I'm glad I'm not the only one concerned about safety and maybe even a bit paranoid
I grew up in Iowa and my Dad and I would always work on our cars together. No earthquakes to worry about there. He had a heavy duty hydraulic jack (unlike my scrawny little guy) and used that as primary support. He was very safety-conscious, and never trusted jack stands, but used huge tree stumps with 4x4s on top of them as secondary support, usually under the bumpers. Can't do that on my GT...no tree stumps and I sure wouldn't trust the bumpers. He never had any accidents in over 50 years, but I was always nervous getting under a car or watching him.
My father-in-law, who is NOT safety-conscious at all, had a car up on ramps, and somehow it fell off them when he was under it. I still don't know how he survived. His chest was sore for a couple weeks, never went to the doctor, and went right back to working on cars.
I'm happy being paranoid...better safe than sorry. Especially now that I'm in California and don't have the luxury of my Dad's workshop and being able to ask his advice on things.