A powerful earthquake and tsunami predicted to occur in the Nankai Trough off the Pacific coast of Japan in the near future could cause economic damage of up to ¥1.466 quadrillion in total, the Japan Society of Civil Engineers said Wednesday.

The association said that the damage would be spread over the course of 22 years, or the hypothetical timeframe for Japan to complete its reconstruction efforts following the expected disaster.

In March, the government said that the estimated damage from the possible Nankai Trough disaster to assets, which include buildings and factories, would come to ¥225 trillion.

The association said that the disaster could cost the country a further ¥1.241 quadrillion in damage caused by long-term stagnation in economic activities due to damaged manufacturing facilities, roads and ports, on top of the asset damage.

In 2018, the association estimated that property damage from the disaster would come to ¥170 trillion, based on a government estimate. At the time, it also said that economic damage in the 20 years until the country fully bounces back from the disaster would come to ¥1.240 quadrillion.

The association only made a slight tweak in its latest damage prediction, in light of progress in the country’s preparations for earthquakes and tsunamis.

If the country invests over ¥58 trillion on public infrastructure, such as roads, ports, embankments and buildings, economic damage would be reduced by 30%, or ¥396 trillion, the association said.

Satoshi Fujii, who heads a subcommittee of the association that compiled the damage prediction, said at a news conference on Wednesday that strengthening road networks is particularly important.

He cited the example of slow progress of reconstruction in Suzu, Ishikawa Prefecture, where roads were blocked, compared to the city of Nanao, following a major quake in Noto Peninsula in January 2024.

“Strengthening road networks, in particular, has a positive impact on reconstruction,” he said.