Yeah, I moved since that picture was taken. They are still on concrete though.
And no, I haven't done anything re: earthquakes. To be honest, I have been living in Southern Cal since college, some 20+ years, and I have yet to experience anything of consequence. Not saying it won't happen, but it is so seldom.
What I did though is remove 500 of my most pricey posters and they are now stored in a climate controlled storage facility. Posters like Vertigo, Rear Window, Laura, etc... I still have some quality posters at the house, but nothing that would be hard to replace. Well, a few
I'm much closer to the beach, so I was a little concerned with humidity, but it's a non issue, though. I would be much more panicked if I was living in Florida.
T