Japan Hazard Map Lookup: Flood, Tsunami, Landslide

Check any list of Japanese coordinates against Japan's official hazard maps: river flood depth, flood duration, house-collapse zones, pluvial flooding, storm surge, tsunami and landslide (sediment disaster) warning zones, in English. Source: the Hazard Map Portal Site (ハザードマップポータルサイト) of the Geospatial Information Authority of Japan (GSI), official open data. No API key, no login, no personal data. One flat JSON/CSV row per location (up to 1,000 per run) with a plain-English hazardSummary, for $5 per 1,000 hazard checks, via the Apify API or MCP for AI agents.

Screening only. The Hazard Map Portal's terms say its maps cannot be used by Japanese real-estate brokers for the statutory explanation of important matters (重要事項説明). For official purposes check the municipal hazard map. none means "no hazard published at this point", not "no risk".

Why use it?

	Official portal (disaportal.gsi.go.jp)	MLIT Real Estate Information Library API (free)	This Actor
Language	Japanese only	Japanese docs and responses	English (+ original Japanese labels)
Access	Browser	API key applied for in Japanese, then reviewed	No API key; your Apify account
Many locations at once	One point at a time, by hand	One map tile / area per call; you decode it	Up to 1,000 points per run, one row each
Output	Map image	GeoJSON / vector tiles per layer	Flat JSON / CSV / Excel rows with a summary sentence
Price	Free	Free	$0.005 per location

Paid alternatives exist in Japan (hazard reports from geotechnical consultancies, price on request; property document investigations from about ¥38,500 per property, which cover much more than hazards). This Actor is the quick screening step before those.

What can you do with Japan Hazard Map Lookup?

1. Screen a property list or portfolio in bulk. Paste the coordinates of up to 1,000 properties (from your CSV, database or geocoded listings, for example from SUUMO, at home or akiya (vacant house) banks) and get flood, tsunami and landslide columns for every one. Objects with lat/lng plus label or url are accepted as they are, so each row maps back to your listing.
2. Due diligence for foreign buyers, funds and lenders. Screen a portfolio or a shortlist of Japanese properties in English before ordering a full local investigation.
3. AI agents. Answer "Is this place in Japan at risk of flooding, tsunami or landslides?" with the ready-made one-sentence hazardSummary.

How to use it

1. Click Start to try the default input (a point in Edogawa, Tokyo: river flooding 3 to 5 m and storm surge 3 to 5 m).
2. Replace it with your own coordinates as "latitude,longitude" strings in decimal degrees (up to 1,000).
3. Run, then download the rows as JSON, CSV or Excel, or call the Actor via the API.

Need coordinates from addresses? Geocode them first (addresses are not supported yet).

Input

Only locations is required.

{
  "locations": [
    "35.7069,139.8683",
    { "latitude": 35.3080, "longitude": 139.5470, "label": "Listing 42" },
    { "lat": 35.6896, "lng": 139.7006, "url": "https://example.com/listing/43" }
  ]
}

Field	Type	Notes
locations	array, required	Strings "lat,lon", arrays [lat, lon] or objects with latitude/longitude or lat/lng/lon. label, id, url or name is copied to the label column so you can match rows back. Max 1,000.

Output

Real output (2026-10-06) for "35.7069,139.8683" (Edogawa, Tokyo), shortened:

{
  "status": "ok",
  "latitude": 35.7069,
  "longitude": 139.8683,
  "hazardSummary": "Hazards at this point: river flooding 3 to 5 m; storm surge 3 to 5 m.",
  "hazardCount": 2,
  "worstInundationDepth": "3 to 5 m",
  "worstInundationSource": "river flooding",
  "inRiverFloodZone": true,
  "inTsunamiZone": false,
  "inStormSurgeZone": true,
  "inSedimentDisasterZone": false,
  "floodDepthMax": "3 to 5 m",
  "floodDepthMaxJa": "3m～5m",
  "floodDepthPlanned": "0.5 to 3 m",
  "floodDuration": "2 weeks or more",
  "houseCollapseOverflowZone": false,
  "houseCollapseErosionZone": false,
  "pluvialFloodDepth": "none",
  "stormSurgeDepth": "3 to 5 m",
  "tsunamiDepth": "none",
  "debrisFlowZone": "none",
  "steepSlopeZone": "none",
  "landslideZone": "none",
  "mapUrl": "https://disaportal.gsi.go.jp/maps/?ll=35.7069,139.8683&z=16&base=pale&vs=c1j0l0u0"
}

Field	Meaning
status	ok (charged) or error (free). A point with no published hazard is an ok row with none values
reason / error	Only on error rows: invalid_input, outside_japan, source_unavailable (GSI did not answer; run again later) or colour_not_in_legend (a map colour did not exactly match the official legend, usually on a zone edge; unknownLayers names the unclear layers), plus one English sentence on how to fix it
hazardSummary / hazardCount	One-sentence summary and number of hazards found
worstInundationDepth / worstInundationSource	Deepest class among river flooding, storm surge, tsunami and pluvial flooding
floodDepthMax / floodDepthPlanned	River flood depth for the maximum assumed rainfall (想定最大規模) and the planned-scale rainfall (計画規模)
floodDuration	How long the water stays (浸水継続時間)
houseCollapseOverflowZone / houseCollapseErosionZone	Inside a house-collapse zone (家屋倒壊等氾濫想定区域) by overflow or bank erosion
pluvialFloodDepth	Inland / sewer flooding depth (内水), some municipalities only
stormSurgeDepth / tsunamiDepth	Storm surge (高潮) and tsunami (津波) inundation depth
debrisFlowZone / steepSlopeZone / landslideZone	special_warning_zone (red zone), warning_zone (yellow zone), ..._planned, none or not_available (Kyoto Prefecture, see FAQ)
...Ja	The official Japanese legend label
mapUrl	Link to the same point on the official portal map
attribution / disclaimer	Source credit and the screening-only notice, on every row

How much does it cost?

Pay per event: $0.005 per ok row ("hazard check") = $5 per 1,000 locations, plus Apify's standard $0.00005 per run. error rows (bad coordinates, outside Japan, source down, unclear colour) are free.

Use	Locations	Cost
One property	1	about $0.005
A shortlist	50	about $0.25
A full listing export (max per run)	1,000	about $5.00

Tip: set a maximum cost per run in the run options; the Actor stops before it would go over it.

Use via API & MCP (AI agents)

curl -X POST "https://api.apify.com/v2/acts/japan-open-data~japan-property-hazard-lookup/run-sync-get-dataset-items?token=<YOUR_APIFY_TOKEN>" \
  -H "Content-Type: application/json" \
  -d '{"locations": ["35.7069,139.8683", "35.3080,139.5470"]}'

MCP: add the Actor through the Apify MCP server (https://mcp.apify.com) with ?tools=japan-open-data/japan-property-hazard-lookup.

Recommended for agents:

• Call it with {"locations": ["<lat>,<lon>"]} and answer from hazardSummary; use mapUrl as the link to show.
• Always check status. On error, show the error sentence (it says what to fix); it was not charged.
• Send all points in one call (up to 1,000) rather than one call per point. About 2 to 3 seconds per location; use the synchronous endpoint for up to about 50 points and an asynchronous run for more.
• Always tell the user this is screening data, not a legal hazard disclosure.

FAQ

Can I use it for the official hazard explanation in a Japanese property sale? No. The portal's terms exclude that use. Use it to decide which properties need a closer look.

Does none mean the place is safe? No. It means no hazard is published for that point. Some prefecture-managed rivers, storm surge areas and pluvial flooding maps are not on the portal yet.

Why not use MLIT's free Real Estate Information Library API? It is a good source if you read Japanese, can apply for a key and want to decode map tiles yourself. This Actor needs no key, takes a plain list of points and returns one English row per point, ready for a spreadsheet or an AI agent.

How fresh is the data? Every run reads the live official map tiles, so you get what the portal shows that day.

Why do Kyoto points show not_available for landslide zones? Kyoto Prefecture's sediment-disaster data may not be used commercially, so the Actor never reads it. Points in Kyoto Prefecture or within about 1 km of its border or coast get not_available for the three sediment layers (flood, storm surge and tsunami are still returned). Osaka, Kobe, Nara and Otsu get normal values.

How accurate is it? The Actor reads the zoom-17 map tile (about 1 m per pixel) under each point and reports a class only when the colour exactly matches the official legend; otherwise it returns a free error row instead of guessing. Zone boundaries themselves are approximate (1:25,000 to 1:50,000 for sediment zones).

Known limitations

• Coordinates only; no address geocoding yet.
• none can mean "not mapped yet" (some prefecture rivers, storm surge in 18 prefectures, pluvial flooding in about 65 municipalities).
• Points at sea may return none; points on a zone edge may return a free colour_not_in_legend error row. The house-collapse (overflow) layer is drawn as rings, so a point within about 12 m outside its edge can return that error.
• Reservoir failure, large-scale fill and liquefaction layers are not included (third-party rights).
• The same point sent twice is checked and charged twice.

Data source and license

• 出典：ハザードマップポータルサイト（https://disaportal.gsi.go.jp/）を加工して作成。Source: Hazard Map Portal Site (GSI), open data under the Public Data License (PDL) 1.0, processed by Japan Open Data. The processed values are not published by the Government of Japan.
• Sediment disaster warning zones: 国土数値情報（土砂災害警戒区域データ）, Ministry of Land, Infrastructure, Transport and Tourism (MLIT), based on prefectural data (CC BY 4.0 with prefecture conditions). Prefectural credits include: Chiba Prefecture (ちば情報マップ, CC BY 4.0), Niigata Prefecture (CC BY 4.0), Fukui Prefecture (福井県オープンデータライブラリ, CC BY 4.0), Nagano Prefecture (信州砂防情報マップ, CC BY 4.0), Aichi Prefecture (マップあいち, CC BY 2.1 JP), Tottori Prefecture (CC BY 2.1 JP), Hiroshima Prefecture (土砂災害ポータルひろしま / DoboX, CC BY), Fukuoka Prefecture (CC BY 2.1 JP), Nagasaki Prefecture (長崎県オープンデータカタログ, CC BY 4.0), Kagoshima Prefecture (CC BY 4.0), and data published by Miyagi, Yamagata, Fukushima, Ishikawa, Shizuoka, Shiga and Kochi Prefectures. Zone positions are approximate and are not legal documents.
• Kyoto Prefecture's sediment-disaster data is never used (not licensed for commercial use).
• Kyoto Prefecture outline: 国土数値情報（行政区域データ）N03, 2025-01-01, MLIT (CC BY 4.0), simplified by Japan Open Data.
• Not affiliated with or endorsed by GSI, MLIT or any prefecture or municipality. Provided as is.

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Feedback

Found a wrong value or need another layer (for example address input)? Open an issue on the Issues tab with your input and what you expected.