The Pawnee Nation filed a lawsuit on Friday in tribal court in Oklahoma against 27 oil and gas producers, seeking damages for an earthquake they said was caused from man-made activity related to hydraulic fracturing, or fracking. The Native American group claimed that wastewater injected into disposal wells helped trigger a 5.8-magnitude earthquake in September, the strongest on record in the state, that damaged several Pawnee Nation buildings, including several that are more than 100 years old.