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Accumulated absorbed dose rate - T=13.03.2011 - 29.03.2015(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 3956.26
Fukushima I MP8 570942.000 3956.26
Fukushima I MP6 240668.000 3956.26
Yamada Futaba Town 176983.000 2948.07 3513.02
Fukushima I MP2 140420.000 3956.26
Fukushima I MP5 111325.000 3956.26
Fukushima [32] (distance from Fukushima I: 30 km) 101500.000 2508.29 4027.39
Fukushima I MP3 93730.602 3956.26
Fukushima I MP4 86821.500 3956.26
Fukushima [33] (distance from Fukushima I: 30 km) 77197.703 2508.29 4027.39
Fukushima [79] (distance from Fukushima I: 40 km) 54008.602 2457.17 3945.31
Fukushima [31] (distance from Fukushima I: 30 km) 40677.398 2508.29 4027.39
Ono Okuma Town 38610.500 2722.07 3513.02
Shinzan Futaba Town 38332.801 2470.43 3513.02
Fukushima I MP1 31496.801 3956.26
Yonomori Tomioka Town 29815.900 2814.52 3513.02
Fukushima [46] (distance from Fukushima I: 20 km) 28842.500 2508.29 4027.39
Tomioka Tomioka Town 25324.500 3030.23 3513.02
Fukushima [62] (distance from Fukushima I: 40 km) 16464.100 2508.29 4027.39
Fukushima [61] (distance from Fukushima I: 40 km) 13102.800 2508.29 4027.39
Shimo-Kooriyama Tomioka Town 13057.000 3009.71 3513.02
Fukushima [21] (distance from Fukushima I: 30 km) 12103.800 2508.29 4027.39
Fukushima [3] (distance from Fukushima I: 45 km) 11985.000 2508.29 4027.39
Kami-kooriyama Tomioka Town 11803.900 2362.57 3513.02
Fukushima II MP3 11060.600 3956.26
Fukushima II MP1 10903.000 3956.26
Kooriyama Futaba Town 10352.900 2752.89 3513.02
Fukushima II MP4 9696.330 3956.26
Fukushima [34] (distance from Fukushima I: 30 km) 9540.450 2504.88 4021.92
Fukushima II MP5 9382.150 3956.26
Fukushima [2] (distance from Fukushima I: 55 km) 8841.760 2508.29 4027.39
Matsudate Naraha Town 8410.890 3215.13 3513.02
Shigeoka Naraha Town 8115.970 3554.1 3513.02
Fukushima II MP2 7875.320 3956.26
Namie Namie Town 7321.210 2593.69 3513.02
Radiation dose at Shirasawa branch office, Motomiya 7287.920 3972.67
Fukushima II MP6 7062.690 3956.26
Fukushima II MP7 6511.580 3953.52
Fukushima [1] (distance from Fukushima I: 60 km) 5615.310 2508.29 4027.39
Fukushima [11] (distance from Fukushima I: 40 km) 5491.310 2508.29 4027.39
Fukushima [63] (distance from Fukushima I: 45 km) 5448.820 2508.29 4027.39
Fukushima [45] (distance from Fukushima I: 20 km) 3981.200 2508.29 4027.39
Fukushima [42] (distance from Fukushima I: 30 km) 3850.600 2508.29 4027.39
Fukushima [10] (distance from Fukushima I: 40 km) 3734.160 2508.29 4027.39
Fukushima [78] (distance from Fukushima I: 45 km) 3716.820 2503.18 4019.18
Futatsunuma Hirono Town 3520.340 3081.6 3513.02
Fukushima [4] (distance from Fukushima I: 50 km) 3386.310 2508.29 4027.39
Fukushima [7] (distance from Fukushima I: 45 km) 3313.930 2508.29 4027.39
Radiation dose at Koriyama joint government building, Koriyama 3232.890 3969.94
Fukushima [15] (distance from Fukushima I: 35 km) 3178.670 2508.29 4027.39
Kiyohashi Namie Town 3162.000 2275.24 3513.02
Fukushima [71] (distance from Fukushima I: 25 km) 3161.650 2503.18 4019.18
Radiation dose at Agricultural center, Koriyama 3128.960 3969.94
Fukushima [41] (distance from Fukushima I: 20 km) 3111.490 2508.29 4027.39
Radiation dose at Koriyama city office, Koriyama 2803.520 3969.94
Fukushima [44] (distance from Fukushima I: 30 km) 2535.550 2508.29 4027.39
Fukushima [72] (distance from Fukushima I: 30 km) 2344.620 2503.18 4019.18
Fukushima [43] (distance from Fukushima I: 20 km) 2244.110 2508.29 4027.39
Yamadaoka Naraha Town 2205.340 2732.36 3513.02
Radiation dose at Iwane Fureai Plaza, Motomiya 2169.060 3972.67
Fukushima [22] (distance from Fukushima I: 35 km) 2020.650 2508.29 4027.39
Kuji Hitachi City 1990.890 6234.62 4038.34
Hitachinaka Hitachinaka City 1951.950 2737.59 4035.6
Fukushima [76] (distance from Fukushima I: 25 km) 1945.520 2503.18 4019.18
Fukushima [80] (distance from Fukushima I: 25 km) 1876.860 2503.18 4019.18
Momiyama Hokota City 1837.540 3123.23 4038.34
Fukushima [77] (distance from Fukushima I: 25 km) 1802.490 2503.18 4019.18
Horiguchi Hitachinaka City 1779.410 2729.5 4041.07
Onuma Hitachi City 1776.950 2324.61 4035.6
Fukushima [6] (distance from Fukushima I: 45 km) 1741.180 2508.29 4027.39
Tsukuriya Hokota City 1736.890 2627.29 4038.34
Radiation dose at Big palette Fukushima, Koriyama 1668.540 3969.94
Nemoto Hitachioomiya City 1633.190 2926.41 4035.6
Fukushima [13] (distance from Fukushima I: 40 km) 1624.150 2508.29 4027.39
Fukushima [23] (distance from Fukushima I: 35 km) 1551.750 2508.29 4027.39
Radiation dose at Tsukidatemachi kamitedo, Date 1545.300 3978.14
Fukushima [14] (distance from Fukushima I: 35 km) 1543.460 2508.29 4027.39
Radiation dose at JAEA Oarai (P12) 1512.140 3994.56
Radiation dose at Ose administration center, Koriyama 1494.270 3969.94
Araji Hokota City 1437.760 2633.17 4038.34
Ishigami Tokai Village 1431.690 2397.04 4038.34
Mawatari Hitachinaka City 1422.870 2768.99 4038.34
Radiation dose at JAEA Oarai (P11) 1399.370 3994.56
Onuki Oarai Town 1387.990 2875.26 4038.34
Sawa Hitachinaka City 1353.770 2171.19 4035.6
Toyooka Tokai Village 1321.760 2639.09 4038.34
Ajigaura Hitachinaka City 1313.890 2595.99 4035.6
Fukushima [5] (distance from Fukushima I: 45 km) 1282.090 2508.29 4027.39
Geiger Counter Feeds from Asao Kawasaki 1266.620 3948.05
Radiation dose at Tamokami elementary school, Koriyama 1256.140 3969.94
Isohama Oarai Town 1250.540 2505.79 4032.86
Ebisawa Ibaraki Town 1222.240 6803.88 4035.6
Muramatsu Tokai Village 1203.520 2662.72 4038.34
Kamitoda Hokota City 1184.740 2184.49 4038.34
Yanagisawa Hitachinaka City 1166.970 2224.29 4035.6
Tokushuku Hokota City 1159.730 1971.95 4038.34
Tasaki Hokota City 1153.300 2326.43 4008.24
Fukushima [20] (distance from Fukushima I: 45 km) 1145.390 2508.29 4027.39
Kadobe Naka City 1086.580 5298.21 4035.6
Radiation dose at Date city office, Date 1076.050 3972.67
Oshinobe Tokai Village 1041.340 2485.6 4038.34
Oba Mito City 1037.670 8165.23 4038.34
Godai Naka City 1031.270 2154.95 4038.34
Ishikawa Mito City 1030.810 2540.45 4041.07
Isobe Hitachiota City 1013.130 12256.7 4038.34
Yatabe Ibaraki Town 996.127 2131.36 4038.34
Radiation dose at Motomiya city office, Motomiya 992.703 3972.67
Fukushima [73] (distance from Fukushima I: 35 km) 981.984 2503.18 4019.18
Fukushima [75] (distance from Fukushima I: 45 km) 960.529 2503.18 4019.18
Yokobori Naka City 930.280 2497.39 4038.34
Sugaya Naka City 926.186 3816.58 4041.07
Kounosu Naka City 926.087 1948.32 4038.34
Funaishikawa Tokai Village 900.399 2585.95 4038.34
Nukada Naka City 899.900 2334.82 4032.86
Uridura Naka City 890.113 2228.69 4032.86
Shiraki Tsuruga City 881.330 4732.31 4041.07
Motokomezaki Naka City 880.851 2073.02 4005.5
Shiraki pass Tsuruga City 850.284 4956.8 4041.07
Radiation dose in Yamamoto 846.633 3994.56
Yoshizawa Mito City 837.646 2255.34 4038.34
Radiation dose at JAEA Oarai (P7) 831.135 3994.56
Mayumi Hitachiota City 828.119 2237.63 4038.34
Urasoko Tsuruga City 826.465 3928.81 4041.07
Nemoto Hitachioomiya City 825.588 2519.31 4035.6
Takenami Mihama Town 804.283 4123.77 4041.07
Radiation dose at JAEA Oarai (P15) 780.207 3994.56
Tateishi Tsuruga City 780.092 3267.14 4041.07
Radiation dose at JAEA Oarai (P14) 770.174 3994.56
Radiation dose at JAEA Oarai (P13) 769.612 3994.56
Ukishima Kawasaki Ward 735.475 7709.94 4041.07
Kume Hitachiota City 713.958 2190.37 4038.34
Radiation dose at JAEA Oarai (P2) 712.011 3994.56
Fukushima [74] (distance from Fukushima I: 35 km) 706.552 2503.18 4019.18
Nyuu Mihama Town 674.787 3757.49 4041.07
Fukushima [52] (distance from Fukushima I: 40 km) 672.743 2508.29 4027.39
Radiation dose in Iwanuma 670.242 3994.56
Fukushima [51] (distance from Fukushima I: 40 km) 665.376 2508.29 4027.39
Tsuruga Tsuruga City 655.360 3314.39 4041.07
Shiohama Kawasaki Ward 653.536 2646.8 4041.07
Radiation dose in Kakuda 649.863 3994.56
Sakajiri Mihama Town 649.252 4383.75 4041.07
North point of Kinki University Atomic Energy Research Instirute Station 639.566 2753.14 4041.07
Radiation dose in Onagawa (MP-2) 632.968 3991.82
Kumatori town Nishi primary school Station 631.491 3290.74 4041.07
Oshima Kawasaki Ward 630.402 2522.73 4041.07
Izumisano municipal Oike athletic field Station 629.920 3710.24 4041.07
Atom-kyoudou nursery school Station 625.566 3562.52 4041.07
South point of Kinki University Atomic Energy Research Instirute Station 625.202 3243.49 4041.07
Nakamachi Omaezaki City 623.494 4176.94 4041.07
Uraga Yokosuka City 622.492 1979.17 4041.07
Goritoge Shika Town 622.143 4436.92 4041.07
Kumatori town Minami primary school Station 606.134 3775.21 4041.07
Radiation dose at JAEA Oarai (P1) 603.643 3997.3
Yamanotedai-No.1 Park Station 599.140 3521.16 4041.07
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 595.502 4013.71
Noumi Shika Town 594.021 4389.63 4041.07
Radiation dose in Watari 591.851 3994.56
Hairando Yokosuka City 588.667 2481.36 4041.07
Fukushima [12] (distance from Fukushima I: 40 km) 588.291 2508.29 4027.39
Ningyotoge Kagamino Town 574.857 3521.16 4041.07
Ten-no Kagamino Town 569.960 4218.31 4041.07
Funagura Yokosuka City 563.909 2339.57 4041.07
Chidori Kawasaki Ward 560.211 2262.75 4041.07
Radiation dose at JAEA Oarai (P16) 556.365 3994.56
Shika Shika Town 551.376 4230.12 4041.07
Higashiosaka municipal Kamikosaka primary scool Station 550.277 2747.22 4041.07
Sahara Yokosuka City 547.404 2191.86 4041.07
Kazanashi Shika Town 545.377 3970.18 4041.07
Akasumi Shika Town 544.970 3633.42 4041.07
Kurahashi Maizuru City 540.820 3308.47 4041.07
Obama Obama City 540.809 2959.91 4041.07
Sakuragaike community hall Omaezaki City 540.772 4283.29 4041.07
Shirowa primary school Omaezaki City 535.692 4194.67 4041.07
Radiation dose at JAEA Oarai (P5) 529.759 3994.56
Uenohara Omaezaki City 529.333 4312.85 4041.07
Kumano Shika Town 529.019 4117.89 4041.07
Izumisano municipal Hineno filtration plant Station 527.471 3550.72 4041.07
Nishi-hamasada Matsue City 525.089 3924.64 4024.66
Kouno Minami-Echizen Town 525.028 2977.63 4041.07
Kurihama Yokosuka City 523.708 2369.1 4041.07
Osaka prefectural Kumatori off-site-center Station 522.808 3273.02 4041.07
Ogasa branch Kikugawa City 522.039 4357.11 4027.39
Izumisano municipal Hineno primary scool Station 518.181 2841.76 4041.07
Shirasuna Omaezaki City 499.479 4224.23 4041.07
Jitougata primary school Makinohara City 498.059 4052.88 4041.07
Kataku Matsue City 497.007 3148.95 4041.07
Nishihemi Yokosuka City 496.917 1890.55 4041.07
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 496.721 4013.71
Satsuma-sendai monitoring center Satsuma-sendai City 495.302 3101.7 4041.07
Otomi Takahama Town 494.821 3473.9 4041.07
Otsu Nanao City 493.895 3485.71 4041.07
The Observation point for comparison Tatsunokuchi 493.454 2871.29 4041.07
Hitsuhama Ohi Town 492.630 3231.69 4041.07
Kijiyama Misasa Town 489.284 3278.94 4041.07
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 487.055 4013.71
Hiraba Omaezaki City 485.878 4224.23 4041.07
Tayu Matsue City 484.956 3284.86 4041.07
Hamaokakita primary school Omaezaki City 484.537 4327.68 4027.39
Oitomi Ayabe City 474.670 4165.14 4041.07
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 472.017 4013.71
Kashiwazaki-shigai Kashiwazaki City 470.822 3314.39 4041.07
Mitsu Matsue City 466.897 3143.07 4041.07
Tonomachi Kawasaki Ward 463.967 3981.98 4041.07
Daitou branch Kakegawa City 463.829 4262.92 4027.39
Fukura Shika Town 462.493 3964.26 4041.07
Nagasawa Yokosuka City 462.365 2315.92 4041.07
The athletic field Station of Kinki University 461.661 2617.23 4041.07
Koura Matsue City 461.049 3751.57 4041.07
Sakurasan Ward Omaezaki City 459.434 4088.32 4041.07
Tsuchikawa Nanao City 458.915 3857.91 4041.07
Kumatori Town office Station 457.917 2699.97 4041.07
Shinkango Omaezaki City 449.013 4732.31 4041.07
Ogurui Takahama Town 448.279 3095.78 4041.07
Kusabue Omaezaki City 444.162 4460.53 4041.07
Omaezaki City monitoring center 443.946 4377.83 4041.07
Akawase Kagamino Town 442.246 2699.97 4041.07
Ibaraki 442.139 1981.06 4032.86
Hinode Town Yokosuka City 438.324 1559.71 4041.07
Nishiyama Kashiwazaki City 437.251 4690.94 4041.07
Kariwa Kariwa Village 436.307 3538.88 4041.07
Osaka prefectural Hineno high scool Station 435.745 3154.87 4041.07
Miyagawa Kashiwazaki City 435.245 3491.63 4041.07
Radiation dose in Natori 434.640 3994.56
Kami-koubu Matsue City 433.868 3432.54 4041.07
Shimo-Takamachi Kariwa Village 433.192 3852.03 4041.07
Osaka prefectural Sano supporting school Station 432.398 3438.46 4041.07
Arahama Kashiwazaki City 428.874 3597.97 4041.07
Doai Kashiwazaki City 425.681 3385.28 4041.07
Owashi Matsue City 424.452 3355.76 4041.07
Okayasu Maizuru City 422.568 3952.45 4041.07
Katsuyama Kariwa Village 421.280 3597.97 4041.07
Kita-koubu Matsue City 420.683 3680.67 4041.07
Kichisaka Maizuru City 413.065 4803.2 4041.07
Nagai Ohi Town 410.699 3490.44 4032.86
Shiokumi Maizuru City 407.938 5978.91 4041.07
Miyadome Ohi Town 407.831 2894.93 4041.07
Kariwa Kariwa Village 407.617 3727.96 4041.07
Ueno Satsuma-sendai City 394.248 2705.85 4041.07
Power Station-South 389.191 3940.65 4041.07
Radiation dose at JAEA Oarai (P6) 386.963 3994.56
Power Station- 385.546 3846.11 4041.07
Takae Satsuma-sendai City 379.551 2741.3 4041.07
Hokawaduura Genkai Town 378.015 4174 4041.07
Kou Itimatsu Suetsugu 377.929 3013.08 4041.07
Minato Satsuma-sendai City 377.656 2510.89 4041.07
Iwanai Iwanai Town 376.336 4091.47 4038.34
Hattari Kyowa Town 373.047 3979.28 4038.34
Chatsu Tomari Village 371.011 3802.16 4038.34
Oyama Maizuru City 358.223 3462.1 4041.07
Kodaira Satsuma-sendai City 355.545 2540.45 4041.07
Kayanuma Tomari Village 354.809 3382.99 4038.34
Anojiri Obama City 353.215 2835.84 4041.07
Kushi Genkai Town 349.738 5760.3 4041.07
Yamaguchi 348.715 4528.13 4032.86
Sadahongou Matsue City 348.228 3527.08 4041.07
Sakibe Karatsu City 347.801 5458.99 4041.07
Hirao Genkai Town 343.814 5754.38 4041.07
The Meteorological Obsevatory of kyowa Town 343.275 3772.66 4038.34
Minami-Horoni Kyowa Town 335.180 3536.48 4038.34
Kounoura Takahama Town 330.353 2989.44 4041.07
Kyoudomarisaki Karatsu City 328.622 5848.92 4041.07
Horikappu Jinja Tomari Village 328.230 3660.47 4038.34
Hukada-kita Matsue City 327.031 2900.82 4041.07
Radiation dose in KEK, Tsukuba 326.240 4013.71
Herokaruusu Tomari Village 324.242 3796.28 4038.34
Yorita Satsuma-sendai City 323.218 2971.71 4041.07
Kamoenai Kamoenai Village 322.032 3205.87 4038.34
Radiation dose in Onagawa (MP-6) 316.267 3991.82
Imamura Genkai Town 314.749 49568 4041.07
Yamanaka Takahama Town 314.185 3857.91 4041.07
Sendai (Miyagi) 312.585 1814.79 4032.86
Radiation dose in Onagawa (MP-1) 300.147 3991.82
Gumisaki Satsuma-sendai City 295.693 2398.66 4041.07
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 286.142 4013.71
Aomori Aomori City 285.372 2438.34 4038.34
Misawa City hall Misawa City 283.728 4729.1 4038.34
Kashu Ikata Town 277.173 2475.44 4041.07
Noheji Town Office Noheji Town 272.004 2090.02 4038.34
Takasimamati 271.103 2634.96 4041.07
Radiation dose in Onagawa (MP-3) 270.563 3991.82
Kucho Ikata Town 269.545 2185.97 4041.07
Radiation dose in Marumori 269.436 3994.56
Kawanagata Ikata Town 266.821 2132.8 4041.07
Tochigi 260.733 2370.19 4032.86
Chikagawa Mutu City 256.719 2721.73 4038.34
Yokohama Town Office Yokohama Town 254.846 3335.77 4038.34
Tokyo 251.877 2794.7 4032.86
Hiranuma Rokkasho Village 251.186 2190.37 4038.34
Taisei Ikata Town 246.293 1601.08 4041.07
Chitose-daira Rokkasho Village 245.868 2361.61 4038.34
Gifu 243.951 3891.36 4032.86
Fukkoshi Yokohama Town 243.102 2290.76 4038.34
Shimane 240.651 3891.36 4032.86
Sunagomata Higashidoori Village 238.012 3312.14 4038.34
Obuchi Rokkasho Village 237.506 2633.17 4038.34
Tomari Rokkasho Village 230.636 3684.1 4038.34
kanagawa 226.339 2440.94 4032.86
Saitama 219.770 2122.56 4032.86
Ikatagoshi Ikata Town 217.515 2014.62 4041.07
Touhoku Branch office Touhoku Town 215.416 1906.98 4038.34
Radiation dose at Tohoku University 214.824 3994.56
Odanosawa Higashidoori Village 210.287 2639.09 4038.34
Kagawa 205.829 2723.95 4032.86
Oippe Higashidoori Village 205.182 2273.05 4038.34
Oita 200.921 3006.96 4032.86
Touhoku Town office Touhoku Town 200.811 8820.58 4038.34
Kuchogoshi Ikata Town 198.646 2044.18 4041.07
Minatoura Ikata Town 186.776 1837.38 4041.07
Radiation dose in Koyadori, Ojika 184.905 3989.09
Toyama 184.580 5200.27 4032.86
Fukushima [9] (distance from Fukushima I: 45 km) 184.232 2508.29 4027.39
Radiation dose in Tukahama, Ojika 183.417 3989.09
Chiba 182.407 1556.54 4032.86
Nara 182.387 2830.08 4032.86
Okayama 181.976 3679.1 4032.86
Yamagata 181.598 2900.83 4032.86
Ehime 180.745 2617.82 4032.86
Ishikawa 180.445 4510.44 4032.86
Niigata 177.483 5412.53 4032.86
Hiroshima 176.816 2440.94 4032.86
Mie 174.867 2791.17 4032.86
Fukui 170.045 3431.47 4032.86
Radiation dose in Terama, Ojika 168.036 3989.09
Yamanashi 164.561 2264.06 4032.86
Nagano 162.242 3445.62 4032.86
Saga 161.421 3042.34 4032.86
Tottori 161.392 2794.7 4032.86
Radiation dose in Enoshima, Ojika 160.091 3989.09
Osaka 159.103 2157.94 4032.86
Ibaraki-city Environment 157.249 3948.05
Aichi 149.345 2617.82 4032.86
Toyonoura Ikata Town 149.214 2109.16 4041.07
Shizuoka 148.639 2706.26 4032.86
Kyoto 144.522 3077.71 4032.86
Kagoshima 144.449 3335.96 4032.86
Tokushima 143.627 2370.19 4032.86
Gunma 143.572 1591.92 4032.86
Hyogo 139.710 2688.58 4032.86
Fukuoka 136.511 2794.7 4032.86
Wakayama 133.857 1981.06 4032.86
Radiation at Tamaki-cho Mie Japan 133.138 3948.05
Akita 132.832 3042.34 4032.86
Shiga 124.919 2157.94 4032.86
Nagasaki 109.459 2440.94 4032.86
Hokkaido 109.189 3714.48 4032.86
Kumamoto 103.568 2370.19 4032.86
Aomori 101.819 3608.35 4032.86
Miyazaki 100.354 2348.97 4032.86
Kochi 95.931 2688.58 4032.86
Fukushima [35] (distance from Fukushima I: 35 km) 91.917 2499.77 4013.71
Iwate 90.324 2971.58 4032.86
Environment Feeds from Ohta 83.623 3948.05
Okinawa 82.305 2034.12 4032.86
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