Japan will set a goal of reducing an estimated life toll of up to 298,000 deaths from a potential megaquake occurring in the Nankai Trough by around 80% over the next 10 years according to a report by Kyodo News.
A new report issued by the Japanese government in March 2025 says there is an 80% probability of a magnitude 8 to 9 earthquake along a tremulous seabed zone known as the Nankai Trough. The document, which is a revised document of a basic plan released in 2014, estimates that the country’s economy could lose as much as $1.81tn in the event of a long-anticipated megaquake off its Pacific coast, which could trigger devastating tsunamis, the collapse of hundreds of buildings and potentially killing about 300,000 people.
In addition to minimising the death toll, the government will aim to halve the maximum number of buildings expected to be completely destroyed in the quake from the current estimate of 2.35m.
A draft of the revised plan for disaster prevention containing the new goals was approved at a panel meeting of the ruling Liberal Democratic Party and a formal decision is expected to be made at a government disaster management council meeting which could take place by early July this year.
Local governments in the projected disaster zones will also be urged to update their local measures accordingly.
The 2014 basic plan aimed to cut the projected death toll of 332,000 by around 80% and the number of buildings expected to be completely destroyed—then estimated at 2.5m— by around half. However, revised estimates released in March showed only slight reductions in both, underscoring inadequate progress in disaster preparedness.
To address this, the revised plan will emphasise rigorous monitoring of progress across proposed measures. This includes ensuring all local governments designated as tsunami-risk areas release hazard maps for the largest class of tsunami and conduct evacuation drills within about five years.