[Disaster Prevention Day 2026] Kochi City Real Estate Market Prepares for the Nankai Trough Earthquake: An In-Depth Analysis of Land Price Trends and Demand Gaps Between Tsunami Inundation Zones and Elevated Areas (Asahi and Asakura)

As Japan approaches "Disaster Prevention Day" (防災の日) on September 1, 2026, a heightened sense of vigilance against natural disasters is once again sweeping the nation. In particular, Kochi City, Kochi Prefecture (高知県高知市) faces severe projected tsunami damage from the imminent Nankai Trough Megaquake (南海トラフ巨大地震). Consequently, it is one of the areas where quantifying disaster risks is most strictly demanded in the real estate market.

Since the explanation of flood risks became mandatory in real estate transactions in recent years, hazard maps have clearly transformed from mere reference materials into crucial factors in price determination. In Kochi City, which features a low-elevation terrain open to the sea, a rapid polarization in real estate demand and land price trends is occurring between the highly convenient central urban areas and the elevated/inland areas that more easily avoid tsunami risks.

Based on the latest actual data (4,074 transaction records in Kochi City from 2021 to 2025) acquired by "Bukken Mekiki Research" (物件目利きリサーチ), this article provides a thorough analysis of the differences in demand and land prices between the projected tsunami inundation zones in central Kochi City and the elevated areas represented by Asahi-machi (旭町) and Asakura (朝倉). We present future property evaluation methods and investment strategies incorporating hazard maps that B2B real estate professionals (developers, investors, and brokers) must know.

1. Approaching Disaster Prevention Day: Vigilance Against the Nankai Trough Earthquake and the Importance of Hazard Maps

Around September 1st every year, media coverage and municipal awareness campaigns intensify, bringing the disaster prevention awareness of both consumers and businesses to a peak. As of 2026, drawing from the lessons of past earthquakes, the risk assessment standards for purchasing and developing real estate have become extremely strict.

Kochi Prefecture, in particular, is an area projected to experience maximum-class seismic tremors and massive tsunamis should the Nankai Trough Megaquake occur. Although Kochi City is the prefectural capital, most of its urban area is located on a low-lying delta. Therefore, in real estate evaluation, "elevation" and "projected inundation depth" directly translate to the ability to maintain asset value and, ultimately, the safety that protects lives.

In B2B real estate transactions and investment property evaluations, hazard maps have become the most critical item in due diligence. Financial institutions are also adopting an increasingly cautious lending stance toward areas with high inundation risks in their collateral assessments. Real estate professionals are required to weigh "convenience and profitability" against "disaster risk," exercising an extremely high level of discernment.

2. Geographical Features of Kochi City and the Current Status of Projected Tsunami Inundation Zones

Kochi City is flanked by Urado Bay (浦戸湾) to the south, with its central urban area spreading across an alluvial plain formed by rivers such as the Kagami River (鏡川) that runs east to west through the city. Due to these geographical features, a massive tsunami would pose a risk of long-term flooding across extensive areas of the city center.

We acquired data for central Kochi City (around Ohashidori Station (大橋通駅): Latitude 33.5597, Longitude 133.5311) using Bukken Mekiki Research. The results brought to light a very severe reality within the hazard information provided by the Geospatial Information Authority of Japan (国土地理院). The flood risk for this area is determined to be "At Risk," with a maximum projected inundation depth reaching "Rank 4 (5 to 10 meters)." An inundation depth of 5 to 10 meters is a catastrophic level where a typical two-story wooden house would be completely submerged, with water reaching the third floor. Real estate professionals are obligated to present this fact and issue strong warnings to investors and buyers considering purchasing or developing properties in this area during the mandatory disclosure of important matters prior to purchase.

Furthermore, because Kochi City is backed by steep mountainous terrain, it is also judged to be "At Risk" for sediment disasters, with projected complex disaster phenomena including "debris flows," "collapses of steep slopes," and "landslides." It is essential to correctly recognize the area's characteristics—harboring not only flood risks but also sediment disaster risks simultaneously—and conduct pinpoint topographical evaluations.

3. Real Estate Demand and Impact on Land Prices in the Central Urban Area (Lowlands)

While hazard risks exist, the center of Kochi City possesses overwhelming lifestyle convenience and commercial value. Looking at actual data, the nearest station to the target area, Ohashidori Station on the Tosaden Traffic (とさでん交通) line, serves 2,296 passengers daily, functioning as a vital transit hub for citizens. In terms of city planning information, the zoning is designated as a "Commercial Zone," with a building coverage ratio of "80%" and a floor area ratio of "400%," indicating extremely high development potential for high-rise condominiums and commercial buildings.

Additionally, the surrounding environment falls within the school districts of Harimayabashi Elementary School (はりまや橋小学校) and Johoku Junior High School (城北中学校), with 26 medical facilities densely packed within the radius (including Kyoseikai Geji Hospital (医療法人共生会下司病院), Takeshitakai Takeshita Hospital (特定医療法人竹下会竹下病院), and Minami Hospital (南病院), among others). In an aging regional city, such robust medical infrastructure is a powerful advantage for both end-users and investors.

For Kochi City as a whole (Municipality Code: 39201), the number of transaction samples between 2021 and 2025 amounted to 4,074, with an average transaction price of approximately 20.42 million yen, a median of 15 million yen, and an average unit price of about 79,000 yen/sqm. The highest recorded transaction price was 720 million yen, showing that massive capital is flowing into prime commercial lands and large-scale development sites.

However, looking at residential transactions from a micro perspective, there are scattered cases where inundation risks and aging buildings are driving down prices. For instance, close to the city center in Takeshima-cho (竹島町) (Category I Residential Zone, 60% coverage / 200% FAR), a wooden house built in 1975 (land and building, 40 sqm) traded for only 4 million yen. Similarly, a wooden house built in 1971 in Tenjin-cho (天神町) (land and building, 100 sqm) traded at a low price of 5.2 million yen. (*There is also an extreme example of a minimum transaction price of 1,000 yen, but this is presumed to involve special rights adjustments or a micro-parcel transaction.) Even in highly convenient central areas, "old wooden houses" in zones burdened with inundation risks (Rank 4) struggle to maintain resale value and are currently positioned at the bottom tier of this price polarization.

4. Demand Shift and Rising Land Prices in Elevated/Inland Areas like Asahi-machi and Asakura

Driven by concerns over hazard risks in the central urban area, a noticeable demand shift is occurring among end-users (especially families with children and first-time homebuyers) toward elevated and inland areas that can avoid tsunami inundation risks, such as the northern foothills and the western Asahi-machi and Asakura areas.

This "premium for security" is clearly reflected in actual transaction unit prices. For example, in the Tsukanohara (塚ノ原) area (Category I Mid/High-Rise Exclusive Residential Zone, 60% coverage / 200% FAR) located on the elevated grounds of northwestern Kochi City, a residential lot (land only, 165 sqm) traded for 19 million yen, recording a unit price of 110,000 yen/sqm. This significantly exceeds the citywide average of about 79,000 yen/sqm.

Moreover, in the Iriake-cho (入明町) area (Category I Mid/High-Rise Exclusive Residential Zone, 60% coverage / 200% FAR), which is located north of Kochi Castle and combines access to the city center with the safety of high ground, a residential lot (land only, 180 sqm) also traded for 19 million yen, at 110,000 yen/sqm.

These data points corroborate the existence of a robust demand to "live on safe high ground with low tsunami risks, even if it means being slightly further from the city center," which is pushing up (or stabilizing at high levels) land prices. Areas with low disaster risks are evaluated by the market as having a lower risk of asset depreciation, making it easier to find buyers during future resales.

5. The "Polarization" of Real Estate Evaluation Brought About by Hazard Maps

As we have seen, the real estate market in Kochi City is fluctuating between two value standards: "lowlands with excellent lifestyle convenience and commercial value but high hazard risks" and "elevated areas that may lag the center in infrastructure but guarantee safety." This has triggered a clear polarization phenomenon.

The table below extracts, compares, and organizes characteristic transaction samples from the actual data acquired this time.

What can be read from this table is the fact that even if the building coverage and floor area ratios in the zoning are identical (all residential types here are 60%/200%), there is a stark difference in asset value depending on the elevation and whether the property falls within a hazard zone. While vacant lots (land only) on high ground like Iriake-cho and Tsukanohara trade for 19 million yen, properties in lowlands like Kotobuki-cho and Tenjin-cho sink to the 5 to 6 million yen range, even with a building on over 100 sqm of land. Factoring in demolition costs, the effective land valuation for old properties in lowlands becomes even lower. Hazard risk now functions as a powerful discount factor that can no longer be ignored in real estate evaluation.

6. Quantifying Disaster Risks and Due Diligence in B2B Transactions

When real estate developers and institutional investors engage in B2B transactions, how they quantify this "disaster risk" and reflect it in the project's financial planning (cap rates and yields) becomes extremely important.

For instance, an area like the vicinity of Ohashidori Station—a "Commercial Zone (80/400)" where "26 medical facilities are densely packed"—is highly attractive as a development site for senior-oriented condominiums, medical malls, or income-producing residences. However, as mentioned earlier, the risks of "inundation depths of 5 to 10 meters (Rank 4)" and "debris flows, collapses of steep slopes, and landslides" weigh heavily.

When developing on such land, investors must incorporate measures like the following into their business continuity plans (BCP):

• Elevating the building or adopting a piloti structure (Placing living spaces and critical equipment on the 3rd floor or higher)
• Installing emergency power generators on the roof (Preventing blackouts caused by flooding)
• Reinforcing retaining walls and improving ground conditions against sediment disasters

Naturally, these disaster prevention measures entail substantial initial investments (initial costs). Therefore, at the land acquisition stage, rigorous negotiations are required to determine whether enough business viability can be secured to absorb the additional construction costs, or how far the land acquisition price can be reduced. We are in an era where the due diligence capability to accurately decipher hazard map information and quantify it as a cost determines the competitiveness of real estate professionals.

7. Area Selection and Risk Analysis Methods Using "Bukken Mekiki Research"

In a market like Kochi City—which exhibits extreme volatility ranging from a maximum transaction price of 720 million yen to a minimum of 1,000 yen, and where hazard risks for each area are intricately intertwined—a data-driven approach is indispensable for conducting highly accurate real estate evaluations.

By utilizing Bukken Mekiki Research, you can instantly acquire and centralize real estate transaction price information (API) from the Ministry of Land, Infrastructure, Transport and Tourism (国交省), hazard maps from the Geospatial Information Authority of Japan, and surrounding infrastructure data (stations, schools, medical facilities, etc.) simply by specifying the latitude and longitude of any location. Tasks such as extracting the average unit price (e.g., 110,000 yen/sqm) for specific neighborhoods (like Iriake-cho or Tsukanohara) from a vast sample of 4,074 records between 2021 and 2025, and comparing them with neighboring market prices in light of city planning designations (e.g., Category I Mid/High-Rise), can be completed in a fraction of the time.

Even in areas with thin publicly available transaction data or when special transaction conditions are involved, by cross-referencing macro environmental data such as the abundance of nearby medical facilities and school districts (like Harimayabashi Elementary School), you can logically verify the "validity" or "distortion" of the prices indicated by the data. A tool that visualizes hazard information and transaction market prices simultaneously serves as a powerful shield against overlooking risks.

8. Conclusion: Real Estate Investment Strategies in Kochi City Incorporating Disaster Risks

Amidst unprecedented vigilance toward the Nankai Trough Earthquake, the real estate market in Kochi City is being restructured along two axes: "convenience" and "safety."

The central urban area (lowland area), symbolized by the vicinity of Ohashidori Station, has a high concentration of commercial functions and medical infrastructure, continuing to harbor tremendous potential. However, because it carries a severe hazard risk of 5 to 10-meter inundation depths, development requires advanced disaster-prevention design and cost-bearing. On the other hand, elevated areas such as Asahi-machi, Asakura, and Tsukanohara attract solid demand, particularly from end-users, due to the absolute peace of mind of avoiding tsunami risks, thereby driving up land prices.

The key to future real estate investment strategies in Kochi City lies in clarifying the target demographic. For active seniors prioritizing medical access, high-rise residences with maximized disaster-prevention features in the city center are ideal. For families with children, detached housing developments in elevated areas are preferable. Accurately grasping the structure of risk and return through data and formulating plans optimized for the characteristics of the area are the conditions for success.

Taking Disaster Prevention Day as an opportunity, let us break away from intuitive area evaluations and practice meticulous real estate discernment based on actual data and hazard information.

Check the latest land prices and hazard information for Kochi City on Mekiki Research 👉