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Accumulated absorbed dose rate - T=13.03.2011 - 10.12.2016(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 5658.05
Fukushima I MP8 570942.000 5658.05
Fukushima I MP6 240668.000 5658.05
Yamada Futaba Town 176983.000 4376.19 5214.82
Fukushima I MP2 140420.000 5658.05
Fukushima I MP5 111325.000 5658.05
Fukushima [32] (distance from Fukushima I: 30 km) 101500.000 3568.18 5729.18
Fukushima I MP3 93730.602 5658.05
Fukushima I MP4 86821.500 5658.05
Fukushima [33] (distance from Fukushima I: 30 km) 77197.703 3568.18 5729.18
Fukushima [79] (distance from Fukushima I: 40 km) 54008.602 3517.06 5647.1
Fukushima [31] (distance from Fukushima I: 30 km) 40677.398 3568.18 5729.18
Ono Okuma Town 38610.500 4040.7 5214.82
Shinzan Futaba Town 38332.801 3667.16 5214.82
Fukushima I MP1 31496.801 5658.05
Yonomori Tomioka Town 29815.900 4177.94 5214.82
Fukushima [46] (distance from Fukushima I: 20 km) 28842.500 3568.18 5729.18
Tomioka Tomioka Town 25324.500 4498.15 5214.82
Fukushima [62] (distance from Fukushima I: 40 km) 16464.100 3568.18 5729.18
Fukushima [61] (distance from Fukushima I: 40 km) 13102.800 3568.18 5729.18
Shimo-Kooriyama Tomioka Town 13057.000 4467.68 5214.82
Fukushima [21] (distance from Fukushima I: 30 km) 12103.800 3568.18 5729.18
Fukushima [3] (distance from Fukushima I: 45 km) 11985.000 3568.18 5729.18
Kami-kooriyama Tomioka Town 11803.900 3507.06 5214.82
Fukushima II MP3 11060.600 5658.05
Fukushima II MP1 10903.000 5658.05
Kooriyama Futaba Town 10352.900 4086.45 5214.82
Fukushima II MP4 9696.330 5658.05
Fukushima [34] (distance from Fukushima I: 30 km) 9540.450 3564.77 5723.71
Fukushima II MP5 9382.150 5658.05
Fukushima [2] (distance from Fukushima I: 55 km) 8841.760 3568.18 5729.18
Matsudate Naraha Town 8410.890 4772.61 5214.82
Shigeoka Naraha Town 8115.970 5275.79 5214.82
Fukushima II MP2 7875.320 5658.05
Namie Namie Town 7321.210 3850.14 5214.82
Radiation dose at Shirasawa branch office, Motomiya 7287.920 5674.46
Fukushima II MP6 7062.690 5658.05
Fukushima II MP7 6511.580 5655.31
Fukushima [1] (distance from Fukushima I: 60 km) 5615.310 3568.18 5729.18
Fukushima [11] (distance from Fukushima I: 40 km) 5491.310 3568.18 5729.18
Fukushima [63] (distance from Fukushima I: 45 km) 5448.820 3568.18 5729.18
Fukushima [45] (distance from Fukushima I: 20 km) 3981.200 3568.18 5729.18
Fukushima [42] (distance from Fukushima I: 30 km) 3850.600 3568.18 5729.18
Fukushima [10] (distance from Fukushima I: 40 km) 3734.160 3568.18 5729.18
Fukushima [78] (distance from Fukushima I: 45 km) 3716.820 3563.06 5720.98
Futatsunuma Hirono Town 3520.340 4574.4 5214.82
Fukushima [4] (distance from Fukushima I: 50 km) 3386.310 3568.18 5729.18
Fukushima [7] (distance from Fukushima I: 45 km) 3313.930 3568.18 5729.18
Radiation dose at Koriyama joint government building, Koriyama 3232.890 5671.73
Fukushima [15] (distance from Fukushima I: 35 km) 3178.670 3568.18 5729.18
Kiyohashi Namie Town 3162.000 3377.42 5214.82
Fukushima [71] (distance from Fukushima I: 25 km) 3161.650 3563.06 5720.98
Radiation dose at Agricultural center, Koriyama 3128.960 5671.73
Fukushima [41] (distance from Fukushima I: 20 km) 3111.490 3568.18 5729.18
Radiation dose at Koriyama city office, Koriyama 2803.520 5671.73
Fukushima [44] (distance from Fukushima I: 30 km) 2535.550 3568.18 5729.18
Fukushima [72] (distance from Fukushima I: 30 km) 2344.620 3563.06 5720.98
Fukushima [43] (distance from Fukushima I: 20 km) 2244.110 3568.18 5729.18
Yamadaoka Naraha Town 2205.340 4055.98 5214.82
Radiation dose at Iwane Fureai Plaza, Motomiya 2169.060 5674.46
Fukushima [22] (distance from Fukushima I: 35 km) 2020.650 3568.18 5729.18
Kuji Hitachi City 1990.890 8861.95 5740.13
Hitachinaka Hitachinaka City 1951.950 3892.02 5737.39
Fukushima [76] (distance from Fukushima I: 25 km) 1945.520 3563.06 5720.98
Fukushima [80] (distance from Fukushima I: 25 km) 1876.860 3563.06 5720.98
Momiyama Hokota City 1837.540 4439.38 5740.13
Fukushima [77] (distance from Fukushima I: 25 km) 1802.490 3563.06 5720.98
Horiguchi Hitachinaka City 1779.410 3878.95 5742.86
Onuma Hitachi City 1776.950 3304.89 5737.39
Fukushima [6] (distance from Fukushima I: 45 km) 1741.180 3568.18 5729.18
Tsukuriya Hokota City 1736.890 3734.46 5740.13
Radiation dose at Big palette Fukushima, Koriyama 1668.540 5671.73
Nemoto Hitachioomiya City 1633.190 4160.46 5737.39
Fukushima [13] (distance from Fukushima I: 40 km) 1624.150 3568.18 5729.18
Fukushima [23] (distance from Fukushima I: 35 km) 1551.750 3568.18 5729.18
Radiation dose at Tsukidatemachi kamitedo, Date 1545.300 5679.94
Fukushima [14] (distance from Fukushima I: 35 km) 1543.460 3568.18 5729.18
Radiation dose at JAEA Oarai (P12) 1512.140 5696.35
Radiation dose at Ose administration center, Koriyama 1494.270 5671.73
Araji Hokota City 1437.760 3742.82 5740.13
Ishigami Tokai Village 1431.690 3407.17 5740.13
Mawatari Hitachinaka City 1422.870 3935.86 5740.13
Radiation dose at JAEA Oarai (P11) 1399.370 5696.35
Onuki Oarai Town 1387.990 4086.92 5740.13
Sawa Hitachinaka City 1353.770 3086.77 5737.39
Toyooka Tokai Village 1321.760 3751.22 5740.13
Ajigaura Hitachinaka City 1313.890 3690.7 5737.39
Fukushima [5] (distance from Fukushima I: 45 km) 1282.090 3568.18 5729.18
Geiger Counter Feeds from Asao Kawasaki 1266.620 5649.84
Radiation dose at Tamokami elementary school, Koriyama 1256.140 5671.73
Isohama Oarai Town 1250.540 3563.18 5734.66
Ebisawa Ibaraki Town 1222.240 9673.04 5737.39
Muramatsu Tokai Village 1203.520 3784.81 5740.13
Kamitoda Hokota City 1184.740 3105.06 5740.13
Yanagisawa Hitachinaka City 1166.970 3162.26 5737.39
Tokushuku Hokota City 1159.730 2802.94 5740.13
Tasaki Hokota City 1153.300 3314.17 5710.03
Fukushima [20] (distance from Fukushima I: 45 km) 1145.390 3568.18 5729.18
Kadobe Naka City 1086.580 7532.44 5737.39
Radiation dose at Date city office, Date 1076.050 5674.46
Oshinobe Tokai Village 1041.340 3533.05 5740.13
Oba Mito City 1037.670 11606.1 5740.13
Godai Naka City 1031.270 3063.06 5740.13
Ishikawa Mito City 1030.810 3610.3 5742.86
Isobe Hitachiota City 1013.130 17421.8 5740.13
Yatabe Ibaraki Town 996.127 3029.53 5740.13
Radiation dose at Motomiya city office, Motomiya 992.703 5674.46
Fukushima [73] (distance from Fukushima I: 35 km) 981.984 3563.06 5720.98
Fukushima [75] (distance from Fukushima I: 45 km) 960.529 3563.06 5720.98
Yokobori Naka City 930.280 3549.82 5740.13
Sugaya Naka City 926.186 5423.83 5742.86
Kounosu Naka City 926.087 2769.36 5740.13
Funaishikawa Tokai Village 900.399 3675.7 5740.13
Nukada Naka City 899.900 3320.06 5734.66
Uridura Naka City 890.113 3169.15 5734.66
Shiraki Tsuruga City 881.330 6725.2 5742.86
Motokomezaki Naka City 880.851 2953.78 5707.3
Shiraki pass Tsuruga City 850.284 7044.23 5742.86
Radiation dose in Yamamoto 846.633 5696.35
Yoshizawa Mito City 837.646 3205.76 5740.13
Radiation dose at JAEA Oarai (P7) 831.135 5696.35
Mayumi Hitachiota City 828.119 3180.58 5740.13
Urasoko Tsuruga City 826.465 5583.32 5742.86
Nemoto Hitachioomiya City 825.588 3581.69 5737.39
Takenami Mihama Town 804.283 5860.39 5742.86
Radiation dose at JAEA Oarai (P15) 780.207 5696.35
Tateishi Tsuruga City 780.092 4643 5742.86
Radiation dose at JAEA Oarai (P14) 770.174 5696.35
Radiation dose at JAEA Oarai (P13) 769.612 5696.35
Ukishima Kawasaki Ward 735.475 10956.8 5742.86
Kume Hitachiota City 713.958 3113.42 5740.13
Radiation dose at JAEA Oarai (P2) 712.011 5696.35
Fukushima [74] (distance from Fukushima I: 35 km) 706.552 3563.06 5720.98
Nyuu Mihama Town 674.787 5339.86 5742.86
Fukushima [52] (distance from Fukushima I: 40 km) 672.743 3568.18 5729.18
Radiation dose in Iwanuma 670.242 5696.35
Fukushima [51] (distance from Fukushima I: 40 km) 665.376 3568.18 5729.18
Tsuruga Tsuruga City 655.360 4710.16 5742.86
Shiohama Kawasaki Ward 653.536 3761.42 5742.86
Radiation dose in Kakuda 649.863 5696.35
Sakajiri Mihama Town 649.252 6229.85 5742.86
North point of Kinki University Atomic Energy Research Instirute Station 639.566 3912.55 5742.86
Radiation dose in Onagawa (MP-2) 632.968 5693.62
Kumatori town Nishi primary school Station 631.491 4676.56 5742.86
Oshima Kawasaki Ward 630.402 3585.11 5742.86
Izumisano municipal Oike athletic field Station 629.920 5272.7 5742.86
Atom-kyoudou nursery school Station 625.566 5062.79 5742.86
South point of Kinki University Atomic Energy Research Instirute Station 625.202 4609.4 5742.86
Nakamachi Omaezaki City 623.494 5935.96 5742.86
Uraga Yokosuka City 622.492 2812.64 5742.86
Goritoge Shika Town 622.143 6305.41 5742.86
Kumatori town Minami primary school Station 606.134 5365.04 5742.86
Radiation dose at JAEA Oarai (P1) 603.643 5699.09
Yamanotedai-No.1 Park Station 599.140 5004 5742.86
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 595.502 5715.5
Noumi Shika Town 594.021 6238.21 5742.86
Radiation dose in Watari 591.851 5696.35
Hairando Yokosuka City 588.667 3526.32 5742.86
Fukushima [12] (distance from Fukushima I: 40 km) 588.291 3568.18 5729.18
Ningyotoge Kagamino Town 574.857 5004 5742.86
Ten-no Kagamino Town 569.960 5994.74 5742.86
Funagura Yokosuka City 563.909 3324.82 5742.86
Chidori Kawasaki Ward 560.211 3215.65 5742.86
Radiation dose at JAEA Oarai (P16) 556.365 5696.35
Shika Shika Town 551.376 6011.52 5742.86
Higashiosaka municipal Kamikosaka primary scool Station 550.277 3904.14 5742.86
Sahara Yokosuka City 547.404 3114.9 5742.86
Kazanashi Shika Town 545.377 5642.11 5742.86
Akasumi Shika Town 544.970 5163.54 5742.86
Kurahashi Maizuru City 540.820 4701.74 5742.86
Obama Obama City 540.809 4206.4 5742.86
Sakuragaike community hall Omaezaki City 540.772 6087.08 5742.86
Shirowa primary school Omaezaki City 535.692 5961.14 5742.86
Radiation dose at JAEA Oarai (P5) 529.759 5696.35
Uenohara Omaezaki City 529.333 6129.1 5742.86
Kumano Shika Town 529.019 5852.03 5742.86
Izumisano municipal Hineno filtration plant Station 527.471 5046.01 5742.86
Nishi-hamasada Matsue City 525.089 5584.14 5726.45
Kouno Minami-Echizen Town 525.028 4231.58 5742.86
Kurihama Yokosuka City 523.708 3366.78 5742.86
Osaka prefectural Kumatori off-site-center Station 522.808 4651.37 5742.86
Ogasa branch Kikugawa City 522.039 6198.22 5729.18
Izumisano municipal Hineno primary scool Station 518.181 4038.49 5742.86
Shirasuna Omaezaki City 499.479 6003.16 5742.86
Jitougata primary school Makinohara City 498.059 5759.64 5742.86
Kataku Matsue City 497.007 4475.05 5742.86
Nishihemi Yokosuka City 496.917 2686.7 5742.86
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 496.721 5715.5
Satsuma-sendai monitoring center Satsuma-sendai City 495.302 4407.9 5742.86
Otomi Takahama Town 494.821 4936.85 5742.86
Otsu Nanao City 493.895 4953.62 5742.86
The Observation point for comparison Tatsunokuchi 493.454 4080.46 5742.86
Hitsuhama Ohi Town 492.630 4592.63 5742.86
Kijiyama Misasa Town 489.284 4659.78 5742.86
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 487.055 5715.5
Hiraba Omaezaki City 485.878 6003.16 5742.86
Tayu Matsue City 484.956 4668.19 5742.86
Hamaokakita primary school Omaezaki City 484.537 6156.36 5729.18
Oitomi Ayabe City 474.670 5919.18 5742.86
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 472.017 5715.5
Kashiwazaki-shigai Kashiwazaki City 470.822 4710.16 5742.86
Mitsu Matsue City 466.897 4466.69 5742.86
Tonomachi Kawasaki Ward 463.967 5658.89 5742.86
Daitou branch Kakegawa City 463.829 6064.24 5729.18
Fukura Shika Town 462.493 5633.7 5742.86
Nagasawa Yokosuka City 462.365 3291.22 5742.86
The athletic field Station of Kinki University 461.661 3719.41 5742.86
Koura Matsue City 461.049 5331.44 5742.86
Sakurasan Ward Omaezaki City 459.434 5810.02 5742.86
Tsuchikawa Nanao City 458.915 5482.57 5742.86
Kumatori Town office Station 457.917 3836.99 5742.86
Shinkango Omaezaki City 449.013 6725.2 5742.86
Ogurui Takahama Town 448.279 4399.49 5742.86
Kusabue Omaezaki City 444.162 6338.96 5742.86
Omaezaki City monitoring center 443.946 6221.44 5742.86
Akawase Kagamino Town 442.246 3836.99 5742.86
Ibaraki 442.139 2817.02 5734.66
Hinode Town Yokosuka City 438.324 2216.54 5742.86
Nishiyama Kashiwazaki City 437.251 6666.41 5742.86
Kariwa Kariwa Village 436.307 5029.19 5742.86
Osaka prefectural Hineno high scool Station 435.745 4483.46 5742.86
Miyagawa Kashiwazaki City 435.245 4962.04 5742.86
Radiation dose in Natori 434.640 5696.35
Kami-koubu Matsue City 433.868 4878.06 5742.86
Shimo-Takamachi Kariwa Village 433.192 5474.21 5742.86
Osaka prefectural Sano supporting school Station 432.398 4886.47 5742.86
Arahama Kashiwazaki City 428.874 5113.16 5742.86
Doai Kashiwazaki City 425.681 4810.91 5742.86
Owashi Matsue City 424.452 4768.94 5742.86
Okayasu Maizuru City 422.568 5616.92 5742.86
Katsuyama Kariwa Village 421.280 5113.16 5742.86
Kita-koubu Matsue City 420.683 5230.69 5742.86
Kichisaka Maizuru City 413.065 6825.95 5742.86
Nagai Ohi Town 410.699 4963.34 5734.66
Shiokumi Maizuru City 407.938 8496.77 5742.86
Miyadome Ohi Town 407.831 4114.06 5742.86
Kariwa Kariwa Village 407.617 5297.89 5742.86
Ueno Satsuma-sendai City 394.248 3845.35 5742.86
Power Station-South 389.191 5600.15 5742.86
Radiation dose at JAEA Oarai (P6) 386.963 5696.35
Power Station- 385.546 5465.8 5742.86
Takae Satsuma-sendai City 379.551 3895.73 5742.86
Hokawaduura Genkai Town 378.015 5931.77 5742.86
Kou Itimatsu Suetsugu 377.929 4281.96 5742.86
Minato Satsuma-sendai City 377.656 3568.28 5742.86
Iwanai Iwanai Town 376.336 5815.66 5740.13
Hattari Kyowa Town 373.047 5656.19 5740.13
Chatsu Tomari Village 371.011 5404.43 5740.13
Oyama Maizuru City 358.223 4920.07 5742.86
Kodaira Satsuma-sendai City 355.545 3610.3 5742.86
Kayanuma Tomari Village 354.809 4808.62 5740.13
Anojiri Obama City 353.215 4030.08 5742.86
Kushi Genkai Town 349.738 8186.1 5742.86
Yamaguchi 348.715 6438.91 5734.66
Sadahongou Matsue City 348.228 5012.41 5742.86
Sakibe Karatsu City 347.801 7757.9 5742.86
Hirao Genkai Town 343.814 8177.69 5742.86
The Meteorological Obsevatory of kyowa Town 343.275 5362.49 5740.13
Minami-Horoni Kyowa Town 335.180 5026.79 5740.13
Kounoura Takahama Town 330.353 4248.36 5742.86
Kyoudomarisaki Karatsu City 328.622 8312.04 5742.86
Horikappu Jinja Tomari Village 328.230 5203.02 5740.13
Hukada-kita Matsue City 327.031 4122.42 5742.86
Radiation dose in KEK, Tsukuba 326.240 5715.5
Herokaruusu Tomari Village 324.242 5396.07 5740.13
Yorita Satsuma-sendai City 323.218 4223.17 5742.86
Kamoenai Kamoenai Village 322.032 4556.86 5740.13
Radiation dose in Onagawa (MP-6) 316.267 5693.62
Imamura Genkai Town 314.749 70442.3 5742.86
Yamanaka Takahama Town 314.185 5482.57 5742.86
Sendai (Miyagi) 312.585 2580.6 5734.66
Radiation dose in Onagawa (MP-1) 300.147 5693.62
Gumisaki Satsuma-sendai City 295.693 3408.79 5742.86
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 286.142 5715.5
Aomori Aomori City 285.372 3465.88 5740.13
Misawa City hall Misawa City 283.728 6721.99 5740.13
Kashu Ikata Town 277.173 3517.91 5742.86
Noheji Town Office Noheji Town 272.004 2970.77 5740.13
Takasimamati 271.103 3744.6 5742.86
Radiation dose in Onagawa (MP-3) 270.563 5693.62
Kucho Ikata Town 269.545 3106.54 5742.86
Radiation dose in Marumori 269.436 5696.35
Kawanagata Ikata Town 266.821 3030.97 5742.86
Tochigi 260.733 3370.37 5734.66
Chikagawa Mutu City 256.719 3868.7 5740.13
Yokohama Town Office Yokohama Town 254.846 4741.5 5740.13
Tokyo 251.877 3974.02 5734.66
Hiranuma Rokkasho Village 251.186 3113.42 5740.13
Taisei Ikata Town 246.293 2275.33 5742.86
Chitose-daira Rokkasho Village 245.868 3356.82 5740.13
Gifu 243.951 5533.44 5734.66
Fukkoshi Yokohama Town 243.102 3256.11 5740.13
Shimane 240.651 5533.44 5734.66
Sunagomata Higashidoori Village 238.012 4707.91 5740.13
Obuchi Rokkasho Village 237.506 3742.82 5740.13
Tomari Rokkasho Village 230.636 5236.61 5740.13
kanagawa 226.339 3470.98 5734.66
Saitama 219.770 3018.24 5734.66
Ikatagoshi Ikata Town 217.515 2863.02 5742.86
Touhoku Branch office Touhoku Town 215.416 2710.6 5740.13
Radiation dose at Tohoku University 214.824 5696.35
Odanosawa Higashidoori Village 210.287 3751.22 5740.13
Kagawa 205.829 3873.41 5734.66
Oippe Higashidoori Village 205.182 3230.94 5740.13
Oita 200.921 4275.84 5734.66
Touhoku Town office Touhoku Town 200.811 12537.6 5740.13
Kuchogoshi Ikata Town 198.646 2905.03 5742.86
Minatoura Ikata Town 186.776 2611.14 5742.86
Radiation dose in Koyadori, Ojika 184.905 5690.88
Toyama 184.580 7394.69 5734.66
Fukushima [9] (distance from Fukushima I: 45 km) 184.232 3568.18 5729.18
Radiation dose in Tukahama, Ojika 183.417 5690.88
Chiba 182.407 2213.38 5734.66
Nara 182.387 4024.32 5734.66
Okayama 181.976 5231.62 5734.66
Yamagata 181.598 4124.93 5734.66
Ehime 180.745 3722.5 5734.66
Ishikawa 180.445 6413.76 5734.66
Niigata 177.483 7696.51 5734.66
Hiroshima 176.816 3470.98 5734.66
Mie 174.867 3968.99 5734.66
Fukui 170.045 4879.49 5734.66
Radiation dose in Terama, Ojika 168.036 5690.88
Yamanashi 164.561 3219.46 5734.66
Nagano 162.242 4899.61 5734.66
Saga 161.421 4326.14 5734.66
Tottori 161.392 3974.02 5734.66
Radiation dose in Enoshima, Ojika 160.091 5690.88
Osaka 159.103 3068.54 5734.66
Ibaraki-city Environment 157.249 5649.84
Aichi 149.345 3722.5 5734.66
Toyonoura Ikata Town 149.214 2997.37 5742.86
Shizuoka 148.639 3848.26 5734.66
Kyoto 144.522 4376.45 5734.66
Kagoshima 144.449 4743.67 5734.66
Tokushima 143.627 3370.37 5734.66
Gunma 143.572 2263.68 5734.66
Hyogo 139.710 3823.1 5734.66
Fukuoka 136.511 3974.02 5734.66
Wakayama 133.857 2817.02 5734.66
Radiation at Tamaki-cho Mie Japan 133.138 5649.84
Akita 132.832 4326.14 5734.66
Shiga 124.919 3068.54 5734.66
Nagasaki 109.459 3470.98 5734.66
Hokkaido 109.189 5281.92 5734.66
Kumamoto 103.568 3370.37 5734.66
Aomori 101.819 5131.01 5734.66
Miyazaki 100.354 3340.19 5734.66
Kochi 95.931 3823.1 5734.66
Fukushima [35] (distance from Fukushima I: 35 km) 91.917 3559.66 5715.5
Iwate 90.324 4225.54 5734.66
Environment Feeds from Ohta 83.623 5649.84
Okinawa 82.305 2892.48 5734.66
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