6,100 fatalities forecast in event of major Tokyo quake

The Yomiuri Shimbun

In the event of a magnitude 7.3 earthquake in the Tokyo area, about 6,100 people would die and 194,400 buildings would be destroyed, according to the metropolitan government’s latest estimates.

Those figures are based on the possible impact of an earthquake with a focus under the southern part of central Tokyo, which would cause the most damage in the capital, according to the metropolitan government’s data.

About 40% less damage was forecast compared to estimates compiled in 2012, as a result of disaster prevention and mitigation measures implemented in the last ten years.

A new earthquake disaster management plan will be devised based on the forecast, which was unveiled by the metropolitan government on Wednesday.

The latest study analyzed the possible impact of six earthquakes with different epicenters, including in the southern part of central Tokyo and the eastern part of Tama, a western Tokyo suburb.

In the previous forecast, an earthquake with an epicenter north of Tokyo Bay was predicted to cause the most damage in the capital. However, the government’s Central Disaster Management Council concluded in 2013 that there was a low probability of such an earthquake occurring in the immediate future so it was not included in the latest study.

In the event of an earthquake with an epicenter in the southern part of central Tokyo, Koto, Edogawa, and Arakawa wards would experience tremors with a seismic intensity of 7 on the Japanese shindo scale — the highest level — and 60% of the areas in the capital’s metropolitan wards would experience tremors with an intensity of upper 6.

The most damage would be caused if the earthquake struck on an evening in winter with wind speeds of 8 meters per second, according to the data. About 82,200 buildings would collapse and about 112,200 would be destroyed in subsequent fires.

Among Tokyo’s 23 metropolitan wards, Setagaya Ward would be the worst hit, with about 20,000 buildings predicted to be burned down, followed by Ota Ward, with about 19,000, and Edogawa ward, with about 15,000.

Compared to the 2012 forecast, the number of destroyed buildings has decreased by 109,900, fatalities have fallen by 3,500, and injuries have declined by about 40% to 93,400.

The number of evacuees was estimated to be 2.99 million, down about 400,000, and the number of people who will have difficulty getting home was estimated to be 4.53 million, down about 640,000.

The reduction in damage in the forecasts has been attributed to an increase in the proportion of residential buildings that meet national earthquake resistance standards from 81.2% to 92% in the 10 years through 2020, during which there was a 50% reduction in the area of land with high concentrations of wooden buildings, where the risk of fires spreading is greater.

The decrease in the predicted number of people who will be unable to get home in the event of an earthquake has been attributed to the fact that people are commuting less due to the increased uptake of telework, among other factors.

In the Tokyo metropolitan government’s 2012 forecast compiled following the 2011 Great East Japan Earthquake in 2011, seismic intensity estimates increased from upper 6 to 7 and predicted fatalities doubled compared to a 2006 study.