The cycles between large quakes are way beyond my understanding
the big talk about the soon coming BIG ONE...in California has been going on for so many years that I’m thinking it may be utter speculation
This is good to know, Hoover Dam was designed with Earthquakes in mind.
“Hoover Dam in the US built in the 1930s was the first concrete dam designed against earthquake where both the inertial effects of the dam and the hydrodynamic pressure of the reservoir were taken into account.”
http://www.waterpowermagazine.com/features/featuredam-safety-and-earthquakes