Marian Steinbach: Blog

A Crowdsourced Japan Radiation Spreadsheet


The Japan Ministry of Education, Culture, Sports, Science and Technology (MEXT) publishes real time radiation data on their website, but there are two issues:

  • The site is under heavy load
  • The historic values aren’t available

So I created a Google Docs Spreadsheet to collect the real time data and store the values for later use.

Please, if you can, contribute to the document. Copy the real time values from the original source to the spreadsheet.

And, more important, please spread the word.

Here is the link, again:

Update 2011-03-16 0:03 UTC: Data from the bousai website is now gathered automatically and can be downloaded as CSV.

Update 2011-03-16 20:07 UTC: The original spreadsheet, open to the public for editing, is still available. There is now a Google Docs Spreadsheet with prefecture max values derived from the CSV download mentioned above. That file is read-only for the public. The URL is

Update 2011-03-17 23:40: Information about the location of sensor stations are now available in a Google Doc under

Update 2011-03-19 10:34 UTC: Updated information is available in a new blog post. In brief: The data collection I started manually with the spreadsheet this post was about is now done automatically and available for download. However, people still work with the spreadsheet and have entered additional data sources.

Update 2011-03-22 14:18 UTC: Someone changed the settings for the original crowdsourced spreadsheet so that only a few people can edit now. I decided to leave it that way and updated the meta-information in the sheet so that people don’t waste their time with manually entering stuff, fighting trolls or looking at incomplete data.


Matt on 2011/03/16 at 05:04h GMT:

Great data. I’ve searched for the coordinates of the sensor to visualize this data over time geographically (with wind direction, etc), but cannot find the exact locations. Any chance you know where to find them?


Mike on 2011/03/16 at 09:44h GMT:

The high values in Ibaraki prefecture may be a bit misleading looks like it is the Horiguchi sensor which is much higher than those nearby – however the relative increase is ineresting. Great spreadsheet and links, by the way.

Disaster Prevention and Nuclear Safety Network for Nuclear Environment
Real time radiation data collected via SPEEDI
2011/03/16 16:10


Space Dose Rate List(nGy/h)
Ishigami    717
Toyooka    408
Funaishikawa    205
Yokobori    325
Oshinobe    329
Muramatsu    281
Mawatari    362
Onuki    308
Hiroura    430
Tsukuriya    331
Araji    260
Hitachinaka    467
Ajigaura    303
Ishikawa    250
Horiguchi    1059
Kuji    709
Isobe    448
Kadobe    660
Sugaya    255
Oba    192
Ebisawa    239
Sawa    691
Yanagisawa    305
Motokomezaki    Under servey
Nukada    327
Kounosu    388
Godai    419
Onuma    446
Mayumi    320
Uridura    193
Nemoto    251
Kume    144
Isohama    239
Tasaki    Under servey
Momiyama    544
Yatabe    214
Yoshizawa    196
Kamitoda    181
Tokushuku    165

Marian Steinbach on 2011/03/16 at 09:58h GMT:

@Matt I guess that’s what a lot of people would be interested in right now. I haven’t got the coordinates either. Tried to find one of the Ibaraki stations by name via Google Maps, but it turned out to be a pain without any knowledge of japanese.

Let’s hope someone else can help and knows how get the coordinates. If so, please comment here.

@Mike You’re right, it’s a strong local phenomenon and from the distance we can only guess. The bad thing about the MEXT not publishing historic values in a proper way is that we cannot see if that sensor was always above the others. That’s why time series data is so important. Thanks for your comment!

Bernadette on 2011/03/16 at 22:46h GMT:

Thank you so much for creating this spreadsheet, I have been watching it since 14mar with great concern. This should be in all news (I have read about your work at the Guardian).
I wonder why your are not providing full datea under ? It is so important to see the full (dramatic) history as available in

Thanks again, Bernadette

Marian Steinbach on 2011/03/16 at 23:33h GMT:

@Bernadette: First I created the collaborative spreadsheet as a way to quickly record values, specifically the prefecture maximum values provided on the home page.

Then I came up with a way to record the individual station values which are the basis for that aggregated home page table.

This data is available now at for download in CSV format. While CSV is not the most accessible format for end users, it allows for any kind of reuse, given a few basic technical skills. My hope is that many people come up with useful ways to make this data accessible.

In response to requests, today I also created the spreadsheet you mentioned, containing again the aggregate view based on the data gathered automatically. I am working on updating this sheet automatically so people can refer to it.

I hope this answers your question.

Geir Engdahl on 2011/03/17 at 12:32h GMT:

I have created a first attempt of displaying this data in one map:

It’s updated every 10 minutes with data from the .csv file posted by Marian.

Marian Steinbach on 2011/03/18 at 01:29h GMT:

The coordinates of the stations where all the data comes from are now available.

Thanks to @tordans, @eroninjapan and Reiner Zollmarsch!

Jakob Weichenberger on 2011/03/18 at 04:25h GMT:

Genial! Das ist es, wonach ich die längste Zeit gesucht habe. Die SPEEDI-Website hatte ich in den letzten Tagen immer wieder unter Beobachtung und immer wieder bedauert, dass es keine Zeitreihen-Daten gab, aus der man eine anschauliche Kurve machen könnte.
Auf diese geniale Lösung wär ich nie gekommen. Vielleicht wird in den nächsten Tagen eine TV-Infografik daraus. I will let you know.

Reiner on 2011/03/19 at 01:03h GMT:

Hallo Marian
ich wollte Ihnen ein Scannerprogrämmchen schicken, daß die verfügbaren Stationen direkt ausliest und eine CSV-Datei ausgibt.
Leider “undelivered Mail returned to Sender” …
Beispieldatensatz unter:

Bitte Ihr Postfach aufräumen ..

Tom Sylvester on 2011/03/20 at 00:22h GMT:

Thanks, Marian. I’m tracking it real-time, too. I’d like to know why so much of Fukushima’s data is missing and under survey. I understand that many sites may be damaged from the tsunami, but many are inland. Best.

Ben Dromey on 2011/03/21 at 18:28h GMT:

This is really great work. It looks like data in Fukushima stops being recorded after 5:40am on the 11.3. The earthquake happened local time at 2.46pm. Do you know if the csv data is time stamped local time?

Marian Steinbach on 2011/03/21 at 18:35h GMT:

@Ben: The timestamps in the data you get here are UTC. Add 9 hours and you have local time (JST).

john on 2011/03/22 at 17:46h GMT:

I am updating from data.csv.gz hourly but i’d like to help you and so i would like to download the hourly version, but since the format isn’t the same i would have to rewrite the whole parsing. Could you either provide the same format in hourly, or maybe set up an rsync so we can sync only the differences (or github works fine too).
I have an rsync version (of the non-gzipped file) on rsync://

Stefan Koester-Hirose on 2011/05/13 at 10:58h GMT:

I need your help. My own (Gamma Scout 1) data readings are 5 to 7 times higher than the published data here in Hokkaido. Sieverts are calculated values and the raw countings are not published.
Does anybody know how the published microSievert/hour are calculated ??
I realy need help.
Regards, Stefan
Ps: Cs137 / >30keV / 142 impulses/min=1.0micro Sievert

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