We Must be Prepared for a Tokyo Earthquake and Other Disasters

Seiji Fuji

Many people died in Kanto earthquake firestorms

 The Yomiuri Shimbun began publishing a series in its June 6 Morning Edition, called “Lessons Learned in 100 Years Since the Great Kanto Earthquake.” It said, “September 2023 marks 100 years since the Great Kanto Earthquake in which more the 100,000 people died, making it Japan’s deadliest disaster from the modern era on. What happened during the earthquake, and what have we learned from it? This series examines how Japan is preparing for a near-field earthquake in Tokyo and a megaquake at the Nankai Trough.” The headline of the first article on the front page was, “Firestorm Attacks Evacuees.”

The national government’s Research Commission on Earthquake Disaster Prevention compiled a report two years after the Great Kanto Earthquake on the damage that it caused. The report described the firestorms, saying that the sky turned dark, a tremendous sound rang out, and an evil wind brought rampaging flames.
The magnitude 7.9 earthquake struck at 11:58 a.m. on September 1, 1923. Shaking in the Tokyo metropolitan area reached 7 on the Shindo scale. The disaster resulted in approximately 105,000 dead and missing persons, of whom 90% were victims of fire. Firestorms caused a great deal of damage.
Before she was hospitalized three years ago, Fumiko Ichikawa (age 107), a resident of Hiratsuka City in Kanagawa Prefecture, described the fear she experienced. She said, “There was a thunderous roar, and people were shouting, ‘It’s a tornado!’ I was blown away before I could run.”
Ichikawa was seven years old at the time of the earthquake. The former Army Clothing Depot was near the house where she lived. Her family took refuge at this massive vacant lot with an area of 66,000 square meters. It became the site of a tragedy in which 38,000 of the approximately 40,000 evacuees died due to firestorms and other causes. Today the Tokyo Restoration Memorial Hall, which exhibits information about the disaster, is in this area of Sumida City.
Testimony describes how many people evacuated to the clothing depot site right after the earthquake. By evening it was jam-packed with household belongings and other items brought by wagon. Fires that broke out during the day were continuously spreading and beginning to surround the lot to the north, east, and south.
A firestorm struck. As flames approached from three directions, flying sparks set fire to people’s clothing and objects. Whirling winds amplified the damage. Some have testified to seeing firestorms that were dozens of meters tall. Ichikawa was miraculously saved by falling into a far-away puddle, but many people were killed or injured.
The National Research Institute of Fire and Disaster (NRIFD, Tokyo) in the Ministry of Internal Affairs and Communications’ Fire and Disaster Management Agency shot a video of their experiment to determine what phenomena took place.
They ignited liquid fuel in small, evenly spaced containers. Each flame was several dozens of centimeters high. Dozens of seconds after sending in a wind, the flames drew together in the center to form a tornado shape, reaching a height of three meters.
This combustion created a vortex of air bringing together multiple flames. It is believed that this phenomenon occurred in multiple places at the same time. NRIFD Senior Chief Researcher Masahiko Shinohara emphasized, “To prevent this, the fire must be stopped before it grows to a large size.”
Tokyo’s fire brigade was being modernized at the time of the earthquake, which occurred at lunchtime. It set off 134 kitchen fires and other blazes in what was then Tokyo City (today’s central Tokyo), of which 77 spread because they were not promptly extinguished. The Metropolitan Police Department’s Firefighting Division had only 38 fire trucks. Hydrants installed at roughly 7,200 locations were rendered mostly unusable when the earthquake cut off the water supply.
The conditions were unfavorable in many ways. A typhoon brought a powerful 10-meter wind. Firefighters were able to stop the flames from spreading in less than 30% of these locations. The city continued burning for 46 hours, causing over 110 firestorms. Flames destroyed 3,466 hectares, about half the size of the area inside the Yamanote Line.
Firestorms were also seen at the time of the 2011 Great East Japan Earthquake, when fires broke out after the tsunami. “This could happen today,” warned Shinohara.
There is a 70% possibility of a near-field earthquake striking Tokyo within the next 30 years. Both firefighting organizations and citizens must improve their overall capabilities, including efforts to extinguish fires.
Local firefighting is extremely important – fires would likely cause 40% of deaths

 The article continues on page two under the title, “Community Strength is Key for Early-stage Firefighting.”

Simultaneous fires also broke out in many locations after the Great Hanshin Earthquake, causing a serious tragedy. Even in contemporary times, the question of how to respond with limited firefighting abilities is an urgent issue.
It is predicted that 26.4% of Tokyo’s waterworks would be cut off after a near-field earthquake. The Tokyo Fire Department divides the metropolitan area into 250-meter square zones and has confirmed their water intake points (fire cisterns and rivers). However, it is possible that water from cisterns and other points might run out during prolonged firefighting, which would limit its efforts.
There is also fear that their arrival on scene could be delayed by road damage and collapsed buildings.
Early-stage firefighting efforts by civilians and local firefighters would be essential in these circumstances, but there are many challenges.
In FY2020, each local disaster prevention organization in Tokyo conducted just 0.35 disaster drills, less than half the number 10 years ago. Fewer people are volunteering as civilian firefighters throughout Japan due to the declining birthrate and other causes. This total fell below 800,000 for the first time last year.
The article concludes as follows:
A Nankai Trough earthquake is expected to cause fires that will burn up to 750,000 buildings, mainly from the Tokai region to Kinki and Shikoku. University of Tokyo Professor Yu Hiroi, who works in urban disaster prevention, stated, “Community strength is key for handling many concurrent fires. Each region must consider how to enhance and maintain their firefighting abilities.”

 According to this article, an earthquake directly under the Tokyo metropolitan area would damage 194,431 buildings and result in 6,148 deaths and 93,435 injuries. Fires would cause approximately 58% of this building damage and roughly 40% of these deaths, with 623 building fires (excluding those put out in the early stage), 112,232 destroyed buildings, and 2,482 deaths. I agree that it will be extremely important to take steps to deal with the fires that would accompany an earthquake.

According to predictions, better building construction would save lives

 There has long been a saying that the most fearful things are “earthquakes, thunder, fires, and fathers.” This shows that people remember the terrible damage that earthquakes bring. Looking back at major quakes in Japan since 1885, the deadliest was the magnitude 7.9 Great Kanto Earthquake, when 105,385 people died or went missing. This was followed in order by the Great East Japan Earthquake of 2011 (magnitude 9.0; 22,312 deaths and missing persons), the 1896 Meiji Sanriku Earthquake (magnitude 8.2; 21,959), the 1891 Owari Earthquake (magnitude 8.0; 7,273), and the 1995 Great Hanshin Earthquake (magnitude 7.3; 6,437). The primary causes of death differed by earthquake. I wrote as follows in my December 2022 essay:

The number of victims has also differed greatly according to the era, time of day, and region where the earthquake occurs. The Great Kanto Earthquake was at 11:58 a.m., when many households were using fire to cook their lunches. And because many homes were made from wood, 87.1% of the people who died in that disaster were killed by the subsequent large-scale fires. Around 10% were crushed to death when their homes collapsed. During the 1995 Great Hanshin Earthquake, 83.3% of the victims were killed by falling buildings while just 12.8% were burned to death. Among the victims of the 2011 Great East Japan Earthquake, 92.4% drowned to death in the tsunami. Earthquake measures should take into consideration all of these dangers: fire, collapsing buildings, and tsunamis.

 Approximately 90% of Great Kanto Earthquake deaths were caused by fire. Today we expect that fire would account for about 40% of deaths after an earthquake. The actual scale of predicted deaths is also smaller at just 1/17th the previous number, largely due to modern fireproof and earthquake-resistant building construction. During the Great Hanshin Earthquake, there was apparently less harm to buildings conforming to the new seismic resistance standard established in 1981. Even more buildings meet this standard today, roughly 30 years after that disaster. But although buildings are designed to reduce the risk of fires and collapse, we must still continue working to save lives.

The worst-case scenario is a compound disaster, including burst levees

 The Tokyo Metropolitan Government released its latest predictions in May 2022 about the damage that could result from an earthquake below the city. The government says there would be no tsunami after a near-field earthquake. A tsunami of up to 2 to 2.6 meters would result from an ocean trench earthquake, such as a Nankai megathrust earthquake, but would likely cause little damage in the city itself. However, a tsunami of up to 28 meters could strike Oshima and other Insular Area islands, damaging 1,258 buildings and killing 952 people. Another type of water-related disaster is flooding caused by earthquakes. NHK NEWS WEB discussed this topic in its article from January 15, 2020, “Keywords for Surviving a Near-field Tokyo Earthquake.”

Flooding can occur after an earthquake when river levees are significantly damaged by shaking or liquefication, causing river water to flow into a city.
The risk of serious damage is higher in so-called “zero-meter zones” below sea level, including eastern Tokyo, Nagoya, and other locations.
For instance, 1.76 million people live in zero-meter zones on Tokyo Bay, where levees have been installed for protection. Nobuyuki Tsuchiya is the former head of Edogawa City’s Civil Engineering Division who currently studies disaster planning at the Japan RiverFront research Center. He pointed out the possibility that repeated earthquakes could destroy levees and cause flooding while cities are also dealing with quake damage.
Even without rainfall, floods spread quickly in zero-meter zones. Tens of thousands of people might die if they are not promptly evacuated. The Tokyo Metropolitan Government is currently reinforcing levees to prepare for a major earthquake.
It is fully possible that a major earthquake could strike at an unfavorable timing when river levels are high due to a typhoon or other cause. Heavy rain could also fall after the levees are harmed by the earthquake. Severe damage would result if the earthquake was compounded with another disaster.
Yasuo Nihei of the Tokyo University of Science and other people are researching what would happen if an earthquake damaged levees, then heavy rain caused them to rupture.
Previous research has analyzed past earthquakes across Japan and compared them with locations where water damage led to burst levees. There were many examples of destroyed levees where strong shaking was recorded on the Shindo scale.
The researchers conducted an experiment with equipment simulating levees and rivers to investigate this mechanism. They released water (equivalent to a heavy rain) at the “damaged levees.” Water penetrated even through small cracks, showing that the dirt inside the levees was quickly eroded, leading to a breach.
If a near-field earthquake hit when there was a high level of water due to a typhoon or the like, the Arakawa River that runs near central Tokyo could overflow its banks. According to a document published by the Cabinet Office about predicted water damage, water would flow towards central Tokyo and pour into subway tunnels, submerging 81 stations on 17 lines. (The metropolitan government formed a committee to discuss flood measures. It includes subway companies, companies that administer train station buildings and underground shopping centers, and other parties, and is urgently working to come up with specific flood measures. For example, Tokyo Metro is aiming to complete construction work to prevent underground flooding, including emergency waterproof gates at underground tunnel entrances. It plans for countermeasures to be in place by the end of FY2027.)

 We must be vigilant against water damage. Some residents of zero-meter zones are forming their own disaster planning organizations and buying inflatable boats with outboard motors.
 APA Hotel has grown dramatically through focused hotel development in Tokyo. In the 10-year period from 2014 until our 2023 forecasts, our cumulative sales amount is 1.1531 trillion yen with ordinary income of 265.5 billion yen. However, I think these numbers are possible only because Tokyo did not suffer major damage from a near-field earthquake or other disaster during this time. The expected damage shrinks with each new prediction thanks to building improvements and other measures, but I believe we must also be wary of a compound disaster. We should be prepared in many ways, from community and corporate disaster planning to earthquake-resistance efforts and disaster supplies in individual homes.

June 13 (Tuesday), 5:00 p.m.