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Accumulated absorbed dose rate - T=13.03.2011 - 03.05.2016(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 5053.39
Fukushima I MP8 570942.000 5053.39
Fukushima I MP6 240668.000 5053.39
Yamada Futaba Town 176983.000 3868.77 4610.16
Fukushima I MP2 140420.000 5053.39
Fukushima I MP5 111325.000 5053.39
Fukushima [32] (distance from Fukushima I: 30 km) 101500.000 3191.59 5124.53
Fukushima I MP3 93730.602 5053.39
Fukushima I MP4 86821.500 5053.39
Fukushima [33] (distance from Fukushima I: 30 km) 77197.703 3191.59 5124.53
Fukushima [79] (distance from Fukushima I: 40 km) 54008.602 3140.47 5042.45
Fukushima [31] (distance from Fukushima I: 30 km) 40677.398 3191.59 5124.53
Ono Okuma Town 38610.500 3572.19 4610.16
Shinzan Futaba Town 38332.801 3241.95 4610.16
Fukushima I MP1 31496.801 5053.39
Yonomori Tomioka Town 29815.900 3693.51 4610.16
Fukushima [46] (distance from Fukushima I: 20 km) 28842.500 3191.59 5124.53
Tomioka Tomioka Town 25324.500 3976.59 4610.16
Fukushima [62] (distance from Fukushima I: 40 km) 16464.100 3191.59 5124.53
Fukushima [61] (distance from Fukushima I: 40 km) 13102.800 3191.59 5124.53
Shimo-Kooriyama Tomioka Town 13057.000 3949.65 4610.16
Fukushima [21] (distance from Fukushima I: 30 km) 12103.800 3191.59 5124.53
Fukushima [3] (distance from Fukushima I: 45 km) 11985.000 3191.59 5124.53
Kami-kooriyama Tomioka Town 11803.900 3100.41 4610.16
Fukushima II MP3 11060.600 5053.39
Fukushima II MP1 10903.000 5053.39
Kooriyama Futaba Town 10352.900 3612.63 4610.16
Fukushima II MP4 9696.330 5053.39
Fukushima [34] (distance from Fukushima I: 30 km) 9540.450 3188.18 5119.06
Fukushima II MP5 9382.150 5053.39
Fukushima [2] (distance from Fukushima I: 55 km) 8841.760 3191.59 5124.53
Matsudate Naraha Town 8410.890 4219.23 4610.16
Shigeoka Naraha Town 8115.970 4664.07 4610.16
Fukushima II MP2 7875.320 5053.39
Namie Namie Town 7321.210 3403.71 4610.16
Radiation dose at Shirasawa branch office, Motomiya 7287.920 5069.81
Fukushima II MP6 7062.690 5053.39
Fukushima II MP7 6511.580 5050.66
Fukushima [1] (distance from Fukushima I: 60 km) 5615.310 3191.59 5124.53
Fukushima [11] (distance from Fukushima I: 40 km) 5491.310 3191.59 5124.53
Fukushima [63] (distance from Fukushima I: 45 km) 5448.820 3191.59 5124.53
Fukushima [45] (distance from Fukushima I: 20 km) 3981.200 3191.59 5124.53
Fukushima [42] (distance from Fukushima I: 30 km) 3850.600 3191.59 5124.53
Fukushima [10] (distance from Fukushima I: 40 km) 3734.160 3191.59 5124.53
Fukushima [78] (distance from Fukushima I: 45 km) 3716.820 3186.48 5116.32
Futatsunuma Hirono Town 3520.340 4044 4610.16
Fukushima [4] (distance from Fukushima I: 50 km) 3386.310 3191.59 5124.53
Fukushima [7] (distance from Fukushima I: 45 km) 3313.930 3191.59 5124.53
Radiation dose at Koriyama joint government building, Koriyama 3232.890 5067.07
Fukushima [15] (distance from Fukushima I: 35 km) 3178.670 3191.59 5124.53
Kiyohashi Namie Town 3162.000 2985.81 4610.16
Fukushima [71] (distance from Fukushima I: 25 km) 3161.650 3186.48 5116.32
Radiation dose at Agricultural center, Koriyama 3128.960 5067.07
Fukushima [41] (distance from Fukushima I: 20 km) 3111.490 3191.59 5124.53
Radiation dose at Koriyama city office, Koriyama 2803.520 5067.07
Fukushima [44] (distance from Fukushima I: 30 km) 2535.550 3191.59 5124.53
Fukushima [72] (distance from Fukushima I: 30 km) 2344.620 3186.48 5116.32
Fukushima [43] (distance from Fukushima I: 20 km) 2244.110 3191.59 5124.53
Yamadaoka Naraha Town 2205.340 3585.69 4610.16
Radiation dose at Iwane Fureai Plaza, Motomiya 2169.060 5069.81
Fukushima [22] (distance from Fukushima I: 35 km) 2020.650 3191.59 5124.53
Kuji Hitachi City 1990.890 7928.45 5135.47
Hitachinaka Hitachinaka City 1951.950 3481.84 5132.74
Fukushima [76] (distance from Fukushima I: 25 km) 1945.520 3186.48 5116.32
Fukushima [80] (distance from Fukushima I: 25 km) 1876.860 3186.48 5116.32
Momiyama Hokota City 1837.540 3971.75 5135.47
Fukushima [77] (distance from Fukushima I: 25 km) 1802.490 3186.48 5116.32
Horiguchi Hitachinaka City 1779.410 3470.54 5138.21
Onuma Hitachi City 1776.950 2956.59 5132.74
Fukushima [6] (distance from Fukushima I: 45 km) 1741.180 3191.59 5124.53
Tsukuriya Hokota City 1736.890 3341.07 5135.47
Radiation dose at Big palette Fukushima, Koriyama 1668.540 5067.07
Nemoto Hitachioomiya City 1633.190 3722 5132.74
Fukushima [13] (distance from Fukushima I: 40 km) 1624.150 3191.59 5124.53
Fukushima [23] (distance from Fukushima I: 35 km) 1551.750 3191.59 5124.53
Radiation dose at Tsukidatemachi kamitedo, Date 1545.300 5075.28
Fukushima [14] (distance from Fukushima I: 35 km) 1543.460 3191.59 5124.53
Radiation dose at JAEA Oarai (P12) 1512.140 5091.7
Radiation dose at Ose administration center, Koriyama 1494.270 5067.07
Araji Hokota City 1437.760 3348.55 5135.47
Ishigami Tokai Village 1431.690 3048.26 5135.47
Mawatari Hitachinaka City 1422.870 3521.27 5135.47
Radiation dose at JAEA Oarai (P11) 1399.370 5091.7
Onuki Oarai Town 1387.990 3656.41 5135.47
Sawa Hitachinaka City 1353.770 2761.46 5132.74
Toyooka Tokai Village 1321.760 3356.08 5135.47
Ajigaura Hitachinaka City 1313.890 3301.75 5132.74
Fukushima [5] (distance from Fukushima I: 45 km) 1282.090 3191.59 5124.53
Geiger Counter Feeds from Asao Kawasaki 1266.620 5045.18
Radiation dose at Tamokami elementary school, Koriyama 1256.140 5067.07
Isohama Oarai Town 1250.540 3187.48 5130
Ebisawa Ibaraki Town 1222.240 8653.61 5132.74
Muramatsu Tokai Village 1203.520 3386.12 5135.47
Kamitoda Hokota City 1184.740 2777.97 5135.47
Yanagisawa Hitachinaka City 1166.970 2828.99 5132.74
Tokushuku Hokota City 1159.730 2507.69 5135.47
Tasaki Hokota City 1153.300 2963.22 5105.38
Fukushima [20] (distance from Fukushima I: 45 km) 1145.390 3191.59 5124.53
Kadobe Naka City 1086.580 6738.61 5132.74
Radiation dose at Date city office, Date 1076.050 5069.81
Oshinobe Tokai Village 1041.340 3160.88 5135.47
Oba Mito City 1037.670 10383.6 5135.47
Godai Naka City 1031.270 2740.41 5135.47
Ishikawa Mito City 1030.810 3230.18 5138.21
Isobe Hitachiota City 1013.130 15586.6 5135.47
Yatabe Ibaraki Town 996.127 2710.4 5135.47
Radiation dose at Motomiya city office, Motomiya 992.703 5069.81
Fukushima [73] (distance from Fukushima I: 35 km) 981.984 3186.48 5116.32
Fukushima [75] (distance from Fukushima I: 45 km) 960.529 3186.48 5116.32
Yokobori Naka City 930.280 3175.88 5135.47
Sugaya Naka City 926.186 4852.77 5138.21
Kounosu Naka City 926.087 2477.64 5135.47
Funaishikawa Tokai Village 900.399 3288.5 5135.47
Nukada Naka City 899.900 2970 5130
Uridura Naka City 890.113 2835 5130
Shiraki Tsuruga City 881.330 6017.11 5138.21
Motokomezaki Naka City 880.851 2640.84 5102.64
Shiraki pass Tsuruga City 850.284 6302.55 5138.21
Radiation dose in Yamamoto 846.633 5091.7
Yoshizawa Mito City 837.646 2868.07 5135.47
Radiation dose at JAEA Oarai (P7) 831.135 5091.7
Mayumi Hitachiota City 828.119 2845.55 5135.47
Urasoko Tsuruga City 826.465 4995.46 5138.21
Nemoto Hitachioomiya City 825.588 3204.22 5132.74
Takenami Mihama Town 804.283 5243.36 5138.21
Radiation dose at JAEA Oarai (P15) 780.207 5091.7
Tateishi Tsuruga City 780.092 4154.15 5138.21
Radiation dose at JAEA Oarai (P14) 770.174 5091.7
Radiation dose at JAEA Oarai (P13) 769.612 5091.7
Ukishima Kawasaki Ward 735.475 9803.16 5138.21
Kume Hitachiota City 713.958 2785.45 5135.47
Radiation dose at JAEA Oarai (P2) 712.011 5091.7
Fukushima [74] (distance from Fukushima I: 35 km) 706.552 3186.48 5116.32
Nyuu Mihama Town 674.787 4777.63 5138.21
Fukushima [52] (distance from Fukushima I: 40 km) 672.743 3191.59 5124.53
Radiation dose in Iwanuma 670.242 5091.7
Fukushima [51] (distance from Fukushima I: 40 km) 665.376 3191.59 5124.53
Tsuruga Tsuruga City 655.360 4214.23 5138.21
Shiohama Kawasaki Ward 653.536 3365.39 5138.21
Radiation dose in Kakuda 649.863 5091.7
Sakajiri Mihama Town 649.252 5573.92 5138.21
North point of Kinki University Atomic Energy Research Instirute Station 639.566 3500.61 5138.21
Radiation dose in Onagawa (MP-2) 632.968 5088.96
Kumatori town Nishi primary school Station 631.491 4184.17 5138.21
Oshima Kawasaki Ward 630.402 3207.64 5138.21
Izumisano municipal Oike athletic field Station 629.920 4717.55 5138.21
Atom-kyoudou nursery school Station 625.566 4529.74 5138.21
South point of Kinki University Atomic Energy Research Instirute Station 625.202 4124.09 5138.21
Nakamachi Omaezaki City 623.494 5310.97 5138.21
Uraga Yokosuka City 622.492 2516.51 5138.21
Goritoge Shika Town 622.143 5641.53 5138.21
Kumatori town Minami primary school Station 606.134 4800.17 5138.21
Radiation dose at JAEA Oarai (P1) 603.643 5094.43
Yamanotedai-No.1 Park Station 599.140 4477.14 5138.21
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 595.502 5110.85
Noumi Shika Town 594.021 5581.4 5138.21
Radiation dose in Watari 591.851 5091.7
Hairando Yokosuka City 588.667 3155.04 5138.21
Fukushima [12] (distance from Fukushima I: 40 km) 588.291 3191.59 5124.53
Ningyotoge Kagamino Town 574.857 4477.14 5138.21
Ten-no Kagamino Town 569.960 5363.57 5138.21
Funagura Yokosuka City 563.909 2974.75 5138.21
Chidori Kawasaki Ward 560.211 2877.08 5138.21
Radiation dose at JAEA Oarai (P16) 556.365 5091.7
Shika Shika Town 551.376 5378.58 5138.21
Higashiosaka municipal Kamikosaka primary scool Station 550.277 3493.08 5138.21
Sahara Yokosuka City 547.404 2786.94 5138.21
Kazanashi Shika Town 545.377 5048.06 5138.21
Akasumi Shika Town 544.970 4619.88 5138.21
Kurahashi Maizuru City 540.820 4206.71 5138.21
Obama Obama City 540.809 3763.51 5138.21
Sakuragaike community hall Omaezaki City 540.772 5446.19 5138.21
Shirowa primary school Omaezaki City 535.692 5333.5 5138.21
Radiation dose at JAEA Oarai (P5) 529.759 5091.7
Uenohara Omaezaki City 529.333 5483.77 5138.21
Kumano Shika Town 529.019 5235.88 5138.21
Izumisano municipal Hineno filtration plant Station 527.471 4514.73 5138.21
Nishi-hamasada Matsue City 525.089 4994.51 5121.79
Kouno Minami-Echizen Town 525.028 3786.05 5138.21
Kurihama Yokosuka City 523.708 3012.3 5138.21
Osaka prefectural Kumatori off-site-center Station 522.808 4161.63 5138.21
Ogasa branch Kikugawa City 522.039 5544.06 5124.53
Izumisano municipal Hineno primary scool Station 518.181 3613.29 5138.21
Shirasuna Omaezaki City 499.479 5371.1 5138.21
Jitougata primary school Makinohara City 498.059 5153.22 5138.21
Kataku Matsue City 497.007 4003.88 5138.21
Nishihemi Yokosuka City 496.917 2403.82 5138.21
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 496.721 5110.85
Satsuma-sendai monitoring center Satsuma-sendai City 495.302 3943.8 5138.21
Otomi Takahama Town 494.821 4417.06 5138.21
Otsu Nanao City 493.895 4432.06 5138.21
The Observation point for comparison Tatsunokuchi 493.454 3650.83 5138.21
Hitsuhama Ohi Town 492.630 4109.08 5138.21
Kijiyama Misasa Town 489.284 4169.16 5138.21
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 487.055 5110.85
Hiraba Omaezaki City 485.878 5371.1 5138.21
Tayu Matsue City 484.956 4176.69 5138.21
Hamaokakita primary school Omaezaki City 484.537 5506.62 5124.53
Oitomi Ayabe City 474.670 5295.96 5138.21
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 472.017 5110.85
Kashiwazaki-shigai Kashiwazaki City 470.822 4214.23 5138.21
Mitsu Matsue City 466.897 3996.4 5138.21
Tonomachi Kawasaki Ward 463.967 5063.07 5138.21
Daitou branch Kakegawa City 463.829 5424.22 5124.53
Fukura Shika Town 462.493 5040.54 5138.21
Nagasawa Yokosuka City 462.365 2944.69 5138.21
The athletic field Station of Kinki University 461.661 3327.8 5138.21
Koura Matsue City 461.049 4770.1 5138.21
Sakurasan Ward Omaezaki City 459.434 5198.29 5138.21
Tsuchikawa Nanao City 458.915 4905.32 5138.21
Kumatori Town office Station 457.917 3433 5138.21
Shinkango Omaezaki City 449.013 6017.11 5138.21
Ogurui Takahama Town 448.279 3936.27 5138.21
Kusabue Omaezaki City 444.162 5671.55 5138.21
Omaezaki City monitoring center 443.946 5566.39 5138.21
Akawase Kagamino Town 442.246 3433 5138.21
Ibaraki 442.139 2520 5130
Hinode Town Yokosuka City 438.324 1983.17 5138.21
Nishiyama Kashiwazaki City 437.251 5964.51 5138.21
Kariwa Kariwa Village 436.307 4499.67 5138.21
Osaka prefectural Hineno high scool Station 435.745 4011.41 5138.21
Miyagawa Kashiwazaki City 435.245 4439.59 5138.21
Radiation dose in Natori 434.640 5091.7
Kami-koubu Matsue City 433.868 4364.46 5138.21
Shimo-Takamachi Kariwa Village 433.192 4897.84 5138.21
Osaka prefectural Sano supporting school Station 432.398 4371.98 5138.21
Arahama Kashiwazaki City 428.874 4574.81 5138.21
Doai Kashiwazaki City 425.681 4304.38 5138.21
Owashi Matsue City 424.452 4266.83 5138.21
Okayasu Maizuru City 422.568 5025.53 5138.21
Katsuyama Kariwa Village 421.280 4574.81 5138.21
Kita-koubu Matsue City 420.683 4679.96 5138.21
Kichisaka Maizuru City 413.065 6107.26 5138.21
Nagai Ohi Town 410.699 4440.02 5130
Shiokumi Maizuru City 407.938 7602.16 5138.21
Miyadome Ohi Town 407.831 3680.9 5138.21
Kariwa Kariwa Village 407.617 4740.09 5138.21
Ueno Satsuma-sendai City 394.248 3440.48 5138.21
Power Station-South 389.191 5010.52 5138.21
Radiation dose at JAEA Oarai (P6) 386.963 5091.7
Power Station- 385.546 4890.31 5138.21
Takae Satsuma-sendai City 379.551 3485.55 5138.21
Hokawaduura Genkai Town 378.015 5307.23 5138.21
Kou Itimatsu Suetsugu 377.929 3831.12 5138.21
Minato Satsuma-sendai City 377.656 3192.58 5138.21
Iwanai Iwanai Town 376.336 5203.04 5135.47
Hattari Kyowa Town 373.047 5060.38 5135.47
Chatsu Tomari Village 371.011 4835.14 5135.47
Oyama Maizuru City 358.223 4402.05 5138.21
Kodaira Satsuma-sendai City 355.545 3230.18 5138.21
Kayanuma Tomari Village 354.809 4302.08 5135.47
Anojiri Obama City 353.215 3605.76 5138.21
Kushi Genkai Town 349.738 7324.2 5138.21
Yamaguchi 348.715 5760 5130
Sadahongou Matsue City 348.228 4484.66 5138.21
Sakibe Karatsu City 347.801 6941.09 5138.21
Hirao Genkai Town 343.814 7316.67 5138.21
The Meteorological Obsevatory of kyowa Town 343.275 4797.61 5135.47
Minami-Horoni Kyowa Town 335.180 4497.28 5135.47
Kounoura Takahama Town 330.353 3801.06 5138.21
Kyoudomarisaki Karatsu City 328.622 7436.88 5138.21
Horikappu Jinja Tomari Village 328.230 4654.94 5135.47
Hukada-kita Matsue City 327.031 3688.38 5138.21
Radiation dose in KEK, Tsukuba 326.240 5110.85
Herokaruusu Tomari Village 324.242 4827.66 5135.47
Yorita Satsuma-sendai City 323.218 3778.52 5138.21
Kamoenai Kamoenai Village 322.032 4076.84 5135.47
Radiation dose in Onagawa (MP-6) 316.267 5088.96
Imamura Genkai Town 314.749 63025.5 5138.21
Yamanaka Takahama Town 314.185 4905.32 5138.21
Sendai (Miyagi) 312.585 2308.5 5130
Radiation dose in Onagawa (MP-1) 300.147 5088.96
Gumisaki Satsuma-sendai City 295.693 3049.89 5138.21
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 286.142 5110.85
Aomori Aomori City 285.372 3100.79 5135.47
Misawa City hall Misawa City 283.728 6013.91 5135.47
Kashu Ikata Town 277.173 3147.51 5138.21
Noheji Town Office Noheji Town 272.004 2657.83 5135.47
Takasimamati 271.103 3350.34 5138.21
Radiation dose in Onagawa (MP-3) 270.563 5088.96
Kucho Ikata Town 269.545 2779.46 5138.21
Radiation dose in Marumori 269.436 5091.7
Kawanagata Ikata Town 266.821 2711.85 5138.21
Tochigi 260.733 3015 5130
Chikagawa Mutu City 256.719 3461.17 5135.47
Yokohama Town Office Yokohama Town 254.846 4242.04 5135.47
Tokyo 251.877 3555 5130
Hiranuma Rokkasho Village 251.186 2785.45 5135.47
Taisei Ikata Town 246.293 2035.77 5138.21
Chitose-daira Rokkasho Village 245.868 3003.21 5135.47
Gifu 243.951 4950 5130
Fukkoshi Yokohama Town 243.102 2913.12 5135.47
Shimane 240.651 4950 5130
Sunagomata Higashidoori Village 238.012 4211.99 5135.47
Obuchi Rokkasho Village 237.506 3348.55 5135.47
Tomari Rokkasho Village 230.636 4684.99 5135.47
kanagawa 226.339 3105 5130
Saitama 219.770 2700 5130
Ikatagoshi Ikata Town 217.515 2561.58 5138.21
Touhoku Branch office Touhoku Town 215.416 2425.07 5135.47
Radiation dose at Tohoku University 214.824 5091.7
Odanosawa Higashidoori Village 210.287 3356.08 5135.47
Kagawa 205.829 3465 5130
Oippe Higashidoori Village 205.182 2890.59 5135.47
Oita 200.921 3825 5130
Touhoku Town office Touhoku Town 200.811 11217 5135.47
Kuchogoshi Ikata Town 198.646 2599.17 5138.21
Minatoura Ikata Town 186.776 2336.22 5138.21
Radiation dose in Koyadori, Ojika 184.905 5086.22
Toyama 184.580 6615 5130
Fukushima [9] (distance from Fukushima I: 45 km) 184.232 3191.59 5124.53
Radiation dose in Tukahama, Ojika 183.417 5086.22
Chiba 182.407 1980 5130
Nara 182.387 3600 5130
Okayama 181.976 4680 5130
Yamagata 181.598 3690 5130
Ehime 180.745 3330 5130
Ishikawa 180.445 5737.5 5130
Niigata 177.483 6885 5130
Hiroshima 176.816 3105 5130
Mie 174.867 3550.5 5130
Fukui 170.045 4365 5130
Radiation dose in Terama, Ojika 168.036 5086.22
Yamanashi 164.561 2880 5130
Nagano 162.242 4383 5130
Saga 161.421 3870 5130
Tottori 161.392 3555 5130
Radiation dose in Enoshima, Ojika 160.091 5086.22
Osaka 159.103 2745 5130
Ibaraki-city Environment 157.249 5045.18
Aichi 149.345 3330 5130
Toyonoura Ikata Town 149.214 2681.78 5138.21
Shizuoka 148.639 3442.5 5130
Kyoto 144.522 3915 5130
Kagoshima 144.449 4243.5 5130
Tokushima 143.627 3015 5130
Gunma 143.572 2025 5130
Hyogo 139.710 3420 5130
Fukuoka 136.511 3555 5130
Wakayama 133.857 2520 5130
Radiation at Tamaki-cho Mie Japan 133.138 5045.18
Akita 132.832 3870 5130
Shiga 124.919 2745 5130
Nagasaki 109.459 3105 5130
Hokkaido 109.189 4725 5130
Kumamoto 103.568 3015 5130
Aomori 101.819 4590 5130
Miyazaki 100.354 2988 5130
Kochi 95.931 3420 5130
Fukushima [35] (distance from Fukushima I: 35 km) 91.917 3183.07 5110.85
Iwate 90.324 3780 5130
Environment Feeds from Ohta 83.623 5045.18
Okinawa 82.305 2587.5 5130
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