- What is “Database for Radioactive Substance Monitoring Data”?
- What does this Database Provide?
- Recommended Environment
- How to Display Measured Data
- How to Displays Graphs
- How to Confirm Details of Measured Data
- How to Download Measured Data
- How to Change Map Settings
- How to Change the Map Display
- How to Print the Map
- How to Change the color of measurement data
- How to Display Geographic Information
- How to Search Measured Data
- How to Download Measured Data by Fiscal Year
- About CSV files
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. 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.
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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.
Recommended Environment
- PC
- Windows
- Mac
- Linux
- Tablet
- Android
- iOS
- Smart Phone
- Android
- iOS
- Browsers
- Apple Safari 18.2 Or later
- Google Chrome 131 Or later
- Chromium 120 Or later
- Microsoft Edge 132 Or later
- Mozilla Firefox 134 Or later
How to Display Measured Data
1. Top page

2. Contents page

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.

The measured data is displayed on the map in the form of meshes, points or administrative regions depending on the content.

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

Clicking on a mesh, point or administrative region displays a popup with details of the measured data.
The popup displays the mesh code, reference date, measured value and measured items of interest2. If the reference date is a period, it means that the selected data contains several data with a reference date with that period.
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In the case of sea area data, measurement point number is also displayed.↩︎
How to Displays Graphs


Select a measurement point (mesh, point or administrative region) displayed on the map and click graph button to display the measured data for the selected measurement point in the graph.
Graphs are displayed as time change graphs or depth distribution graphs3 depending on the content. Up to 6 measurement points can be selected for graph display. (For multiple time points depth distribution graphs, only one point can be displayed.)
- 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.
- By clicking on the measurement point (mesh, point or administrative region) on the map or the legend on the graph, you can display/hide that point on the graph.
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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

Select a measurement point on the map and click the "Table" button to display details of the selected data4.
- 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 date5 from the measured date values will be displayed to the right of the value column in the table.
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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). The measurement point number is also displayed.↩︎
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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

You can download the measured data selected on the map from upper right buttons on the graph area or table area in CSV, KML and SHP format. The CSV files are encoded in Shift_JIS.
How to Change Map Settings

Click the control button to display the map panel.

- 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 (meshes, points or administrative regions) 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 Get current position 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.
- Click the Print Page button to print the the map.
- Click the Make Link button to create a URL for the displayed map.
- Click the Change Color button to change the display color of measurement data.

- 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

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.

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.

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

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

The print page allows PDF output, PNG output and printing at the specified page size.
How to change the display color of measurement data


Click the [Change color] button on the Map Control panel to display the color change dialog. Specify the color for the minimum and maximum values and click the [draw] button.

Intermediate colors are supplemented from the specified minimum and maximum value colors, and the data display colors and legend are changed.
If you click the [Search] button and change the data to be displayed or move to another page, the data display color will be reset to the default value.
How to Display Geographic Information

Click the layer button to display the layers panel. Geographical information can be displayed on the displayed map.

Check the checkbox of administrative district, it will be displayed on the map.


When you select a "Bathymetric" or "Sediment", the selected geographic information will be displayed on the map.
Click the button


When you select a "Fukushima Daiichi Nuclear Power Plant" or "ALPS Treated water drain", the selected geographic information will be displayed on the map. Clicking on the icon to display the facility name in a pop-up.


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.
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English map is available in small scale only.↩︎
How to Search Measured Data
1. Detail search page

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.

- 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

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.

- 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 | 値 | 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) |
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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.↩︎
Top page displays contents such as air dose rate and radioactive concentration.