On Sept. 1, 1923, Tokyo and Yokohama were engulfed by horrific fires spawned by the Great Kanto Earthquake.

A century later, Japanese should ask themselves whether the nation’s capital, a prosperous metropolis bustling with glittering buildings and throbbing with businesses, is less vulnerable to earthquakes.

And they should ask whether society can respond calmly to a major disaster without being dangerously misled by false information. There are still many questions and doubts about the nation’s preparedness for a major quake.

During the Great Kanto Earthquake, numerous aftershocks followed the main shock. Powerful shaking caused buildings to collapse, started large-scale fires, sent tsunami waves crashing into wide coastal areas and triggered many massive landslides.

Because of the wide range of calamitous events it precipitated, the gigantic earthquake is sometimes referred to as a “department of disasters.” Strong winds caused by a typhoon compounded the damage by spreading fires fast and far and wide. More than 105,000 people were killed.

TOKYO STILL VULNERABLE

The project to rebuild the ravaged imperial capital after the 1923 seismic devastation was led by Shimpei Goto (1857-1929), a bureaucrat and statesman, who was appointed as home minister the day after the earthquake.

Goto devised a grand plan to reconstruct the capital, which involved large-scale rezoning, road building and park development projects.

Not all the projects in the blueprint were completed, but some of the legacies from the mammoth undertaking, such as major roads and iron bridges that are resistant to flames, are still used today.

Twenty-two years after the earthquake, however, Tokyo again burned to ashes during a major air raid. The efforts to rebuild the city after World War II did not go according to plan in some aspects, including rezoning.

Urban development projects related to the 1964 Tokyo Olympics and during Japan’s high-growth era expanded the capital to areas vulnerable to disasters such as reclaimed land. A network of expressways built to snake around Tokyo marred the cityscape.

Now, a raft of redevelopment projects is under way in various parts of the capital, reshaping the face of the metropolis.

Since 2000, deregulation has led to a proliferation of new skyscrapers. In a major seismic event, so-called “long period ground motion,” long and slow shaking, could cause elevators in high-rises to stop, trapping people inside.

In the aftermath of a powerful quake, many residents of high-rise condominiums will be forced to climb up flights of stairs while carrying food and water.

In bay areas, people’s lives could be seriously disrupted by damage caused by liquefaction to all types of buildings, water works and gas supply networks.

Nearly 90 percent of the casualties from the 1923 earthquake were due to fires. The damage from fires was worsened because of the predominance of wooden houses and buildings at the time and also as many fleeing people carried household goods that burned easily.

There are still areas with wooden houses that catch fire easily standing roof to roof in Tokyo.

A major quake can trigger and spread fires in such wide areas that could easily overwhelm the local firefighting capability.

The danger of conflagration in areas congested with wooden structures was underscored by the 1995 Great Hanshin Earthquake, which flattened the city of Kobe and its vicinity, and the 2016 large-scale fire that burned numerous buildings in Itoigawa, Niigata Prefecture.

It is difficult for residents to decide when to give up efforts to extinguish a major blaze at an early stage and take refuge in designated evacuation areas for local communities.

URBAN DEVELOPMENT FROM LONG-TERM OUTLOOK

Tokyo sits atop the intersection of three tectonic plates that regularly cause earthquakes of various scales. The Great Kanto Earthquake was a magnitude 8.0-class ocean-trench earthquake caused by the release of strain accumulated in tectonic plates.

The government is taking steps to better prepare Tokyo for an inland earthquake of magnitude 7 or so occurring beneath the capital. Japan has been struck frequently by quakes of this size, including the Kobe temblor.

Japan’s systems for disaster response and mitigation have changed every time a major disaster occurred. It is important to tackle the problems uncovered by the disasters one by one.

But there are possibilities of disasters posing huge threats that have not occurred in modern times. They include violent volcanic eruptions, such as the eruption of Mount Fuji during the Edo Period (1603-1868).

It should not be forgotten either that Tokyo’s lowland areas below the mean sea level are particularly vulnerable to flooding.

A major earthquake that rocks the capital would also deliver a huge blow to the Japanese economy as a whole. The damage caused by the Kanto quake amounted to 5.5 billion yen, nearly four times the national budget at that time.

By comparison, the 2011 Great East Japan Earthquake caused some 17 trillion yen of damage, less than 20 percent of the budget.

A magnitude-7 quake occurring right under Tokyo would cause 95 trillion yen in damage and one similar in strength to the 1923 quake would cost the nation 160 trillion yen, according to government estimates in 2013.

If such a disaster strikes Tokyo in the coming years, a nation with an aging population amid low birthrates would have to tackle the colossal challenge of recovery and reconstruction. It is also vital to create an efficient system to receive aid from other countries.

Fundamentally, the only way to deal with this horrifying risk is by rectifying the concentration of economic and other activities in Tokyo, which inevitably increases the damage from a disaster, and high-risk urban structures through long-term efforts.

In his writing titled “Natural Disasters and National Defense,” Torahiko Terada (1878-1935), a Japanese physicist and essayist, noted, “it seems that the authorities were too preoccupied with short-term state affairs and the people with their daily lives to pay serious attention to such advice,” referring to warnings about major disasters.

It is certainly important to deal with short-term problems. But efforts should also be made to make society less vulnerable to disasters to reduce potential damage even if they do not improve convenience or produce profits.

HEIGHTENED UNCERTAINTY

The 1923 earthquake created a complicated confusion of information. There were even false newspaper reports about the assassination of a senior politician that did not occur and the eruption of a volcano that did not take place.

False rumors spread about armed uprisings, arsons and poisoning of wells by Koreans. Neighborhood watch groups, troops and police officers who believed such false rumors killed or injured many Koreans.

Some newspapers also published such false rumors about Koreans. There were incidents where socialists were killed as well.

In Chiba Prefecture, nine members of a group of peddlers from Kagawa Prefecture were killed by a local band of vigilantes who mistook them for Koreans.

Tatsuya Mori, who directed a film about the “Fukuda village incident,” as the tragedy is called, warns that even ordinary and good people could perpetrate such evils. “Everyone has the potential to do so.”

In today’s networked society, where information spreads far faster and in widely different ways than in those days, disasters tend to produce a harmful confusion of information.

During the 2016 Kumamoto Earthquakes, a false rumor spread that a lion had escaped from a zoo. There were also rumors about fires triggered by the 2011 Tohoku earthquake, saying a rain of harmful substances would fall from the skies.

The development of the internet has created a society where dubious information spreads fast and wide and extreme views and opinions cause serious divisions. Policymakers need to make decisions cautiously as they respond to major disasters, keeping these facts in mind.

During the century since the seismic devastation of Tokyo and Yokohama, society and citizens have changed radically. The risk of a disaster causing damage of an unimaginable kind is growing.

There is no room for complacency when it comes to the nation’s ability to deal with serious disasters.

--The Asahi Shimbun, Sept. 1