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Accumulated absorbed dose rate - T=13.03.2011 - 26.04.2018(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 7031.52
Fukushima I MP8 570942.000 7031.52
Fukushima I MP6 240668.000 7031.52
Yamada Futaba Town 176983.000 5528.79 6588.29
Fukushima I MP2 140420.000 7031.52
Fukushima I MP5 111325.000 7031.52
Fukushima [32] (distance from Fukushima I: 30 km) 101500.000 4423.58 7102.66
Fukushima I MP3 93730.602 7031.52
Fukushima I MP4 86821.500 7031.52
Fukushima [33] (distance from Fukushima I: 30 km) 77197.703 4423.58 7102.66
Fukushima [79] (distance from Fukushima I: 40 km) 54008.602 4372.46 7020.58
Fukushima [31] (distance from Fukushima I: 30 km) 40677.398 4423.58 7102.66
Ono Okuma Town 38610.500 5104.94 6588.29
Shinzan Futaba Town 38332.801 4633.01 6588.29
Fukushima I MP1 31496.801 7031.52
Yonomori Tomioka Town 29815.900 5278.32 6588.29
Fukushima [46] (distance from Fukushima I: 20 km) 28842.500 4423.58 7102.66
Tomioka Tomioka Town 25324.500 5682.86 6588.29
Fukushima [62] (distance from Fukushima I: 40 km) 16464.100 4423.58 7102.66
Fukushima [61] (distance from Fukushima I: 40 km) 13102.800 4423.58 7102.66
Shimo-Kooriyama Tomioka Town 13057.000 5644.37 6588.29
Fukushima [21] (distance from Fukushima I: 30 km) 12103.800 4423.58 7102.66
Fukushima [3] (distance from Fukushima I: 45 km) 11985.000 4423.58 7102.66
Kami-kooriyama Tomioka Town 11803.900 4430.74 6588.29
Fukushima II MP3 11060.600 7031.52
Fukushima II MP1 10903.000 7031.52
Kooriyama Futaba Town 10352.900 5162.73 6588.29
Fukushima II MP4 9696.330 7031.52
Fukushima [34] (distance from Fukushima I: 30 km) 9540.450 4420.18 7097.18
Fukushima II MP5 9382.150 7031.52
Fukushima [2] (distance from Fukushima I: 55 km) 8841.760 4423.58 7102.66
Matsudate Naraha Town 8410.890 6029.61 6588.29
Shigeoka Naraha Town 8115.970 6665.32 6588.29
Fukushima II MP2 7875.320 7031.52
Namie Namie Town 7321.210 4864.18 6588.29
Radiation dose at Shirasawa branch office, Motomiya 7287.920 7047.94
Fukushima II MP6 7062.690 7031.52
Fukushima II MP7 6511.580 7028.78
Fukushima [1] (distance from Fukushima I: 60 km) 5615.310 4423.58 7102.66
Fukushima [11] (distance from Fukushima I: 40 km) 5491.310 4423.58 7102.66
Fukushima [63] (distance from Fukushima I: 45 km) 5448.820 4423.58 7102.66
Fukushima [45] (distance from Fukushima I: 20 km) 3981.200 4423.58 7102.66
Fukushima [42] (distance from Fukushima I: 30 km) 3850.600 4423.58 7102.66
Fukushima [10] (distance from Fukushima I: 40 km) 3734.160 4423.58 7102.66
Fukushima [78] (distance from Fukushima I: 45 km) 3716.820 4418.47 7094.45
Futatsunuma Hirono Town 3520.340 5779.2 6588.29
Fukushima [4] (distance from Fukushima I: 50 km) 3386.310 4423.58 7102.66
Fukushima [7] (distance from Fukushima I: 45 km) 3313.930 4423.58 7102.66
Radiation dose at Koriyama joint government building, Koriyama 3232.890 7045.2
Fukushima [15] (distance from Fukushima I: 35 km) 3178.670 4423.58 7102.66
Kiyohashi Namie Town 3162.000 4266.96 6588.29
Fukushima [71] (distance from Fukushima I: 25 km) 3161.650 4418.47 7094.45
Radiation dose at Agricultural center, Koriyama 3128.960 7045.2
Fukushima [41] (distance from Fukushima I: 20 km) 3111.490 4423.58 7102.66
Radiation dose at Koriyama city office, Koriyama 2803.520 7045.2
Fukushima [44] (distance from Fukushima I: 30 km) 2535.550 4423.58 7102.66
Fukushima [72] (distance from Fukushima I: 30 km) 2344.620 4418.47 7094.45
Fukushima [43] (distance from Fukushima I: 20 km) 2244.110 4423.58 7102.66
Yamadaoka Naraha Town 2205.340 5124.24 6588.29
Radiation dose at Iwane Fureai Plaza, Motomiya 2169.060 7047.94
Fukushima [22] (distance from Fukushima I: 35 km) 2020.650 4423.58 7102.66
Kuji Hitachi City 1990.890 10982.4 7113.6
Hitachinaka Hitachinaka City 1951.950 4823.72 7110.86
Fukushima [76] (distance from Fukushima I: 25 km) 1945.520 4418.47 7094.45
Fukushima [80] (distance from Fukushima I: 25 km) 1876.860 4418.47 7094.45
Momiyama Hokota City 1837.540 5501.62 7113.6
Fukushima [77] (distance from Fukushima I: 25 km) 1802.490 4418.47 7094.45
Horiguchi Hitachinaka City 1779.410 4806.65 7116.34
Onuma Hitachi City 1776.950 4096.04 7110.86
Fukushima [6] (distance from Fukushima I: 45 km) 1741.180 4423.58 7102.66
Tsukuriya Hokota City 1736.890 4628.02 7113.6
Radiation dose at Big palette Fukushima, Koriyama 1668.540 7045.2
Nemoto Hitachioomiya City 1633.190 5156.44 7110.86
Fukushima [13] (distance from Fukushima I: 40 km) 1624.150 4423.58 7102.66
Fukushima [23] (distance from Fukushima I: 35 km) 1551.750 4423.58 7102.66
Radiation dose at Tsukidatemachi kamitedo, Date 1545.300 7053.41
Fukushima [14] (distance from Fukushima I: 35 km) 1543.460 4423.58 7102.66
Radiation dose at JAEA Oarai (P12) 1512.140 7069.82
Radiation dose at Ose administration center, Koriyama 1494.270 7045.2
Araji Hokota City 1437.760 4638.38 7113.6
Ishigami Tokai Village 1431.690 4222.42 7113.6
Mawatari Hitachinaka City 1422.870 4877.62 7113.6
Radiation dose at JAEA Oarai (P11) 1399.370 7069.82
Onuki Oarai Town 1387.990 5064.82 7113.6
Sawa Hitachinaka City 1353.770 3825.71 7110.86
Toyooka Tokai Village 1321.760 4648.8 7113.6
Ajigaura Hitachinaka City 1313.890 4574.22 7110.86
Fukushima [5] (distance from Fukushima I: 45 km) 1282.090 4423.58 7102.66
Geiger Counter Feeds from Asao Kawasaki 1266.620 7023.31
Radiation dose at Tamokami elementary school, Koriyama 1256.140 7045.2
Isohama Oarai Town 1250.540 4416.58 7108.13
Ebisawa Ibaraki Town 1222.240 11988.7 7110.86
Muramatsu Tokai Village 1203.520 4690.42 7113.6
Kamitoda Hokota City 1184.740 3848.02 7113.6
Yanagisawa Hitachinaka City 1166.970 3919.27 7110.86
Tokushuku Hokota City 1159.730 3473.62 7113.6
Tasaki Hokota City 1153.300 4111.35 7083.5
Fukushima [20] (distance from Fukushima I: 45 km) 1145.390 4423.58 7102.66
Kadobe Naka City 1086.580 9335.63 7110.86
Radiation dose at Date city office, Date 1076.050 7047.94
Oshinobe Tokai Village 1041.340 4378.42 7113.6
Oba Mito City 1037.670 14383.2 7113.6
Godai Naka City 1031.270 3795.98 7113.6
Ishikawa Mito City 1030.810 4473.74 7116.34
Isobe Hitachiota City 1013.130 21590.4 7113.6
Yatabe Ibaraki Town 996.127 3754.42 7113.6
Radiation dose at Motomiya city office, Motomiya 992.703 7047.94
Fukushima [73] (distance from Fukushima I: 35 km) 981.984 4418.47 7094.45
Fukushima [75] (distance from Fukushima I: 45 km) 960.529 4418.47 7094.45
Yokobori Naka City 930.280 4399.2 7113.6
Sugaya Naka City 926.186 6721 7116.34
Kounosu Naka City 926.087 3432 7113.6
Funaishikawa Tokai Village 900.399 4555.2 7113.6
Nukada Naka City 899.900 4115.23 7108.13
Uridura Naka City 890.113 3928.18 7108.13
Shiraki Tsuruga City 881.330 8333.6 7116.34
Motokomezaki Naka City 880.851 3664.61 7080.77
Shiraki pass Tsuruga City 850.284 8728.94 7116.34
Radiation dose in Yamamoto 846.633 7069.82
Yoshizawa Mito City 837.646 3972.82 7113.6
Radiation dose at JAEA Oarai (P7) 831.135 7069.82
Mayumi Hitachiota City 828.119 3941.62 7113.6
Urasoko Tsuruga City 826.465 6918.64 7116.34
Nemoto Hitachioomiya City 825.588 4439.11 7110.86
Takenami Mihama Town 804.283 7261.97 7116.34
Radiation dose at JAEA Oarai (P15) 780.207 7069.82
Tateishi Tsuruga City 780.092 5753.43 7116.34
Radiation dose at JAEA Oarai (P14) 770.174 7069.82
Radiation dose at JAEA Oarai (P13) 769.612 7069.82
Ukishima Kawasaki Ward 735.475 13577.2 7116.34
Kume Hitachiota City 713.958 3858.38 7113.6
Radiation dose at JAEA Oarai (P2) 712.011 7069.82
Fukushima [74] (distance from Fukushima I: 35 km) 706.552 4418.47 7094.45
Nyuu Mihama Town 674.787 6616.94 7116.34
Fukushima [52] (distance from Fukushima I: 40 km) 672.743 4423.58 7102.66
Radiation dose in Iwanuma 670.242 7069.82
Fukushima [51] (distance from Fukushima I: 40 km) 665.376 4423.58 7102.66
Tsuruga Tsuruga City 655.360 5836.64 7116.34
Shiohama Kawasaki Ward 653.536 4661.01 7116.34
Radiation dose in Kakuda 649.863 7069.82
Sakajiri Mihama Town 649.252 7719.79 7116.34
North point of Kinki University Atomic Energy Research Instirute Station 639.566 4848.28 7116.34
Radiation dose in Onagawa (MP-2) 632.968 7067.09
Kumatori town Nishi primary school Station 631.491 5795.01 7116.34
Oshima Kawasaki Ward 630.402 4442.53 7116.34
Izumisano municipal Oike athletic field Station 629.920 6533.73 7116.34
Atom-kyoudou nursery school Station 625.566 6273.61 7116.34
South point of Kinki University Atomic Energy Research Instirute Station 625.202 5711.8 7116.34
Nakamachi Omaezaki City 623.494 7355.61 7116.34
Uraga Yokosuka City 622.492 3485.32 7116.34
Goritoge Shika Town 622.143 7813.42 7116.34
Kumatori town Minami primary school Station 606.134 6648.16 7116.34
Radiation dose at JAEA Oarai (P1) 603.643 7072.56
Yamanotedai-No.1 Park Station 599.140 6200.76 7116.34
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 595.502 7088.98
Noumi Shika Town 594.021 7730.15 7116.34
Radiation dose in Watari 591.851 7069.82
Hairando Yokosuka City 588.667 4369.68 7116.34
Fukushima [12] (distance from Fukushima I: 40 km) 588.291 4423.58 7102.66
Ningyotoge Kagamino Town 574.857 6200.76 7116.34
Ten-no Kagamino Town 569.960 7428.46 7116.34
Funagura Yokosuka City 563.909 4119.98 7116.34
Chidori Kawasaki Ward 560.211 3984.71 7116.34
Radiation dose at JAEA Oarai (P16) 556.365 7069.82
Shika Shika Town 551.376 7449.24 7116.34
Higashiosaka municipal Kamikosaka primary scool Station 550.277 4837.86 7116.34
Sahara Yokosuka City 547.404 3859.86 7116.34
Kazanashi Shika Town 545.377 6991.49 7116.34
Akasumi Shika Town 544.970 6398.46 7116.34
Kurahashi Maizuru City 540.820 5826.22 7116.34
Obama Obama City 540.809 5212.4 7116.34
Sakuragaike community hall Omaezaki City 540.772 7542.88 7116.34
Shirowa primary school Omaezaki City 535.692 7386.82 7116.34
Radiation dose at JAEA Oarai (P5) 529.759 7069.82
Uenohara Omaezaki City 529.333 7594.94 7116.34
Kumano Shika Town 529.019 7251.61 7116.34
Izumisano municipal Hineno filtration plant Station 527.471 6252.82 7116.34
Nishi-hamasada Matsue City 525.089 6923.48 7099.92
Kouno Minami-Echizen Town 525.028 5243.62 7116.34
Kurihama Yokosuka City 523.708 4171.98 7116.34
Osaka prefectural Kumatori off-site-center Station 522.808 5763.79 7116.34
Ogasa branch Kikugawa City 522.039 7684.14 7102.66
Izumisano municipal Hineno primary scool Station 518.181 5004.35 7116.34
Shirasuna Omaezaki City 499.479 7438.88 7116.34
Jitougata primary school Makinohara City 498.059 7137.12 7116.34
Kataku Matsue City 497.007 5545.31 7116.34
Nishihemi Yokosuka City 496.917 3329.26 7116.34
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 496.721 7088.98
Satsuma-sendai monitoring center Satsuma-sendai City 495.302 5462.1 7116.34
Otomi Takahama Town 494.821 6117.55 7116.34
Otsu Nanao City 493.895 6138.34 7116.34
The Observation point for comparison Tatsunokuchi 493.454 5056.34 7116.34
Hitsuhama Ohi Town 492.630 5691.01 7116.34
Kijiyama Misasa Town 489.284 5774.22 7116.34
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 487.055 7088.98
Hiraba Omaezaki City 485.878 7438.88 7116.34
Tayu Matsue City 484.956 5784.64 7116.34
Hamaokakita primary school Omaezaki City 484.537 7632.24 7102.66
Oitomi Ayabe City 474.670 7334.82 7116.34
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 472.017 7088.98
Kashiwazaki-shigai Kashiwazaki City 470.822 5836.64 7116.34
Mitsu Matsue City 466.897 5534.95 7116.34
Tonomachi Kawasaki Ward 463.967 7012.28 7116.34
Daitou branch Kakegawa City 463.829 7518.04 7102.66
Fukura Shika Town 462.493 6981.06 7116.34
Nagasawa Yokosuka City 462.365 4078.35 7116.34
The athletic field Station of Kinki University 461.661 4608.95 7116.34
Koura Matsue City 461.049 6606.52 7116.34
Sakurasan Ward Omaezaki City 459.434 7199.55 7116.34
Tsuchikawa Nanao City 458.915 6793.79 7116.34
Kumatori Town office Station 457.917 4754.65 7116.34
Shinkango Omaezaki City 449.013 8333.6 7116.34
Ogurui Takahama Town 448.279 5451.68 7116.34
Kusabue Omaezaki City 444.162 7855 7116.34
Omaezaki City monitoring center 443.946 7709.36 7116.34
Akawase Kagamino Town 442.246 4754.65 7116.34
Ibaraki 442.139 3491.71 7108.13
Hinode Town Yokosuka City 438.324 2746.66 7116.34
Nishiyama Kashiwazaki City 437.251 8260.75 7116.34
Kariwa Kariwa Village 436.307 6231.98 7116.34
Osaka prefectural Hineno high scool Station 435.745 5555.74 7116.34
Miyagawa Kashiwazaki City 435.245 6148.76 7116.34
Radiation dose in Natori 434.640 7069.82
Kami-koubu Matsue City 433.868 6044.7 7116.34
Shimo-Takamachi Kariwa Village 433.192 6783.43 7116.34
Osaka prefectural Sano supporting school Station 432.398 6055.13 7116.34
Arahama Kashiwazaki City 428.874 6336.04 7116.34
Doai Kashiwazaki City 425.681 5961.49 7116.34
Owashi Matsue City 424.452 5909.49 7116.34
Okayasu Maizuru City 422.568 6960.28 7116.34
Katsuyama Kariwa Village 421.280 6336.04 7116.34
Kita-koubu Matsue City 420.683 6481.67 7116.34
Kichisaka Maizuru City 413.065 8458.45 7116.34
Nagai Ohi Town 410.699 6152.08 7108.13
Shiokumi Maizuru City 407.938 10528.9 7116.34
Miyadome Ohi Town 407.831 5097.98 7116.34
Kariwa Kariwa Village 407.617 6564.94 7116.34
Ueno Satsuma-sendai City 394.248 4765.01 7116.34
Power Station-South 389.191 6939.49 7116.34
Radiation dose at JAEA Oarai (P6) 386.963 7069.82
Power Station- 385.546 6773 7116.34
Takae Satsuma-sendai City 379.551 4827.44 7116.34
Hokawaduura Genkai Town 378.015 7350.43 7116.34
Kou Itimatsu Suetsugu 377.929 5306.04 7116.34
Minato Satsuma-sendai City 377.656 4421.68 7116.34
Iwanai Iwanai Town 376.336 7207.2 7113.6
Hattari Kyowa Town 373.047 7009.58 7113.6
Chatsu Tomari Village 371.011 6697.58 7113.6
Oyama Maizuru City 358.223 6096.76 7116.34
Kodaira Satsuma-sendai City 355.545 4473.74 7116.34
Kayanuma Tomari Village 354.809 5959.2 7113.6
Anojiri Obama City 353.215 4993.92 7116.34
Kushi Genkai Town 349.738 10143.9 7116.34
Yamaguchi 348.715 7981.06 7108.13
Sadahongou Matsue City 348.228 6211.19 7116.34
Sakibe Karatsu City 347.801 9613.3 7116.34
Hirao Genkai Town 343.814 10133.5 7116.34
The Meteorological Obsevatory of kyowa Town 343.275 6645.6 7113.6
Minami-Horoni Kyowa Town 335.180 6229.58 7113.6
Kounoura Takahama Town 330.353 5264.4 7116.34
Kyoudomarisaki Karatsu City 328.622 10300 7116.34
Horikappu Jinja Tomari Village 328.230 6447.98 7113.6
Hukada-kita Matsue City 327.031 5108.34 7116.34
Radiation dose in KEK, Tsukuba 326.240 7088.98
Herokaruusu Tomari Village 324.242 6687.22 7113.6
Yorita Satsuma-sendai City 323.218 5233.19 7116.34
Kamoenai Kamoenai Village 322.032 5647.2 7113.6
Radiation dose in Onagawa (MP-6) 316.267 7067.09
Imamura Genkai Town 314.749 87289.4 7116.34
Yamanaka Takahama Town 314.185 6793.79 7116.34
Sendai (Miyagi) 312.585 3198.66 7108.13
Radiation dose in Onagawa (MP-1) 300.147 7067.09
Gumisaki Satsuma-sendai City 295.693 4224.04 7116.34
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 286.142 7088.98
Aomori Aomori City 285.372 4295.18 7113.6
Misawa City hall Misawa City 283.728 8330.4 7113.6
Kashu Ikata Town 277.173 4359.26 7116.34
Noheji Town Office Noheji Town 272.004 3681.6 7113.6
Takasimamati 271.103 4640.16 7116.34
Radiation dose in Onagawa (MP-3) 270.563 7067.09
Kucho Ikata Town 269.545 3849.5 7116.34
Radiation dose in Marumori 269.436 7069.82
Kawanagata Ikata Town 266.821 3755.86 7116.34
Tochigi 260.733 4177.58 7108.13
Chikagawa Mutu City 256.719 4794.38 7113.6
Yokohama Town Office Yokohama Town 254.846 5876.02 7113.6
Tokyo 251.877 4925.81 7108.13
Hiranuma Rokkasho Village 251.186 3858.38 7113.6
Taisei Ikata Town 246.293 2819.5 7116.34
Chitose-daira Rokkasho Village 245.868 4160.02 7113.6
Gifu 243.951 6858.72 7108.13
Fukkoshi Yokohama Town 243.102 4035.22 7113.6
Shimane 240.651 6858.72 7108.13
Sunagomata Higashidoori Village 238.012 5834.4 7113.6
Obuchi Rokkasho Village 237.506 4638.38 7113.6
Tomari Rokkasho Village 230.636 6489.6 7113.6
kanagawa 226.339 4302.29 7108.13
Saitama 219.770 3741.12 7108.13
Ikatagoshi Ikata Town 217.515 3547.74 7116.34
Touhoku Branch office Touhoku Town 215.416 3359.18 7113.6
Radiation dose at Tohoku University 214.824 7069.82
Odanosawa Higashidoori Village 210.287 4648.8 7113.6
Kagawa 205.829 4801.1 7108.13
Oippe Higashidoori Village 205.182 4004.02 7113.6
Oita 200.921 5299.92 7108.13
Touhoku Town office Touhoku Town 200.811 15537.6 7113.6
Kuchogoshi Ikata Town 198.646 3599.8 7116.34
Minatoura Ikata Town 186.776 3235.62 7116.34
Radiation dose in Koyadori, Ojika 184.905 7064.35
Toyama 184.580 9165.74 7108.13
Fukushima [9] (distance from Fukushima I: 45 km) 184.232 4423.58 7102.66
Radiation dose in Tukahama, Ojika 183.417 7064.35
Chiba 182.407 2743.49 7108.13
Nara 182.387 4988.16 7108.13
Okayama 181.976 6484.61 7108.13
Yamagata 181.598 5112.86 7108.13
Ehime 180.745 4614.05 7108.13
Ishikawa 180.445 7949.88 7108.13
Niigata 177.483 9539.86 7108.13
Hiroshima 176.816 4302.29 7108.13
Mie 174.867 4919.57 7108.13
Fukui 170.045 6048.14 7108.13
Radiation dose in Terama, Ojika 168.036 7064.35
Yamanashi 164.561 3990.53 7108.13
Nagano 162.242 6073.08 7108.13
Saga 161.421 5362.27 7108.13
Tottori 161.392 4925.81 7108.13
Radiation dose in Enoshima, Ojika 160.091 7064.35
Osaka 159.103 3803.47 7108.13
Ibaraki-city Environment 157.249 7023.31
Aichi 149.345 4614.05 7108.13
Toyonoura Ikata Town 149.214 3714.23 7116.34
Shizuoka 148.639 4769.93 7108.13
Kyoto 144.522 5424.62 7108.13
Kagoshima 144.449 5879.79 7108.13
Tokushima 143.627 4177.58 7108.13
Gunma 143.572 2805.84 7108.13
Hyogo 139.710 4738.75 7108.13
Fukuoka 136.511 4925.81 7108.13
Wakayama 133.857 3491.71 7108.13
Radiation at Tamaki-cho Mie Japan 133.138 7023.31
Akita 132.832 5362.27 7108.13
Shiga 124.919 3803.47 7108.13
Nagasaki 109.459 4302.29 7108.13
Hokkaido 109.189 6546.96 7108.13
Kumamoto 103.568 4177.58 7108.13
Aomori 101.819 6359.9 7108.13
Miyazaki 100.354 4140.17 7108.13
Kochi 95.931 4738.75 7108.13
Fukushima [35] (distance from Fukushima I: 35 km) 91.917 4415.06 7088.98
Iwate 90.324 5237.57 7108.13
Environment Feeds from Ohta 83.623 7023.31
Okinawa 82.305 3585.24 7108.13
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