This was close to DYI with me and the local handyman figuring out a good way to tie my house to its foundation. Not a full retrofit but pretty good for my 100yo house with nothing remotely close to modern design. Here are some resources I found useful though.
https://dnr.wa.gov/sites/default/files/2025-03/ger_homeowner...
https://www.wabo.org/earthquake-home-retrofit
