Let’s Get Started

What is “Database for Radioactive Substance Monitoring Data”?

Japan Atomic Energy Agency (JAEA) regularly collects and publishes via an online database1 environmental monitoring data related to the TEPCO Fukushima Daiichi Nuclear Power Plant accident, published by various organizations including the Secretariat of the Nuclear Regulation Authority, Fukushima Prefecture, research organizations and so on. Gathered data are converted into a common file format (CSV format) suitable for analyzing the spatial distributions and temporal changes of radioactive materials. Geographical data useful for this analysis, such as elevation, soil, vegetation, land-use and snow coverage data etc. are also published on the same website. Various maps and graphs showing distributions of radioactive materials are also available on the website to promote intuitive understanding for users.

This website is run by trust costs of the FY2023 Expenses for Radioactive Material Measurement Survey and Disaster Prevention Measures for Nuclear Facilities.

  1. The database aggregates environmental monitoring data such as air dose rates and radioactive concentrations on the ground surface, in soil, seawater, marine sediments, river water, river sediments, groundwater and food for Fukushima and neighboring prefectures. Note that as JAEA updates the database at periodic intervals, data value difference might occur between values in the database and those published by original organizations, for instance, when an organization revises its data subsequent to its aggregation and registration in the JAEA database.↩︎

What does this Database Provide?

  • This database displays distribution maps of radioactive concentration or dose rate based on the results from radioactive substance surveys.
  • This database displays graphs of time change of radioactive concentration or dose rate based on the results from radioactive substance surveys.
  • Download of survey results of radioactive substances is available with various file formats including CSV, SHP and KML.
  • PC
    • Windows
    • Mac
    • Linux
  • Tablet
    • Android
    • iOS
  • Smart Phone
    • Android
    • iOS
  • Browsers
    • Apple Safari 14.0 Or later
    • Google Chrome 86 Or later
    • Google Chromium 86 Or later
    • Microsoft Edge 87 Or later
    • Mozilla Firefox 82 Or later

How to Display Measured Data

1. Top page

Top page

Top page displays contents such as air dose rate and radioactive concentration.

  • Display information about this site.
  • Selecting a content takes you to the contents page, which displays the measured data for the selected content. Click to display a description of each content.
  • Display histories about this site.
  • Display description about this site.

2. Contents page

Search condition

When you move to the contents page, the search condition panel will appear. Select the measured period and measured item for the data you wish to display on the map and click Render Map.

  • Changing large classification will take you to another contents page.
  • Selecting a middle classification allows you to select all measured items included the selected middle classification.
  • Select the measured period from the pull-down or slider. You can select a period of up to one year.
  • Select measured items you wish to display on the map. Click to display the details of each measured item.
Map view

The measured data is displayed on the map in the form of a mesh or points, depending on the content.

Reload measured data

Clicking the reload button after moving the map will update the map with the measured data.

Popup details of measured data

Clicking on a mesh or point displays a popup with details of the measured data.

The popup displays the mesh code, reference date, measured value and measured items of interest. If the reference date is a period, it means that the selected data contains several data with a reference date with that period.

How to Displays Graphs

1. Detailed data

Detailed data

Select a measurement point (mesh or point) displayed on the map and click detailed data button to display the measured data for the selected measurement point in the graph or table.

2. Time change graph or depth distribution graph


Open the time change graph or depth distribution graph tab in the detailed data panel to graphically display the measured data for the measurement point selected on the map.

Graphs are displayed as time change graphs or depth distribution graphs2 depending on the content. Up to 6 measurement points can be selected for graph display.

  • Turning on the “Y-Axis Logarithmic” and “X-Axis Logarithmic” will change the vertical and horizontal axes of the graph to be displayed in logarithmic form.
  • Clicking the PNG output button in the graph will download the displayed graph in PNG format.

  1. In the case of sea area data, the unit of “Upper depth of sampling” and “Lower depth of sampling” are not expressed in (cm) but in (m).↩︎

How to Confirm Details of Measured Data

1. Measured data table

Measured data table

Selecting the measured data table tab in the detailed data panel displays a table3 detailing the measured data selected on the map.

  • If you specify a date for the physical reduce and click the Calculate button, a value that takes into account the physical reduce at the specified date4 from the measured date values will be displayed to the right of the value column in the table.

  1. In the case of sea area data, the unit of “Upper depth of sampling” and “Lower depth of sampling” are not expressed in (cm) but in (m).↩︎

  2. It’s possible to select before March 11, 2011 or far future, but the calculated value of such setting doesn’t make the sense because the value is calculated by the simple physical reduce system.↩︎

How to Download Measured Data

Download buttons

You can download the measured data selected on the map from upper right buttons on the detailed data panel in CSV, KML and SHP format. The CSV files are encoded in Shift_JIS.

How to Change Map Settings

Map panel

Click the map button to display the map panel.

Change map settings
  • Turn on automatic data update to automatically update the measured data after the map is moved.
  • Turning on range selection allows you to select measurement points (mesh or points) by range. Clicking Deselect All button will deselect the measurement points.
  • When the map is moved, the longitude and latitude are automatically updated to the center of the map. If you set the longitude and latitude and click Move button, the map will move the position where the specified longitude and latitude is centered.
  • When the button is clicked and allow access to location information, a marker is plotted at the current location on the map and the longitude and latitude values are updated to the current location. Note that there may be errors in the location information acquired due to device conditions.
  • The map display can be changed.
  • The map can be printed.
  • Click the Make Link button to create a URL for the displayed map.
Move by place names
  • Longitude and latitude can be obtained from place names and landmarks. Place name search can only be performed in Japanese language. This function is created using the Geographical Survey Institute API. Excessive access will be restricted, so please refrain from using the function to search a large number of locations.
  • When you select a search result link, a marker is plotted at the selected location on the map and the map will move so that the selected location is at the center.

How to Change the Map Display

Switch the base map

Open map control tab on map panel.

You can switch the base map by selecting from five types: Standard map, Pale color map, Blank map, Aerial photo image and English.

Display grid

When the graticule is turned on, grid lines of longitude and latitude are displayed on the map. The range of the grid lines changes as the map is zoomed in and out.

Displayed mini map

When the mini map is turned on, a mini map is displayed to confirm the current location in a wide area.

How to Print the Map

Move print page

Open map control tab on map panel.

Clicking the Print Page button takes you to a page where you can print the map.

Print page

The print page allows PDF output, PNG output and printing at the specified page size.

How to Display Geographic Information

Layer tab

You can display geographic information on the map you are viewing. To display geographic information on a map, open the layer tab in the map panel.

Administrative district

If you check the areas where returning is difficult, the areas will be indicated on the map with a shaded blue box.

Geographic information

Select elevation, vegetation, land-use, accumulated snow, soil, bathymetric, sediment and population to display the selected geographic information on the map.

If is displayed, zoom in on the map5 until it disappears.


Checking a junior high school or elementary school will display a landmark at the location of the school. Clicking on a landmark will display a popup with the name of the school.

  1. English map is available in small scale only.↩︎

How to Search Measured Data

1. Detail search page

Search condition

The Search link in the header will take you to the detail search page.

  • Select a large category from the pull-down menu.
  • Select the period from the pull-down or slider.
  • Select the air dose rate type or nuclide (major nuclide and other nuclide). If neither is checked, all will be searched. In addition, other nuclides can be switched between display and non-display by turning the toggle button on and off. Even if you turn off the toggle button after checking other nuclides to hide them, the checked other nuclides will be included in the search conditions.
  • You can specify the measurement location by prefectures, municipality and mesh code.
  • You can search for measured data by keywords.
  • You can select measured items.
  • Display the number of measured data corresponding to the selected criteria. If the number of items exceeds 200,000, please narrow down the search conditions before performing a search.
  • Click Search to display the search results in the table.
Search results
  • Select the measured data in the table and click Show on map button, then move the contents page and display the search results on the map.
  • Click Download CSV button to download the search results in CSV format. The CSV files are encoded in Shift_JIS.

How to Download Measured Data by Fiscal Year

1. Download by Year page

Download by year page

The Download link in the header will take you to the download by year page. The download by year page allows you to download measured data for each measured item by fiscal year.

  • Select a large category.
  • Select a middle category.
  • Select the measured item for which you want to download the data by fiscal year.
  • You can download the data by fiscal year.
Download selected measured items
  • Select the character code of the CSV files.
  • Click the link to download measured data by fiscal year in CSV format.
  • Display a description of the selected measured item.

About CSV files

1. Unified Format

To facilitate comparative analysis among different survey items, we have prepared a CSV file with a unified header. The header structure is as follows:

No. ヘッダー名 Header Name
1 測定カテゴリー Category
2 測定種別 Measurement type
3 事業者 Organization
4 代表メッシュコード Mesh code
5 緯度 Latitude
6 経度 Longitude
7 都道府県 Prefecture
8 市町村 City, Town, Village
9 測定地点番号など No. Measurement point
10 試料採取開始日 Start date of sampling
11 試料採取完了日 Finish date of sampling
12 補正基準日 Correction base date
13 Value
14 統計誤差 Statistical error
15 検出下限値 Detection lower limit
16 単位 Unit
17 試料の質量(kg) Mass of sample (kg)
186 採取深度上端または測定の高さ(cm) Upper depth of sampling or Height of Measurement(cm)
19 採取深度下端(cm) Lower depth of sampling(cm)
20 濁度 Turbidity
21 SS濃度(mg/L) SS concentration (mg/L)
22 水深(m) Water depth(m)
23 含水率(%) Water content(%)
24 試料の状態 State of sample
25 測定方法 Measurement method
26 調査地点の状況 State of sampling point
27 試料の種類(大分類) Kind of sample(large classification)
28 試料の種類(中分類) Kind of sample(middle classification)
29 試料の種類(小分類) Kind of sample(small classification)
30 備考 note
31 事業ID Project ID
32 基準地域メッシュ Basic Grid Square
33 MeshID_250m MeshID_250m
34 MeshID_100m MeshID_100m
35 MeshID_50m MeshID_50m
36 MeshID_20m MeshID_20m
37 福島第一原発からの距離(km) Distance from FDNPP(km)

  1. The header item “Upper depth of sampling or Height of Measurement(cm)” indicates “Height of Measurement(cm)” when the measured data is air dose rate and “Upper depth of sampling(cm)” when the measured data is not air dose rate.↩︎