Yokohama's 18 wards ranked by natural hazard exposure — 398 traded districts checked against official data

Yokohama holds both a coastal plain and an inland ridge inside one city. That is why "which ward is safest" has no single answer here: flooding, landslides, and liquefaction each bite in different places.

This article checks the districts where homes and land actually changed hands, one by one, against official data — 398 districts across 18 wards from the most recent quarter, not general impressions about terrain.

What this article shows

• For each of the 18 wards, what share of traded districts falls inside a flood, landslide, or liquefaction-prone area
• Aoba has the fewest — all 23 traded districts clear on all three
• Minami, Naka, and Tsurumi have the most (68–71%)
• The low-hazard wards split in two on population. Aoba, Midori, and Tsuzuki hold up; Izumi, Seya, Konan, and Asahi fall sharply
• Only Tsuzuki satisfies both

Method — checking the districts where people actually buy

1. Collect every district that recorded a transaction in the most recent quarter, ward by ward, from MLIT's Real Estate Information Library (398 districts across 18 wards).
2. Geocode each district name to get a representative point.
3. Confirm the formatted address still contains the same ward and district. Districts that resolve somewhere else are dropped rather than counted.
4. Check that point against flood inundation zones, landslide alert zones, and the liquefaction tendency map. Only ratings on the "prone" side are counted, not merely being inside the surveyed area.

A ward is never judged from a single point. What you see is the share of the places people are actually buying.

What this check cannot tell you

• The result is for each district's representative point. Within one district, one side of a street can differ from the other.
• Districts with no transactions in the quarter are not included, so the denominator is not every district in the ward.
• Hazard zones are assumptions published by government bodies. They are revised, and they do not describe a specific building's construction or ground work.
• The median unit price mixes property types. It is not an official land price and should not be read as one.

Ranked by hazard exposure

"Any" counts districts hitting at least one of the three (a district hitting two still counts once).

The spread is wide. The inland ridge wards — Aoba, Midori, Izumi, Asahi — sit at 0–10%, while the wards near the water — Minami, Naka, Tsurumi, Nishi — run 65–71%. In Naka, 30 of 43 traded districts carry a liquefaction-prone rating, the highest count of the 18 wards.

The low-hazard wards split in two on population

This is what makes Yokohama different. A low hazard share does not by itself make a ward the one to pick — wards with similar exposure diverge sharply by 2050.

Among the low-exposure wards, Aoba (-6.2%), Midori (-4.0%), and Tsuzuki (+2.9%) hold their population. Seya (-20.3%), Konan (-17.6%), Izumi (-15.2%), and Asahi (-14.4%) do not. Low hazard and a maintained neighbourhood are not the same thing.

Tsuzuki is the ward that satisfies both: 14% exposure, +2.9% projected to 2050 — one of the few still growing — and at 18.1% the lowest share of residents aged 65+ in the city.

Conversely, most of the growing wards sit on the high-exposure side. Nishi (+8.9%), Kohoku (+5.3%), and Tsurumi (+2.2%) are all at 64% or above, and Naka has the highest net in-migration of the 18 wards at 1.52%. A high-exposure ward is not a ward to rule out — it is one where the checking has to happen address by address.

Ward by ward

• Aoba — all 23 traded districts clear on all three. -6.2% to 2050, 21.9% aged 65+.
• Tsuzuki — 14% exposure, +2.9% to 2050, 18.1% aged 65+, the youngest of the 18. The only ward strong on both counts.
• Midori — 6% (1 of 16 districts), -4.0% to 2050.
• Seya, Konan, Izumi, Asahi — low exposure at 8–13%, but -20.3% to -14.4% projected to 2050.
• Kanazawa — 53% exposure and -23.6% to 2050, the steepest decline of the 18, with net migration slightly negative at -0.07%.
• Naka, Minami, Tsurumi, Nishi — 65–71% exposure, but Nishi and Tsurumi are projected to grow and Naka leads the city on net in-migration.

What to verify before buying

A ward-level share narrows a shortlist; it does not answer for an address. Within one district, one side of a street can differ from the other. Once you have candidates, check at the address level.

• Whether the address sits inside a flood inundation zone, and if so the assumed depth
• Which part of the plot falls inside a landslide alert or special alert zone
• Whether the liquefaction rating is on the prone side, and whether ground improvement was recorded
• Nearby transaction prices, and how the district's population moved over 10 years

SafeLand checks an address against the public data on the spot. No account required.

Sources and definitions

• Traded districts, transaction counts, median unit price: MLIT Real Estate Information Library
• Flood, landslide, and liquefaction layers: same library
• Population, ageing rate, net migration, 2050 projection: e-Stat (Statistics Bureau of Japan)
• District representative points: Google Geocoding, each verified to land in the same ward and district