when the ground heaves and you see a lot of ground damage, it doesn t matter what you do to the structure, it is going to collapse. so, you know, there is only so much you can do, but what one should do is retrofit buildings if you know you are in a seismically active area as we are in california. i did a story on the fact that the middle of our country is they see their share of small earthquakes and they are preparing for a potential big one and they were talking about reinforcing buildings along that fault line, the new madras fault and trying to talk cities into reinforcing buildings. but you are saying, depending on the earthquake, it doesn t matter, because it can still do damage. reporter: that s correct. in the earthquakes in 1811, 1812, they were in the range of sizes from 7 to 8. they rerouted the mississippi and they did a great deal of damage, which you can see still