absorbed dose rate Japonsko (stations map)

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< V_max

< 10 * V_max

< 100 * V_max

> 100 * V_max

Units: absorbed dose rate [μGy/h]

In cases of x-rays and gamma rays and electrons absorbed by human tissue Gray is often converted into Sievert by assuming 1 Gy/h = 1 SV/h (see information below).
Roentgen equivalent in man (rem): 1 Sv = 100 rem
Please note: The y-axis displaying the absorbed dose rate and accumulation plots can vary depending on location and time frame.

Data source - Absorbed dose rate:

	Dataset 1	Dataset 2	Dataset 3	Dataset 4
Source	MEXT Readings	MEXT (SPEEDI)	TEPCO	Pachube
Data available	since 13.3.2011 or 15.3.2011 hourly averages	since 1.1.2010 10 minute data	since 14.4.2011 10 minute data	since 22.3.2011 different sources with 10 minute data or hourly averages
	hourly averages	hourly averages	hourly averages	hourly averages
band V_max-V_min	Minimum value (V_min) and maximum value (V_max) from usual value band: "Usual value band means a range of the maximum and minimum value observed before the earthquake" [MEXT: e.g. pdf])	Minimum value (V_min) and maximum value (V_max) calculated with the data of the respective locations from 1.1.2010 to 10.3.2011 (from hourly averages)	no value band	no value band

Sometimes data is not transmitted due to maintenance or for other reasons. Missing data is not bridged by lines. Only values refering to sequential hours are connected.

Accumulated absorbed dose rate:

	Dataset 1, Dataset 2, Dataset 3 and Dataset 4
	Accumulated dose rate = summation of hourly averages of absorbed dose rate Accumulation period: 13.3.2011 up to today
❚ ❚	❚Accumulation of original data Missing values: ❚Accumulation of interpolated data: Missing values are approximated since original data of average absorbed dose rate is not available for every hour. Missing data points are computed by linear interpolation. ∅Missing data at the beginning of the period: Missing values at the beginning of the accumulation period (13.3.) will be set to 0. In those cases the calculated accumulation values show below the actual accumulation values. Regarding the assessment of the timeline: Radiation releases during the initial hydrogen explosions. All data taken into account in the accumulation is shown in the graph ‘interpolated raw data’ (top left button above the graph).
	The red graph shows the accumulation of 0,114 μGy/h based on an estimated average for Japan of 1000 μGy per year (equates 0,114 μGy/h 24 hours 365 days). The accumulation starts with the first available value of the data set after 13.3.2011 (see missing values above).
	The green graph shows the accumulation of V_max. The accumulation starts with the first available value of the data set after 13.3.2011 (see missing values above).

Colour scale:

< V_max

< 10 * V_max

< 100 * V_max

> 100 * V_max

The colour scale is based on the maximum Value (Vmax) measured at the location of the Geiger counter prior to the accident. Therefore allowing to spell out the changes in comparison to the values prior to the accident.

Natural radiation:

Total annual natural radiation dose for people living in Japan is estimated to be about 1000 microsieverts [RERF's Messages]
Map of natural radiation levels in Japan [JAEA]
All living organisms are continually exposed to ionizing radiation,which has always existed naturally. The sources of that exposure are cosmic rays that come from outer space and from the surface of the Sun, terrestrial radionuclides that occur in the Earth’s crust, in building materials and in air, water and foods and in the human body itself. For more information see
- Background radiation [wiki]
- Exposures from natural radiation sources [UNSCEAR 2000 report Vol. I Annex B]
- [Report of the United Nations Scientific Committee on the Effects of Atomic Radiation to the General Assembly] [UNSCEAR]
The worldwide average background dose for a human being is about 2400 microsieverts per year

Health effects - information:

Health effects [U.S. Environmental Protection Agency]
Dose comparisons for ionising radiation [Health Protection Agency (UK)]
Japan nuclear concerns [WHO]
Fukushima Nuclear Power Plant Accident - .pdf [ICRP]

Units: absorbed dose rate [Gy/h]

Absorbed dose [Gy]:

The unit gray, [Gy], measures radiation which is absorbed into any material.

Equivalent dose [Sv]:

The unit sievert, [Sv], specifically measures radiation which is absorbed by a person.
The equivalent dose to a person is found by multiplying the absorbed dose, in gray, by a radiation weighting factor (W_R ).
The radiation weighting factor W_R is introduced to allow for the different relative biological effects of different types of ionizing radiation on human tissue.

In terms of SI base units:

1 Sv = 1 Gy ⋅ W_R

where Sv=sievert, Gy=gray, W_R =weighting factor specific to each type of radiation and tissue.

Radiation weighting factor (W_R ):

For x-rays and gamma rays and electrons absorbed by human tissue, W_R is 1. For alpha particles it is 20. To compute Sieverts from Grays, simply multiply by W_R . This is obviously a simplification. The radiation weighting factor W_R approximates what otherwise would be very complicated computations. The values for W_R change periodically as new research refines the approximations [1].

Effective dose [Sv]:

The probability of a harmful effect from radiation exposure depends on what part or parts of the body are exposed. Some organs are more sensitive to radiation than others. A tissue weighting factor is used to take this into account. When an equivalent dose to an organ is multiplied by the tissue weighting factor for that organ the result is the effective dose to that organ. If more than one organ is exposed then the effective dose, is the sum of the effective doses to all exposed organs [1].

Tissue weighting factor:

see table European nuclear society

more information:

Radiation Protection Video [Ionactive Consulting]
Gray [wiki]
Sievert [wiki]
Rem [wiki]
Orders of magnitude (radiation) [wiki]
Dosimetry & Shielding [nucleonica.net/wiki]
[1] Units for Measuring Radiation [Australien Radiation Protection and Nuclear Safety Agency]
Radiation effects from Fukushima I nuclear accidents [Wiki]

Absorbed dose rate

Fukushima I Jaderná elektrárna

ATTENTION: These products are highly uncertain based on limited information for the source terms. Please use with caution and understand that the values are likely to change.