DISASTERSLargest Fire Death Toll Belongs to Aftermath of 1923 Japan Earthquake

Fires that raged in the days following the 1 September 1923 magnitude 7.9 Kantō earthquake killed roughly 90% of the 105,000 people who perished in and around Tokyo, making it one of the deadliest natural disasters in history—comparable to the number of people killed in the World War II atomic bombing of Hiroshima.

The story of the conflagration, not well-known outside of Japan, holds important lessons for earthquake scientists, emergency response teams and city planners, according to a new paper published in the Bulletin of the Seismological Society of America. The paper is part of a BSSA special issue on the 1923 Kantō earthquake.

The fires—which were foreseen and foretold by a contemporary seismologist—led to the first lessons in earthquake protection for schoolchildren in Japan after the earthquake. More recently, the history of earthquake-related fires in Japan has led to seismic shutoff valves being placed on gas meters throughout the country.

The threat of earthquake conflagrations has not disappeared. The authors say places with strong seismic shaking and a large inventory of wood-framed buildings– the U.S. West Coast including Los Angeles, San Francisco and Seattle, Japan and parts of New Zealand—must emphasize fire prevention and response as part of their earthquake mitigation plans.

The researchers found that fewer than 5% of the literature written about the 1923 Kantō earthquake discusses the fire in detail, despite that fact that fire storms caused the majority of damage and deaths compared to severe ground shaking and liquefaction. Recent calculations put the fire losses at a total of almost ¥ 1.5 billion. For comparison, Japan’s total national budget for 1923 was ¥ 1.37 billion.

For these reasons, the authors say, the event should be known as Kantō Daikasai or the Great Kantō Fire Disaster instead of the more common name of Kantō Daishinsai or Great Kantō Earthquake Disaster.

Foreseen and Foretold
The conflagration following the earthquake had been envisioned in 1905 by Imamura Akitsune, an assistant professor of seismology at Tokyo Imperial University. He theorized a seismic gap in the region and suggested a large earthquake was due. He warned that citizens of Tokyo would have no place to shelter from fires triggered by such an earthquake. He suggested measures such as abolishing kerosene lanterns and creating setbacks between new buildings to lessen the danger.