Damage Forecast for Massive Tokyo Quake to Be Reviewed, with Figures Likely to Be Revised Down

Yomiuri Shimbun file photo
High-rise condominiums are seen by Tokyo Bay in August.

The government intends to review next fiscal year its damage predictions for a possible earthquake directly under the Tokyo metropolitan area, according to sources.

The review will also focus on measures to prevent large-scale fires, which would account for most of the damage to people and buildings, and those to ensure safety in high-rise condominiums, which have increased rapidly in number. It will be the first review in about 10 years.

The Cabinet Office is expected to include the budget for the review in its budgetary request for the next fiscal year, and will spend one year compiling damage predictions and a basic plan for quake measures.

There is a 70% chance that a magnitude 7 earthquake will hit the metropolitan area within the next 30 years.

In December 2013, the government released damage predictions for a magnitude 7.3 earthquake under south-central Tokyo, which would heavily impact the capital’s ability to function. According to the figures, the metropolitan center could be hit by an earthquake registering as high as 7 on the Japanese seismic intensity scale of 7, and the temblor would kill an estimated 23,000 people, including 16,000 deaths from fires. Some 610,000 buildings would be completely wrecked or burnt down, and the economic damage would reach ¥95 trillion.

Following up, the government formulated a basic plan in March 2015 to reduce the damage by half in 10 years. The plan calls for 95% of houses to be earthquake-resistant, 25% of houses to have breakers that shut off power in strong tremors, and the near elimination of dangerous areas with crowded wooden housing.

The current review would take into account the progress made on these measures. The share of earthquake-resistant houses in Tokyo rose to 92% in fiscal 2019, and damage predictions are expected to fall in scale to a certain extent.

On the other hand, dense areas of wooden housing remain across the city, and only 8.3% of buildings in Tokyo had earthquake-sensitive breakers in fiscal 2020, leaving fire prevention a major issue.

The boom in high-rise condominiums also means measures must be taken to assist residents who get trapped on upper floors.