100th anniversary of
the Great Kanto Earthquake
How fires spread across Tokyo for 46 hours
The Great Kanto Earthquake occurred on Sept. 1, 1923. Fires triggered by the quake were initially localized. How did they turn into infernos that burned down 40% of the Japanese capital? Here is a reconstruction of how the fires lasted for 46 hours, based on records.
Fires fanned by strong winds engulf wooden neighborhoods
The earthquake that hit central Tokyo at 11:58 a.m. registered magnitude 7.9. Striking as families were cooking meals, the quake caused fires at numerous places. Blazes that were not immediately extinguished merged and grew. Fanned by strong winds, they turned into massive firestorms and engulfed communities where many people lived and worked in wooden buildings.
Massive quake hits at lunchtime
The earthquake hit at lunchtime, when families were cooking over fires on traditional stoves ("kamado") and charcoal grills ("shichirin"). Records show that fires broke out at 98 locations from when the earthquake struck just before noon until 11 p.m. Although 27 of the fires were extinguished immediately, the other 71 spread.
Fires expanded to Asakusa Ward (now the east part of Taito Ward), Kanda Ward (now the north part of Chiyoda Ward) and Honjo Ward (now the south part of Sumida Ward), with some places surrounded by flames.
Fires merged and destroyed more than half of Asakusa, Kanda and Honjo wards.
Fires intensified further, leaving numerous people with nowhere to escape.
Fires bore down on the site of the former Army Clothing Depot in Honjo Ward from the north, east and south, spreading to household goods brought there by evacuees seeking shelter in the large open space.
Southerly winds turned into westerly ones toward the evening. The wind direction also shifted again later, expanding the spread of fires.
Fires spread to Fukagawa Ward (now the west part of Koto Ward) as well.
A spate of firestorms had hit Tokyo wards by this time.
Fires intensified in Fukagawa Ward.
Fires in Kyobashi Ward (now the south part of Chuo Ward) spread to Tsukishima across the Sumida River.
Seven fires broke out in Kyobashi Ward due to flying sparks.
Asakusa Park was spared from destruction.
Temperatures rose sharply from this time in Kojimachi Ward (now the south part of Chiyoda Ward) due to fires, exceeding 45 degrees Celsius as of 1 a.m.
The spread of fires further progressed in five wards -- Asakusa, Kanda, Fukagawa, Honjo and Nihonbashi (now the north part of Chuo Ward) -- with most areas destroyed in the fires at around 3 a.m.
Much of the north of Shiba Ward (now the east part of Minato Ward) was destroyed by fire.
Fires gradually spread in the southeast of Shitaya Ward (now the west part of Taito Ward).
On Sept. 2, winds turned southerly in the morning and their speed increased toward noon.
Fires in Shitaya Ward spread to the west as well.
The spread of fires still continued. It was not until 10 a.m. on Sept. 3 that they were finally put out.
The spread of fires continued for 46 hours
Tokyo burned for 46 hours after the earthquake struck. At the time, the area of the city totaled 79.4 square kilometers. Of that, the fires burned 34.7 sq. km, or over 40%.
The Great Kanto Earthquake saw about 40% of Tokyo destroyed by fire.
More than 90% of the deaths in the quake were caused by fires. Buildings at the time lacked earthquake and fire resistance, compounding the damage.
Water outages and strong winds also contribute to the expansion of damage
As the earthquake occurred at lunchtime, simultaneous fires started in traditional stoves ("kamado") and charcoal grills ("shichirin"). While water outages caused by the quake made it impossible to battle the fires, the blazes spread due to the strong winds that were blowing in the Kanto region.
Because many people took household goods with them while evacuating, not only did they block avenues of escape, but fires also spread to their belongings, causing tremendous damage.
Halfway down the road to the goal of resolving the city's Achilles' heel: dense wooden housing
If a huge earthquake occurred directly beneath the capital, areas with dense wooden housing will become central Tokyo's Achilles' heel. Such areas have halved in the past decade but still account for just over 10% of the total area of Tokyo's 23 wards. According to damage estimates by the Tokyo Metropolitan Government, about 40% of the deaths resulting from such a quake would be caused by fires. Resolving the issue of areas with close-set wooden housing will be central to the reduction of damage.
Tokyo's dense wooden housing areas still total 8,600 hectares
Changes in Tokyo's dense wooden housing areas
In the wake of the massive 2011 Great East Japan Earthquake, the Tokyo Metropolitan Government established a "special fireproof zone system" in 2012 and encouraged the demolition or rebuilding of aging wooden structures. Areas with dense wooden houses in Tokyo totaled 8,600 hectares as of 2020, down significantly from 16,000 in 2010.
Fireproof target yet to be achieved
The current situation of 'fireproof area rate' in each development district (%)
The Tokyo Metropolitan Government uses the "fireproof area rate" as an indicator of progress made in its efforts to resolve the issue of dense wooden housing areas. It is the percentage of things such as vacant lots and fire-resistant buildings in a district. The government designated 28 high-risk areas as "development districts" and is aiming to achieve a 70% fireproof area rate on average there. The initial target year for achieving the rate was fiscal 2020, but the current rate still stands at 65% on average.
Long-term perspective needed to resolve issue of dense wooden housing areas
Lying behind the slow progress on resolving the issue of dense wooden housing is the aging of residents and restrictions on the use of land in areas where roads are narrow. Just rebuilding individual buildings is not enough. Itsuki Nakabayashi, a Tokyo Metropolitan University professor emeritus specializing in urban disaster prevention, said that resolving the issue of areas with dense wooden housing depends on how narrow streets can be widened, in addition to the development of roads with a certain width that is highly effective in blocking the spread of a fire. "The government needs to think about how to proceed with community development while staying close to residents from a long-term perspective," Nakabayashi said.
Earthquake-prone Japan needs to learn lessons from the past and prepare
The human and material damage from a massive quake would be enormous
It is now 100 years since the Great Kanto Earthquake. The cityscape has changed drastically due to high-rise condominiums and other buildings. People now rarely think of the 1923 tragedy. But the Japanese government says there is an approximately 70% chance that an earthquake in the magnitude 7 class will occur within 30 years. It is necessary to reflect on the past and extend preparations one by one.
|Great Kanto Earthquake||Great Hanshin Earthquake||Great East Japan Earthquake|
|Date and time of occurrence||Sept. 1, 1923|
|Jan. 17, 1995|
|Mar. 11, 2011|
|Size of earthquake|
|Direct deaths and missing people||105,000||5,500||18,000|
|Completely destroyed or burned houses||290,000||110,000||120,000|
|Economic damage||5.5 billion yen||9.6 trillion yen||16.9 trillion yen|
|As a percentage of GDP||37%||2%||3%|