Federal regulators have shut down 17 wastewater disposal wells in the Osage Nation of northeastern Oklahoma following a weekend earthquake that matched the state's strongest on record, state officials confirmed Tuesday. Because the wells are located on tribal land, Oklahoma regulators have no jurisdiction over oil- and gas-producing facilities in the region, reports the AP. The 17 wells are located in a 211-square-mile area within Osage County, near where a magnitude 5.6 temblor struck Saturday, leaving one man with a minor head injury. At least 11 homes and several Oklahoma State University campus buildings were reportedly damaged. “The USGS cannot currently conclude whether or not this particular earthquake was caused by industrial-related, human activities,” the USGS said in a statement, via the Wall Street Journal. “However, we do know that many earthquakes in Oklahoma have been triggered by wastewater fluid injection.”
"We are working closely with the state of Oklahoma, the Bureau of Indian Affairs, and the Osage Nation to evaluate available information and take appropriate next steps to protect public health and the environment," an EPA rep says. State regulators, which since 2013 have asked wastewater-well owners to reduce disposal volumes in parts of the state, already had ordered 37 wells in a 514 square-mile area around the epicenter of Saturday's earthquake to shut down within seven to 10 days because of previous connections between the injection of wastewater and earthquakes. Meanwhile, two more earthquakes of magnitude 4.1 and 3.6 rattled northwest Oklahoma on Tuesday, in an area away from Saturday's quake. There were no reports of damage or injuries.