1923 Great Kantō earthquake collapsed due to urbanization. The 1923 earthquake led to record-high morbidity due to unsanitary conditions following the earthquake, and it prompted the establishment of antityphoid measures and the building of urban infrastructure. The Honda Point Disaster on the United States west coast, in which seven US Navy destroyers ran aground and 23 lives were lost, has been attributed to navigational errors caused by unusual currents set up by the earthquake in Japan. Beginning in 1960, every September 1 is designated as Disaster Prevention Day to commemorate the earthquake and remind people of the importance of preparedness, as August and September
1923 Great Kantō earthquake 1923 Great Kantō earthquake The struck the Kantō Plain on the Japanese main island of Honshū at 11:58:44 JST (02:58:44 UTC) on Saturday, September 1, 1923. Varied accounts indicate the duration of the earthquake was between four and ten minutes. The earthquake had a magnitude of 7.9 on the moment magnitude scale (), with its focus deep beneath Izu Ōshima Island in Sagami Bay. The cause was a rupture of part of the convergent boundary where the Philippine Sea Plate is subducting beneath the Okhotsk Plate along the line of the Sagami Trough. Massacres such as the Kantō Massacre were