OP correctly points out that you can already find these throughout "the entire Mountain West", broad portions of which does have to deal with similar quakes (see: Washington, Oregon, BC, etc.).

Rock sheds like this can already be found in Big Sur, CA, Rogers Pass, BC, Snoqualmie Pass, WA and other places.

Further, Yosemite isn't necessarily in the most seismically active area of CA - while there are certainly earthquake concerns taken into account, it's not really relevant to the degree you've suggested it is throughout the thread.