Those tremors you feel in your high-rise building may not be an earthquake.  Ten minutes of violent shaking in a 39-story Seoul skyscraper were attributed in 2011 to “17 middle-aged people” doing Tae Bo to “The Power” by early 1990s German hitmakers Snap!

Every building has its own natural resonances that can be excited by rhythmic activity.  In most buildings these resonances are relatively docile and hard to excite, but when wide structural spans and thin slabs lead to a low natural frequency, it doesn’t take many kickboxers to get things…kind of hectic.

Tags: frequency, music, vibration