There was no “oversight”, The building has always been designed to resist earthquakes. 

There are 4 categories of seismic design. 

Category 1 – “Buildings and structures that normally are not subject to human occupancy (e.g., equipment storage sheds, barns, and other agricultural buildings…”

Category 2 – “Most buildings and structures of ordinary occupancy (e.g., residential, commercial, and industrial buildings)…”

Category 3 – “Buildings and structures that: • Have large numbers of occupants (e.g., high-rise office buildings…• Shelter persons with limited mobility (e.g., jails, schools, …• Support lifelines and utilities important to a community’s welfare…”

Category 4 – “Buildings and structures that: • Are essential to post-earthquake response (e.g., hospitals, police stations, fire stations, and emergency communications…”

https://c.ymcdn.com/sites/www.nibs.org/resource/resmgr/BSSC/P-749_Chapter5.pdf

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