Photo/Illutration Tall buildings stand around Shinjuku Station in Tokyo. (Asahi Shimbun file photo)

An earthquake of magnitude 7 or higher in the Tokyo area would kill up to 18,000 people and destroy about 400,000 buildings, according to a government expert panel’s estimates released on Dec. 19.

The figures were down from estimates made in 2013, which projected 23,000 deaths and 610,000 buildings collapsed or razed from such an earthquake, which has long been expected to hit the capital.

The decrease in estimated deaths and destroyed buildings reflects progress in seismic reinforcement and fire prevention measures.

However, the government’s disaster reduction target of “roughly halving” the damage by the end of fiscal 2024 has not been achieved.

The Cabinet Office plans to create a basic countermeasure plan within this fiscal year based on the latest estimates.

The expert panel estimated the scale of damage if a magnitude 7.3 earthquake struck beneath Tokyo and registered a maximum seismic intensity of 7 on the Japanese scale of 7.

Such a quake would have the greatest impact on the capital’s core functions, and damage would be maximized if it occurred on a dry winter evening with winds blowing at 28.8 kph.

Fires would cause roughly 70 percent of the deaths and building damage, the panel said.

With Japanese society aging, more people are staying at home, leading to a higher estimated casualty count from building collapses and fires. The estimate also took into account the population growth in Tokyo and surrounding areas.

Earthquake countermeasures, however, have advanced in the Tokyo area.

For example, the proportion of residences with seismic reinforcement rose from 79 percent in 2008 to 90 percent in 2023.

The Tokyo area also had 2,500 hectares of “high-density areas considered dangerous during an earthquake” because of the many wooden houses there. These dangerous areas have been reduced in size by 82 percent.

The latest estimates did not include high-rise condominium towers, which have been increasing mainly in coastal areas, because no major quake damage has been confirmed in such structures and quantitative figures were unavailable.

The latest report for the first time also estimated the number of indirect deaths caused by fatigue and stress during evacuation, worsening of injuries or aggravation of pre-existing illnesses.

The projections ranged from 16,000 to 41,000 so-called quake-related deaths.

The figures were based on fatalities in Iwate and Miyagi prefectures following the Great East Japan Earthquake in 2011 and those after the Noto Peninsula Earthquake in 2024.

CASHLESS PAYMENT SUSPENSION POSSIBLE

A major Tokyo earthquake would cause economic losses of 83 trillion yen ($532 billion), including 45 trillion yen from damage to homes and corporate offices, and 38 trillion yen from declining production and services due to prolonged power and water outages, the panel said.

Reflecting recent social changes, the report pointed out risks that could destabilize society, such as the suspension of cashless payments using smartphones and the spread of disaster misinformation on social media.

The panel also simulated damages from an earthquake of magnitude 8, similar to the magnitude 7.9 Great Kanto Earthquake that killed more than 105,000 people in 1923.

In the worst case scenario, fatalities could reach 23,000 and 414,000 buildings would be destroyed or razed, according to the report.

About 30 percent of Japan’s population is concentrated in Tokyo and three surrounding prefectures.

The report emphasized the importance of government, citizens, businesses and communities each viewing preparedness as their own responsibility and taking concrete measures.

“In a disaster of national crisis level, damage can be minimized when self-help, mutual assistance and public support work together,” the report said.

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