Tornado Alley (PROG)

[F6]

fuagf -- that sounds like something to stop buildups of mechanical resonance, standing waves at a/the harmonic frequency, in structures like bridges or buildings -- Tesla built a small device that would generate waves at a/the harmonic frequency of whatever it was attached to that he claimed nearly brought down the NYC building in which his lab was located ( http://kwc.org/mythbusters/2006/08/episode_60_earthquake_machine.html )