By Lorraine Chow
ven though scientists are pretty certain that wastewater injection from fracking and conventional drilling has led to the unprecedented spate of earthquakes rollicking Oklahoma, Texas and other states in recent years. Definitive proof, however, is rare. But now, in a study published Thursday in Science, researchers have fastened another nail in the “man-made earthquakes” coffin.
Using satellite imagery, the researchers found that a series of earthquakes that struck Texas between 2012 and 2013— including the largest-ever quake recorded in eastern Texas—were caused by the injection of large volumes of wastewater from oil and gas activities into deep underground wells.
As Mashable explained from the study:
Wastewater not only puts pressure on underground fault lines, causing “induced” earthquakes, but also pushes up the surface of the ground—a phenomenon called “uplifting” that can be seen from space.
Researchers used satellite images of ground uplifting to show how wastewater disposal in eastern Texas eventually triggered a magnitude-4.8 earthquake in May 2012, the largest earthquake recorded in that half of the Lone Star state.
“Our research is the first to provide an answer to the questions of why some wastewater injection causes earthquakes, where it starts and why it stops,” said study co-author William Ellsworth, a geophysics professor at Stanford’s School of Earth, Energy & Environmental Sciences.