Just five years ago Japan's "worst case" quake scenario was an 8.6 quake every 500 years! (tags)
In 2006, the government predicted that the worst Japanese quake would be an 8.6, occuring once every 500 years! (The current one was 9.0). They said that a 72 ft. tsunami would cause 2,700 deaths -- the current one was just half as tall, but will likely be four times as deadly. Nuclear disasters weren't predicted either....