Japan's central government has designated 723 municipalities across 30 prefectures for intensified disaster mitigation efforts in response to newly revised damage estimates from a potential Nankai Trough megaquake — an event that experts warn has an 80 per cent chance of occurring within the next 30 years.

The municipalities, stretching from Ibaraki Prefecture in the east to Okinawa in the south, are expected to face tremors of at least a lower 6 intensity on the Japanese seismic scale, along with tsunamis measuring 3 meters or higher. These areas have now been officially designated as “disaster preparedness promotion areas”, Caliber.Az reports, citing Japanese media.

As part of this new designation, the central government is calling on municipal authorities to draft concrete disaster prevention plans tailored to the specific risks in each locality. These plans will include measures such as strengthening infrastructure to withstand earthquakes and increasing stockpiles of emergency supplies. Although the central government will not provide direct financial support, it will offer technical guidance and input to municipalities and businesses as they formulate their disaster readiness strategies.

In addition to municipal efforts, managers of hospitals, department stores, and other facilities with high foot traffic in the designated areas will be required to develop detailed evacuation plans to ensure the safety of occupants in the event of a disaster.

The decision was formalised at a July 1 meeting of the Cabinet’s Central Disaster Management Council, which followed a comprehensive review of potential damage from a massive Nankai Trough earthquake. The council also announced an updated national goal: over the next decade, Japan aims to reduce the potential death toll by 80 per cent and cut the number of buildings completely destroyed or burned down by 50 per cent.

Japan’s original basic disaster prevention plan for a Nankai Trough quake was established in 2014, based on earlier projections estimating that such an event could kill 332,000 people and destroy or burn down 2.5 million buildings. At the time, the government set a similar target of reducing fatalities by 80 per cent and structural destruction by 50 per cent within 10 years.

However, updated damage estimates released in March this year, using the latest topographical and hazard data, present a slightly less catastrophic—but still dire—scenario. The worst-case estimates now project around 298,000 deaths and the total destruction of approximately 2.35 million buildings.

In light of these new figures, the government has revised its basic disaster preparedness plan. Although the original 2014 targets were not met, officials have opted to maintain the same ambitious reduction goals, emphasising the importance of aiming high despite past setbacks. A Cabinet Office official explained that the government believes it is essential to "continue to set a high goal."

To meet these objectives, the new strategy will be two-pronged: first, implementing measures to “protect lives” by reducing direct deaths from earthquakes and tsunamis, and second, adopting measures to “connect lives” by preventing secondary disaster-related fatalities.

The central government has identified 205 specific measures to be pursued by ministries, local governments, and private sector actors. These include creating tsunami evacuation routes, conducting regular disaster preparedness drills, and establishing evacuation centres that can provide comfort and safety for displaced residents.

Municipalities designated as disaster preparedness promotion areas will be required to draw up comprehensive disaster prevention plans that incorporate these measures, customised to local conditions. The central government will closely monitor the progress of each municipality’s efforts.

The revised damage estimates have had particular implications for Nagasaki Prefecture. According to the new data released in March, the projected inundation area for a tsunami in Nagasaki has grown to 1,970 hectares, up from 1,540 hectares in the previous 2012 estimates. The estimated number of tsunami-related deaths in the prefecture has also risen sharply, from around 80 in the earlier assessment to about 500 under the worst-case scenario.

On a more hopeful note, the central government’s modelling suggests that in Nagasaki Prefecture, the tsunami could take approximately two hours to reach coastal areas, providing a crucial window for evacuation. The prefectural disaster prevention division believes that, under the right conditions—such as widespread public awareness and timely evacuation orders—the death toll in the prefecture could potentially be reduced to zero.

By Tamilla Hasanova

Source: caliber.az