Scarlett –
my husband, being from the east coast (Philly), was SUPER paranoid about earthquakes when we moved here. He has since 100% changed his paranoia to fires.

There are things you can do to retrofit an older house. We haven’t spent much at all… (of course Hubby is doing the work.) It’s mainly just fixing things if we open a wall for some other reason.

That said – some of the classic mid-century features are things you need to consider for seismic… walls of bricks or stone around a fireplace wall… Hubby took out a lot of our brick around the fireplace to remove the weight – and then put wire and stucco over the remainder (more tuscan than mid-60’s now)… so that if an earthquake happens that brick won’t come landing in our living room and konk someone in the head.

As I said – my husband has shifted his previous paranoia from earthquakes to fire. (We’re right above San Clemente and have a deep canyon off shoot near our house). So now it’s about fire hardening the house… smaller screens on the soffit vents, nothing flamable right next to the house…

You can ALWAYS find a reason to decide against a house or neighborhood. But a lot of the issues can be addressed.