Radiation Monitoring Updates


Here are some charts that we (Tsukuba residents) made from the Ibaraki radiation levels that are being published on the Ibaraki Prefecture website.

I hope you will be able to read these charts and understand more about the radiation levels in Ibaraki prefecture in the aftermath of the 2011 Sendai Earthquake and how they are changing.

Linear Scale Graph
Radiation Levels in Ibaraki Prefecture

Click on the image to see a larger image.

Log Scale Graph
Radiation Levels in Ibaraki Prefecture

Click on the image to see a larger image.

Here is another graph showing the same data, just in case there is a problem with the one above (which is automatically generated).

(It may take a moment to load, so please be patient.)

Here is a chart showing only data from March 15 to 17, but the monitoring site is located in Tsukuba (at a research facility called the National Institute for Advanced Industrial Science and Technology – AIST). The “normal” level around that site is 0.06 microsieverts/hour. The levels are clearly above normal, but nowhere near “dangerous”.

Here is the source of the AIST data.

Here is data from another research institute in Tsukuba, the National Institute for Materials Science. The normal level for that part of Tsukuba is 0.1 microsieverts/hour.

And here is a link to a page where you will be able to see the readings taken by the High Energy Accelerator Research Organization (KEK), also in Tsukuba. Readings are reported basically in real-time. The normal level for that part of Tsukuba is 0.07 to 0.09 microSv/h. Again, the levels are higher than that, but still well below anything anyone would consider dangerous. The page is written in Japanese, but you can see the current reading in the box at the top of the screen.


Here is the chart for Fukushima based on the Fukushima radiation levels that are being published to the Fukushima Prefectural website.

(It may take a moment to load, so please be patient.)

NOTE ABOUT THE THRESHOLD: According to this chart by the National Institute of Radiological Sciences (kindly translated into English by one of our Tsukuba residents), the maximum allowable amount of radiation that won’t show any clinical symptoms is 200 millisieverts/year. This translates to a sustained amount of 22.83 microsieverts/hour. Thus, we decided to use this as a threshold value. Please note that this should be a SUSTAINED dosage, meaning you should get 22.83 microsieverts/hour continuously for ONE YEAR for it to be cause for concern. Any sudden spike should be okay if it does not last for several hours (or days).

You can see the original data and the charts in this Google Docs spreadsheet.

And here is a map that will show you where the monitoring sites are in relation to Tsukuba. Click on “view larger map” to see the legend.

(Updated March 16, 2011 at 12:31)

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18 Responses to Radiation Monitoring Updates

  1. Pingback: Current Status | News for Tsukuba Residents

  2. Thank you very much for these useful information durring the unfortunate time in Japan. God Bless You all.
    If you can make a table to write the normal radiation level and the current radiation level that you recived after every hour.
    Thank you

  3. Adam Lebowitz says:

    Thanks for arranging the data. It’s very helpful,

  4. Carina De Guzman says:

    Thank you so much for working to keep us all informed. We Tsukuba foreign residents are very fortunate to have you.

  5. Karina Pourreaux says:

    This chart is very helpful to understand the flucturations of radiation levels.
    As a measure unit, are you using microsieverts or millisieverts ?

  6. Nina says:

    mSv or mkSv?
    Thank you. Just one moment: on the graph for Fukushima and area vertical axis
    label is misleading: units are given simultaneously as microSieverts (mkSv), and milliSieverts (mSv, in the brakets).
    But 1 mSv = 1000 mkSv.
    Seems that given are mSv, but please correct the graph.


  7. Adam Lebowitz says:

    The US Embassy has recommended all citizens within an 80 km radius of the Fukushima plants stay indoors if leaving the area is not feasible.

    Tsukuba is about 160km away from the plants.

  8. Jaimee says:

    Shaney: On top of things, as always, thank you. These graphs really help us get a clearer picture of what is happening in areas near the plants, as various media reports are REALLY confusing. The confusion is adding to panic in Japan and elsewhere.

  9. Marco Brazil says:

    Many many thanks! You’re doing a great job in creating a well informed public. Kudos!

  10. Chen Zh says:

    Thank you for your work.
    Good job!

  11. David Doe says:

    What makes you believe that the values given by a prefecture,
    an official agency, are true ?

    We see that the announcements of the jananese government
    are ridiculous, they change every few hours and we all know
    that they tried to trivialize from the beginning.

    In some years, maybe, we may know a bit better what truly is
    happening for over a week now in Fukushima.

    Imagine : cooling the innermost of a nuclear power plant by
    throwing water over it with helicopters like in a forest fire …
    i think that shows pretty much how despaired they are.
    but this is like fighting a huge fire with a coffee-cup.

    so since we see what official statements in japan (and of course anyplace else)
    are worth, what makes you think these official values are any better ?
    i my oppinion they have only one background : to calm down the public.

    i would trust values given by greenpeace f.e. a lot more.

  12. Jundo Cohen says:

    I second what everyone says. You really help hold this community together in so many ways with your writing, Shaney.

    Peace, Jundo Cohen

  13. David Doe says:

    btw., check back greenpeace!
    the true values are given in millisievert !

    to falsify that to mikrosievert is the politics of the lying tokyo electric power co.,
    which is the company that ruined japan (what the japanese still havent realized by now).

    that all those false values are repeated here should show everone the true value
    of these statements.
    i think, sites and pages like this are made by the friends of nuclear power.

    and the japanese government, instead of helping the people of japan, backs up the criminals of tepco.
    all people living in a at least 160 km radius around fukushima are playing roulette with their health. and they still don’t know, almoust 3 weeks after the incident.

    the area around fukushima (and that includes tokyo), is identical to the area around chernobyl, only that in chernobyl there was a sarcophagus made of conrete built around the destroyed reactor, in fukushima there is no shelter whatsoever around 4 reactors.
    that means, fukushima is a lot worse than chernobyl.
    you live in the worst case scenario, and you dont even realize it.

    • Shaney says:


      The level of atmospheric radiation at one of the research institutes in Tsukuba right now (April 2, 2011) is between 0.1 and 0.2 microsieverts/hour.


      The normal environmental dose at that institute is between 0.07 – 0.09 μSv/h. Levels are slightly higher than normal, but nowhere near the millisievert range.

      I know that these readings can be trusted because other people at other institutes are doing the same monitoring and coming up with similar values. Tsukuba has a large population of scientists due to its concentration of research institutes and some of the scientists are doing their own independent monitoring and coming up with similar values.

      Please do not promote hysteria by talking about things of which you do not have a good understanding. We are trying to put our lives back together here after a very hard couple of weeks. If you would like to help us, please take some time to learn more about the situation in Japan from more reliable sources than Greenpeace.

      Thank you.

      • David Doe says:

        there is no more reliable source than greenpeace.

        you and your fellows are LYING to the japenese people.
        it will take some years until japan understands, but this is the fact :

        fukushima is WORSE than chernobyl !
        even tokyo is WORSE than pripyat !

        it doesnt help you and your fellows to libel others as not understanding the facts, while you obvioulsy lie to the people.

        only because others lie more, this is no excuse.
        any average intelligent person knows what i going on in

        you, as well as tepco criminals and the criminals still in the japanese government are in fact KILLING many people with their lies, as anybody in an 160 km (1oo miles!) radius around fukushima is playing with her/his health, many will die a horrific death, others will give birth to horribly deformed children, before they die a horrific death.
        do you want me to describe this death ?
        i do you a favour and dont, anybody that wants to know can inform himself on the internet. it is beyond any imagination.

        believe noone else than greenpeace.
        even they underestimate the facts, but they are closest to reality in their statements.

        the area around fukushima i dying as the people that are still there are.
        anybody that lives there and is at least fairly intelligent :
        run as far and as fast as you can !

        look to chernobyl, which is only 1/4 as bad as fukushima is today.
        i feel very sorry for you, as sadly i am talking to people that are already dead, it only will take a few more years (which luckily i dont have to live).

        lets remeber the lies of the supporters of nuclear power :
        nuclear plants in japan are completely safe, even for earthquakes.
        do i need to say more ?

        stop your lying comments, and finally admit : the values that you LIE down to microsievert are in fact MILLISIEVERT (!),
        shame on you !

  14. Shaney says:

    1. Tsukuba is 170 km from the nuclear plants. Tokyo is even further away.

    2. From Greenpeace blog:

    Our team’s findings confirmed those by the Fukushima Prefectural Government for Iitate, and those of the International Atomic Energy Agency.

    From: http://www.greenpeace.org/international/en/news/Blogs/makingwaves/expanded-fukushima-radiation-monitoring-team-/blog/34077

    3. Greenpeace is reporting in microsieverts, not millisieverts.

    4. The International Atomic Energy Agency and the Nuclear and Industrial and Safety Agency (Japan) are reliable sources of information.

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