Great Kantō Earthquake Strikes Japan
Japan in the early 1920s was recovering from World War I and undergoing rapid urbanization and industrialization. The Kantō Plain, home to Tokyo and Yokohama, sat atop a seismically active zone where tectonic plates converge. At 11:58 a.m. on September 1, a magnitude 7.9 earthquake struck near noon, just as many residents prepared lunch over open flames. The initial shaking collapsed buildings across the region, and subsequent fires, fueled by high winds from a passing typhoon and broken water mains, raged for days. Over 140,000 people died, mostly from the fires, and more than a million were left homeless in one of the deadliest natural disasters in Japanese history.
Why it matters: The catastrophe prompted major reforms in Japanese building codes, urban planning, and disaster preparedness, establishing September 1 as Disaster Prevention Day. It also exposed social tensions, leading to rumors, vigilante violence, and long-term shifts in how Japan approached seismic risk and national resilience.