California Earthquake Codes

[Paul Wolfson]

I am looking to buy a two-story single family home in SoCal. I was hoping that after the 1994 Northridge Earthquake, building codes improved for residential properties, but I'm not exactly sure what year did the codes changed significantly. Some say that homes built in 1980s have very good earthquake codes, but others say that after the 1994 earthquake is when it really improved.

Questions

1. Do you know what year, specifically after 1994, did major earthquake code changes go in effect?

2. When the big one hits, in terms of damage, will there be much difference between earthquake codes of a house built in 1989 vs. 2004?