Stretching nearly 800 kilometers beneath the Pacific, the Nankai Trough marks where the Philippine Sea Plate subducts under the Eurasian Plate. Historical records show devastating megaquakes have struck every 100 to 200 years over the last 1,400 years—the last major event occurred in 1946.
TOKYO, JAPAN – Japan’s government has acknowledged that far more remains to be done to shield the nation from a catastrophic “megaquake” and tsunami that experts warn could claim up to 300,000 lives. The revised strategy, unveiled this week, accelerates construction of protective embankments, the creation of dedicated evacuation buildings and the expansion of public drills to boost readiness across the archipelago.
RELEVANT SUSTAINABLE GOALS
Tokyo Sounds the Alarm on a 75–82% Probability
In January, a government-appointed panel raised its 30-year forecast for a massive rupture along the Nankai Trough to between 75% and 82%, underscoring the growing inevitability of a major seismic event off Japan’s Pacific coast. That assessment prompted a March update estimating the combined death toll from a quake and ensuing tsunami could reach 298,000, with economic damages soaring to an estimated US$2 trillion.
Yet, officials concede that steps taken since the Central Disaster Management Council’s 2014 preparedness plan would cut fatalities by only 20%—far short of the original goal to slash deaths by 80%, according to Kyodo News.
The 2014 blueprint called for a series of measures designed to fortify infrastructure and sharpen emergency response. This week’s update goes further, recommending:
- Embankment Construction: Seawalls and flood barriers in vulnerable coastal zones.
- Evacuation Buildings: Dedicated, earthquake-proof shelters strategically sited near shorelines.
- Regular Drills: Nationwide exercises to practice rapid evacuation and interagency coordination.
Prime Minister Shigeru Ishiba stressed at a government meeting that “the nation, municipalities, companies and non-profits must come together to save as many lives as possible,” local media reported.
Nankai Trough: A Fault Line with a 1,400-Year Recordty
Stretching nearly 800 kilometers beneath the Pacific, the Nankai Trough marks where the Philippine Sea Plate subducts under the Eurasian Plate. Historical records show devastating megaquakes have struck every 100 to 200 years over the last 1,400 years—the last major event occurred in 1946. In August, the Japan Meteorological Association (JMA) issued, then withdrew a public advisory on heightened seismic risk, underscoring the difficulty of precise quake forecasting.
Unfounded fears amplified on social media and by a reissued 2021 manga prediction that a major disaster would strike on July 5, 2025, have deterred some foreign visitors. Hong Kong–based Greater Bay Airlines trimmed its summer schedules to Japan in May, citing rapidly falling demand. Official figures show arrivals from Hong Kong fell 11.2% year-on-year in May, even as visitors from mainland China and South Korea rose 44.8% and 11.8%, respectively.
Ryoichi Nomura, head of the JMA, underscored in May that “current science cannot specify the location, time or magnitude of an earthquake,” urging citizens to prepare without succumbing to anxiety-driven actions.
The new preparedness plan, backed by accelerated infrastructure projects and more frequent drills, aims to unify government agencies, businesses and civil society in a coordinated defense against nature’s worst-case scenario. By marrying hard science with regular public engagement, Japan hopes to transform looming risk into collective resilience.
Lead image courtesy AP pic (A Japanese government panel raised the chance of a major earthquake in the Nankai Trough off Japan to 75-82% within the next 30 years)
