I spent nearly 15 years in the earthquake business, as instrumentation tech. I still have some interest left. California is an interesting locale for quakes, given the many faults that traverse it.
Old joke: Q: How do you find an active earthquake zone fault? A: Look for a nuclear power plant.
In the following article is one Seismologist's learned opinion, I'm sure though that if you ask ten Seismologists you would at least 20 opinions.
One can be reasonably sure that they will all agree that the big one is a question of when. All the ones I worked with agreed on that point 30 years ago. If I had to guess, the big one is now a lot closer in time than when I was in the research community.
Is California overdue for a big earthquake? - CSMonitor.com
An excerpt:
"
Q: How does California fit into the world of earthquake storms?A: Most of the motion between the Pacific and North American plates occurs along coastal California. In the last hundred years, there has been only one significant earthquake along those plates: the 1989 Loma Prieta earthquake, also known as the World Series earthquake.
But during the previous hundred years before that, there were five significant earthquakes along the California coast, in 1812, 1838, 1857, 1868, and 1906.
Large earthquakes are the major means by which seismic energy gets released after building up between the two tectonic plates. And so one or more large earthquakes are in California’s future. It is a matter of when."
