Kagawa Prefecture (香川県) — Earthquake Risk & History
Shikoku region · Based on HERP official data
Kagawa sits on Shikoku's north coast surrounded by the Seto Inland Sea. The many islands partially attenuate Nankai Trough tsunami, but internal wave reflection can concentrate waves at unexpected points. The Sanuki Fault System includes inland active faults.
Fault Lines & Seismic Characteristics
Active Faults & Trenches
- Nankai Trough (indirect)
- Sanuki Fault System
Seismic Characteristics
Kagawa Prefecture is surrounded by the Seto Inland Sea on Shikoku's north side. The many islands partially attenuate Nankai Trough tsunami, but internal wave reflection and bay geometry can concentrate them at unexpected coastal points. The Sanuki Fault System includes inland active faults.
Earthquake History
- M8.0
1946
Nankai earthquake — some tsunami reached Kagawa coast via Seto Inland Sea
※ Showing M6.5+ or historically significant events. Source: JMA database.
Future Probability — HERP Official Assessment
30-Year Probability (Official Figure)
Earthquake Research Committee 2023 assessment. Seto Inland Sea routing means longer tsunami arrival compared to the Pacific side, but evacuation is still required. Low-lying Takamatsu coastal areas need evacuation planning.
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
- ✅ Kagawa Prefecture official disaster prevention page (Japanese) — includes shelter maps
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
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Seto Inland Sea islands and Kagawa tsunami simulation
Kagawa's islands attenuate tsunami from the Nankai Trough, but internal wave reflection can concentrate them at unexpected coastal points. Low-lying Takamatsu areas need evacuation planning.
Source: 가가와현 방재과 (2022) -
Earthquake preparedness for Takamatsu, Naoshima, and Seto Ohashi Bridge visitors
If strong shaking occurs while crossing the Seto Ohashi Bridge, stop your vehicle immediately and follow road authority guidance. On islands like Naoshima, ferry service may suspend after an earthquake — know the island's evacuation sites before visiting. Carrying a few days of water and food supplies is recommended when visiting offshore islands.
Source: 가가와현 방재과·혼시 세토 도로주식회사 (2023)
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.