers aren’t sure when they may have more information to present to the community regarding the Azle earthquakes.
“It all depends on what data may tell us and interpretations of these kind of results often contain some ambiguity so we can’t promise something that we can’t deliver,” Ellsworth said.
Injection wells are used to inject into the ground, through layers of rock and shale, waste fluids used in oil and gas drilling operations. There are reportedly several injection wells in the area near Reno that officials have cited as the epicenter of the recent Azle-area quakes.
Ellsworth couldn’t say whether the seismic activity in the area might have been triggered by human activity.
“Very generally, we do know that there are tectonic earthquakes, natural earthquakes, that occur in Texas so I don’t think that anyone has jumped to the conclusion that these are induced at this point,” Ellsworth said.
However, he did note that after scientific studies of earthquakes in the Barnett Shale, Prof. Cliff Frohlich, the senior research scientist at the Institute for Geophysics at the University of Texas in Austin, found many of the recent earthquakes are associated with injection.