Yamaguchi Prefecture (山口県) — Earthquake Risk & History
Chugoku region · Based on HERP official data
Yamaguchi occupies the westernmost tip of Honshu, facing both the Japan Sea and Seto Inland Sea. The 2013 M6.6 Yamaguchi-ken Hokubu earthquake caused housing damage in Hagi City. Japan Sea tsunami risk applies to coastal areas.
Fault Lines & Seismic Characteristics
Active Faults & Trenches
- Nagato–Iwakuni Fault System
- Yamaguchi–Ishimi Fault Zone
Seismic Characteristics
Yamaguchi Prefecture occupies the westernmost tip of Honshu, facing both the Japan Sea and Seto Inland Sea. The Nagato-Iwakuni Fault Zone runs east–west through the southern part of the prefecture. The 2013 M6.6 Yamaguchi-ken Hokubu earthquake originated on the Japan Sea side, with possible links to the Japan Sea Eastern Margin Fault Zone under study.
Earthquake History
- M6.6
2013
Yamaguchi-ken Hokubu earthquake — housing damage in Hagi City; numerous injured
- M5.9
1987
Mine earthquake — central Yamaguchi; injuries reported
- M7.0
1666
Early Edo period Yamaguchi earthquake — coastal damage in western Yamaguchi per historical records
※ Showing M6+ or historically significant events. Source: JMA database.
Future Probability — HERP Official Assessment
30-Year Probability (Official Figure)
Long-term evaluation by the Earthquake Research Committee. Japan Sea tsunami arrival can be fast — confirm evacuation routes before coastal travel.
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
- ✅ Yamaguchi 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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Japan Sea coastal earthquake risk in northern Yamaguchi
The 2013 earthquake demonstrated that M6+ events can occur in northern Yamaguchi. Links with the Japan Sea Eastern Margin Fault Zone are under investigation.
Source: 야마구치현 방재과 (2020) -
Earthquake safety for Hagi, Shimonoseki, and Akiyoshidai visitors
Yamaguchi's top tourist sites include Hagi castle town, Shimonoseki (Kanmon Straits), and Akiyoshidai limestone plateau. Shimonoseki's Kanmon Strait location warrants tsunami awareness. The Japan Sea coast (Hagi) faces faster tsunami arrival from Japan Sea Eastern Margin faults — confirm evacuation routes at coastal accommodations.
Source: 야마구치현 관광·방재과 (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.