Quote Originally Posted by Gilligan View Post
Right, but I'm not talking about a basketball sized rock in the Atlantic, but in a swimming pool. Thats the scale that came to mind.
If you displace hundreds of billions of gallons of water they have to go somewhere, so the result is a tsunami. Just like if you shook a stone slab at the bottom of a swimming pool it wouldn't make much difference but if a tectonic plate shakes at the bottom of the ocean it does.