I'd be more concerned about buying "soft story" (what non-civil engineers call "top heavy") real estate. But modern high density housing is engineered to withst

I'd be more concerned about buying "soft story" (what non-civil engineers call "top heavy") real estate. But modern high density housing is engineered to withstand earthquakes. For example one of the tallest residential buildings in SF, 1 Rincon Hill, was engineered either all kinds of weight balancing measures and reinforcements. So long story short, I'd never buy "soft story" real estate, but the newer or retrofitted stuff should be fine.