There was essentially a man made sink hole. The pool deck collapsed next to the part building that collapsed first. There was a condo owner on the phone with her husband when it happened.
Tks for the responce. Was thinking more natural vs man-made. Techniques back then have improved today for better assessment prior to building.
See pic 58..
https://www.washingtonpost.com/photography/interactive/2021/photos-building-collapse-miami-dade/