Japan Hazard & Insurance Check- Home
- Guide
How to Read Japan's Hazard Maps and Review Fire and Earthquake Insurance
What flood depths mean, what landslide zones are, and which insurance covers which disaster (checked 2026-10-31).
Flood depth guide
| Depth | Rough meaning |
|---|---|
| Under 0.5 m | Water under the floor (up to knee height) |
| 0.5–3 m | Above the ground floor, up to its ceiling |
| 3–5 m | Up to the second floor |
| 5–10 m | Above the second-floor eaves |
| 10 m or more | Third or fourth floor and higher |
River flooding assumes the largest conceivable rainfall (rarer than once in 1,000 years). Tsunami maps assume the largest-class tsunami.
Landslide warning zones
A warning zone (yellow zone) is where a landslide could endanger residents. A special warning zone (red zone) is where buildings could be destroyed and residents seriously harmed; building and development are restricted. These zones must be explained in property transactions.
Which insurance covers what
| Disaster | Insurance |
|---|---|
| River flooding, storm surge, rain-induced landslides | Flood cover (suisai) in fire insurance, if included |
| Typhoon wind, hail, snow | Wind, hail and snow cover in fire insurance |
| Earthquake shaking, fire caused by earthquakes, tsunami, earthquake-induced landslides, eruptions | Earthquake insurance (not paid by fire insurance) |
Many flood covers pay when water rises above the floor or more than 45 cm above ground level, or when damage exceeds a set share; terms differ by insurer and product.
Flood rating classes (suisai tochi)
For fire insurance starting from October 2024, flood premiums vary by municipality in five classes (GIROJ reference rates; adoption differs by insurer). Look up your municipality on the GIROJ flood class search (Japanese). The class reflects the municipality as a whole, not your building, so combine it with the point check on this site.
Earthquake insurance basics
- It is added to fire insurance, at 30–50% of the fire insurance amount (up to ¥50 million for the building and ¥10 million for contents).
- Premiums depend on prefecture and structure class, with one discount (base isolation, seismic grade, seismic diagnosis or building year). Use the premium calculator.
- Shaking forecasts (such as the probability of intensity 6- or stronger within 30 years) are on NIED's J-SHIS.
What this site cannot tell you
- Drainage flooding, irrigation-pond failure, liquefaction and local shaking
- Rivers not yet on the Hazard Map Portal, or assumptions not yet updated
- Differences due to each building's height, fill or foundation
Municipal hazard maps may cover these; find them via the Hazard Map Portal.
Primary sources (Japanese): Hazard Map Portal / open data / GIROJ flood classes / GIROJ earthquake base rates / MOF earthquake insurance base premiums