Ok, here's the scoop - you are told that a big fault zone rips every 1500 years, and the last one was 1500 years ago. Quel Horreur! It could happen any day now!
Then, somebody steps in and says - Whoops, we found a big one only 500 years ago!
Now, do you hype all this up to get more grant money, or do you say - whew!