Final answer:
Seismic codes in Japan were developed in response to the 1923 Great Kanto Earthquake, a devastating event that underlined the need for earthquake-resistant construction and had significant social repercussions.
Step-by-step explanation:
Seismic codes in Japan did not develop until after a significant event in the nation's history. The development of seismic codes was largely in response to the 1923 Great Kanto Earthquake, which measured 7.8 on the Richter scale and resulted in the devastation of Yokohama and Tokyo. This catastrophic event, which claimed nearly 150,000 lives due to the earthquake, fires, and tsunamis, underlined the necessity for earthquake-resistant construction practices. In the aftermath, it became evident that buildings had to be designed to withstand seismic activities, leading to the implementation of seismic codes to protect against future disasters. Additionally, the earthquake had social repercussions as well, as rumors and subsequent violence against Koreans showed a different kind of societal response to disaster.