What if Everyone Jumped?

When I was a kid, I remember someone telling me that if everyone in China jumped up and down at the same time, they could cause a tsunami that would wipe out the entire United States.  As a kid this seemed perfectly plausible to me.  Well, now as an adult, with a slightly more scientific/quantitative view of things, I'm curious as to just how realistic this scenario is.  The video above is an exploration of this question to help us understand just how much we humans can effect the Earth... at least as far as jumping is concerned.