The Great Kanto earthquake (Kanto daishinsai) struck the Kanto Plain on the main island of Honshu at 11:58:44 a.m. on Saturday, September 1, 1923 and lasted for about 4 to 10 minutes. The earthquake had a magnitude of 7.9 on the Moment magnitude scale (Mw), and a focus deep beneath Izu Oshima Island in the Sagami Bay, due to a rupture at the subduction zone of the Philippine Sea Plate and the Okhotsk Plate along the Sagami Trough.
The earthquake struck at lunchtime when many people were cooking meals over fire, thus many people died as a result of the many large fires that broke out. Some fires developed into firestorms that swept across cities.People fled toward the Sumida River, drowning by the hundreds when bridges collapsed.
Many people died when their feet became stuck on melting tarmac. Tens of thousands of working-class Japanese found refuge in an empty patch of ground near the river. The flames closed in from all directions, and then, at 4 p.m., a 300-foot-tall “fire tornado” blazed across the area. Of the 44,000 people who had gathered there, only 300 survived.
The earthquake broke water mains all over the city, and putting out the fires took nearly two full days until late in the morning of September 3. An estimated 6,400 people were killed and 381,000 houses were destroyed by the fire alone.
During the Great Kanto Earthquake, two Ben Line ships, the Bengloe and the Benreoch, which were in Yokohama at the time, helped in rescuing and providing relief to the victims of the disaster.