The issue on real faults is they span massive areas. The San Andreas fault system spans basically the entire coast of California.

Even if we could identify the right points there's a big liability shift both legal and political between doing nothing and intentionally setting off an earthquake that would be hard to predict the size of. It's part of why ~~proscribed~~ prescribed burns fell out of favor, it's way easier to do nothing and blame nature than defending damage caused by intentional acts. It gets into messy areas where it's hard to convince people that the damage was lesser than it otherwise would have been in the future.

It's been theorized and allegedly attempted - https://en.wikipedia.org/wiki/Tectonic_weapon

Project Plowshare says hello:

https://en.wikipedia.org/wiki/Project_Plowshare

nuclear acupuncture

Never, fer get it, in a word, insurance.

Sounds like a plot for a Superhero movie ;)

Imagine if they trigger the California Big One and all of LA, San Diego and the SF Bay (and innumerable towns) are swallowed "because of man-made actions", I wouldn't want to be the Governor or President to approve that one lol