Oklahoma earthquake: Are oil storage terminals safe from shaking?

A magnitude 5.0 earthquake struck Oklahoma Sunday evening, the epicenter focused just a mile west of Cushing, which houses one of the world’s largest oil storage facilities.

Building facades in the city’s downtown area crumbled and windows shattered, stoking fears that key infrastructure related to the energy industry may also have suffered damage.

This is just the most recent in a series of thousands of earthquakes to have afflicted the state over the past few years, almost all of which are blamed upon activities related to oil and gas production. Some of this relates to hydraulic fracturing, or fracking, but most is linked to the practice of injecting wastewater from oil production into the ground.

Officials reported a few injuries in the immediate aftermath of this latest tremor and ordered some areas evacuated, but the damage appeared limited to commercial buildings in the city center.

The town, which houses nearly 8,000 people, lies about 50 miles northeast of Oklahoma City, but Sunday’s earthquake was reportedly felt as far away as Iowa, Texas, and Illinois. Just last week, another quake, magnitude 4.3, struck 25 miles further north, forcing several oil wells to shut down. About two months ago, one of the strongest ever recorded in Oklahoma – magnitude 5.6 –shook the area around Perry, just northwest of Cushing.

Earthquakes are generally natural phenomena, but scientists are linking more and more of them to underground oil and gas work, which has the ability to alter pressure points, thereby causing shifts in the Earth. Indeed, the Oklahoma Geological Survey released a report last year declaring that many of the earthquakes assailing the state are caused by injection into the ground of wastewater from oil production.

The controversial practice of fracking employs similar methods, injecting water, sand, and chemicals under high pressure into rock to facilitate the extraction of natural gas and other products. Yet the geological survey’s report said just a small percentage of wastewater injected into Oklahoma’s wells comes from fracking.

The Cushing quake is one of the largest to strike the state, and officials are still liaising with energy companies to determine what damage may have been inflicted. The countryside surrounding the city houses tanks containing 58.5 million barrels of oil, as of Oct. 28, one of the world’s largest oil storage terminals. The town bills itself as the “Pipeline Crossroads of the World.”

This report included material from the Associated Press and Reuters.