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
2011 Virginia earthquake East Coast earthquakes, equations that predict ground shaking might need to be revised." In addition to the great landslide distances recorded, the landslides from the 2011 Virginia earthquake occurred in an area 20 times larger than expected from studies of worldwide earthquakes. Scientists plotted the landslide locations that were farthest out and then calculated the area enclosed by those landslides. The observed landslides from the Virginia earthquake enclose an area of about , while previous studies indicated an expected area of about from an earthquake of similar magnitude. It is estimated that approximately one-third of the U.S. population might have