[The Lone Ranger]

Ah, I see. In that case, what he'd be referring to is the supposition that different parts of the statue's base have a different coefficient of friction with the support than others.

Picture a table with 4 legs. On 3 of those legs, the end is capped with grease, while the end of the fourth leg is capped with sandpaper. The fourth leg is going to experience much more friction with the floor than will any of the others.

So, if you vibrate the floor or otherwise subject the table to any sort of lateral stress, the fourth leg will be much more resistant to movement than will the other 3 legs. The result is that the table will have a tendency to rotate around that fourth leg.

I imagine that's what the physicist is referring to. If one part of the statue has greater friction against the support than do other portions (perhaps due to unevenness in either the statue base or the support, or because something sticky has somehow gotten attached to it), then vibrations will not cause the statue to move in a uniform manner. Where the statue is in contact with its support, whatever portion has the highest friction will be most resistant to movement, and so the statue will tend to rotate around that point.

Say the left side of the statue moves easily, but the right side is much more resistant to movement. In that case, the statue will tend to pivot around its right side.

That would explain not why it turns, but not necessarily why it always rotates in the same direction. After all, if it were on a perfectly level surface, it could rotate in either direction. But if it's inclined at all, then it will preferentially rotate in one direction, because of the Earth's gravity; the side that moves will tend to "fall" toward gravity.

Cheers,

Michael