Using recent seismic data and studies of ancient fault lines, scientists have concluded that an increase in earthquake activity in parts of the United States is directly tied to hydraulic fracturing, which results in the disposal of pressurized wastewater deep into cracks in the earth’s crust.
Since 2008, states such as Texas, Kansas, and Oklahoma have experienced record numbers of earthquakes, both big and small. In Oklahoma, the number jumped from one to two per year to more than 800. Texas’ earthquake rate has increased six-fold in recent years. Many scientists have argued that these increases are the result of increased hydraulic fracturing, or fracking, activity in the central U.S., but others have contested that conclusion.
A team of geologists from Southern Methodist University in Dallas and the U.S. Geological Survey examined geological structures in Texas’s Fort Worth Basin dating back 450 million years. “There hasn’t been activity along these faults for 300 million years,” Beatrice Magnani, a seismologist at Southern Methodist University and lead author of the new study, told Scientific American. “Geologically, we usually define these faults as dead.” The scientists then compared the Texas data with seismic activity in northern Mississippi, which has experienced continuous fault activity for the past 65 million years.
The scientists concluded that Texas’ recent earthquakes can’t be explained by natural geological processes. Rather, they are “of induced origin,” they wrote in the study, published last week in the journal Science Advances.
“There is no other explanation” for this rise in earthquakes, Magnani told The Washington Post.
Editor’s note: This story has been edited for clarity.