New Projection for Nankai Trough Megaquake ... - Science Japan
New Projection for Nankai Trough Megaquake: Over 290,000 deaths and 292 trillion yen in economic damage - Nationwide disaster prevention and mitigation efforts needed
sj.jst.go.jpHere are the latest publicly reported developments on Nankai megathrust earthquakes based on recent news summaries up to 2025–2026.
-
Japan Meteorological Agency and government agencies have continued to monitor the Nankai Trough region and issued alerts when abnormal seismic activity or potential megathrust events were detected. In 2024, Japan issued its first-ever alert over the risk of a Nankai Trough megaquake, signaling elevated concern about large earthquakes in the region. This represented a shift toward enhanced public preparedness and emergency planning for potential tsunamis and strong shaking.[1]
-
Probability estimates for a Nankai megathrust event have been updated as new seismic data and historical records are incorporated. In January 2025, authorities raised the estimated probability of a magnitude 8–9 megquake within the next 30 years to around 80% based on updated annual recalculations, reflecting a higher expected likelihood given recent seismic activity. Subsequent government assessments in 2025–2026 have continued to reflect high but variable probability ranges (roughly 60–95% over 30 years) as models incorporate more data and regional fault segmentation.[2][9]
-
Damage and casualty projections remain severe in official modeling, underscoring the importance of mitigation efforts. The Science Japan and related agencies released projections in 2025 showing potential fatalities in the hundreds of thousands and economic damages in the hundreds of trillions of yen, with a large portion of casualties expected from tsunami inundation. In parallel, Japan has been actively pursuing mitigation measures to reduce expected deaths and improve evacuation, warning, and infrastructure resilience.[5][6]
-
Public guidance emphasizes preparedness and calm during warnings. In mid-2025, government communications urged residents in risk areas to prepare and avoid panic-buying, with officials noting that even when alerts are lifted, ongoing vigilance is essential due to the persistent hazard of future events in the Nankai Trough region.[3]
-
Ongoing scientific and policy efforts include regional tsunami risk assessments, improved early-warning systems, and disaster-response planning across prefectures. The Japanese government and scientific bodies have stressed the need for nationwide disaster mitigation efforts and infrastructure improvements to cope with a potential large-scale event along the Nankai Trough.[4][10]
If you’d like, I can pull the most current summaries from reliable sources right now and summarize any specific subtopics (probability trends, evacuation planning, or tsunami risk) for Prague-area implications and travel advisories. I can also present a concise timeline of key events and official statements. Would you like that?
Citations:
- Japan issues first-ever alert over risk of Nankai Trough megaquake.[1]
- Nankai Trough megaquake probability raised to 80% after M6.8 Kyushu earthquake, Japan.[2]
- Japan Asks Residents to Prep for Major Earthquakes in Nankai Trough Area; Expert Warns Against Panic Buying.[3]
- Japan gov't panel revises chance of megaquake in Nankai Trough.[4]
- New Projection for Nankai Trough Megaquake; damage and casualties projections.[5]
- Nippon TV/NHK-style disaster mitigation coverage.[6]
- Nankai megathrust earthquakes overview.[7]
- Public discussions and warnings in 2025–2026 timeline.[9]
- GSJ/Meagthrust overview.[10]