Kanagawa Prefecture (神奈川県) — Earthquake Risk & History
Kanto region · Based on HERP official data
Kanagawa was the hardest-hit area in the 1923 Great Kanto Earthquake. The Sagami Trough — where the Philippine Sea Plate subducts — runs just south of the prefecture and has generated M8-class earthquakes on roughly a 200–400 year cycle. About 100 years have elapsed since 1923.
Fault Lines & Seismic Characteristics
Active Faults & Trenches
- Sagami Trough
- Isehara Fault
- Mochikuna Fault
Seismic Characteristics
The Sagami Trough runs beneath the sea south of Kanagawa, where the Philippine Sea Plate subducts beneath the Eurasian and North American plates. Both the 1923 Great Kanto Earthquake (M7.9) and the 1703 Genroku Kanto Earthquake (M8.2) originated here. M8-class events have recurred on roughly a 200–400 year cycle. Coastal reclaimed land in Yokohama and Kawasaki faces high liquefaction risk.
Earthquake History
- M7.9
1923
Great Kanto Earthquake — Yokohama devastated, Kamakura struck by tsunami; 32,000+ dead in Kanagawa Prefecture
📖 Wikipedia - M9.0
- M8.2
1703
Genroku Kanto Earthquake — Sagami Trough event; coastal tsunami killed thousands
※ Showing M7+ or Intensity 5+ events. Source: JMA database, Cabinet Office.
Future Probability — HERP Official Assessment
30-Year Probability (Official Figure)
Long-term evaluation by the Earthquake Research Committee. Approximately 100 years have passed since the 1923 disaster. Kanagawa also lies within the 70% (30-year) probability zone for a Tokyo Metropolitan M7 earthquake.
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
- ✅ Kanagawa 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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Sagami Trough earthquake recurrence cycle and risk
The Sagami Trough has produced M8-class earthquakes roughly every 200–400 years. With about 100 years elapsed since 1923, the research community is closely monitoring this area.
Source: 내각부 중앙방재회의 (2021) -
Liquefaction risk in Yokohama and Kawasaki coastal reclaimed land
Kanagawa's coastal reclaimed land faces high liquefaction risk in a major earthquake. The 2011 disaster demonstrated this across nearby Chiba and Urayasu. Yokohama's Port area and waterfront reclaimed zones carry similar vulnerability.
Source: 가나가와현 방재회의 (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.