A 5.8-magnitude earthquake and a series of smaller aftershocks in Oklahoma led to the discovery of a new fault line and stoked fears among some scientists about activity along other unknown faults that could be triggered by oil and gas wastewater that’s being injected deep underground.
State and federal regulators on Monday said 32 disposal wells in northeastern Oklahoma must shut down because they are too near the newly discovered fault line that produced the state’s strongest earthquake on record on Sept. 3.
Jeremy Boak, head of the Oklahoma Geological Survey, said it’s possible that a large “pulse” of disposed wastewater is slowly moving deep underground and triggered the temblor along the new fault located near the town of Pawnee, farther east than most of the previous earthquake activity in Oklahoma.
“My inclination is to worry about the (fault) we don’t know about yet, more so than about another very large earthquake in this area,” Boak said. “My general feeling is that the rate of earthquakes is declining. I’m more concerned, I think, about whether there’s another one of these faults out here that is cued up and ready to go.”