Its interesting to look back in time at scientists forecast for future quake activity for a given area and then evaluae whether or not this activity has occured within the time period that was forecasted.

In this article, written shortly after the Northridge earthquake, Lucile Jones warns that for the foreseeable future, LA should expect to experience a 5.0 or greater quake every year. It is now 2003, 9 years later and outside of the aftershock zone of Northridge, the biggest quake within the LA metro area has been a 4.2 in West Hollywood-Sept. of 2001. So LA did not experience a 5.0 or greater quake every year since Northridge.

I give credit to the scientist to making a hypothesis so soon after Northridge and posting in the press. It'd be interesting to see what other theories like this one they have developed since.