Nagano Prefecture (長野県) — Earthquake Risk & History
Chubu region · Based on HERP official data
Nagano is landlocked but has multiple active faults and volcanoes. The Matsumoto Basin Eastern Margin Fault carries an M7.4 risk, and Mt. Ontake's 2014 eruption killed 58 hikers without adequate warning.
Fault Lines & Seismic Characteristics
Active Faults & Trenches
- Itoigawa–Shizuoka Tectonic Line
- Matsumoto Basin E Margin Fault
- Shiojiri–Matsumoto Fault System
Seismic Characteristics
Both the Itoigawa-Shizuoka Tectonic Line and the Matsumoto Basin Eastern Margin Fault run through Nagano Prefecture. Active volcano Mt. Ontake (Ontakesan) poses both volcanic earthquake and eruption risk. The 2014 Ontake eruption killed 58 hikers — always check JMA volcanic alert levels before mountaineering here.
Earthquake History
- M6.7
2011
Northern Nagano earthquake — significant building collapse in Iiyama City
- M6.8
1984
Western Nagano earthquake — landslide on Mt. Ontake
※ Showing M6.5+ or Intensity 5+ events. Source: JMA database.
Future Probability — HERP Official Assessment
30-Year Probability (Official Figure)
Long-term evaluation by the Earthquake Research Committee. When visiting Matsumoto or Matsushiro, check both earthquake and volcanic alert information.
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
- ✅ Nagano 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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Risk assessment of the Matsumoto Basin Eastern Margin Fault
An M7.4 earthquake on the Matsumoto Basin Eastern Margin Fault could produce Intensity 6+ across Matsumoto City. Despite being a popular tourist destination, the area carries significant earthquake risk.
Source: 나가노현 방재과 (2022) -
Lessons from the 2014 Mt. Ontake eruption — current mountaineering precautions
The 2014 Ontake eruption killed 58 hikers with little advance warning. Volcanic earthquakes can be difficult to detect before an eruption begins. Check JMA volcanic alert levels before climbing. Popular tourist spots like Matsumoto and Karuizawa lie outside the volcanic hazard zone.
Source: 기상청 화산부·나가노현 관광부 (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.