>Expand where? Think of the ocean bed as a trampoline. Obviously much more rigid, but that's the image in my head. >It can't go down because there is already

>Expand where? Think of the ocean bed as a trampoline. Obviously much more rigid, but that's the image in my head. >It can't go down because there is already other stuff there. Why not? Rocks and sand can be compressed with sufficient pressure.