Marian Steinbach: Blog

An Update on Radiation Data from Japan


It’s time to give a brief update on my efforts to make radiation data provided by the Japanese administration more accessible.

The good news: I can now offer you a way more complete raw data download with higher data quality. Data now goes back until March 1. This means, the complete development of the nuclear crisis since the earth quake and Tsunami is covered.

Please see the Japan Radiation Open Data page for details on the download.

Some bad facts remain. Fukushima and Miyagi prefectures still don’t report values to the SPEEDI system (which is the source of the data). Their values are lacking since 2011-03-11 05:40 UTC. And Ishikawa prefecture hasn’t contributed values since yesterday.

I’m curious to see how grassroots projects like geigercrowd and pachube make progress in closing the data gap.

In the meantime, people have started using the data available. The example below is a screenshot from a Japan Radiation Map created by Geir Endahl.

Eron Villarreal has contributed a data dashboard using Tableau Software.

Please comment to let others know what you are doing with the radiation data.

Update: I have done a draft animation to visualize the “burst” effects in Ibaraki around March 14.


Tom Sylvester on 2011/03/21 at 18:45h GMT:

I’d been using your data to display it with some software I wrote:

…but I see you’ve discontinued it. Can you tell me how to get the data myself?

Thank you,

-Tom Sylvester

Marian Steinbach on 2011/03/21 at 18:54h GMT:

Hi Tom! Actually the data feed is up and running. See here:

I’ve just discontinued to manually update the Google Docs spreadsheet as soon as I had the automatic harvesting in place. Others have still entered data there though.

Jan Helebrant on 2011/03/24 at 14:12h GMT:

Hi Marian,
I would like to say thank you very much.
This is perfect for me, as I am creating GIS maps (in Quantum GIS) for National Radiation Protection Institute in Prague (Czech Republic) and your data files save me a lot of time.

PS: it is a pity, that it is not possible to get the data which uses for the maps. It would be nice to have a complete dataset, but OK I know I cannot have all I want :-)

Ken Sievers on 2011/03/24 at 14:56h GMT:

Dear Marian, I am very impressed with the work you have done in finding and displaying this data. I am doing research on the radiation dangers in Japan and was pleased to find hard data. Still, I have two questions. First, is it not odd that there is no data from Fukushima, Yamagata, and a range of other prefectures next to or near the damaged reactors? I can only conclude that they are much higher than Ibarki, the highest levels given to the public. Second, I took some data from the Japan Times graphic Japan Radiation Maximum by Prefecture, located just above your graph on the Visual data updates. Taking the readings they give for Ibarki from 15 to 23 March, I got an average of 1049 nG/h, quite a bit higher than yours. Any ideas??

Marian Steinbach on 2011/03/24 at 15:10h GMT:

@Jan: Thanks for the feedback!

@Ken: I don’t know about Yamagata. It seems as if there aren’t any SPEEDI sensor stations in Yamagata. Yamagata doesn’t even appear in the lists on

As for Fukushima: We can only speculate why they don’t report real time data to the SPEEDI system.

The sensor system, as I imagin it, is a technical system that isn’t fail safe. With a disaster like it happened in Japan, I wouldn’t be suprised if some sensor stations (or communication networks) had been destroyed.

As a side note: Ishikawa prefecture, which hasn’t reported since March 16, came back with realtime data today.

Regarding the Japan Times graphic: I haven’t seen that one and I don’t know which sources they use, so I cannot explain the difference. Can you provide a URL?

Vincent on 2011/03/25 at 08:25h GMT:

Hi! great data set! I would like to also harvest the source data automatically to include the wind data to add in my visualizations/analysis. Are you crawling all the data from and do you have any idea how to get the past data? I’m looking at the side and I can’t seem to find links to get past data. on 2011/03/28 at 12:15h GMT:

Hi Marian!

Great work! We’ve added your data to – and thanks for refering to on

Jan Helebrant on 2011/03/29 at 11:47h GMT:

as I am not able to manage downloading hourly data, I download sometimes the whole archive. I needed to somehow solve the filtering of the data for single days (as normal spreadsheet is unable to load the whole file) and I found a nice solution for this – more in this article:
hope it will be helpful for more people :-)

Marls on 2011/04/04 at 16:05h GMT:


such a great service! Thank you for that. Are the any limitation on how the data is used?

Also would you be so kind to publish Google spreadsheet with the station data as csv so we can parse that? (Share->Publis to the web->Get a link to the published data->CSV)

Marian Steinbach on 2011/04/05 at 09:15h GMT:

@Marls: As far as I’m concerned, there are no limitations.

As for the CSV download link: Thanks for pointing me to that. I didn’t know about that feature. Here is the download link:

Marls on 2011/04/06 at 01:50h GMT:

@Marian: Thanks for the Google spreadsheet URL.

I spotted an error in the Google document. I believe in line 211 the prefecture ID should be 42 for Nagasaki.

Francisco González on 2011/05/31 at 10:48h GMT:

Hi Marian, I’m for some time monitoring environmental radiation data in Japan with different systems. Yesterday and today I noticed something strange in Saga Prefecture, near Genkai reactors, in Hokawaduura meters (ID 1410000010), Hirao (ID 1410000002) and Imamura (ID 1410000001). Hokawaduura on 31/05/2011 between 0:30 and 3:30 UTC values ​​occurred up to 7 times higher than normal (max 232 nGy/h), in Hirao on 31/05/2011 between 3:30 and 5:00 UTC values ​​up to 8 times higher than normal (max 227 nGy/h) and Imamura on 30/05/2011 between 1:30 and 3:50 UTC values ​​up to 7 times higher normal (max 185 nGy/h).

I tried to compare these measurements with your data but I can’t access to historical file on your website, could you tell me if these abnormal measurements have recorded in the historical file too?

Thank you very much for your help.
Regards, Fran.

Marian Steinbach on 2011/05/31 at 11:02h GMT:

Hi Fran! I’m glad I’m not the only one who noticed it. In fact I have posted this to flickr and planned to reach out to some folks who might be able to look for an answer.

I’m not exactly sure what you mean by “I tried to compare these measurements with your data but I can’t access to historical file on your website”.

You can get an overview of all available data (complete and last 3 days) here:

So the download, which contains all values since March 1, should also have the Saga values in it. If not, it’s a bug in my CSV export.

As for an explanation for the high values: I was thinking that there might have been a nuclear fuel transport or something like that. In Germany, fuel elements are transported to the plants by railway and by trucks. Maybe these containers (they are called “Castor” here) emit notable radiation.

Also note that there has been a similar spike in SAGA/Nagasaki on March 2 and 3, 2011 (UTC).

Francisco González on 2011/05/31 at 19:47h GMT:

Hi Marian, thank you very much, the transport theory is reasonable (high readings occurred along a main road with the wind from that direction).

The trouble downloading the old values I had with Internet Explorer, then I tried Firefox and had no problems.

Francisco González on 2011/06/01 at 12:20h GMT:

Today Kyoudomarisaki (213 nGy/h at 1:30 UTC), What is happening? Are they testing dosimeters?

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