Environmental activist Erin Brockovich is helping Oklahoma‘s Pawnee Nation take on several fracking companies in a lawsuit alleging that damages to its tribal buildings and reservation property was the result of man-made, or induced, earthquakes.

National Geographic reports that the Native American tribe has retained the law firm Weitz & Luxenberg, with the aid of Brockovich, to sue Eagle Road Oil LLC, Cummings Oil Company, and 25 other oil and gas companies.

In September 2016, a magnitude 5.8 earthquake—the state’s largest ever recorded—struck near the town of Pawnee. The tribe alleges that wastewater injected into wells operated by the defendants caused the record-breaking quake and is seeking damages to real and personal property, market value losses, as well as punitive damages.

The lawsuit accuses the defendants of “knowingly causing” the tremors and that their actions “constitute wanton or reckless disregard for public or private safety.”

The case will be heard in tribal court. “The Nation wanted this to be an assertion of their sovereignty,” Curt Marshall, counsel for Weitz & Luxenberg representing the Pawnee, told National Geographic. “After all, they are a nation, a sovereign nation: they have jurisdiction, even over non-Indians, on their land.”

A growing body of research has linked Oklahoma’s alarming spate of earthquakes to wastewater disposal deep underground. These fluids can cause pressure changes to faults and make them more likely to move. Scientists have dubbed this phenomenon as “induced earthquakes” as they are triggered by human activities as opposed to “natural” seismicity.

The Midwestern state is not previously known for seismic activity. Before 2009, Oklahoma felt two earthquakes per year. But in 2014, the numbers jumped to about 2,500 in 2014, 4,000 in 2015 and 2,500 in 2016.

The U.S. Geological Survey said that the decline in 2016 quakes could be due to injection restrictions implemented by the state officials.

Although there were fewer tremors last year, Oklahoma felt more 4.0+ quakes in 2016 than in any other year. Another damaging quake struck the state in November—a 5.0 near Cushing, one of the largest oil hubs in the world.

Earlier this year, Brockovich and lawyers from Weitz & Luxenberg traveled to the state to speak with residents about the earthquake swarm.

“The communities definitely [are] feeling frustrated and voiceless and helpless and not sure where to turn” Brockovich said after a Pawnee meeting in January.

Brockovich, who currently lives in Los Angeles, recounted to National Geographic about her summers in Oklahoma as a child.

“The only thing I’d worry about growing up there was tornadoes,” Brockovich said. “Now I’d be afraid not of a tornado, but an earthquake? That’s just bizarre.”

It’s difficult, she added, “to go back to Oklahoma, to see how on edge [the Pawnee people] are. The question they keep asking is, ‘When will it end?'”