On Saturday, a magnitude 5.6 earthquake shook north central Oklahoma, prompting the U.S. Geological Survey (USGS) to investigate whether the quake was caused by the oil and gas industry’s practice of underground wastewater disposal. The quake, which is reportedly the largest in the state’s history, damaged some buildings but there have been no reports of injuries or deaths. Many environmental scientists have long suspected that industrial activities like this are linked to, and can even cause, earthquakes, and hopefully soon the USGS will have answers about what is happening in Oklahoma.
Saturday’s earthquake occurred near the city of Pawnee at 8:03 a.m. local time and was reportedly felt in six surrounding states. The quake was somewhat unusual because it occurred on a fault that seismologists didn’t even know existed. In fact, the fault that triggered the quake runs perpendicular to the larger well-known fault system. This is the key feature of the earthquake that piqued the interest of USGS researchers, who suspect that human activity may be partially responsible for kicking off the tremor. The Environmental Protection Agency is also investigating the causes and implications of the earthquake.
“Without studying the specifics of the wastewater injection and oil and gas production in this area, the USGS cannot currently conclude whether or not this particular earthquake was caused by industrial-related, human activities,” the USGS said in a statement. “However, we do know that many earthquakes in Oklahoma have been triggered by wastewater fluid injection.”
State regulators at the Oklahoma Corporation Commission have ordered oil and gas operators to shut down 35 disposal wells that may have contributed to this weekend’s earthquake in what Governor Mary Fallin has called “a mandatory directive.” The wells located within five miles of a 10-mile section of the fault linked to the quake, and they have been ordered to shut down within seven days, and all the other wells must be shut down within 10 days.
Last year, a series of earthquakes in Oklahoma had many scientists and environmentalists pointing fingers at fracking, the common practice in the oil and gas industry of injecting high-pressure liquids underground to open fissures, in an effort to gain access to oil and gas. As industry activity in the state has steadily grown, so too have the number of earthquakes measuring at least 3.0 on the Richter scale. After the magnitude 5.1 quake between Tulsa and Oklahoma City in February, 2015, residents feared that the worst was yet to come. With this weekend’s quake now being called the strongest ever in the state, and plenty of oil and gas industry drilling ongoing, nobody is sure at this point what to expect next.