When worlds collide!

I haven't thought about this for a while, but for some reason during some obscenly productive internet browsing I came upon this: http://www.space.com/scienceastronomy/050822_asteroid_apophis.html If you can't be bothered clicking the link, it basically describes the impending 32,000km close encounter Earth will have with a 350m wide asteroid called Apophis in 2029. 32,000km sounds an awful lot, but it's closer than the moon which is almost 380,000km away, so yes, a close shave. So, if this chunk of rock happened to hit our dear old planet earth, what would happen? Thanks to the University of Arizona, they've worked out a simple computer program to help out here: http://www.lpl.arizona.edu/impacteffects/ The likely scenario is that Apophis would strike the earth in water, probably deep ocean somewhere about 2km in depth. So, if you were 1000km away, what would you feel? Well, not much apparently. You'd hear it, almost as loud as heavy traffic, you may feel a slight tremor about 3 minutes later, but otherwise nothing. If you were 100km away, you will suffer third degree burns over most of your body and your ears would be damaged by the noise. Even if Apophis landed on solid ground, the effects within a 100km radius would be survivable. So, I guess should all this eventuate you would be pretty darn unlucky to be at the epicentre of such a collision, but I'm sure there are some parts of the world that would benefit from such an event.