Ihmisten aiheuttamia maanjäristyksiä

Tesla: Man Out of Time
Margaret Cheney

He attached an oscillator no larger than an alarm clock to a steel link 2' long and 2" thick.

"For a long time nothing happened, but at last the great steel link began to tremble, increased its trembling until it dilated and contracted like a beating heart, and finally broke. Sledgehammers could not have done it", he told a reporter, "crowbars could not have done it, but a fusillade of taps, no one of which would have harmed a baby, did it."

Pleased with this beginning, he put the little oscillator in his coat pocket. Finding a half-built steel building in the Wall Street district, 10 stories high with nothing up but the steelwork, he clamped the oscillator to one of the beams.

"In a few minutes I could feel the beam trembling. Gradually the trembling increased in intensity and extended throughout the whole great mass of steel. Finally the structure began to creak and weave, and the steelworkers came to the ground panic-stricken, believing that there had been an earthquake. Before anything serious happened, I took off the oscillator, put it in my pocket, and went away. But if I had kept on 10 minutes more, I could have laid that building flat in the street. And with the same oscillator I could drop Brooklyn Bridge in less than an hour."