Japan Warns of Potential Megaquake with Estimated $1.8 Trillion in Damage and 300,000 Fatalities

Japan Warns of Potential Megaquake with Estimated $1.8 Trillion in Damage and 300,000 Fatalities

Japan could face economic losses of up to $1.81 trillion if a long-anticipated megaquake occurs along its Pacific coastline, according to a government report released on Monday. The quake could generate destructive tsunamis, lead to the collapse of numerous buildings, and result in approximately 300,000 fatalities.

The latest estimates from Japan’s Cabinet Office indicate that economic damage could reach 270.3 trillion yen—nearly half of the nation's total GDP—marking a significant increase from the previous estimate of 214.2 trillion yen. The revision reflects updated inflation data as well as new assessments of terrain and flood risks.

Japan, a country highly susceptible to earthquakes, faces an estimated 80% likelihood of experiencing a magnitude 8 to 9 earthquake in the Nankai Trough—a tectonically active zone off the southwest Pacific coast. In the worst-case scenario, involving a magnitude 9 quake, approximately 1.23 million people may be forced to evacuate, with nearly 298,000 potential casualties from tsunamis and building collapses, especially if the event occurs at night during winter.

The Nankai Trough extends around 900 km (600 miles) and is the result of the Philippine Sea Plate subducting beneath the Eurasian Plate. These tectonic forces have historically produced major earthquakes approximately every 100 to 150 years.

Japan issued its first-ever megaquake advisory last year, warning of an increased likelihood of a magnitude 9 event in the region after a magnitude 7.1 earthquake struck near the trough. The nation has vivid memories of the catastrophic 2011 magnitude 9 earthquake, which triggered a massive tsunami and caused the Fukushima nuclear disaster, resulting in over 15,000 deaths.