Oklahoma Grapples With Earthquake Spike—And Evidence of Industry's Role

Spike in seismic activity is linked with oil and gas wastewater disposal.

Bricks fell from three sides of this home in Sparks, Oklahoma, after two earthquakes hit the area in less than 24 hours in November 2011.


Customers who stop by Mike Kahn's insurance agency in Oklahoma City are increasingly looking to buy a policy that was unheard of a decade ago: earthquake insurance.

Kahn, who opened the Lynnae Insurance Group in 2002, said he sold earthquake coverage to two homeowners during the first decade he was in business. During the past six months, he sold more than 125 policies.

"We used to get to that part of the policy, and I'd tell customers, 'You don't need that. This is Oklahoma,'" Kahn said, referring to the days when earthquake coverage was an add-on to a homeowner policy. "We used to laugh about it."

But much has changed in Oklahoma, which leads the continental United States in earthquakes so far this year. From 1978 to 2008, Oklahoma experienced an average of one earthquake a year of magnitude 3 and higher, according to the U.S. Geological Survey. As of last week, the state experienced 258 earthquakes in that range, almost twice as many as California.

A growing body of research has tied the spike to wastewater injection, a process in which water from oil and natural gas extraction, including fracking, is pumped into underground wells for disposal. Research has also tied wastewater injection to quakes in Arkansas, Colorado, Ohio, and Texas.

But none of those states have seen as many earthquakes as Oklahoma. Because the oil and gas industry is a major employer in the state, the possibility that drillers might be responsible for the earthquake surge has put industry on the defensive and residents on edge, while sending state and local governments scrambling to respond. (Related: "Scientists Warn of Quake Risk From Fracking Operations.")

"The anger is palpable," said John Wood, a member of the city council in Guthrie, Oklahoma, a small city near the epicenter of a 4.3 magnitude quake that struck in mid-July, one of seven earthquakes that hit in the state in a two-day period. "Our bread and butter is oil and gas, so we have been very slow to question the industry on quakes. But it's becoming a daily occurrence."

Although the majority of the quakes have been harmless, they range from temblors that are barely felt to a 5.7 magnitude quake in 2011 that damaged homes. People can feel vibrations of a magnitude 3 temblor. A magnitude 4 quake feels like a heavy truck striking a building. At magnitudes 5 to 6, according to the USGS, dishes break, heavy furniture moves, chimneys fall, and a poorly built home can sustain serious damage.