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Accumulated absorbed dose rate - T=13.03.2011 - 29.07.2014(see missing values above)

< Acc. Vmax < 2 * Acc. Vmax < 4 * Acc. Vmax > 4 * Ac.. Vmax
Stations: 353 Acc. abs. dose rate
μGy/T
Acc. Vmax
μGy/T
Acc. Vmean
μGy/T
Fukushima I MP7 696005.000 3291.41
Fukushima I MP8 570942.000 3291.41
Fukushima I MP6 240668.000 3291.41
Yamada Futaba Town 176983.000 2390.14 2848.18
Fukushima I MP2 140420.000 3291.41
Fukushima I MP5 111325.000 3291.41
Fukushima [32] (distance from Fukushima I: 30 km) 101500.000 2094.22 3362.54
Fukushima I MP3 93730.602 3291.41
Fukushima I MP4 86821.500 3291.41
Fukushima [33] (distance from Fukushima I: 30 km) 77197.703 2094.22 3362.54
Fukushima [79] (distance from Fukushima I: 40 km) 54008.602 2043.1 3280.46
Fukushima [31] (distance from Fukushima I: 30 km) 40677.398 2094.22 3362.54
Ono Okuma Town 38610.500 2206.91 2848.18
Shinzan Futaba Town 38332.801 2002.89 2848.18
Fukushima I MP1 31496.801 3291.41
Yonomori Tomioka Town 29815.900 2281.86 2848.18
Fukushima [46] (distance from Fukushima I: 20 km) 28842.500 2094.22 3362.54
Tomioka Tomioka Town 25324.500 2456.75 2848.18
Fukushima [62] (distance from Fukushima I: 40 km) 16464.100 2094.22 3362.54
Fukushima [61] (distance from Fukushima I: 40 km) 13102.800 2094.22 3362.54
Shimo-Kooriyama Tomioka Town 13057.000 2440.11 2848.18
Fukushima [21] (distance from Fukushima I: 30 km) 12103.800 2094.22 3362.54
Fukushima [3] (distance from Fukushima I: 45 km) 11985.000 2094.22 3362.54
Kami-kooriyama Tomioka Town 11803.900 1915.45 2848.18
Fukushima II MP3 11060.600 3291.41
Fukushima II MP1 10903.000 3291.41
Kooriyama Futaba Town 10352.900 2231.9 2848.18
Fukushima II MP4 9696.330 3291.41
Fukushima [34] (distance from Fukushima I: 30 km) 9540.450 2090.81 3357.07
Fukushima II MP5 9382.150 3291.41
Fukushima [2] (distance from Fukushima I: 55 km) 8841.760 2094.22 3362.54
Matsudate Naraha Town 8410.890 2606.66 2848.18
Shigeoka Naraha Town 8115.970 2881.48 2848.18
Fukushima II MP2 7875.320 3291.41
Namie Namie Town 7321.210 2102.83 2848.18
Radiation dose at Shirasawa branch office, Motomiya 7287.920 3307.82
Fukushima II MP6 7062.690 3291.41
Fukushima II MP7 6511.580 3288.67
Fukushima [1] (distance from Fukushima I: 60 km) 5615.310 2094.22 3362.54
Fukushima [11] (distance from Fukushima I: 40 km) 5491.310 2094.22 3362.54
Fukushima [63] (distance from Fukushima I: 45 km) 5448.820 2094.22 3362.54
Fukushima [45] (distance from Fukushima I: 20 km) 3981.200 2094.22 3362.54
Fukushima [42] (distance from Fukushima I: 30 km) 3850.600 2094.22 3362.54
Fukushima [10] (distance from Fukushima I: 40 km) 3734.160 2094.22 3362.54
Fukushima [78] (distance from Fukushima I: 45 km) 3716.820 2089.1 3354.34
Futatsunuma Hirono Town 3520.340 2498.4 2848.18
Fukushima [4] (distance from Fukushima I: 50 km) 3386.310 2094.22 3362.54
Fukushima [7] (distance from Fukushima I: 45 km) 3313.930 2094.22 3362.54
Radiation dose at Koriyama joint government building, Koriyama 3232.890 3305.09
Fukushima [15] (distance from Fukushima I: 35 km) 3178.670 2094.22 3362.54
Kiyohashi Namie Town 3162.000 1844.64 2848.18
Fukushima [71] (distance from Fukushima I: 25 km) 3161.650 2089.1 3354.34
Radiation dose at Agricultural center, Koriyama 3128.960 3305.09
Fukushima [41] (distance from Fukushima I: 20 km) 3111.490 2094.22 3362.54
Radiation dose at Koriyama city office, Koriyama 2803.520 3305.09
Fukushima [44] (distance from Fukushima I: 30 km) 2535.550 2094.22 3362.54
Fukushima [72] (distance from Fukushima I: 30 km) 2344.620 2089.1 3354.34
Fukushima [43] (distance from Fukushima I: 20 km) 2244.110 2094.22 3362.54
Yamadaoka Naraha Town 2205.340 2215.26 2848.18
Radiation dose at Iwane Fureai Plaza, Motomiya 2169.060 3307.82
Fukushima [22] (distance from Fukushima I: 35 km) 2020.650 2094.22 3362.54
Kuji Hitachi City 1990.890 5208.19 3373.49
Hitachinaka Hitachinaka City 1951.950 2286.58 3370.75
Fukushima [76] (distance from Fukushima I: 25 km) 1945.520 2089.1 3354.34
Fukushima [80] (distance from Fukushima I: 25 km) 1876.860 2089.1 3354.34
Momiyama Hokota City 1837.540 2609.04 3373.49
Fukushima [77] (distance from Fukushima I: 25 km) 1802.490 2089.1 3354.34
Horiguchi Hitachinaka City 1779.410 2280.43 3376.22
Onuma Hitachi City 1776.950 1941.64 3370.75
Fukushima [6] (distance from Fukushima I: 45 km) 1741.180 2094.22 3362.54
Tsukuriya Hokota City 1736.890 2194.75 3373.49
Radiation dose at Big palette Fukushima, Koriyama 1668.540 3305.09
Nemoto Hitachioomiya City 1633.190 2444.3 3370.75
Fukushima [13] (distance from Fukushima I: 40 km) 1624.150 2094.22 3362.54
Fukushima [23] (distance from Fukushima I: 35 km) 1551.750 2094.22 3362.54
Radiation dose at Tsukidatemachi kamitedo, Date 1545.300 3313.3
Fukushima [14] (distance from Fukushima I: 35 km) 1543.460 2094.22 3362.54
Radiation dose at JAEA Oarai (P12) 1512.140 3329.71
Radiation dose at Ose administration center, Koriyama 1494.270 3305.09
Araji Hokota City 1437.760 2199.66 3373.49
Ishigami Tokai Village 1431.690 2002.4 3373.49
Mawatari Hitachinaka City 1422.870 2313.12 3373.49
Radiation dose at JAEA Oarai (P11) 1399.370 3329.71
Onuki Oarai Town 1387.990 2401.89 3373.49
Sawa Hitachinaka City 1353.770 1813.49 3370.75
Toyooka Tokai Village 1321.760 2204.6 3373.49
Ajigaura Hitachinaka City 1313.890 2168.31 3370.75
Fukushima [5] (distance from Fukushima I: 45 km) 1282.090 2094.22 3362.54
Geiger Counter Feeds from Asao Kawasaki 1266.620 3283.2
Radiation dose at Tamokami elementary school, Koriyama 1256.140 3305.09
Isohama Oarai Town 1250.540 2092.69 3368.02
Ebisawa Ibaraki Town 1222.240 5682.97 3370.75
Muramatsu Tokai Village 1203.520 2224.34 3373.49
Kamitoda Hokota City 1184.740 1824.85 3373.49
Yanagisawa Hitachinaka City 1166.970 1857.85 3370.75
Tokushuku Hokota City 1159.730 1647.3 3373.49
Tasaki Hokota City 1153.300 1940.55 3343.39
Fukushima [20] (distance from Fukushima I: 45 km) 1145.390 2094.22 3362.54
Kadobe Naka City 1086.580 4425.35 3370.75
Radiation dose at Date city office, Date 1076.050 3307.82
Oshinobe Tokai Village 1041.340 2076.38 3373.49
Oba Mito City 1037.670 6820.96 3373.49
Godai Naka City 1031.270 1800.17 3373.49
Ishikawa Mito City 1030.810 2122.49 3376.22
Isobe Hitachiota City 1013.130 10238.8 3373.49
Yatabe Ibaraki Town 996.127 1780.46 3373.49
Radiation dose at Motomiya city office, Motomiya 992.703 3307.82
Fukushima [73] (distance from Fukushima I: 35 km) 981.984 2089.1 3354.34
Fukushima [75] (distance from Fukushima I: 45 km) 960.529 2089.1 3354.34
Yokobori Naka City 930.280 2086.24 3373.49
Sugaya Naka City 926.186 3188.67 3376.22
Kounosu Naka City 926.087 1627.56 3373.49
Funaishikawa Tokai Village 900.399 2160.22 3373.49
Nukada Naka City 899.900 1949.9 3368.02
Uridura Naka City 890.113 1861.27 3368.02
Shiraki Tsuruga City 881.330 3953.74 3376.22
Motokomezaki Naka City 880.851 1728.94 3340.66
Shiraki pass Tsuruga City 850.284 4141.29 3376.22
Radiation dose in Yamamoto 846.633 3329.71
Yoshizawa Mito City 837.646 1884.03 3373.49
Radiation dose at JAEA Oarai (P7) 831.135 3329.71
Mayumi Hitachiota City 828.119 1869.24 3373.49
Urasoko Tsuruga City 826.465 3282.43 3376.22
Nemoto Hitachioomiya City 825.588 2104.27 3370.75
Takenami Mihama Town 804.283 3445.32 3376.22
Radiation dose at JAEA Oarai (P15) 780.207 3329.71
Tateishi Tsuruga City 780.092 2729.62 3376.22
Radiation dose at JAEA Oarai (P14) 770.174 3329.71
Radiation dose at JAEA Oarai (P13) 769.612 3329.71
Ukishima Kawasaki Ward 735.475 6441.48 3376.22
Kume Hitachiota City 713.958 1829.76 3373.49
Radiation dose at JAEA Oarai (P2) 712.011 3329.71
Fukushima [74] (distance from Fukushima I: 35 km) 706.552 2089.1 3354.34
Nyuu Mihama Town 674.787 3139.3 3376.22
Fukushima [52] (distance from Fukushima I: 40 km) 672.743 2094.22 3362.54
Radiation dose in Iwanuma 670.242 3329.71
Fukushima [51] (distance from Fukushima I: 40 km) 665.376 2094.22 3362.54
Tsuruga Tsuruga City 655.360 2769.1 3376.22
Shiohama Kawasaki Ward 653.536 2211.34 3376.22
Radiation dose in Kakuda 649.863 3329.71
Sakajiri Mihama Town 649.252 3662.52 3376.22
North point of Kinki University Atomic Energy Research Instirute Station 639.566 2300.19 3376.22
Radiation dose in Onagawa (MP-2) 632.968 3326.98
Kumatori town Nishi primary school Station 631.491 2749.34 3376.22
Oshima Kawasaki Ward 630.402 2107.68 3376.22
Izumisano municipal Oike athletic field Station 629.920 3099.82 3376.22
Atom-kyoudou nursery school Station 625.566 2976.41 3376.22
South point of Kinki University Atomic Energy Research Instirute Station 625.202 2709.86 3376.22
Nakamachi Omaezaki City 623.494 3489.74 3376.22
Uraga Yokosuka City 622.492 1653.55 3376.22
Goritoge Shika Town 622.143 3706.95 3376.22
Kumatori town Minami primary school Station 606.134 3154.1 3376.22
Radiation dose at JAEA Oarai (P1) 603.643 3332.45
Yamanotedai-No.1 Park Station 599.140 2941.85 3376.22
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 595.502 3348.86
Noumi Shika Town 594.021 3667.44 3376.22
Radiation dose in Watari 591.851 3329.71
Hairando Yokosuka City 588.667 2073.12 3376.22
Fukushima [12] (distance from Fukushima I: 40 km) 588.291 2094.22 3362.54
Ningyotoge Kagamino Town 574.857 2941.85 3376.22
Ten-no Kagamino Town 569.960 3524.3 3376.22
Funagura Yokosuka City 563.909 1954.66 3376.22
Chidori Kawasaki Ward 560.211 1890.48 3376.22
Radiation dose at JAEA Oarai (P16) 556.365 3329.71
Shika Shika Town 551.376 3534.17 3376.22
Higashiosaka municipal Kamikosaka primary scool Station 550.277 2295.24 3376.22
Sahara Yokosuka City 547.404 1831.25 3376.22
Kazanashi Shika Town 545.377 3316.99 3376.22
Akasumi Shika Town 544.970 3035.64 3376.22
Kurahashi Maizuru City 540.820 2764.15 3376.22
Obama Obama City 540.809 2472.94 3376.22
Sakuragaike community hall Omaezaki City 540.772 3578.59 3376.22
Shirowa primary school Omaezaki City 535.692 3504.55 3376.22
Radiation dose at JAEA Oarai (P5) 529.759 3329.71
Uenohara Omaezaki City 529.333 3603.29 3376.22
Kumano Shika Town 529.019 3440.4 3376.22
Izumisano municipal Hineno filtration plant Station 527.471 2966.55 3376.22
Nishi-hamasada Matsue City 525.089 3276.31 3359.81
Kouno Minami-Echizen Town 525.028 2487.74 3376.22
Kurihama Yokosuka City 523.708 1979.33 3376.22
Osaka prefectural Kumatori off-site-center Station 522.808 2734.53 3376.22
Ogasa branch Kikugawa City 522.039 3637.83 3362.54
Izumisano municipal Hineno primary scool Station 518.181 2374.23 3376.22
Shirasuna Omaezaki City 499.479 3529.25 3376.22
Jitougata primary school Makinohara City 498.059 3386.09 3376.22
Kataku Matsue City 497.007 2630.88 3376.22
Nishihemi Yokosuka City 496.917 1579.51 3376.22
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 496.721 3348.86
Satsuma-sendai monitoring center Satsuma-sendai City 495.302 2591.4 3376.22
Otomi Takahama Town 494.821 2902.37 3376.22
Otsu Nanao City 493.895 2912.23 3376.22
The Observation point for comparison Tatsunokuchi 493.454 2398.9 3376.22
Hitsuhama Ohi Town 492.630 2700 3376.22
Kijiyama Misasa Town 489.284 2739.48 3376.22
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 487.055 3348.86
Hiraba Omaezaki City 485.878 3529.25 3376.22
Tayu Matsue City 484.956 2744.43 3376.22
Hamaokakita primary school Omaezaki City 484.537 3613.26 3362.54
Oitomi Ayabe City 474.670 3479.88 3376.22
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 472.017 3348.86
Kashiwazaki-shigai Kashiwazaki City 470.822 2769.1 3376.22
Mitsu Matsue City 466.897 2625.96 3376.22
Tonomachi Kawasaki Ward 463.967 3326.85 3376.22
Daitou branch Kakegawa City 463.829 3559.19 3362.54
Fukura Shika Town 462.493 3312.05 3376.22
Nagasawa Yokosuka City 462.365 1934.9 3376.22
The athletic field Station of Kinki University 461.661 2186.64 3376.22
Koura Matsue City 461.049 3134.35 3376.22
Sakurasan Ward Omaezaki City 459.434 3415.7 3376.22
Tsuchikawa Nanao City 458.915 3223.2 3376.22
Kumatori Town office Station 457.917 2255.76 3376.22
Shinkango Omaezaki City 449.013 3953.74 3376.22
Ogurui Takahama Town 448.279 2586.45 3376.22
Kusabue Omaezaki City 444.162 3726.67 3376.22
Omaezaki City monitoring center 443.946 3657.58 3376.22
Akawase Kagamino Town 442.246 2255.76 3376.22
Ibaraki 442.139 1654.46 3368.02
Hinode Town Yokosuka City 438.324 1303.1 3376.22
Nishiyama Kashiwazaki City 437.251 3919.17 3376.22
Kariwa Kariwa Village 436.307 2956.65 3376.22
Osaka prefectural Hineno high scool Station 435.745 2635.82 3376.22
Miyagawa Kashiwazaki City 435.245 2917.18 3376.22
Radiation dose in Natori 434.640 3329.71
Kami-koubu Matsue City 433.868 2867.81 3376.22
Shimo-Takamachi Kariwa Village 433.192 3218.28 3376.22
Osaka prefectural Sano supporting school Station 432.398 2872.75 3376.22
Arahama Kashiwazaki City 428.874 3006.02 3376.22
Doai Kashiwazaki City 425.681 2828.33 3376.22
Owashi Matsue City 424.452 2803.66 3376.22
Okayasu Maizuru City 422.568 3302.18 3376.22
Katsuyama Kariwa Village 421.280 3006.02 3376.22
Kita-koubu Matsue City 420.683 3075.12 3376.22
Kichisaka Maizuru City 413.065 4012.97 3376.22
Nagai Ohi Town 410.699 2915.02 3368.02
Shiokumi Maizuru City 407.938 4995.24 3376.22
Miyadome Ohi Town 407.831 2418.65 3376.22
Kariwa Kariwa Village 407.617 3114.63 3376.22
Ueno Satsuma-sendai City 394.248 2260.68 3376.22
Power Station-South 389.191 3292.32 3376.22
Radiation dose at JAEA Oarai (P6) 386.963 3329.71
Power Station- 385.546 3213.34 3376.22
Takae Satsuma-sendai City 379.551 2290.29 3376.22
Hokawaduura Genkai Town 378.015 3487.28 3376.22
Kou Itimatsu Suetsugu 377.929 2517.36 3376.22
Minato Satsuma-sendai City 377.656 2097.79 3376.22
Iwanai Iwanai Town 376.336 3417.88 3373.49
Hattari Kyowa Town 373.047 3324.16 3373.49
Chatsu Tomari Village 371.011 3176.2 3373.49
Oyama Maizuru City 358.223 2892.51 3376.22
Kodaira Satsuma-sendai City 355.545 2122.49 3376.22
Kayanuma Tomari Village 354.809 2826.04 3373.49
Anojiri Obama City 353.215 2369.28 3376.22
Kushi Genkai Town 349.738 4812.6 3376.22
Yamaguchi 348.715 3781.63 3368.02
Sadahongou Matsue City 348.228 2946.79 3376.22
Sakibe Karatsu City 347.801 4560.86 3376.22
Hirao Genkai Town 343.814 4807.65 3376.22
The Meteorological Obsevatory of kyowa Town 343.275 3151.55 3373.49
Minami-Horoni Kyowa Town 335.180 2954.26 3373.49
Kounoura Takahama Town 330.353 2497.61 3376.22
Kyoudomarisaki Karatsu City 328.622 4886.64 3376.22
Horikappu Jinja Tomari Village 328.230 3057.83 3373.49
Hukada-kita Matsue City 327.031 2423.57 3376.22
Radiation dose in KEK, Tsukuba 326.240 3348.86
Herokaruusu Tomari Village 324.242 3171.29 3373.49
Yorita Satsuma-sendai City 323.218 2482.8 3376.22
Kamoenai Kamoenai Village 322.032 2678.08 3373.49
Radiation dose in Onagawa (MP-6) 316.267 3326.98
Imamura Genkai Town 314.749 41412.9 3376.22
Yamanaka Takahama Town 314.185 3223.2 3376.22
Sendai (Miyagi) 312.585 1515.61 3368.02
Radiation dose in Onagawa (MP-1) 300.147 3326.98
Gumisaki Satsuma-sendai City 295.693 2004.03 3376.22
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 286.142 3348.86
Aomori Aomori City 285.372 2036.91 3373.49
Misawa City hall Misawa City 283.728 3950.53 3373.49
Kashu Ikata Town 277.173 2068.17 3376.22
Noheji Town Office Noheji Town 272.004 1745.93 3373.49
Takasimamati 271.103 2201.45 3376.22
Radiation dose in Onagawa (MP-3) 270.563 3326.98
Kucho Ikata Town 269.545 1826.33 3376.22
Radiation dose in Marumori 269.436 3329.71
Kawanagata Ikata Town 266.821 1781.91 3376.22
Tochigi 260.733 1979.45 3368.02
Chikagawa Mutu City 256.719 2273.64 3373.49
Yokohama Town Office Yokohama Town 254.846 2786.59 3373.49
Tokyo 251.877 2333.98 3368.02
Hiranuma Rokkasho Village 251.186 1829.76 3373.49
Taisei Ikata Town 246.293 1337.67 3376.22
Chitose-daira Rokkasho Village 245.868 1972.81 3373.49
Gifu 243.951 3249.84 3368.02
Fukkoshi Yokohama Town 243.102 1913.63 3373.49
Shimane 240.651 3249.84 3368.02
Sunagomata Higashidoori Village 238.012 2766.85 3373.49
Obuchi Rokkasho Village 237.506 2199.66 3373.49
Tomari Rokkasho Village 230.636 3077.57 3373.49
kanagawa 226.339 2038.54 3368.02
Saitama 219.770 1772.64 3368.02
Ikatagoshi Ikata Town 217.515 1683.17 3376.22
Touhoku Branch office Touhoku Town 215.416 1593.03 3373.49
Radiation dose at Tohoku University 214.824 3329.71
Odanosawa Higashidoori Village 210.287 2204.6 3373.49
Kagawa 205.829 2274.89 3368.02
Oippe Higashidoori Village 205.182 1898.83 3373.49
Oita 200.921 2511.24 3368.02
Touhoku Town office Touhoku Town 200.811 7368.41 3373.49
Kuchogoshi Ikata Town 198.646 1707.87 3376.22
Minatoura Ikata Town 186.776 1535.09 3376.22
Radiation dose in Koyadori, Ojika 184.905 3324.24
Toyama 184.580 4342.97 3368.02
Fukushima [9] (distance from Fukushima I: 45 km) 184.232 2094.22 3362.54
Radiation dose in Tukahama, Ojika 183.417 3324.24
Chiba 182.407 1299.94 3368.02
Nara 182.387 2363.52 3368.02
Okayama 181.976 3072.58 3368.02
Yamagata 181.598 2422.61 3368.02
Ehime 180.745 2186.26 3368.02
Ishikawa 180.445 3766.86 3368.02
Niigata 177.483 4520.23 3368.02
Hiroshima 176.816 2038.54 3368.02
Mie 174.867 2331.02 3368.02
Fukui 170.045 2865.77 3368.02
Radiation dose in Terama, Ojika 168.036 3324.24
Yamanashi 164.561 1890.82 3368.02
Nagano 162.242 2877.59 3368.02
Saga 161.421 2540.78 3368.02
Tottori 161.392 2333.98 3368.02
Radiation dose in Enoshima, Ojika 160.091 3324.24
Osaka 159.103 1802.18 3368.02
Ibaraki-city Environment 157.249 3283.2
Aichi 149.345 2186.26 3368.02
Toyonoura Ikata Town 149.214 1762.15 3376.22
Shizuoka 148.639 2260.12 3368.02
Kyoto 144.522 2570.33 3368.02
Kagoshima 144.449 2786 3368.02
Tokushima 143.627 1979.45 3368.02
Gunma 143.572 1329.48 3368.02
Hyogo 139.710 2245.34 3368.02
Fukuoka 136.511 2333.98 3368.02
Wakayama 133.857 1654.46 3368.02
Radiation at Tamaki-cho Mie Japan 133.138 3283.2
Akita 132.832 2540.78 3368.02
Shiga 124.919 1802.18 3368.02
Nagasaki 109.459 2038.54 3368.02
Hokkaido 109.189 3102.12 3368.02
Kumamoto 103.568 1979.45 3368.02
Aomori 101.819 3013.49 3368.02
Miyazaki 100.354 1961.72 3368.02
Kochi 95.931 2245.34 3368.02
Fukushima [35] (distance from Fukushima I: 35 km) 91.917 2085.7 3348.86
Iwate 90.324 2481.7 3368.02
Environment Feeds from Ohta 83.623 3283.2
Okinawa 82.305 1698.78 3368.02
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 Vmax-Vmin
Minimum value (Vmin) and maximum value (Vmax) 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 (Vmin) and maximum value (Vmax) 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 Vmax. The accumulation starts with the first available value of the data set after 13.3.2011 (see missing values above).



Colour scale:
< Vmax < 10 * Vmax < 100 * Vmax > 100 * Vmax
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:
Health effects - information:
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 (WR ).
The radiation weighting factor WR 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 ⋅ WR

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

Radiation weighting factor (WR ):

For x-rays and gamma rays and electrons absorbed by human tissue, WR is 1. For alpha particles it is 20. To compute Sieverts from Grays, simply multiply by WR . This is obviously a simplification. The radiation weighting factor WR approximates what otherwise would be very complicated computations. The values for WR 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:

Fukushima I Nuclear power plant

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.
Cloud spread Fukushima
Cloud spread Fukushima
Cloud spread Fukushima
Summary

Japan nuclear accident