DOI: 10.5281/zenodo.17762536
title: Japan 5th-Mesh Hazard Summary and Population Exposure Dataset (GSI Hazard Info Tiles + Census Mesh Data)

description: Summary

This dataset provides integrated hydro-meteorological and tsunami hazard information and population exposure based on Japan's 5th-level standard grid (commonly known as the 250 m mesh). In addition to the nationwide dataset, 47 prefecture-level datasets are also provided.

Detailed documentation in Japanese:https://note.com/utsuken_tokai/n/n088529043f99

Key Features





Multiple hazard types  — including flood, storm surge (hightide), tsunami, building-collapse zones, and landslides  — are integrated into a single, standardized nationwide 5th-mesh dataset.




Users can visualize Japan-wide multi-hazard patterns immediately by loading the CSV into any GIS tool, without the need to collect and overlay multiple layers manually.




Hazard levels and pixel-based ratio values allow straightforward integration with other Census 5th-mesh datasets.



USE CASES



Overview-level municipal disaster management and hazard assessment

GIS-based visualization of multi-hazard patterns

Academic research in disaster risk, urban planning, and geography

Preliminary analysis of elderly-population vulnerability

Educational materials for geography and disaster risk reduction

University lectures and community disaster-preparedness workshops


Note: This dataset is an aggregated estimation derived from zoom-15 hazard tiles converted into 5th-mesh units. It is not suitable for precise disaster-risk evaluation, evacuation decision-making, administrative judgment, or operational vulnerability assessments.

HAZARD INFORMATION

Hazard information is generated using a modified version of the program used in the Hazard Information Outline API (https://doi.org/10.1109/KST65016.2025.11003278), retrieving raster tiles (zoom level 15) from the Hazard Map Open Data provided by the Geospatial Information Authority of Japan (GSI).

Please note that the GSI hazard map tiles cover only designated regions and rivers, and therefore do not represent nationwide coverage for all hazard types.

Population exposure calculations use the 5th-mesh population data from the 2020 Population Census (250 m mesh, JGD2011), as published on e-Stat on 2025-10-09.

Mesh units classified as “suppressed mesh” (秘匿メッシュ) in the census are excluded from hazard aggregation and exposure calculations.

Hazard raster tiles were retrieved from the GSI Hazard Map Open Data between 17 and 24 November 2025.

Hazard categories included in this dataset

Hydro-meteorological and tsunami hazards





Flood inundation (design flood scale)




Flood inundation (assumed maximum scale)




Hightide inundation (assumed maximum scale)




Tsunami inundation (assumed maximum scale)




Hazardous zone for building collapse (flood flow)




Hazardous zone for building collapse (bank erosion)



Landslide hazards





Debris flow




Steep slope failure




Landslide



(Landslide warning areas and special warning areas are not distinguished.)

COLUMNS

Mesh center coordinates





lon — Mesh center longitude (6 decimal places)




lat — Mesh center latitude (6 decimal places)



Flood, hightide, tsunami hazards





Inundation depth level





flood_l1  — Flood inundation (design flood scale: inundation depth level 0–8)




flood_l1_ratio




flood_l2 — Flood inundation (assumed maximum scale: inundation depth level 0–8)




flood_l2_ratio




hightide — Hightide inundation (assumed maximum scale: inundation depth level 0–8)




hightide_ratio




tsunami — Tsunami inundation (assumed maximum scale: inundation depth level 0–8)




tsunami_ratio




Building-collapse hazard zones (Hazard zones where wooden residential buildings are assumed to collapse due to flood flow or bank erosion)





kaokutoukai_hanran — Flood flow (TRUE/FALSE)




kaokutoukai_hanran_ratio




kaokutoukai_kagan — Bank erosion (TRUE/FALSE)




kaokutoukai_kagan_ratio





Landslide hazards





dosekiryukeikaikuiki — Debris flow (TRUE/FALSE)




dosekiryukeikaikuiki_ratio




kyukeishakeikaikuiki — Steep slope failure (TRUE/FALSE)




kyukeishakeikaikuiki_ratio




jisuberikeikaikuiki — Landslide (TRUE/FALSE)




jisuberikeikaikuiki_ratio



Boolean items use uppercase TRUE / FALSE.

 

About the “_ratio” columns

Range: 0.000–1.000

Each ratio represents:



Number of hazard-applicable pixels / Total pixels in the mesh






Pixel count per mesh varies by latitude.



For flood (design scale and assumed maximum scale), hightide, and tsunami inundation:





Each “*_ratio” value represents the proportion of pixels within the mesh whose inundation depth level is 1 or greater,divided by the total number of pixels in the mesh.




Pixels with depth level 0 (“Not applicable”) are excluded from the numerator.




Depth levels range from 0 to 8, following the official GSI hazard legend.




Example:A value of tsunami_ratio = 0.40 means that 40% of the pixels within the mesh have a tsunami inundation depth level of 1 or higher.



 

In addition, the hazard-only CSV files (hazard levels and ratio values) can be joined with other 5th-mesh Census datasets using the mesh code. This allows users to combine hazard information with demographic or household statistics for extended analysis.

LEGEND (Flood / Hightide / Tsunami inundation Depth Levels)

Based on the official GSI hazard legend:








Value
Meaning (Depth)




8
≥ 20.0 m


7
10.0 – 20.0 m


6
5.0 – 10.0 m


5
3.0 – 5.0 m


4
1.0 – 3.0 m


3
0.5 – 1.0 m


2
0.3 – 0.5 m


1
≤ 0.3 m


0
Not applicable






AGGREGATION METHOD





Each mesh is assigned its center coordinates (lon, lat) based on the official mesh code.




Flood, Hightide, Tsunami depth levels→ The maximum value within the mesh is used.




Building-collapse hazard zones→ TRUE if any pixel within the mesh falls inside the hazard zone.




Landslide hazards→ Warning and special-warning areas are not distinguished.→ TRUE if any pixel belongs to either category.



POPULATION DATA AND SUPPRESSED MESHES

Population data source:





2020 Population Census, 5th-mesh data (250 m mesh, JGD2011)




Updated: 2025-10-09



Meshes marked as “suppressed mesh” are excluded from hazard aggregation and population exposure calculations.

POPULATION EXPOSURE

Population exposure (exposure_*) is calculated by multiplying:



Mesh population (total or age 65+) × hazard ratio


Two exposure categories are provided:





total — total population




over65 — population aged 65+



Exposure CSVs include corresponding hazard levels and ratio values, allowing independent use without joining additional files.

DATASET STRUCTURE

The dataset consists of nationwide CSV files and three ZIP archives containing 47 prefecture-level files for each data type.

1. Nationwide Files



5thmesh_japan_hazard.csv

5thmesh_japan_exposure_total.csv

5thmesh_japan_exposure_over65.csv



2. Prefecture-Level ZIP Archives

Each ZIP archive contains 47 CSV files (one for each prefecture).

(A) Hazard Data







 



5thmesh_prefectures_hazard.zip

    ├ 01_hokkaido_hazard.csv

    ├ 02_aomori_hazard.csv

    ├ 03_iwate_hazard.csv


    ...

    └ 47_okinawa_hazard.csv



(B) Population Exposure (Total Population)





 


5thmesh_prefectures_exposure_total.zip

    ├ 01_hokkaido_exposure_total.csv


    ├ 02_aomori_exposure_total.csv

    ...


    └ 47_okinawa_exposure_total.csv



(C) Population Exposure (Population Aged 65+)





 


5thmesh_prefectures_exposure_over65.zip

    ├ 01_hokkaido_exposure_over65.csv

    ├ 02_aomori_exposure_over65.csv

 ...

    └ 47_okinawa_exposure_over65.csv



 

DISCLAIMER

This dataset integrates multiple open data sources (GSI hazard tiles and census mesh data). Minor inconsistencies may remain due to limitations of the original datasets. Users should verify applicability for their specific purpose.

This dataset is provided without warranty of accuracy.

The authors assume no responsibility for any damages arising from dataset use.

 

SOURCES





Geospatial Information Authority of Japan (GSI): Hazard Map Open Data (Raster Tiles)




e-Stat: 2020 Population Census (Population and Household Mesh Data)




National Land Numerical Information: Standard Regional Mesh Codes