Not sure where to begin with retrofitting our home, or how much we even need to do. We’re near a major fault line, so it seems important to at least investigate.
It would be the installation of posts and beams at any point load spot of the building. This is mainely at corners. It would be fitted with Simpson hardware that has been approved to help with stand earthquakes. If you have the money it can additionally be the addition of spread footings or momentum footings which require certain types of rebar which is done to spread point loads out and reduce the tensions on the point loads under stressful situations. The last multimillion dollar house I was part of in Hawaii required footings that where 6-10 feet wide 15-20 feet long and 3 feet deep with a certain assembly of Rebar. This the engineers designed to with stand a 8.0 quake and the house to have a 5 foot movement in the slab before the building would fall.