Damage from Tokyo earthquake put at 300 trillion yen

November 21, 2013

THE ASAHI SHIMBUN

A magnitude-7.3 earthquake below Tokyo could cause 300 trillion yen ($3 trillion) in economic damage, according to a member of a government advisory council on natural disasters.

This is triple the estimate given by the central government.

Yoshiaki Kawata, a professor of civil engineering at Kansai University, released the figure at a Nov. 20 symposium held in Tokyo that was sponsored by the Hyogo Earthquake Memorial 21st Century Research Institute and The Asahi Shimbun.

The symposium was titled, "21-Seiki Bunmei Symposium: Gensai--Asueno Sonae" (21st century civilization symposium: In order to decrease damages from disasters--preparations for tomorrow).

Kawata is part of the government's Central Disaster Management Council, which is reviewing anticipated economic damage from a major earthquake under the Japanese capital.

The figure offered by Kawata is more than three times the annual budget of the government's general account and 18 times larger than the damage caused by the 2011 Great East Japan Earthquake.

It also exceeds the government's estimate of 220 trillion yen in damage that could be caused if a magnitude-9.1 earthquake occurred in the Nankai Trough, an oceanic trench that stretches for about 700 kilometers off the coast of Shizuoka Prefecture in central Honshu to Kyushu.

Kawata's estimate may influence the council's current review, which is set for release around the end of the year at the earliest.

For his study, Kawata simulated a magnitude-7.3 earthquake hitting the northern part of Tokyo Bay. The probability of a temblor of that magnitude striking the area within the next 30 years is put at 70 percent. Such an occurrence would be particularly devastating.

According to Kawata's estimate, an earthquake of 7 intensity, the highest mark on the Japanese seismic scale, could result in 48,000 deaths. Economic damage, mainly to buildings and infrastructure, would reach between 200 trillion yen and 300 trillion yen.

Two-thirds of Japan's big companies with capital of 1 billion yen or more are based in the Tokyo metropolitan area. When factoring in the breakdown in political and economic activity, the overall damage would likely exceed 300 trillion yen.

Kawata also simulated an earthquake of magnitude 8.5 or bigger on the border of tectonic plates that stretches from Sagami Bay off Kanagawa Prefecture to waters off Chiba Prefecture. The scale is bigger than magnitude-7.9 Great Kanto Earthquake that hit the Tokyo metropolitan area in 1923.

Kawata estimated that a "Sagami Trough Earthquake" could cause between 280 trillion yen and 420 trillion yen in damage and 124,000 deaths.

http://ajw.asahi.com/article/behind_news/social_affairs/AJ201311210057