The Most Powerful Earthquake to Ever Rumble Through Oklahoma

Oklahoma is a southern state dealing with a sudden increase in seismicity. Although Oklahoma once averaged about one or two earthquakes strong enough to be felt each year, that number has vastly increased since 2009. According to the United States Geological Survey, the rise in seismic activity correlates with an increase in oil production practices in the area that induces earthquakes. Discover the most powerful earthquake to ever rumble through Oklahoma, including its power, the damage it caused, and the casualties it inflicted upon humans and animals in the region.

What Was the Most Powerful Earthquake to Ever Rumble Through Oklahoma?

The most powerful earthquake to ever rumble through Oklahoma was a 5.8 M_w quake on the magnitude moment scale. The earthquake occurred on September 3, 2016, at about 7:02 a.m. CDT, and aftershocks continued for almost four hours following the initial event. These aftershocks rated between 2.6 and 3.6 M_w. This powerful quake beat the previous record set in 2011, a 5.7 M_w earthquake.

The epicenter of the earthquake was located at 36°25′48″N 96°55′55″W, a part of Pawnee County and home of the Pawnee Nation. The quake struck at a depth of 3.4 miles on a strike-slip fault called the Pawnee fault or the Sooner Lake fault, a previously unknown fault. The Pawnee fault is close to the Watchorn and Labette faults.

Originally, the quake was rated a 5.6 M_w, but further analysis revealed its true power. The earthquake was so strong that it was felt as far away as Chicago.

What Caused the September 2016 Earthquake?

A strike-slip fault caused the most powerful earthquake to ever rumble through Oklahoma. In such faults, horizontal shearing forces cause the ground to move parallel to the earth’s surface.

Scientists also explored this earthquake as part of the increase in Oklahoma’s seismicity since 2009. They found that ongoing industrial activity in the area, especially wastewater injections as a part of an oil extraction process, induced earthquakes.

The Sooner State has seen a vast increase in the number of earthquakes, especially those rated 3.0 M_w or higher, quakes that people would notice. The injection of wastewater can induce earthquakes that would not have occurred for decades or centuries.

As a result, the Environmental Protection Agency stepped in and closed dozens of wastewater disposal wells in the region in an effort to prevent future earthquakes from occurring in the region.

Where Is Pawnee County on a Map?

The earthquake’s epicenter was in Pawnee County, a north-central part of Oklahoma. More specifically, the epicenter was about 2 miles south of the Arkansas River. Also, the epicenter was about 10 miles northwest of the city of Pawnee, Oklahoma.

Although the epicenter of the earthquake is not in a very populated part of the state, the seismic event still caused some damage to the region.

How Much Damage Did the Most Powerful Earthquake to Ever Rumble Through Oklahoma Do?

Fortunately, the strongest earthquake to strike the Sooner State did not do a great deal of damage. The earthquake struck an area that was not very populated with people or structures. The maximum intensity of the quake on the Modified Mercalli intensity scale rated VII. So, this event was very strong, but only about a dozen buildings in Pawnee sustained damage.

Fortunately, engineers found that the area’s bridges, dams, and other major pieces of infrastructure survived the shifting ground. Pictures from the city showed that some stones were shaken loose from buildings and fell to the ground. Fortunately, only minimal casualties occurred during this event, and nobody perished.  

How Many Casualties Occurred During This Event?

The earthquake only caused a single reported casualty. An individual walking in Pawnee was struck by bricks shaken loose from a chimney during the earthquake. The man protected a child from the falling bricks, taking the blows himself. Fortunately, he merely sustained some head injuries and was later released from the hospital after treatment.

Although the most powerful earthquake to ever rumble through Oklahoma may have inflicted casualties on local wildlife. Unfortunately, no records exist of the impacts the quake had on animals.

Overall, the most powerful earthquake to ever rumble through Oklahoma was a 5.8 M_w event that injured a single person. Fortunately, this seismic activity occurred in a somewhat desolate part of the state. The ongoing increase in seismic activity in the region, an increase driven by human actions, could see other powerful, potentially deadly earthquakes strike this part of the country. For now, though, Oklahoma has yet to experience a truly devastating quake, and everyone hopes it stays that way.

The photo featured at the top of this post is © Дмитрий Ларичев/iStock via Getty Images