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Accumulated absorbed dose rate - T=13.03.2011 - 24.04.2017(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 6027.41
Fukushima I MP8 570942.000 6027.41
Fukushima I MP6 240668.000 6027.41
Yamada Futaba Town 176983.000 4686.15 5584.18
Fukushima I MP2 140420.000 6027.41
Fukushima I MP5 111325.000 6027.41
Fukushima [32] (distance from Fukushima I: 30 km) 101500.000 3798.22 6098.54
Fukushima I MP3 93730.602 6027.41
Fukushima I MP4 86821.500 6027.41
Fukushima [33] (distance from Fukushima I: 30 km) 77197.703 3798.22 6098.54
Fukushima [79] (distance from Fukushima I: 40 km) 54008.602 3747.1 6016.46
Fukushima [31] (distance from Fukushima I: 30 km) 40677.398 3798.22 6098.54
Ono Okuma Town 38610.500 4326.9 5584.18
Shinzan Futaba Town 38332.801 3926.9 5584.18
Fukushima I MP1 31496.801 6027.41
Yonomori Tomioka Town 29815.900 4473.86 5584.18
Fukushima [46] (distance from Fukushima I: 20 km) 28842.500 3798.22 6098.54
Tomioka Tomioka Town 25324.500 4816.74 5584.18
Fukushima [62] (distance from Fukushima I: 40 km) 16464.100 3798.22 6098.54
Fukushima [61] (distance from Fukushima I: 40 km) 13102.800 3798.22 6098.54
Shimo-Kooriyama Tomioka Town 13057.000 4784.12 5584.18
Fukushima [21] (distance from Fukushima I: 30 km) 12103.800 3798.22 6098.54
Fukushima [3] (distance from Fukushima I: 45 km) 11985.000 3798.22 6098.54
Kami-kooriyama Tomioka Town 11803.900 3755.46 5584.18
Fukushima II MP3 11060.600 6027.41
Fukushima II MP1 10903.000 6027.41
Kooriyama Futaba Town 10352.900 4375.89 5584.18
Fukushima II MP4 9696.330 6027.41
Fukushima [34] (distance from Fukushima I: 30 km) 9540.450 3794.81 6093.07
Fukushima II MP5 9382.150 6027.41
Fukushima [2] (distance from Fukushima I: 55 km) 8841.760 3798.22 6098.54
Matsudate Naraha Town 8410.890 5110.65 5584.18
Shigeoka Naraha Town 8115.970 5649.47 5584.18
Fukushima II MP2 7875.320 6027.41
Namie Namie Town 7321.210 4122.84 5584.18
Radiation dose at Shirasawa branch office, Motomiya 7287.920 6043.82
Fukushima II MP6 7062.690 6027.41
Fukushima II MP7 6511.580 6024.67
Fukushima [1] (distance from Fukushima I: 60 km) 5615.310 3798.22 6098.54
Fukushima [11] (distance from Fukushima I: 40 km) 5491.310 3798.22 6098.54
Fukushima [63] (distance from Fukushima I: 45 km) 5448.820 3798.22 6098.54
Fukushima [45] (distance from Fukushima I: 20 km) 3981.200 3798.22 6098.54
Fukushima [42] (distance from Fukushima I: 30 km) 3850.600 3798.22 6098.54
Fukushima [10] (distance from Fukushima I: 40 km) 3734.160 3798.22 6098.54
Fukushima [78] (distance from Fukushima I: 45 km) 3716.820 3793.1 6090.34
Futatsunuma Hirono Town 3520.340 4898.4 5584.18
Fukushima [4] (distance from Fukushima I: 50 km) 3386.310 3798.22 6098.54
Fukushima [7] (distance from Fukushima I: 45 km) 3313.930 3798.22 6098.54
Radiation dose at Koriyama joint government building, Koriyama 3232.890 6041.09
Fukushima [15] (distance from Fukushima I: 35 km) 3178.670 3798.22 6098.54
Kiyohashi Namie Town 3162.000 3616.64 5584.18
Fukushima [71] (distance from Fukushima I: 25 km) 3161.650 3793.1 6090.34
Radiation dose at Agricultural center, Koriyama 3128.960 6041.09
Fukushima [41] (distance from Fukushima I: 20 km) 3111.490 3798.22 6098.54
Radiation dose at Koriyama city office, Koriyama 2803.520 6041.09
Fukushima [44] (distance from Fukushima I: 30 km) 2535.550 3798.22 6098.54
Fukushima [72] (distance from Fukushima I: 30 km) 2344.620 3793.1 6090.34
Fukushima [43] (distance from Fukushima I: 20 km) 2244.110 3798.22 6098.54
Yamadaoka Naraha Town 2205.340 4343.26 5584.18
Radiation dose at Iwane Fureai Plaza, Motomiya 2169.060 6043.82
Fukushima [22] (distance from Fukushima I: 35 km) 2020.650 3798.22 6098.54
Kuji Hitachi City 1990.890 9432.19 6109.49
Hitachinaka Hitachinaka City 1951.950 4142.57 6106.75
Fukushima [76] (distance from Fukushima I: 25 km) 1945.520 3793.1 6090.34
Fukushima [80] (distance from Fukushima I: 25 km) 1876.860 3793.1 6090.34
Momiyama Hokota City 1837.540 4725.05 6109.49
Fukushima [77] (distance from Fukushima I: 25 km) 1802.490 3793.1 6090.34
Horiguchi Hitachinaka City 1779.410 4128.43 6112.22
Onuma Hitachi City 1776.950 3517.65 6106.75
Fukushima [6] (distance from Fukushima I: 45 km) 1741.180 3798.22 6098.54
Tsukuriya Hokota City 1736.890 3974.76 6109.49
Radiation dose at Big palette Fukushima, Koriyama 1668.540 6041.09
Nemoto Hitachioomiya City 1633.190 4428.31 6106.75
Fukushima [13] (distance from Fukushima I: 40 km) 1624.150 3798.22 6098.54
Fukushima [23] (distance from Fukushima I: 35 km) 1551.750 3798.22 6098.54
Radiation dose at Tsukidatemachi kamitedo, Date 1545.300 6049.3
Fukushima [14] (distance from Fukushima I: 35 km) 1543.460 3798.22 6098.54
Radiation dose at JAEA Oarai (P12) 1512.140 6065.71
Radiation dose at Ose administration center, Koriyama 1494.270 6041.09
Araji Hokota City 1437.760 3983.65 6109.49
Ishigami Tokai Village 1431.690 3626.41 6109.49
Mawatari Hitachinaka City 1422.870 4189.13 6109.49
Radiation dose at JAEA Oarai (P11) 1399.370 6065.71
Onuki Oarai Town 1387.990 4349.9 6109.49
Sawa Hitachinaka City 1353.770 3285.49 6106.75
Toyooka Tokai Village 1321.760 3992.6 6109.49
Ajigaura Hitachinaka City 1313.890 3928.3 6106.75
Fukushima [5] (distance from Fukushima I: 45 km) 1282.090 3798.22 6098.54
Geiger Counter Feeds from Asao Kawasaki 1266.620 6019.2
Radiation dose at Tamokami elementary school, Koriyama 1256.140 6041.09
Isohama Oarai Town 1250.540 3792.68 6104.02
Ebisawa Ibaraki Town 1222.240 10295.8 6106.75
Muramatsu Tokai Village 1203.520 4028.35 6109.49
Kamitoda Hokota City 1184.740 3304.86 6109.49
Yanagisawa Hitachinaka City 1166.970 3365.84 6106.75
Tokushuku Hokota City 1159.730 2983.31 6109.49
Tasaki Hokota City 1153.300 3528.55 6079.39
Fukushima [20] (distance from Fukushima I: 45 km) 1145.390 3798.22 6098.54
Kadobe Naka City 1086.580 8017.36 6106.75
Radiation dose at Date city office, Date 1076.050 6043.82
Oshinobe Tokai Village 1041.340 3760.39 6109.49
Oba Mito City 1037.670 12353 6109.49
Godai Naka City 1031.270 3260.16 6109.49
Ishikawa Mito City 1030.810 3842.5 6112.22
Isobe Hitachiota City 1013.130 18542.8 6109.49
Yatabe Ibaraki Town 996.127 3224.47 6109.49
Radiation dose at Motomiya city office, Motomiya 992.703 6043.82
Fukushima [73] (distance from Fukushima I: 35 km) 981.984 3793.1 6090.34
Fukushima [75] (distance from Fukushima I: 45 km) 960.529 3793.1 6090.34
Yokobori Naka City 930.280 3778.24 6109.49
Sugaya Naka City 926.186 5772.67 6112.22
Kounosu Naka City 926.087 2947.56 6109.49
Funaishikawa Tokai Village 900.399 3912.22 6109.49
Nukada Naka City 899.900 3533.9 6104.02
Uridura Naka City 890.113 3373.27 6104.02
Shiraki Tsuruga City 881.330 7157.74 6112.22
Motokomezaki Naka City 880.851 3144.94 6076.66
Shiraki pass Tsuruga City 850.284 7497.29 6112.22
Radiation dose in Yamamoto 846.633 6065.71
Yoshizawa Mito City 837.646 3412.04 6109.49
Radiation dose at JAEA Oarai (P7) 831.135 6065.71
Mayumi Hitachiota City 828.119 3385.25 6109.49
Urasoko Tsuruga City 826.465 5942.42 6112.22
Nemoto Hitachioomiya City 825.588 3812.27 6106.75
Takenami Mihama Town 804.283 6237.31 6112.22
Radiation dose at JAEA Oarai (P15) 780.207 6065.71
Tateishi Tsuruga City 780.092 4941.63 6112.22
Radiation dose at JAEA Oarai (P14) 770.174 6065.71
Radiation dose at JAEA Oarai (P13) 769.612 6065.71
Ukishima Kawasaki Ward 735.475 11661.5 6112.22
Kume Hitachiota City 713.958 3313.75 6109.49
Radiation dose at JAEA Oarai (P2) 712.011 6065.71
Fukushima [74] (distance from Fukushima I: 35 km) 706.552 3793.1 6090.34
Nyuu Mihama Town 674.787 5683.3 6112.22
Fukushima [52] (distance from Fukushima I: 40 km) 672.743 3798.22 6098.54
Radiation dose in Iwanuma 670.242 6065.71
Fukushima [51] (distance from Fukushima I: 40 km) 665.376 3798.22 6098.54
Tsuruga Tsuruga City 655.360 5013.1 6112.22
Shiohama Kawasaki Ward 653.536 4003.35 6112.22
Radiation dose in Kakuda 649.863 6065.71
Sakajiri Mihama Town 649.252 6630.53 6112.22
North point of Kinki University Atomic Energy Research Instirute Station 639.566 4164.19 6112.22
Radiation dose in Onagawa (MP-2) 632.968 6062.98
Kumatori town Nishi primary school Station 631.491 4977.33 6112.22
Oshima Kawasaki Ward 630.402 3815.69 6112.22
Izumisano municipal Oike athletic field Station 629.920 5611.83 6112.22
Atom-kyoudou nursery school Station 625.566 5388.41 6112.22
South point of Kinki University Atomic Energy Research Instirute Station 625.202 4905.86 6112.22
Nakamachi Omaezaki City 623.494 6317.73 6112.22
Uraga Yokosuka City 622.492 2993.54 6112.22
Goritoge Shika Town 622.143 6710.95 6112.22
Kumatori town Minami primary school Station 606.134 5710.1 6112.22
Radiation dose at JAEA Oarai (P1) 603.643 6068.45
Yamanotedai-No.1 Park Station 599.140 5325.84 6112.22
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 595.502 6084.86
Noumi Shika Town 594.021 6639.43 6112.22
Radiation dose in Watari 591.851 6065.71
Hairando Yokosuka City 588.667 3753.12 6112.22
Fukushima [12] (distance from Fukushima I: 40 km) 588.291 3798.22 6098.54
Ningyotoge Kagamino Town 574.857 5325.84 6112.22
Ten-no Kagamino Town 569.960 6380.3 6112.22
Funagura Yokosuka City 563.909 3538.66 6112.22
Chidori Kawasaki Ward 560.211 3422.47 6112.22
Radiation dose at JAEA Oarai (P16) 556.365 6065.71
Shika Shika Town 551.376 6398.16 6112.22
Higashiosaka municipal Kamikosaka primary scool Station 550.277 4155.24 6112.22
Sahara Yokosuka City 547.404 3315.24 6112.22
Kazanashi Shika Town 545.377 6004.99 6112.22
Akasumi Shika Town 544.970 5495.64 6112.22
Kurahashi Maizuru City 540.820 5004.14 6112.22
Obama Obama City 540.809 4476.94 6112.22
Sakuragaike community hall Omaezaki City 540.772 6478.58 6112.22
Shirowa primary school Omaezaki City 535.692 6344.54 6112.22
Radiation dose at JAEA Oarai (P5) 529.759 6065.71
Uenohara Omaezaki City 529.333 6523.3 6112.22
Kumano Shika Town 529.019 6228.41 6112.22
Izumisano municipal Hineno filtration plant Station 527.471 5370.55 6112.22
Nishi-hamasada Matsue City 525.089 5944.32 6095.81
Kouno Minami-Echizen Town 525.028 4503.74 6112.22
Kurihama Yokosuka City 523.708 3583.32 6112.22
Osaka prefectural Kumatori off-site-center Station 522.808 4950.53 6112.22
Ogasa branch Kikugawa City 522.039 6597.82 6098.54
Izumisano municipal Hineno primary scool Station 518.181 4298.23 6112.22
Shirasuna Omaezaki City 499.479 6389.26 6112.22
Jitougata primary school Makinohara City 498.059 6130.08 6112.22
Kataku Matsue City 497.007 4762.87 6112.22
Nishihemi Yokosuka City 496.917 2859.5 6112.22
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 496.721 6084.86
Satsuma-sendai monitoring center Satsuma-sendai City 495.302 4691.4 6112.22
Otomi Takahama Town 494.821 5254.37 6112.22
Otsu Nanao City 493.895 5272.22 6112.22
The Observation point for comparison Tatsunokuchi 493.454 4342.9 6112.22
Hitsuhama Ohi Town 492.630 4888.01 6112.22
Kijiyama Misasa Town 489.284 4959.48 6112.22
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 487.055 6084.86
Hiraba Omaezaki City 485.878 6389.26 6112.22
Tayu Matsue City 484.956 4968.43 6112.22
Hamaokakita primary school Omaezaki City 484.537 6553.26 6098.54
Oitomi Ayabe City 474.670 6299.88 6112.22
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 472.017 6084.86
Kashiwazaki-shigai Kashiwazaki City 470.822 5013.1 6112.22
Mitsu Matsue City 466.897 4753.97 6112.22
Tonomachi Kawasaki Ward 463.967 6022.85 6112.22
Daitou branch Kakegawa City 463.829 6455.2 6098.54
Fukura Shika Town 462.493 5996.04 6112.22
Nagasawa Yokosuka City 462.365 3502.89 6112.22
The athletic field Station of Kinki University 461.661 3958.63 6112.22
Koura Matsue City 461.049 5674.34 6112.22
Sakurasan Ward Omaezaki City 459.434 6183.69 6112.22
Tsuchikawa Nanao City 458.915 5835.19 6112.22
Kumatori Town office Station 457.917 4083.77 6112.22
Shinkango Omaezaki City 449.013 7157.74 6112.22
Ogurui Takahama Town 448.279 4682.45 6112.22
Kusabue Omaezaki City 444.162 6746.66 6112.22
Omaezaki City monitoring center 443.946 6621.58 6112.22
Akawase Kagamino Town 442.246 4083.77 6112.22
Ibaraki 442.139 2998.46 6104.02
Hinode Town Yokosuka City 438.324 2359.1 6112.22
Nishiyama Kashiwazaki City 437.251 7095.17 6112.22
Kariwa Kariwa Village 436.307 5352.65 6112.22
Osaka prefectural Hineno high scool Station 435.745 4771.82 6112.22
Miyagawa Kashiwazaki City 435.245 5281.18 6112.22
Radiation dose in Natori 434.640 6065.71
Kami-koubu Matsue City 433.868 5191.8 6112.22
Shimo-Takamachi Kariwa Village 433.192 5826.29 6112.22
Osaka prefectural Sano supporting school Station 432.398 5200.75 6112.22
Arahama Kashiwazaki City 428.874 5442.02 6112.22
Doai Kashiwazaki City 425.681 5120.33 6112.22
Owashi Matsue City 424.452 5075.67 6112.22
Okayasu Maizuru City 422.568 5978.18 6112.22
Katsuyama Kariwa Village 421.280 5442.02 6112.22
Kita-koubu Matsue City 420.683 5567.11 6112.22
Kichisaka Maizuru City 413.065 7264.97 6112.22
Nagai Ohi Town 410.699 5283.03 6104.02
Shiokumi Maizuru City 407.938 9043.25 6112.22
Miyadome Ohi Town 407.831 4378.66 6112.22
Kariwa Kariwa Village 407.617 5638.63 6112.22
Ueno Satsuma-sendai City 394.248 4092.67 6112.22
Power Station-South 389.191 5960.33 6112.22
Radiation dose at JAEA Oarai (P6) 386.963 6065.71
Power Station- 385.546 5817.34 6112.22
Takae Satsuma-sendai City 379.551 4146.29 6112.22
Hokawaduura Genkai Town 378.015 6313.28 6112.22
Kou Itimatsu Suetsugu 377.929 4557.36 6112.22
Minato Satsuma-sendai City 377.656 3797.78 6112.22
Iwanai Iwanai Town 376.336 6189.88 6109.49
Hattari Kyowa Town 373.047 6020.15 6109.49
Chatsu Tomari Village 371.011 5752.19 6109.49
Oyama Maizuru City 358.223 5236.51 6112.22
Kodaira Satsuma-sendai City 355.545 3842.5 6112.22
Kayanuma Tomari Village 354.809 5118.04 6109.49
Anojiri Obama City 353.215 4289.28 6112.22
Kushi Genkai Town 349.738 8712.6 6112.22
Yamaguchi 348.715 6853.63 6104.02
Sadahongou Matsue City 348.228 5334.79 6112.22
Sakibe Karatsu City 347.801 8256.86 6112.22
Hirao Genkai Town 343.814 8703.65 6112.22
The Meteorological Obsevatory of kyowa Town 343.275 5707.55 6109.49
Minami-Horoni Kyowa Town 335.180 5350.25 6109.49
Kounoura Takahama Town 330.353 4521.6 6112.22
Kyoudomarisaki Karatsu City 328.622 8846.64 6112.22
Horikappu Jinja Tomari Village 328.230 5537.82 6109.49
Hukada-kita Matsue City 327.031 4387.56 6112.22
Radiation dose in KEK, Tsukuba 326.240 6084.86
Herokaruusu Tomari Village 324.242 5743.29 6109.49
Yorita Satsuma-sendai City 323.218 4494.79 6112.22
Kamoenai Kamoenai Village 322.032 4850.08 6109.49
Radiation dose in Onagawa (MP-6) 316.267 6062.98
Imamura Genkai Town 314.749 74972.9 6112.22
Yamanaka Takahama Town 314.185 5835.19 6112.22
Sendai (Miyagi) 312.585 2746.81 6104.02
Radiation dose in Onagawa (MP-1) 300.147 6062.98
Gumisaki Satsuma-sendai City 295.693 3628.03 6112.22
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 286.142 6084.86
Aomori Aomori City 285.372 3688.9 6109.49
Misawa City hall Misawa City 283.728 7154.53 6109.49
Kashu Ikata Town 277.173 3744.17 6112.22
Noheji Town Office Noheji Town 272.004 3161.93 6109.49
Takasimamati 271.103 3985.44 6112.22
Radiation dose in Onagawa (MP-3) 270.563 6062.98
Kucho Ikata Town 269.545 3306.34 6112.22
Radiation dose in Marumori 269.436 6065.71
Kawanagata Ikata Town 266.821 3225.91 6112.22
Tochigi 260.733 3587.45 6104.02
Chikagawa Mutu City 256.719 4117.63 6109.49
Yokohama Town Office Yokohama Town 254.846 5046.6 6109.49
Tokyo 251.877 4229.98 6104.02
Hiranuma Rokkasho Village 251.186 3313.75 6109.49
Taisei Ikata Town 246.293 2421.67 6112.22
Chitose-daira Rokkasho Village 245.868 3572.82 6109.49
Gifu 243.951 5889.84 6104.02
Fukkoshi Yokohama Town 243.102 3465.63 6109.49
Shimane 240.651 5889.84 6104.02
Sunagomata Higashidoori Village 238.012 5010.85 6109.49
Obuchi Rokkasho Village 237.506 3983.65 6109.49
Tomari Rokkasho Village 230.636 5573.57 6109.49
kanagawa 226.339 3694.54 6104.02
Saitama 219.770 3212.64 6104.02
Ikatagoshi Ikata Town 217.515 3047.16 6112.22
Touhoku Branch office Touhoku Town 215.416 2885.02 6109.49
Radiation dose at Tohoku University 214.824 6065.71
Odanosawa Higashidoori Village 210.287 3992.6 6109.49
Kagawa 205.829 4122.89 6104.02
Oippe Higashidoori Village 205.182 3438.84 6109.49
Oita 200.921 4551.24 6104.02
Touhoku Town office Touhoku Town 200.811 13344.4 6109.49
Kuchogoshi Ikata Town 198.646 3091.87 6112.22
Minatoura Ikata Town 186.776 2779.08 6112.22
Radiation dose in Koyadori, Ojika 184.905 6060.24
Toyama 184.580 7870.97 6104.02
Fukushima [9] (distance from Fukushima I: 45 km) 184.232 3798.22 6098.54
Radiation dose in Tukahama, Ojika 183.417 6060.24
Chiba 182.407 2355.94 6104.02
Nara 182.387 4283.52 6104.02
Okayama 181.976 5568.58 6104.02
Yamagata 181.598 4390.61 6104.02
Ehime 180.745 3962.26 6104.02
Ishikawa 180.445 6826.86 6104.02
Niigata 177.483 8192.23 6104.02
Hiroshima 176.816 3694.54 6104.02
Mie 174.867 4224.62 6104.02
Fukui 170.045 5193.77 6104.02
Radiation dose in Terama, Ojika 168.036 6060.24
Yamanashi 164.561 3426.82 6104.02
Nagano 162.242 5215.19 6104.02
Saga 161.421 4604.78 6104.02
Tottori 161.392 4229.98 6104.02
Radiation dose in Enoshima, Ojika 160.091 6060.24
Osaka 159.103 3266.18 6104.02
Ibaraki-city Environment 157.249 6019.2
Aichi 149.345 3962.26 6104.02
Toyonoura Ikata Town 149.214 3190.15 6112.22
Shizuoka 148.639 4096.12 6104.02
Kyoto 144.522 4658.33 6104.02
Kagoshima 144.449 5049.2 6104.02
Tokushima 143.627 3587.45 6104.02
Gunma 143.572 2409.48 6104.02
Hyogo 139.710 4069.34 6104.02
Fukuoka 136.511 4229.98 6104.02
Wakayama 133.857 2998.46 6104.02
Radiation at Tamaki-cho Mie Japan 133.138 6019.2
Akita 132.832 4604.78 6104.02
Shiga 124.919 3266.18 6104.02
Nagasaki 109.459 3694.54 6104.02
Hokkaido 109.189 5622.12 6104.02
Kumamoto 103.568 3587.45 6104.02
Aomori 101.819 5461.49 6104.02
Miyazaki 100.354 3555.32 6104.02
Kochi 95.931 4069.34 6104.02
Fukushima [35] (distance from Fukushima I: 35 km) 91.917 3789.7 6084.86
Iwate 90.324 4497.7 6104.02
Environment Feeds from Ohta 83.623 6019.2
Okinawa 82.305 3078.78 6104.02
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