My first thought on seeing some of the images was that there must be some criminal negligence involved. There is one area with 20 or so similar looking apartment buildings (about 6 levels each) where every second one has completely pancaked.

I was in Christchurch, New Zealand during the 2011 earthquakes. Only 2 major building completely collapsed. One had been designed by an engineer with insufficient qualifications and the other had design issues that were previously identified but never addressed.