Dunno but it was built before after the '89 quake, which was a catalyst for a lot of new laws.
More from wiki for that building:
As of 2017, a city inspection has found that the building is still safe to occupy, though there has been damage to the foundation and electrical system.[8]
In early September 2018, residents reported hearing various “creaking sounds”. At around 2:30 a.m. on the morning of Saturday, September 8, 2018, residents reported hearing a loud “popping sound”. On Sunday, the following day, a resident located in a corner unit on the 36th floor discovered a cracked window. The glass used in the building’s windows and facade is rated to withstand hurricane force winds, leading to concern that the crack was a symptom of a much larger structural failure.[39]
Cool, thanks. Scanning your links, submillimeter(!) accuracy is possible. The study of the area around the building was done recently, using archived data. They claim accuracy for this kind of analysis of 1-2 mm/year. Freaking amazing.
I would guess the building has had structural issues for years. They probably avoided fixing for 40 years until they had to per requirements. Sounds like work being done on building when it collapsed. Overloaded roof could cause this or not shoring it properly. If it was caused by concrete spalling or corrosion from saltwater you would think other buildings in the area built in same time period would be experiencing the same problems. I don’t think the foundation failed because that just doesn’t really make sense to me. I hate even speculating on this. Just what a horrible tragedy.
I am a little surprised that there are so few reports on people they found. 99 missing but doesnt seem they find people dead or alive in this rubble or CNN just doesnt report it.