I have been asked quite a few times why seeming seemingly unaffected assets are being hit so hard by the tragedy in Japan. While nobody knows for certain why markets do what they do, I will hazard a guess. As a result of 0% interest rates in Japan many Japanese engage in carry trades, because they cannot get any income on domestic assets. These carry trades also happen to be part of the "risk on" trade, and the Japanese are now fleeing to safety.
Many investors carry out momentum strategies which exacerbates these movements. On top of that many hedge funds carry out momentum strategies while calling it a different name. They call it "risk management", which means they sell positions once they start going against them. Add to that the recent rise in leverage and the margin clerk starts getting into the act.
This creates pockets of value for those who were not overly committed heading into this crisis. That said its difficult to know when the vicious circle will end and there might be yet better prices first.