Atmospheric Radioactive Radiation Maps
Fukishima Prefecture Close-Up and also Fukushima and Surrounding Provinces, Japan

These Radioactive Maps are based on official measurements from many provinces and locations in Japan as cited by MAP / Japan quake radioactive material monitoring post MAP and also MEXT (Ministry of Education, Culture, Sports, Science and Technology) and also from Fukushima Prefecture.  For levels  at the damaged powerplant itself, see the range of data at the  TEPCO company website, especially radiation levels and sampling map.  An excellent site, full of radiation information from across Japan that is presented as graphs is found at Fleep,com

 I hope these maps help in understanding the current situation in Japan after the accidents at the Fukushima Nuclear Power Plants, especially the localised spots of high radiation that have not been evacuated.

Major Problem with Lack of Support and Sound Advice from Senior Government Official's and Scientific Advisors
This is especially seen in the predicament of the mayor of Iitate.  “I don’t want to be remembered as the mayor who risked his people’s lives by not evacuating,” said Mr. Kanno, who said he had lost sleep and weight agonizing over whether to stay. “I want us to be remembered as the little village that didn’t give up.”

Fukeshima Radiation 3-5 April
This map is made from data collected from a range of sources as outlined above over the preiod of 3rd to 5th of April.  A more complete set of data immediately around the damaged Nuclear Power Plant help to especially show the uneven spread of irradiation and the release of susbtantial radioactive material from the core at  distances of 15 to 50 km from the NPP in a north-westerly direction.

As stated previously there particularly seems to be a "hot spot" near the village of  Tsushima
(Namie Precinct, Futaba District, Fukushima Prefecture) and also even higher at Hirusone (Namie Precinct, Futaba District, Fukushima Prefecture - 8 km to the east) with levels of up to 74uG/h recorded on the 28 & 29th March.  Exposure to levels of 20uG/h and above are regarded in Japan as consituting a "Medical Emergency" and requiring administration of iodine .

For such localised high levels over this area, it would seem a significant amount of radioactive material from the reactor rods had been deposited here, rather than just radioactive steam or gaseous emmisions.  These levels are the same as those measured at the "West Gate"of the damaged Fukushima Daishi reactor (67uG/h) only a few hundred meters from the reactors.  

There has recent concern about unacceptably high levels of radioactivity at the nearby village of Iitate (10 km to the north), according to Elena Buglova, head of the IAEA's Incident and Emergency Centre, the radiation reading in Iitate village were "about two times higher than levels" at which the agency recommends evacuations.  The reported levels in Iitate of  7-10uG/h are much lower than the readings of between 48 - 82uG/h found in Tsushima and Hirusone precincts - making it very apparent that there is a very serious unresolved issue here.

Local Officials Left Without Strong National Leasdership and With Poor Advice.
One feels a strong sympathy for officials, like the mayor of Iitate village struggling to cope and do the right thing by his village with extremely little effective support. 

Mayor Kanno ... said "that he was fed up with contradictory information about the radiation risks.   ... Mr. Kanno said that he was not trying to ignore the dangers, and that he felt that his village was “not completely safe.” But he also said that without a clear-cut criterion for evacuation, he was reluctant to tell villagers to leave, because that would take them away from their farms and livelihoods, and force them to live in evacuation centers in distant, unfamiliar places.

“I don’t want to be remembered as the mayor who risked his people’s lives by not evacuating,” said Mr. Kanno, who said he had lost sleep and weight agonizing over whether to stay. “I want us to be remembered as the little village that didn’t give up.”

Radiation Fukushima 29th Mar The map is produced from data from the 28 & 29th of March 2011. 

Prefectures outside Fukushima
As shown below, the natural levels of background radiation for Japan are about 0.05uG/h. 
The areas of Japan as indicated on the map below 0.2 uG/h, are within four times of this natural background levels and should be regarded as safe. 
  • This safe area as currently measured, includes all of Japan south and west of a line running approximately between Tokyo and Niigata.
  • Levels of with 0.5uG/h and above would seem to be associated with levels of radiation resulting in unsafe food production.  This region is located mainly in Fukushima (except for the western part of the prefecture), but also included some parts of southern Miyagi and of northern Ibaraki prefectures.
Unless there is new significant releases of radiation over the land of Japan, the radiation levels observed will continue to slowly decrease.  However, for some parts of Japan, the decline to safe levels will take a very long time.


Natural Levels of Radiation in Japan

According to the Japanese
Ministry of Education, Culture, Sports, Science and Technology (MEXT).  Average environmental exposure in Japan for a person per year is 2,400uG, which is equivalent to 0.27uG/h.  A typical Chest Xray is 50uG (equal to about 8 days normal environmental radiation). 

The typical atmospheric radiation ranges found in Japan are 0.017 to 0.080 uG/h, averaging about 0.050 uG/h

(0.022 to 0.044 uG/h Chiba Prefecture, 0.017 to 0.04  uG/h Gunma Prefecture, 0.035 to 0.065 uG/h  Fukushima Prefecture ,0.03   to 0.08  μGy / h at Japan Atomic Energy Agency sites across Japan)

The radiation units given are in uG/h (uGray/h). Radiation units and their conversions are 1 Gray = 1 Sievert = 100 rem (Roentgen equivalent man).
[Google Translate was used to understand the locations and interpret other associated data - with Google Earth used to locate place names.  3DField was used to produce the contours shown on the map.]

TO HOME PAGE       Postharvest Fresh             Revised  Mar 2011  (S. Morris)