The Nankai Trough earthquake refers to a magnitude 8 to 9 class seismic event expected to occur along the trough stretching from off Shizuoka Prefecture to off Miyazaki Prefecture. In the worst-case scenario, deaths in the Kansai region’s two prefectures and four major urban areas alone could reach 79,300.
Historically, the Nankai Trough has generated major earthquakes at intervals of 100 to 200 years, which formed the basis of the previous 80 percent probability estimate for the next event. However, after updating its calculation methods and incorporating new data, a government committee concluded that the likelihood now falls within the 60 to 90 percent range. This revised figure keeps the earthquake risk in the highest classification.
The committee urged continued disaster preparedness, stressing that residents must remain vigilant. The probability distribution is concentrated at 90 percent or higher, underscoring the assessment that such a quake could occur at any time. Committee chair Naoshi Hirata warned, “Our scientific review shows the possibility of occurrence is extremely high. We must remain vigilant against a major quake.”
At the same time, alternative models suggest a lower probability range of 20 to 50 percent. Hirata emphasized, however, that the risk remains significant: “There is uncertainty, but the potential damage would be catastrophic if such an earthquake occurred. Countermeasures should be taken immediately.”
Casualty estimates further illustrate the stakes. If only 20 percent of residents evacuate within 10 minutes, deaths nationwide could approach 300,000. Conversely, if 70 percent evacuate in time, the death toll could fall by about 120,000 to approximately 177,000. This highlights how preparedness and swift evacuation can save many lives.
Although the earthquake is often described as likely to strike within the next 30 years, experts caution that it could occur as soon as a year from now—or even tomorrow. The committee urged residents to confirm evacuation routes, secure furniture, and take everyday precautions, underscoring that readiness is a critical factor in survival.
https://newsonjapan.com/article/147035.php
