- Japan 2026
- Chapter 5
Great earthquake in an ageing region
A conditional statement under stated assumptions, never a prediction.
Contents
- ·Edition home
- ·Executive summary
- 1Japan’s risk is seismic, climatic and demographic at once
- 2Key findings
- 3Systems and sectors at baseline
- 4Risks and capability
- 5Great earthquake in an ageing region
- 6Lenses and readings
- 7The 2027 agenda
- 8Systems in depth
- AMethodology
- BData appendix
- CReferences and record
- ·Complete edition, for print
5.1Assumptions
Scenario SCN-JPN-EQL-01: what is assumed, and what is held constant.
- Baseline
- the 2026 reference state in this edition
- Drivers
- a magnitude 7.5 or larger earthquake in a remote, ageing coastal region in winter, followed by heavy rain within months
- Analogues
- Noto Peninsula 2024; Kumamoto 2016
- Interventions
- none modelled, the specification describes the unmitigated case
- Run state
- narrative specification; quantified Foundry run scheduled for Q1 2027
5.2The cascade, step by step
- 1
SEI → INF
roads and ports cut; communities isolated
Noto 2024
- 2
SEI → WAT
pipes break; supply out for weeks to months
Noto 2024
- 3
WAT → HLT
care homes and hospitals lose water and sanitation
Noto 2024
- 4
CLI → HLT
winter cold raises disaster-related deaths
Noto 2024
- 5
CLI → INF
later heavy rain reopens landslides
September 2024
- 6
HLT → population
older residents relocate; recovery slows
Tōhoku 2011
5.3The scenario as a table of steps
How the shock in scenario SCN-JPN-EQL-01 would travel through Japan’s coupled systems, step by step, under the assumptions the edition states.
| Step | What happens | Source |
|---|---|---|
| 01 SEI to infrastructure | Roads and ports cut; communities isolated. Analogue or source: Noto 2024. | Edition JPN, scenario SCN-JPN-EQL-01, step 1 |
| 02 SEI to water | Pipes break; supply out for weeks to months. Analogue or source: Noto 2024. | Edition JPN, scenario SCN-JPN-EQL-01, step 2 |
| 03 Water to health | Care homes and hospitals lose water and sanitation. Analogue or source: Noto 2024. | Edition JPN, scenario SCN-JPN-EQL-01, step 3 |
| 04 Climate to health | Winter cold raises disaster-related deaths. Analogue or source: Noto 2024. | Edition JPN, scenario SCN-JPN-EQL-01, step 4 |
| 05 Climate to infrastructure | Later heavy rain reopens landslides. Analogue or source: September 2024. | Edition JPN, scenario SCN-JPN-EQL-01, step 5 |
| 06 Health to population | Older residents relocate; recovery slows. Analogue or source: Tōhoku 2011. | Edition JPN, scenario SCN-JPN-EQL-01, step 6 |
A teaching model of a conditional scenario under the edition’s stated assumptions: not a forecast, not a prediction and not a warning. Sources: Japan 2026, scenario SCN-JPN-EQL-01 (2026); Japan 2026, references (NR-CIT-1) (2026).