I don't have any good ideas on how to measure the nuke rumor effect at the moment. But I have been wondering for a couple of months whether 風評 and rumor are the correct words to describe what is happening. If a rumor is "a story or statement in general circulation without confirmation or certainty as to facts," I'm not sure it applies to the current situation.

There are radioactive particles over a wide area of Tohoku and Kanto that were not there before March.
Anyone can see various maps on the internet showing where the particles went. So that's a fact, not a rumor.

Experts are arguing about how dangerous the particles are. On the extremes, one expert said if people laugh, the particles are not harmful at all. Another expert said that 1,000,000 people will be killed by them. But saying they are harmless or dangerous is an opinion, not a rumor. The government seems to want to stifle dissent by labelling opinions it doesn't like "rumors."

I hear the government intends to bring foreigners here on all expense paid vacations to dispel foreign "rumors." It seems that President Lee, Premier Wen and Lady Gaga didn't do the trick. I think it would better help the people whose livelihoods have been destroyed if the money were spent on cleaning up the contamination. And if anybody deserves a free vacation, it is them!

Greg Johnson