You don't think the billions of tons of rock are going to spread out? :p
Seriously though, we see shockwaves from exploding stars affecting the material around them. I don't know the mechanics of what is causing it or how it spreads, but it does.
Interestingly, probably not! When the moon formed it was MUCH closer to earth. The moon is ever so slowly moving away from the planet, bit by bit. So a fresh debris field from a sufficiently similar impact wouldn't reach as far as the moon is today