Kii Strait (紀伊水道) — Earthquake Risk & History
Kinki / Shikoku region · Based on HERP official data
The Kii Strait lies between the Kii Peninsula and Shikoku, directly on the Nankai Trough rupture path. Earthquakes here rapidly deliver tsunami to Wakayama, Tokushima, and Hyogo coasts. Every major historical Nankai event has produced strong shaking and tsunami through this strait.
Fault Lines & Seismic Characteristics
Active Faults & Trenches
- Nankai Trough
- Kii Strait Fault
The Kii Strait lies between the Kii Peninsula and Shikoku, directly on the Nankai Trough rupture path. Earthquakes here rapidly deliver tsunami to Wakayama, Tokushima, and Hyogo coasts. Every major historical Nankai event has produced strong shaking and tsunami through this strait.
Earthquake History
- M4.2
2024
Kii Strait earthquake — Intensity 4; felt in Wakayama and Tokushima
- M8.0
1946
Showa Nankai earthquake — strong shaking in Kii Strait area; coastal tsunami
- M8.4
1854
Ansei Nankai earthquake — tsunami passed through Kii Strait; damage along Kii Peninsula and Shikoku
Future Probability — HERP Official Assessment
Long-term probability for this area is available on the HERP official website.
🔗 HERP Official Website →Traveler Safety Information
Finding Evacuation Shelters
- ✅ Search "避難所" (hinanjo) on Google Maps to find the nearest shelter from your current location
- ✅ Install NHK World or Safety tips (Japan Tourism Agency app) — both send English earthquake alerts
Basic Action Rules
- ✅ At check-in, locate emergency exits and escape routes
- ✅ On strong shaking: protect your head, open a door to secure an exit, do not use elevators
- ✅ Near coasts or rivers: move to high ground immediately — do not wait for a tsunami warning
- ✅ Emergency numbers: Police 110 · Ambulance/Fire 119
- ✅ Contact your embassy in Tokyo for emergency consular assistance
Research & Official Sources AI summary
-
Kii Strait earthquakes and the Nankai Trough
Most earthquakes in the Kii Strait relate to Nankai Trough plate-boundary activity. A Kii Strait event can independently generate tsunami, and may also serve as a precursor to a larger Nankai Trough earthquake.
Source: 일본 기상청 (2023) -
Tsunami arrival time analysis for Kii Strait coasts
An M7 earthquake in the Kii Strait area can deliver tsunami to Wakayama and Tokushima coasts within 10–20 minutes. Immediate evacuation from low-lying coastal areas is critical.
Source: 내각부 중앙방재회의 (2022)
Related Guides
Seismic characteristics and research summaries on this page are AI-generated from publicly available data by JMA, Cabinet Office, and HERP. Historical earthquake data (year, magnitude, damage) is based on official records, but key figures should always be cross-checked with the latest official sources. This page does not predict future earthquakes.