Just to clarify, the improvements in building codes I mentioned applies primarily to California. The revisions were made after the San Fernando Valley earthquake of 1971. The codes, applying to residences and commercial structures, were primarily meant to prevent collapse; the building, even constructed post-1971, may be unusable afterwards. But, a good deal of the collapse-resistance is inherent in wood-frame construction even absent the 1971 code improvements.

Mike Williams in Arroyo Grande, CA
Disclaimer: I am not a professional seismologist - or engineer.