mamoie ReportSAMPLE
A disaster profile for this home — six hazards, from official Japanese government data
Issued: 2026-07-04
Data retrieved: 2026-07-04
Data retrieved: 2026-07-04
Subject location
Around Oshiage 1-1-2, Sumida, Tokyo (foot of Tokyo Skytree)
35.71008, 139.80861
Map: GSI base tiles. ● marks the subject location. Hazard-layer maps appear in each chapter.
Depth:0–0.5m0.5–3m3–5m5–10m10–20m20m+
Map: GSI base tiles. ● marks the subject location. Sources: GSI Japan & Overlay Hazard Map. Switch the official hazard layers (flood / storm surge / tsunami / landslide — maximum-scale assumptions) with the buttons above; zoom and pan freely. In print/PDF, hazard-layer maps appear in each relevant chapter.
Overall assessment
High cautionApplies: Flood-designated area · High earthquake probability · Storm-surge inundation assumed · High liquefaction potential (4 items)
The translation — what this actually means
The headline risks for this location are water and shaking. Cliff collapse and tsunami, by contrast, are not a concern here. In practical terms, heavy rain and typhoons are assumed to bring water here, and earthquake risk — both probability and ground response — deserves attention. Put another way, this is a location where the right preparations are clear — the following chapters walk through them in order.
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Flooding — depth, time to recede, house-collapse risk
Official "Flood" hazard layer (maximum-scale assumption) around the subject location (●).
Depth:0–0.5m0.5–3m3–5m5–10m10–20m20m+
Sources: GSI Japan & Overlay Hazard Map.
Assumed flood depth0.5–3.0mMaximum-scale rainfall (roughly a 1-in-1000-year event)
Time for water to recede1–3 daysFlood duration (same assumption)
House-collapse hazard zoneOutsideNeither overflow current nor bank erosion applies — the building itself is not in a wash-away zone
Pluvial (drainage) floodingNo national data yetOnly 62 municipalities are on the national portal (as of July 2026). Check the municipal pluvial hazard map
The translation — what this actually means
A depth of 0.5–3.0m means water reaching from an adult's waist up to near the first-floor ceiling in deeper spots. The scenario to avoid most is being asleep on the first floor as water rises. On the other hand, this location is not in a house-collapse hazard zone, so in a sturdy building, moving to the second floor or higher ("vertical evacuation") is a realistic option. The key question then becomes whether you can hold out for 1–3 days until the water recedes — that duration of water, food, a portable toilet and power is the preparation benchmark for this home.
Reference: damage vs. premium
Estimated loss ¥11.19M–¥33.01M — set against about ¥20,000 a year
This location has an assumption of above-floor flooding (0.5–3.0m). Applying Japan's official damage-rate tables (MLIT, Manual for Economic Survey of Flood Control) to that assumption, the combined loss to building, contents and vehicle comes to roughly ¥11.19M–¥33.01M (building ¥6.64M–¥20.79M; contents ¥2.89M–¥8.88M; vehicle ¥1.67M–¥3.33M). The range reflects the assumed depth of 50–300cm, calculated at both ends.
The flood-coverage portion of fire insurance costs roughly ¥20,000 a year as a guide. A one-off loss and an annual premium are not directly comparable, so we convert the loss to an annual basis using the exceedance probability of each flood scale. On that basis the flood risk at this location is equivalent to ¥112,000–¥330,000 per year (a planning-scale flood assumption also applies here, and is included). That exceeds the ¥20,000 guide premium: on this measure, flood coverage is on the worthwhile side for this property. Also confirm contents (household goods) flood coverage — it is a separate rider from the building.
Assumptions: floor area 110m², one household, one vehicle, floor height 45cm above ground; prefectural unit value for the building; slope class inferred from the microlandform classification.
The flood-coverage portion of fire insurance costs roughly ¥20,000 a year as a guide. A one-off loss and an annual premium are not directly comparable, so we convert the loss to an annual basis using the exceedance probability of each flood scale. On that basis the flood risk at this location is equivalent to ¥112,000–¥330,000 per year (a planning-scale flood assumption also applies here, and is included). That exceeds the ¥20,000 guide premium: on this measure, flood coverage is on the worthwhile side for this property. Also confirm contents (household goods) flood coverage — it is a separate rider from the building.
Assumptions: floor area 110m², one household, one vehicle, floor height 45cm above ground; prefectural unit value for the building; slope class inferred from the microlandform classification.
An approximation produced by applying Japan's published official formulas to the flood assumption for this point. Actual losses vary greatly with construction, age, foundation height, contents and how the water drains. The annual figure assumes exceedance probabilities of 1/1000 (maximum scale) and 1/100 (planning scale); the latter varies from 1/200 to 1/30 by river, so the annual figure can move by roughly 0.5–3x. This is decision material, not a recommendation to buy or decline insurance — consult an insurer or a licensed adviser.
Storm surge — seawater during typhoons
Official "Storm surge" hazard layer (maximum-scale assumption) around the subject location (●).
Depth:0–0.5m0.5–3m3–5m5–10m10–20m20m+
Sources: GSI Japan & Overlay Hazard Map.
Storm-surge assumption0.5–3.0mInside the maximum-scale typhoon storm-surge assumption
The translation — what this actually means
Beyond river flooding from heavy rain, storm surge — the sea rising under a typhoon's low pressure and wind — is also assumed to inundate this location to 0.5–3.0m. In other words, water can arrive here in two ways: heavy rain and typhoons. When a typhoon approaches, watch not only river levels but also tide levels and high-tide times. The saving grace: storm surge can be anticipated days in advance from the forecast track, so moving early prevents most of the harm.
Earthquake — probability of shaking, and ground amplification
Japan measures shaking with the JMA "shindo" intensity scale (0–7) — it describes what happens where you stand, not the earthquake's magnitude. Rough feel: 5-upper = hard to walk without holding on · 6-lower = hard to stay standing · 6-upper = impossible to stay standing, unsecured furniture is thrown · 7 = the scale's maximum.
30-yr: shindo 5-upper+99.7%Hard to walk without holding on. Assume you will experience this at least once while living here
30-yr: shindo 6-lower+83.2%High even by national standards. Hard to stay standing at this intensity
30-yr: shindo 6-upper+31.5%Impossible to stay standing — shaking at which building collapse can become widespread
Ground amplification×2.28AVS30 = 152 m/s. Soft ground that amplifies shaking more than firm ground
The translation — what this actually means
Shindo 6-lower (on Japan's JMA intensity scale) is shaking strong enough that you cannot stay standing, and buildings with poor earthquake resistance can collapse. The probability of that within 30 years here is 83.2% — realistically, plan on it happening at least once while you live here. Moreover, the ground here is soft: the same earthquake will shake this spot more than nearby firm ground. The building's earthquake resistance (post-1981 "new seismic standard", ideally a seismic grade) and securing furniture are, quite directly, life-saving preparations.
Tokyo Metropolitan hazard survey (押上1丁目 — town-block level)
Building collapseRank 3 / 5How prone the area is to building damage from shaking
FireRank 2 / 5Risk of post-earthquake fire outbreak and spread
OverallRank 2 / 5Ranked 2072 of 5,192 town blocks in Tokyo
Source: 東京都都市整備局「地震に関する地域危険度測定調査（第9回）」（令和4年9月公表） (CC BY 4.0). Tokyo's own survey, one level finer than the national 250m mesh; ranks are relative within Tokyo.
The translation — what this actually means
In Tokyo's town-block survey, 押上1丁目 rates rank 2 overall (2072 of 5,192) — comparatively low within Tokyo. Note this is a relative comparison inside Tokyo; it does not mean the shaking probability itself (above) is low. The basic preparations remain just as worthwhile.
Liquefaction — is the ground itself vulnerable to shaking?
Liquefaction potentialHighEstimated from the landform class "Drained land (polder)". Guideline by the Wakamatsu–Matsuoka method
The translation — what this actually means
Liquefaction is when loose, sandy ground behaves like a liquid during earthquake shaking — buildings tilt, water and gas lines break, roads buckle. Its impact lasts long after the shaking stops. This land is classified as Drained land (polder), with potential rated High. If you are considering a detached house here, always check the geotechnical survey report and whether liquefaction countermeasures (piles, ground improvement) are in place. Note that liquefaction damage is not covered by fire insurance — only earthquake insurance covers it.
Landslide & tsunami
Landslide hazard areaOutsideChecked all three types — steep-slope failure, debris flow, landslide — none apply
Tsunami assumptionOutsideNot within any tsunami inundation assumption
The translation — what this actually means
"Not applicable" is itself valuable information — because we checked. For this location you can set cliff collapse and tsunami aside, and concentrate your preparation elsewhere.
The land's origins and elevation — the root of the risks
Landform classDrained land (polder)Land classification from the national surface-ground dataset
Elevation0.8mMeasured by 1m（レーザ）
The translation — what this actually means
This chapter answers the "why" behind the whole report. This was originally waterside lowland (Drained land (polder), elevation 0.8m) — which is why water reaches it easily (flood, storm surge), and why the ground is soft (amplified shaking, liquefaction). The warnings that looked scattered all trace back to one fact: the land's origin as Drained land (polder). Once you know the land's character, the order of preparations follows naturally.
Elevation relative to the surrounding land
- This point sits at 0.8m. Within 500m the ground ranges from -2m to 5.8m, and the lowest direction is NE — that is where surface water drains.
- The nearest ground 5m higher than this point is 2,740m away to the W — roughly 34 minutes on foot. Standing on the site you cannot tell this; it decides whether leaving on foot is realistic.
- Looking out 3km, 0 of the 8 compass directions are at least 10m higher than this point (elevation ranges -2.8m to 14.9m). With no higher ground in any direction, water spreads out rather than piling up — but it also means there is nowhere close to escape to.
Source: GSI digital elevation model
What was here before
c. 1936–1942
1945–1950
1961–1969
Today
Aerial photographs of the same location across time. Source: Geospatial Information Authority of Japan (GSI) tiles. The circle marks the property in every frame.
- Dark, winding bands are former river channels. Ground there is often soft and prone to liquefaction.
- Regular grids of small rectangles are paddy fields — low, wet land that was later filled and built on.
- A straight coastline that appears only in later photos indicates reclaimed land.
- If the surrounding area was built up long before this plot, this plot was likely the harder land to build on.
Evacuation — where to flee, and where to stay
Shelter names are shown in Japanese, exactly as they appear on local signs — that is what you (or anyone helping you) will need to match on the ground. Addresses are romanized for readability. Tap Map › to open each site in Google Maps.
Subject location① Where to flee (flood-capable)② Where to stay (designated shelter)Dashed rings = walking time (80m/min)
① Emergency evacuation sites — where to flee to survive a flood
Flood-capable designated emergency evacuation sites (GSI national dataset; covered hazards: flood, storm surge, inland flooding). Distances are straight-line; walking assumes 80m/min. Municipally designated sites may be missing — always confirm with the official shelter list of Sumida City (墨田区).
② Designated shelters — where to stay if your home becomes unlivable
Source: GSI “designated shelters” dataset. Facilities for staying after a disaster makes your home unlivable — not guaranteed to open during a flood. Distances are straight-line; walking assumes 80m/min.
The translation — what this actually means
① (where to flee) and ② (where to stay) are separate designations — sometimes the same building, sometimes not. List ① shows facilities in neighboring municipalities because the sites designated by Sumida City (墨田区) itself may be missing from the national dataset. Closer shelters inside Sumida City (墨田区) may in fact open, so always confirm with the official shelter list of Sumida City (墨田区). Note: the ① sites carry the operating condition "will not open if river flooding is imminent". In a major flood of a large river, this is an area where the municipality calls for wide-area evacuation — leaving early for relatives, hotels or other areas. "Just go to the nearby shelter" may not apply here; the basic move is to act early, as soon as the typhoon or rain outlook firms up.
If you live here — preparation priorities
1Make sure your fire insurance includes flood coverageIn Japan, flood coverage (suisai hosho) is an optional part of fire insurance and is increasingly excluded to keep premiums down — so it is worth checking explicitly rather than assuming. Where 0.5m or more of inundation is assumed, it is not optional. Contents coverage is a separate rider from the building; confirm both.
2Add earthquake insuranceFire insurance in Japan does not cover earthquake damage — earthquake insurance is a separate product, attached to a fire policy, and is capped at 30–50% of the fire policy's sum insured. It is also the only policy that covers liquefaction damage to a building.› How liquefaction works in Japan
3Stock for sheltering in place (several days)Water (3L per person per day), food, and a portable toilet — stored upstairs, above the assumed inundation depth. Where water lingers, going upstairs stops being evacuation and becomes living at home without water, power or drainage.
4Prepare for power outageBoth floods and earthquakes tend to cut power, and in Japan restoration to a flooded area can take days. A battery bank large enough to keep phones and lights running is the practical minimum.
5Agree on a family evacuation ruleDecide in advance to move at the forecast stage rather than when water appears, and agree it as a family. Japanese municipalities issue graded evacuation information — deciding which level triggers your departure, before the day, is the whole point.
What the insurance actually costs
- Earthquake insurance in Japan is a government-backed scheme, so the premium does not depend on which insurer you use — it is set by prefecture and building structure. For 東京都, the published annual rate per ¥10,000,000 of cover is ¥27,500 for fire-resistant construction (steel/reinforced concrete) and ¥41,100 for non-fire-resistant construction (typically wood).
- Earthquake cover is capped at 30–50% of the fire policy's sum insured. Taking the upper end, the building would be insured for about ¥17,600,000, which costs roughly ¥48,400 a year if the structure is fire-resistant, or ¥72,300 a year if it is wooden. The structure of this specific building is not something this report can see — it is one of the questions to put to the seller.
- Household contents are insured separately, capped at ¥10,000,000. Insuring them to that cap costs about ¥27,500–¥41,100 a year depending on structure. This matters here because liquefaction damage to a building is covered by earthquake insurance and by nothing else.
- If the building was newly constructed on or after 1 June 1981, a 10% discount applies, bringing the building premium to roughly ¥43,600–¥65,100. Larger discounts (10/30/50%) apply if the building holds a certified seismic grade, and 50% for base-isolated buildings — worth asking about, since they are claimed by the policyholder, not applied automatically.
- Flood coverage is different: it is each insurer's own product, with no published rate, and it varies with the building. We therefore do not put a computed figure on it. The working guide is around ¥20,000 a year — treat that as an order of magnitude, and get an actual quote.
Source: Japan Ministry of Finance, published earthquake-insurance base rates (effective for policies starting on or after 1 October 2022). Earthquake premiums are computed from the base rates published by Japan's Ministry of Finance, applied to a sum insured derived from this building's assessed value. Actual premiums vary with the sum insured, the policy term and which discounts apply. This is decision material, not a recommendation to buy or decline cover — consult an insurer or a licensed adviser.
Before you buy or sign — what to ask and check
- At the legally required property disclosure (jūyō jikō setsumei), receive the flood hazard map explanation (mandatory since 2020) and check that it matches this report
- Check for a raised foundation or ground elevation work (where flooding is assumed, floor height directly becomes the difference in damage)
- Check where electrical equipment, the water heater and AC outdoor units are mounted (ground level, or raised?)
- Ask the municipal office (墨田区) for past flooding and disaster records at this location
- Request the geotechnical survey report (essential for detached and custom-built houses)
- Confirm liquefaction countermeasures (pile foundations, ground improvement) and their details
- Confirm the building meets the post-1981 "new seismic standard" — ideally ask for its seismic grade
- Get a fire (with flood coverage) and earthquake insurance quote before you commit to the purchase
- For condominiums: check where the electrical room and water tanks sit (basements mean long outages if flooded) and the building's disaster plan
- Walk the evacuation route yourself — imagining night, and rain
Below is a message you can send to the seller or agent as it is. It is written in Japanese because that is what they read; forward it to your agent and it will do its job. Each item is followed by an explanation, in English, of why it is worth asking — those explanations are for you, and are not part of the message.
Why each question is worth asking
- Since August 2020, Japanese real-estate agents are legally required to show where the property sits on the municipality's own flood hazard map during the mandatory disclosure. Asking for the municipal map itself is the correct way to verify this — no third-party report, including ours, can substitute for it.
- The assumed inundation depth here is 0.5〜3.0m未満. Floor height translates directly into the size of the loss, and Japanese flood insurance typically pays out only above floor level or above 45cm from ground level — so this number decides both damage and coverage.
- If the distribution board, water heater and AC outdoor units sit low, even shallow flooding means long, expensive restoration. Whether they can be raised is worth knowing before you commit.
- Hazard maps show assumptions, not history. What has actually happened is known only to the seller, the neighbours and the municipality — there is no dataset for it, so it has to be asked.
- Floodwater here is assumed to take 1日〜3日未満 to recede. Where water lingers, the question is not only whether you can leave but whether you can stay — so what exists on the upper floors matters as much as the depth.
- On liquefaction-prone ground, buildings can tilt. A geotechnical survey report is usually produced at construction and held by the seller. Note that in Japan, liquefaction damage to a building is covered only by earthquake insurance — not by fire insurance.
- This location has a 83.2% probability of shindo 6-lower or stronger shaking within 30 years. Buildings whose construction permit was issued on or after 1 June 1981 meet Japan's post-1981 seismic standard — the permit date, not the completion date, is what determines this.
- Sellers in Japan have a duty to disclose defects they know about. Asking in writing is itself worth doing: the answer becomes a record you can rely on if a problem emerges later.
These questions are drawn from what applies to this specific address. They are not legal advice, and the seller is not obliged to answer every one — but asking in writing is itself worth doing.
The verdict — this property on the disaster axis
On the disaster axis, this comes down to whether the conditions below can be met
- There is an inundation assumption here (0.5〜3.0m未満). This is, however, the kind of risk that insurance, preparation and an evacuation plan can handle.
- The ground here is liquefaction-prone, which can leave a building tilted and damage buried utilities.
- There is a 83.2% probability of shindo 6-lower or stronger shaking within 30 years — high even by Japanese standards.
Check that these hold before you proceed
- Flood coverage can be added to the fire insurance — and note that contents (household goods) flood coverage is a separate rider from the building.
- There is a second floor or higher to move to, above the assumed inundation depth. A single-storey house, or a ground-floor unit, does not meet this condition.
- The distribution board, water heater and AC outdoor units sit above the assumed depth — or can be raised.
- Water is assumed to take 1日〜3日未満 to recede. You can store enough water, food, a portable toilet and a power source upstairs to cover that period at home.
- You can obtain the geotechnical survey report and confirm whether pile foundations or ground improvement were carried out. Note that liquefaction damage to a building is covered only by earthquake insurance, so that policy becomes a precondition.
- The building's construction permit was issued on or after 1 June 1981 (Japan's post-1981 seismic standard) — ideally, ask for its seismic grade as well.
This judgement covers the disaster axis only. Whether the price is fair, whether the location suits you, and the condition of the building itself (structure, age, foundation height, deterioration) are not visible in this report — those belong to the agent, an architect, or a home inspection.
Sources, and how to read this report
- Flood depth / duration / house-collapse zones / landslide / tsunami / storm surge: "Overlay Hazard Map" portal (MLIT & Geospatial Information Authority of Japan)
- Earthquake probabilities / landform class / ground amplification: J-SHIS, National Research Institute for Earth Science and Disaster Resilience (Probabilistic Seismic Hazard Maps, 2024 edition)
- Estimated losses: MLIT, “Manual for Economic Survey of Flood Control (draft)” (rev. April 2020) — damage-rate tables by inundation depth; and its supplement “Asset Unit Values and Deflators” (rev. June 2024) — prefectural building unit values.
- Historical aerial photographs: GSI tiles (c. 1936–1942 / 1945–1950 / 1961–1969 / latest), used under the GSI tile terms with attribution.
- Elevation and geocoding: GSI (Geospatial Information Authority of Japan) APIs
- Designated emergency evacuation sites: GSI dataset (based on municipal designations)
- Liquefaction potential: estimated from landform classification (Wakamatsu–Matsuoka method; guideline only)
- Tokyo town-block hazard survey: 東京都都市整備局「地震に関する地域危険度測定調査（第9回）」（令和4年9月公表） (CC BY 4.0)
› Full list of referenced datasets (sources, publication years, resolution — Japanese)
This report is reference information based on public open data. It is not a guarantee of safety, nor investment, purchase or insurance advice. Judgments are made at map-pixel or ~250m-mesh resolution, so values near a boundary may reflect the adjacent zone. For final confirmation, consult the municipality's latest hazard maps and offices. Shelter designations and their operating rules can change. Japanese terms (shindo, place names) are kept where translation could lose precision.
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