1923 Tokyo Earthquake
One of the World’s Worst Disasters of the 20th Century
This natural disaster, also known as the Great Kanto Earthquake of 1923, had a magnitude of 7.9 to 8.4 on the Richter scale. The epicenter of this quake was located south of Tokyo near Oshima Island in Sagami Bay. Numerous aftershocks occurred with epicenters pinpointed between the coast of Sagami Bay and southern Boso Peninsula.
Oshima Island is composed of lava and volcanic rock so it didn’t experience ground level changes or extreme shaking. On the other hand, Tokyo and Yokohama are built on softer soil deposited by rivers and with this instability; there was heavier ground shaking and damage.
Damage Caused by the 1923 Great Tokyo Earthquake
The earthquake struck at 11:58 local time in Tokyo just when many people were preparing lunch on charcoal or wood-burning stoves. During the quake, many of these stoves toppled over and triggered fires that could not be controlled. That is why this event is also known as the Great Tokyo Fire of 1923.
There were high winds due to a typhoon striking northern Japan and this caused the fires to spread quickly and develop into firestorms in many cities. A firestorm occurs when intense fires create their own wind system.
The quake also broke water mains which meant there was a limited water supply for putting out the fires. Cities were reduced to rubble and ashes with the seaport of Yokohama suffering the worst damage where 90% of all homes were destroyed or damaged.
Many homes built on hills and mountains were swept away by landslides. A mountainside collapsed in one village and pushed a parked passenger train plus the station and village structures into the sea below. There were approximately 900 people killed as a result of these landslides.
A tsunami was generated and waves up to 30 feet hit the shores of Oshima Island, Izu Peninsula and Boso Peninsula. Homes were flattened and flash flooding occurred. Over 150 people died as a result of the tsunami.
Many people boarded ships in Yokohama harbor in order to seek refuge but they were not aware of oil seeping into the water. As the fires spread to the harbor, the oil caught fire and many ships did not make it to the open sea.
In the Tokyo - Yokohama area, firestorms burned about 381,000 of the more than 694,000 houses that were partially or completely destroyed by the earthquake. Over 1.9 million people were left homeless in Japan. In Tokyo, 60% of the city’s population was left homeless. The estimated damage caused by the 1923 Great Tokyo Earthquake converted to today’s values would have been at least one billion U.S. dollars.
According to the USGS, there were 142,800 deaths resulting from the 1923 Great Tokyo Earthquake including the firestorms, landslides and the tsunami.
What was Learned from the 1923 Great Tokyo Earthquake
As a result of this earthquake, Japanese construction standards for public buildings were changed based on studies of structures that remained standing. Tokyo was reconstructed with better transportation services and more parks were created as areas of refuge.
Sources:
Historic Earthquakes, Kanto (Kwanto) Japan: U.S. Geological Survey
Behind the Accounts of the Great Kanto Earthquake of 1923: Mai Denawa, Center for Digital Initiatives, Brown University RI
The 1923 Great Kanto Earthquake and Fire: Carol Cameron, National Information Service for Earthquake Engineering, University of California Berkeley
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