In the spring of 2021, Sarper Ozharar—a physicist at NEC Laboratories, which operates the Princeton test bed—noticed a strange signal in the DAS data. “We realized there were some weird things happening,” says Ozharar. “Something that shouldn’t be there. There was a distinct frequency buzzing everywhere.”
https://arstechnica.com/science/2023/12/roar-of-cicadas-was-so-loud-it-was-picked-up-by-fiber-optic-cables/