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Accumulated absorbed dose rate - T=13.03.2011 - 10.02.2016(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 4826.3
Fukushima I MP8 570942.000 4826.3
Fukushima I MP6 240668.000 4826.3
Yamada Futaba Town 176983.000 3678.2 4383.07
Fukushima I MP2 140420.000 4826.3
Fukushima I MP5 111325.000 4826.3
Fukushima [32] (distance from Fukushima I: 30 km) 101500.000 3050.16 4897.44
Fukushima I MP3 93730.602 4826.3
Fukushima I MP4 86821.500 4826.3
Fukushima [33] (distance from Fukushima I: 30 km) 77197.703 3050.16 4897.44
Fukushima [79] (distance from Fukushima I: 40 km) 54008.602 2999.04 4815.36
Fukushima [31] (distance from Fukushima I: 30 km) 40677.398 3050.16 4897.44
Ono Okuma Town 38610.500 3396.23 4383.07
Shinzan Futaba Town 38332.801 3082.26 4383.07
Fukushima I MP1 31496.801 4826.3
Yonomori Tomioka Town 29815.900 3511.57 4383.07
Fukushima [46] (distance from Fukushima I: 20 km) 28842.500 3050.16 4897.44
Tomioka Tomioka Town 25324.500 3780.71 4383.07
Fukushima [62] (distance from Fukushima I: 40 km) 16464.100 3050.16 4897.44
Fukushima [61] (distance from Fukushima I: 40 km) 13102.800 3050.16 4897.44
Shimo-Kooriyama Tomioka Town 13057.000 3755.1 4383.07
Fukushima [21] (distance from Fukushima I: 30 km) 12103.800 3050.16 4897.44
Fukushima [3] (distance from Fukushima I: 45 km) 11985.000 3050.16 4897.44
Kami-kooriyama Tomioka Town 11803.900 2947.69 4383.07
Fukushima II MP3 11060.600 4826.3
Fukushima II MP1 10903.000 4826.3
Kooriyama Futaba Town 10352.900 3434.68 4383.07
Fukushima II MP4 9696.330 4826.3
Fukushima [34] (distance from Fukushima I: 30 km) 9540.450 3046.75 4891.97
Fukushima II MP5 9382.150 4826.3
Fukushima [2] (distance from Fukushima I: 55 km) 8841.760 3050.16 4897.44
Matsudate Naraha Town 8410.890 4011.4 4383.07
Shigeoka Naraha Town 8115.970 4434.32 4383.07
Fukushima II MP2 7875.320 4826.3
Namie Namie Town 7321.210 3236.05 4383.07
Radiation dose at Shirasawa branch office, Motomiya 7287.920 4842.72
Fukushima II MP6 7062.690 4826.3
Fukushima II MP7 6511.580 4823.57
Fukushima [1] (distance from Fukushima I: 60 km) 5615.310 3050.16 4897.44
Fukushima [11] (distance from Fukushima I: 40 km) 5491.310 3050.16 4897.44
Fukushima [63] (distance from Fukushima I: 45 km) 5448.820 3050.16 4897.44
Fukushima [45] (distance from Fukushima I: 20 km) 3981.200 3050.16 4897.44
Fukushima [42] (distance from Fukushima I: 30 km) 3850.600 3050.16 4897.44
Fukushima [10] (distance from Fukushima I: 40 km) 3734.160 3050.16 4897.44
Fukushima [78] (distance from Fukushima I: 45 km) 3716.820 3045.05 4889.23
Futatsunuma Hirono Town 3520.340 3844.8 4383.07
Fukushima [4] (distance from Fukushima I: 50 km) 3386.310 3050.16 4897.44
Fukushima [7] (distance from Fukushima I: 45 km) 3313.930 3050.16 4897.44
Radiation dose at Koriyama joint government building, Koriyama 3232.890 4839.98
Fukushima [15] (distance from Fukushima I: 35 km) 3178.670 3050.16 4897.44
Kiyohashi Namie Town 3162.000 2838.73 4383.07
Fukushima [71] (distance from Fukushima I: 25 km) 3161.650 3045.05 4889.23
Radiation dose at Agricultural center, Koriyama 3128.960 4839.98
Fukushima [41] (distance from Fukushima I: 20 km) 3111.490 3050.16 4897.44
Radiation dose at Koriyama city office, Koriyama 2803.520 4839.98
Fukushima [44] (distance from Fukushima I: 30 km) 2535.550 3050.16 4897.44
Fukushima [72] (distance from Fukushima I: 30 km) 2344.620 3045.05 4889.23
Fukushima [43] (distance from Fukushima I: 20 km) 2244.110 3050.16 4897.44
Yamadaoka Naraha Town 2205.340 3409.07 4383.07
Radiation dose at Iwane Fureai Plaza, Motomiya 2169.060 4842.72
Fukushima [22] (distance from Fukushima I: 35 km) 2020.650 3050.16 4897.44
Kuji Hitachi City 1990.890 7577.86 4908.38
Hitachinaka Hitachinaka City 1951.950 3327.79 4905.65
Fukushima [76] (distance from Fukushima I: 25 km) 1945.520 3045.05 4889.23
Fukushima [80] (distance from Fukushima I: 25 km) 1876.860 3045.05 4889.23
Momiyama Hokota City 1837.540 3796.12 4908.38
Fukushima [77] (distance from Fukushima I: 25 km) 1802.490 3045.05 4889.23
Horiguchi Hitachinaka City 1779.410 3317.16 4911.12
Onuma Hitachi City 1776.950 2825.78 4905.65
Fukushima [6] (distance from Fukushima I: 45 km) 1741.180 3050.16 4897.44
Tsukuriya Hokota City 1736.890 3193.33 4908.38
Radiation dose at Big palette Fukushima, Koriyama 1668.540 4839.98
Nemoto Hitachioomiya City 1633.190 3557.33 4905.65
Fukushima [13] (distance from Fukushima I: 40 km) 1624.150 3050.16 4897.44
Fukushima [23] (distance from Fukushima I: 35 km) 1551.750 3050.16 4897.44
Radiation dose at Tsukidatemachi kamitedo, Date 1545.300 4848.19
Fukushima [14] (distance from Fukushima I: 35 km) 1543.460 3050.16 4897.44
Radiation dose at JAEA Oarai (P12) 1512.140 4864.61
Radiation dose at Ose administration center, Koriyama 1494.270 4839.98
Araji Hokota City 1437.760 3200.48 4908.38
Ishigami Tokai Village 1431.690 2913.47 4908.38
Mawatari Hitachinaka City 1422.870 3365.56 4908.38
Radiation dose at JAEA Oarai (P11) 1399.370 4864.61
Onuki Oarai Town 1387.990 3494.73 4908.38
Sawa Hitachinaka City 1353.770 2639.28 4905.65
Toyooka Tokai Village 1321.760 3207.67 4908.38
Ajigaura Hitachinaka City 1313.890 3155.67 4905.65
Fukushima [5] (distance from Fukushima I: 45 km) 1282.090 3050.16 4897.44
Geiger Counter Feeds from Asao Kawasaki 1266.620 4818.1
Radiation dose at Tamokami elementary school, Koriyama 1256.140 4839.98
Isohama Oarai Town 1250.540 3046.39 4902.91
Ebisawa Ibaraki Town 1222.240 8270.75 4905.65
Muramatsu Tokai Village 1203.520 3236.39 4908.38
Kamitoda Hokota City 1184.740 2655.13 4908.38
Yanagisawa Hitachinaka City 1166.970 2703.83 4905.65
Tokushuku Hokota City 1159.730 2396.8 4908.38
Tasaki Hokota City 1153.300 2831.42 4878.29
Fukushima [20] (distance from Fukushima I: 45 km) 1145.390 3050.16 4897.44
Kadobe Naka City 1086.580 6440.47 4905.65
Radiation dose at Date city office, Date 1076.050 4842.72
Oshinobe Tokai Village 1041.340 3021.11 4908.38
Oba Mito City 1037.670 9924.41 4908.38
Godai Naka City 1031.270 2619.23 4908.38
Ishikawa Mito City 1030.810 3087.41 4911.12
Isobe Hitachiota City 1013.130 14897.4 4908.38
Yatabe Ibaraki Town 996.127 2590.55 4908.38
Radiation dose at Motomiya city office, Motomiya 992.703 4842.72
Fukushima [73] (distance from Fukushima I: 35 km) 981.984 3045.05 4889.23
Fukushima [75] (distance from Fukushima I: 45 km) 960.529 3045.05 4889.23
Yokobori Naka City 930.280 3035.45 4908.38
Sugaya Naka City 926.186 4638.29 4911.12
Kounosu Naka City 926.087 2368.08 4908.38
Funaishikawa Tokai Village 900.399 3143.09 4908.38
Nukada Naka City 899.900 2838.53 4902.91
Uridura Naka City 890.113 2709.5 4902.91
Shiraki Tsuruga City 881.330 5751.18 4911.12
Motokomezaki Naka City 880.851 2523.31 4875.55
Shiraki pass Tsuruga City 850.284 6024.01 4911.12
Radiation dose in Yamamoto 846.633 4864.61
Yoshizawa Mito City 837.646 2741.25 4908.38
Radiation dose at JAEA Oarai (P7) 831.135 4864.61
Mayumi Hitachiota City 828.119 2719.72 4908.38
Urasoko Tsuruga City 826.465 4774.69 4911.12
Nemoto Hitachioomiya City 825.588 3062.46 4905.65
Takenami Mihama Town 804.283 5011.63 4911.12
Radiation dose at JAEA Oarai (P15) 780.207 4864.61
Tateishi Tsuruga City 780.092 3970.55 4911.12
Radiation dose at JAEA Oarai (P14) 770.174 4864.61
Radiation dose at JAEA Oarai (P13) 769.612 4864.61
Ukishima Kawasaki Ward 735.475 9369.9 4911.12
Kume Hitachiota City 713.958 2662.28 4908.38
Radiation dose at JAEA Oarai (P2) 712.011 4864.61
Fukushima [74] (distance from Fukushima I: 35 km) 706.552 3045.05 4889.23
Nyuu Mihama Town 674.787 4566.48 4911.12
Fukushima [52] (distance from Fukushima I: 40 km) 672.743 3050.16 4897.44
Radiation dose in Iwanuma 670.242 4864.61
Fukushima [51] (distance from Fukushima I: 40 km) 665.376 3050.16 4897.44
Tsuruga Tsuruga City 655.360 4027.98 4911.12
Shiohama Kawasaki Ward 653.536 3216.65 4911.12
Radiation dose in Kakuda 649.863 4864.61
Sakajiri Mihama Town 649.252 5327.57 4911.12
North point of Kinki University Atomic Energy Research Instirute Station 639.566 3345.89 4911.12
Radiation dose in Onagawa (MP-2) 632.968 4861.87
Kumatori town Nishi primary school Station 631.491 3999.25 4911.12
Oshima Kawasaki Ward 630.402 3065.87 4911.12
Izumisano municipal Oike athletic field Station 629.920 4509.05 4911.12
Atom-kyoudou nursery school Station 625.566 4329.54 4911.12
South point of Kinki University Atomic Energy Research Instirute Station 625.202 3941.82 4911.12
Nakamachi Omaezaki City 623.494 5076.25 4911.12
Uraga Yokosuka City 622.492 2405.29 4911.12
Goritoge Shika Town 622.143 5392.19 4911.12
Kumatori town Minami primary school Station 606.134 4588.02 4911.12
Radiation dose at JAEA Oarai (P1) 603.643 4867.34
Yamanotedai-No.1 Park Station 599.140 4279.27 4911.12
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 595.502 4883.76
Noumi Shika Town 594.021 5334.73 4911.12
Radiation dose in Watari 591.851 4864.61
Hairando Yokosuka City 588.667 3015.6 4911.12
Fukushima [12] (distance from Fukushima I: 40 km) 588.291 3050.16 4897.44
Ningyotoge Kagamino Town 574.857 4279.27 4911.12
Ten-no Kagamino Town 569.960 5126.52 4911.12
Funagura Yokosuka City 563.909 2843.28 4911.12
Chidori Kawasaki Ward 560.211 2749.93 4911.12
Radiation dose at JAEA Oarai (P16) 556.365 4864.61
Shika Shika Town 551.376 5140.87 4911.12
Higashiosaka municipal Kamikosaka primary scool Station 550.277 3338.7 4911.12
Sahara Yokosuka City 547.404 2663.77 4911.12
Kazanashi Shika Town 545.377 4824.96 4911.12
Akasumi Shika Town 544.970 4415.7 4911.12
Kurahashi Maizuru City 540.820 4020.79 4911.12
Obama Obama City 540.809 3597.18 4911.12
Sakuragaike community hall Omaezaki City 540.772 5205.49 4911.12
Shirowa primary school Omaezaki City 535.692 5097.79 4911.12
Radiation dose at JAEA Oarai (P5) 529.759 4864.61
Uenohara Omaezaki City 529.333 5241.41 4911.12
Kumano Shika Town 529.019 5004.47 4911.12
Izumisano municipal Hineno filtration plant Station 527.471 4315.19 4911.12
Nishi-hamasada Matsue City 525.089 4773.07 4894.7
Kouno Minami-Echizen Town 525.028 3618.72 4911.12
Kurihama Yokosuka City 523.708 2879.17 4911.12
Osaka prefectural Kumatori off-site-center Station 522.808 3977.71 4911.12
Ogasa branch Kikugawa City 522.039 5298.39 4897.44
Izumisano municipal Hineno primary scool Station 518.181 3453.59 4911.12
Shirasuna Omaezaki City 499.479 5133.71 4911.12
Jitougata primary school Makinohara City 498.059 4925.47 4911.12
Kataku Matsue City 497.007 3826.93 4911.12
Nishihemi Yokosuka City 496.917 2297.59 4911.12
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 496.721 4883.76
Satsuma-sendai monitoring center Satsuma-sendai City 495.302 3769.5 4911.12
Otomi Takahama Town 494.821 4221.84 4911.12
Otsu Nanao City 493.895 4236.19 4911.12
The Observation point for comparison Tatsunokuchi 493.454 3489.48 4911.12
Hitsuhama Ohi Town 492.630 3927.47 4911.12
Kijiyama Misasa Town 489.284 3984.9 4911.12
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 487.055 4883.76
Hiraba Omaezaki City 485.878 5133.71 4911.12
Tayu Matsue City 484.956 3992.09 4911.12
Hamaokakita primary school Omaezaki City 484.537 5262.6 4897.44
Oitomi Ayabe City 474.670 5061.9 4911.12
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 472.017 4883.76
Kashiwazaki-shigai Kashiwazaki City 470.822 4027.98 4911.12
Mitsu Matsue City 466.897 3819.77 4911.12
Tonomachi Kawasaki Ward 463.967 4839.31 4911.12
Daitou branch Kakegawa City 463.829 5183.85 4897.44
Fukura Shika Town 462.493 4817.77 4911.12
Nagasawa Yokosuka City 462.365 2814.55 4911.12
The athletic field Station of Kinki University 461.661 3180.73 4911.12
Koura Matsue City 461.049 4559.29 4911.12
Sakurasan Ward Omaezaki City 459.434 4968.55 4911.12
Tsuchikawa Nanao City 458.915 4688.53 4911.12
Kumatori Town office Station 457.917 3281.27 4911.12
Shinkango Omaezaki City 449.013 5751.18 4911.12
Ogurui Takahama Town 448.279 3762.31 4911.12
Kusabue Omaezaki City 444.162 5420.89 4911.12
Omaezaki City monitoring center 443.946 5320.38 4911.12
Akawase Kagamino Town 442.246 3281.27 4911.12
Ibaraki 442.139 2408.45 4902.91
Hinode Town Yokosuka City 438.324 1895.52 4911.12
Nishiyama Kashiwazaki City 437.251 5700.91 4911.12
Kariwa Kariwa Village 436.307 4300.81 4911.12
Osaka prefectural Hineno high scool Station 435.745 3834.12 4911.12
Miyagawa Kashiwazaki City 435.245 4243.38 4911.12
Radiation dose in Natori 434.640 4864.61
Kami-koubu Matsue City 433.868 4171.57 4911.12
Shimo-Takamachi Kariwa Village 433.192 4681.37 4911.12
Osaka prefectural Sano supporting school Station 432.398 4178.76 4911.12
Arahama Kashiwazaki City 428.874 4372.62 4911.12
Doai Kashiwazaki City 425.681 4114.14 4911.12
Owashi Matsue City 424.452 4078.25 4911.12
Okayasu Maizuru City 422.568 4803.42 4911.12
Katsuyama Kariwa Village 421.280 4372.62 4911.12
Kita-koubu Matsue City 420.683 4473.13 4911.12
Kichisaka Maizuru City 413.065 5837.34 4911.12
Nagai Ohi Town 410.699 4243.47 4902.91
Shiokumi Maizuru City 407.938 7266.17 4911.12
Miyadome Ohi Town 407.831 3518.21 4911.12
Kariwa Kariwa Village 407.617 4530.59 4911.12
Ueno Satsuma-sendai City 394.248 3288.43 4911.12
Power Station-South 389.191 4789.07 4911.12
Radiation dose at JAEA Oarai (P6) 386.963 4864.61
Power Station- 385.546 4674.18 4911.12
Takae Satsuma-sendai City 379.551 3331.51 4911.12
Hokawaduura Genkai Town 378.015 5072.67 4911.12
Kou Itimatsu Suetsugu 377.929 3661.8 4911.12
Minato Satsuma-sendai City 377.656 3051.49 4911.12
Iwanai Iwanai Town 376.336 4972.97 4908.38
Hattari Kyowa Town 373.047 4836.61 4908.38
Chatsu Tomari Village 371.011 4621.33 4908.38
Oyama Maizuru City 358.223 4207.49 4911.12
Kodaira Satsuma-sendai City 355.545 3087.41 4911.12
Kayanuma Tomari Village 354.809 4111.85 4908.38
Anojiri Obama City 353.215 3446.4 4911.12
Kushi Genkai Town 349.738 7000.5 4911.12
Yamaguchi 348.715 5505.02 4902.91
Sadahongou Matsue City 348.228 4286.46 4911.12
Sakibe Karatsu City 347.801 6634.32 4911.12
Hirao Genkai Town 343.814 6993.31 4911.12
The Meteorological Obsevatory of kyowa Town 343.275 4585.46 4908.38
Minami-Horoni Kyowa Town 335.180 4298.41 4908.38
Kounoura Takahama Town 330.353 3633.07 4911.12
Kyoudomarisaki Karatsu City 328.622 7108.2 4911.12
Horikappu Jinja Tomari Village 328.230 4449.11 4908.38
Hukada-kita Matsue City 327.031 3525.37 4911.12
Radiation dose in KEK, Tsukuba 326.240 4883.76
Herokaruusu Tomari Village 324.242 4614.18 4908.38
Yorita Satsuma-sendai City 323.218 3611.53 4911.12
Kamoenai Kamoenai Village 322.032 3896.57 4908.38
Radiation dose in Onagawa (MP-6) 316.267 4861.87
Imamura Genkai Town 314.749 60240.1 4911.12
Yamanaka Takahama Town 314.185 4688.53 4911.12
Sendai (Miyagi) 312.585 2206.31 4902.91
Radiation dose in Onagawa (MP-1) 300.147 4861.87
Gumisaki Satsuma-sendai City 295.693 2915.09 4911.12
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 286.142 4883.76
Aomori Aomori City 285.372 2963.67 4908.38
Misawa City hall Misawa City 283.728 5747.98 4908.38
Kashu Ikata Town 277.173 3008.41 4911.12
Noheji Town Office Noheji Town 272.004 2540.3 4908.38
Takasimamati 271.103 3202.27 4911.12
Radiation dose in Onagawa (MP-3) 270.563 4861.87
Kucho Ikata Town 269.545 2656.61 4911.12
Radiation dose in Marumori 269.436 4864.61
Kawanagata Ikata Town 266.821 2591.99 4911.12
Tochigi 260.733 2881.54 4902.91
Chikagawa Mutu City 256.719 3308.12 4908.38
Yokohama Town Office Yokohama Town 254.846 4054.45 4908.38
Tokyo 251.877 3397.63 4902.91
Hiranuma Rokkasho Village 251.186 2662.28 4908.38
Taisei Ikata Town 246.293 1945.79 4911.12
Chitose-daira Rokkasho Village 245.868 2870.41 4908.38
Gifu 243.951 4730.88 4902.91
Fukkoshi Yokohama Town 243.102 2784.3 4908.38
Shimane 240.651 4730.88 4902.91
Sunagomata Higashidoori Village 238.012 4025.74 4908.38
Obuchi Rokkasho Village 237.506 3200.48 4908.38
Tomari Rokkasho Village 230.636 4477.82 4908.38
kanagawa 226.339 2967.55 4902.91
Saitama 219.770 2580.48 4902.91
Ikatagoshi Ikata Town 217.515 2448.37 4911.12
Touhoku Branch office Touhoku Town 215.416 2317.83 4908.38
Radiation dose at Tohoku University 214.824 4864.61
Odanosawa Higashidoori Village 210.287 3207.67 4908.38
Kagawa 205.829 3311.62 4902.91
Oippe Higashidoori Village 205.182 2762.77 4908.38
Oita 200.921 3655.68 4902.91
Touhoku Town office Touhoku Town 200.811 10720.9 4908.38
Kuchogoshi Ikata Town 198.646 2484.29 4911.12
Minatoura Ikata Town 186.776 2232.97 4911.12
Radiation dose in Koyadori, Ojika 184.905 4859.14
Toyama 184.580 6322.18 4902.91
Fukushima [9] (distance from Fukushima I: 45 km) 184.232 3050.16 4897.44
Radiation dose in Tukahama, Ojika 183.417 4859.14
Chiba 182.407 1892.35 4902.91
Nara 182.387 3440.64 4902.91
Okayama 181.976 4472.83 4902.91
Yamagata 181.598 3526.66 4902.91
Ehime 180.745 3182.59 4902.91
Ishikawa 180.445 5483.52 4902.91
Niigata 177.483 6580.22 4902.91
Hiroshima 176.816 2967.55 4902.91
Mie 174.867 3393.33 4902.91
Fukui 170.045 4171.78 4902.91
Radiation dose in Terama, Ojika 168.036 4859.14
Yamanashi 164.561 2752.51 4902.91
Nagano 162.242 4188.98 4902.91
Saga 161.421 3698.69 4902.91
Tottori 161.392 3397.63 4902.91
Radiation dose in Enoshima, Ojika 160.091 4859.14
Osaka 159.103 2623.49 4902.91
Ibaraki-city Environment 157.249 4818.1
Aichi 149.345 3182.59 4902.91
Toyonoura Ikata Town 149.214 2563.26 4911.12
Shizuoka 148.639 3290.11 4902.91
Kyoto 144.522 3741.7 4902.91
Kagoshima 144.449 4055.65 4902.91
Tokushima 143.627 2881.54 4902.91
Gunma 143.572 1935.36 4902.91
Hyogo 139.710 3268.61 4902.91
Fukuoka 136.511 3397.63 4902.91
Wakayama 133.857 2408.45 4902.91
Radiation at Tamaki-cho Mie Japan 133.138 4818.1
Akita 132.832 3698.69 4902.91
Shiga 124.919 2623.49 4902.91
Nagasaki 109.459 2967.55 4902.91
Hokkaido 109.189 4515.84 4902.91
Kumamoto 103.568 2881.54 4902.91
Aomori 101.819 4386.82 4902.91
Miyazaki 100.354 2855.73 4902.91
Kochi 95.931 3268.61 4902.91
Fukushima [35] (distance from Fukushima I: 35 km) 91.917 3041.64 4883.76
Iwate 90.324 3612.67 4902.91
Environment Feeds from Ohta 83.623 4818.1
Okinawa 82.305 2472.96 4902.91
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