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Accumulated absorbed dose rate - T=13.03.2011 - 30.06.2016(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 5212.08
Fukushima I MP8 570942.000 5212.08
Fukushima I MP6 240668.000 5212.08
Yamada Futaba Town 176983.000 4001.94 4768.85
Fukushima I MP2 140420.000 5212.08
Fukushima I MP5 111325.000 5212.08
Fukushima [32] (distance from Fukushima I: 30 km) 101500.000 3290.42 5283.22
Fukushima I MP3 93730.602 5212.08
Fukushima I MP4 86821.500 5212.08
Fukushima [33] (distance from Fukushima I: 30 km) 77197.703 3290.42 5283.22
Fukushima [79] (distance from Fukushima I: 40 km) 54008.602 3239.3 5201.14
Fukushima [31] (distance from Fukushima I: 30 km) 40677.398 3290.42 5283.22
Ono Okuma Town 38610.500 3695.15 4768.85
Shinzan Futaba Town 38332.801 3353.55 4768.85
Fukushima I MP1 31496.801 5212.08
Yonomori Tomioka Town 29815.900 3820.64 4768.85
Fukushima [46] (distance from Fukushima I: 20 km) 28842.500 3290.42 5283.22
Tomioka Tomioka Town 25324.500 4113.47 4768.85
Fukushima [62] (distance from Fukushima I: 40 km) 16464.100 3290.42 5283.22
Fukushima [61] (distance from Fukushima I: 40 km) 13102.800 3290.42 5283.22
Shimo-Kooriyama Tomioka Town 13057.000 4085.61 4768.85
Fukushima [21] (distance from Fukushima I: 30 km) 12103.800 3290.42 5283.22
Fukushima [3] (distance from Fukushima I: 45 km) 11985.000 3290.42 5283.22
Kami-kooriyama Tomioka Town 11803.900 3207.13 4768.85
Fukushima II MP3 11060.600 5212.08
Fukushima II MP1 10903.000 5212.08
Kooriyama Futaba Town 10352.900 3736.98 4768.85
Fukushima II MP4 9696.330 5212.08
Fukushima [34] (distance from Fukushima I: 30 km) 9540.450 3287.02 5277.74
Fukushima II MP5 9382.150 5212.08
Fukushima [2] (distance from Fukushima I: 55 km) 8841.760 3290.42 5283.22
Matsudate Naraha Town 8410.890 4364.46 4768.85
Shigeoka Naraha Town 8115.970 4824.61 4768.85
Fukushima II MP2 7875.320 5212.08
Namie Namie Town 7321.210 3520.87 4768.85
Radiation dose at Shirasawa branch office, Motomiya 7287.920 5228.5
Fukushima II MP6 7062.690 5212.08
Fukushima II MP7 6511.580 5209.34
Fukushima [1] (distance from Fukushima I: 60 km) 5615.310 3290.42 5283.22
Fukushima [11] (distance from Fukushima I: 40 km) 5491.310 3290.42 5283.22
Fukushima [63] (distance from Fukushima I: 45 km) 5448.820 3290.42 5283.22
Fukushima [45] (distance from Fukushima I: 20 km) 3981.200 3290.42 5283.22
Fukushima [42] (distance from Fukushima I: 30 km) 3850.600 3290.42 5283.22
Fukushima [10] (distance from Fukushima I: 40 km) 3734.160 3290.42 5283.22
Fukushima [78] (distance from Fukushima I: 45 km) 3716.820 3285.31 5275.01
Futatsunuma Hirono Town 3520.340 4183.2 4768.85
Fukushima [4] (distance from Fukushima I: 50 km) 3386.310 3290.42 5283.22
Fukushima [7] (distance from Fukushima I: 45 km) 3313.930 3290.42 5283.22
Radiation dose at Koriyama joint government building, Koriyama 3232.890 5225.76
Fukushima [15] (distance from Fukushima I: 35 km) 3178.670 3290.42 5283.22
Kiyohashi Namie Town 3162.000 3088.58 4768.85
Fukushima [71] (distance from Fukushima I: 25 km) 3161.650 3285.31 5275.01
Radiation dose at Agricultural center, Koriyama 3128.960 5225.76
Fukushima [41] (distance from Fukushima I: 20 km) 3111.490 3290.42 5283.22
Radiation dose at Koriyama city office, Koriyama 2803.520 5225.76
Fukushima [44] (distance from Fukushima I: 30 km) 2535.550 3290.42 5283.22
Fukushima [72] (distance from Fukushima I: 30 km) 2344.620 3285.31 5275.01
Fukushima [43] (distance from Fukushima I: 20 km) 2244.110 3290.42 5283.22
Yamadaoka Naraha Town 2205.340 3709.12 4768.85
Radiation dose at Iwane Fureai Plaza, Motomiya 2169.060 5228.5
Fukushima [22] (distance from Fukushima I: 35 km) 2020.650 3290.42 5283.22
Kuji Hitachi City 1990.890 8173.44 5294.16
Hitachinaka Hitachinaka City 1951.950 3589.49 5291.42
Fukushima [76] (distance from Fukushima I: 25 km) 1945.520 3285.31 5275.01
Fukushima [80] (distance from Fukushima I: 25 km) 1876.860 3285.31 5275.01
Momiyama Hokota City 1837.540 4094.48 5294.16
Fukushima [77] (distance from Fukushima I: 25 km) 1802.490 3285.31 5275.01
Horiguchi Hitachinaka City 1779.410 3577.73 5296.9
Onuma Hitachi City 1776.950 3048 5291.42
Fukushima [6] (distance from Fukushima I: 45 km) 1741.180 3290.42 5283.22
Tsukuriya Hokota City 1736.890 3444.32 5294.16
Radiation dose at Big palette Fukushima, Koriyama 1668.540 5225.76
Nemoto Hitachioomiya City 1633.190 3837.07 5291.42
Fukushima [13] (distance from Fukushima I: 40 km) 1624.150 3290.42 5283.22
Fukushima [23] (distance from Fukushima I: 35 km) 1551.750 3290.42 5283.22
Radiation dose at Tsukidatemachi kamitedo, Date 1545.300 5233.97
Fukushima [14] (distance from Fukushima I: 35 km) 1543.460 3290.42 5283.22
Radiation dose at JAEA Oarai (P12) 1512.140 5250.38
Radiation dose at Ose administration center, Koriyama 1494.270 5225.76
Araji Hokota City 1437.760 3452.02 5294.16
Ishigami Tokai Village 1431.690 3142.46 5294.16
Mawatari Hitachinaka City 1422.870 3630.08 5294.16
Radiation dose at JAEA Oarai (P11) 1399.370 5250.38
Onuki Oarai Town 1387.990 3769.4 5294.16
Sawa Hitachinaka City 1353.770 2846.83 5291.42
Toyooka Tokai Village 1321.760 3459.78 5294.16
Ajigaura Hitachinaka City 1313.890 3403.82 5291.42
Fukushima [5] (distance from Fukushima I: 45 km) 1282.090 3290.42 5283.22
Geiger Counter Feeds from Asao Kawasaki 1266.620 5203.87
Radiation dose at Tamokami elementary school, Koriyama 1256.140 5225.76
Isohama Oarai Town 1250.540 3286.08 5288.69
Ebisawa Ibaraki Town 1222.240 8921.16 5291.42
Muramatsu Tokai Village 1203.520 3490.76 5294.16
Kamitoda Hokota City 1184.740 2863.82 5294.16
Yanagisawa Hitachinaka City 1166.970 2916.46 5291.42
Tokushuku Hokota City 1159.730 2585.18 5294.16
Tasaki Hokota City 1153.300 3055.33 5264.06
Fukushima [20] (distance from Fukushima I: 45 km) 1145.390 3290.42 5283.22
Kadobe Naka City 1086.580 6946.94 5291.42
Radiation dose at Date city office, Date 1076.050 5228.5
Oshinobe Tokai Village 1041.340 3258.56 5294.16
Oba Mito City 1037.670 10704.4 5294.16
Godai Naka City 1031.270 2825.08 5294.16
Ishikawa Mito City 1030.810 3329.94 5296.9
Isobe Hitachiota City 1013.130 16068.2 5294.16
Yatabe Ibaraki Town 996.127 2794.16 5294.16
Radiation dose at Motomiya city office, Motomiya 992.703 5228.5
Fukushima [73] (distance from Fukushima I: 35 km) 981.984 3285.31 5275.01
Fukushima [75] (distance from Fukushima I: 45 km) 960.529 3285.31 5275.01
Yokobori Naka City 930.280 3274.02 5294.16
Sugaya Naka City 926.186 5002.64 5296.9
Kounosu Naka City 926.087 2554.2 5294.16
Funaishikawa Tokai Village 900.399 3390.12 5294.16
Nukada Naka City 899.900 3061.87 5288.69
Uridura Naka City 890.113 2922.7 5288.69
Shiraki Tsuruga City 881.330 6202.94 5296.9
Motokomezaki Naka City 880.851 2722.97 5261.33
Shiraki pass Tsuruga City 850.284 6497.2 5296.9
Radiation dose in Yamamoto 846.633 5250.38
Yoshizawa Mito City 837.646 2956.7 5294.16
Radiation dose at JAEA Oarai (P7) 831.135 5250.38
Mayumi Hitachiota City 828.119 2933.48 5294.16
Urasoko Tsuruga City 826.465 5149.74 5296.9
Nemoto Hitachioomiya City 825.588 3303.29 5291.42
Takenami Mihama Town 804.283 5405.3 5296.9
Radiation dose at JAEA Oarai (P15) 780.207 5250.38
Tateishi Tsuruga City 780.092 4282.45 5296.9
Radiation dose at JAEA Oarai (P14) 770.174 5250.38
Radiation dose at JAEA Oarai (P13) 769.612 5250.38
Ukishima Kawasaki Ward 735.475 10105.9 5296.9
Kume Hitachiota City 713.958 2871.52 5294.16
Radiation dose at JAEA Oarai (P2) 712.011 5250.38
Fukushima [74] (distance from Fukushima I: 35 km) 706.552 3285.31 5275.01
Nyuu Mihama Town 674.787 4925.18 5296.9
Fukushima [52] (distance from Fukushima I: 40 km) 672.743 3290.42 5283.22
Radiation dose in Iwanuma 670.242 5250.38
Fukushima [51] (distance from Fukushima I: 40 km) 665.376 3290.42 5283.22
Tsuruga Tsuruga City 655.360 4344.38 5296.9
Shiohama Kawasaki Ward 653.536 3469.33 5296.9
Radiation dose in Kakuda 649.863 5250.38
Sakajiri Mihama Town 649.252 5746.06 5296.9
North point of Kinki University Atomic Energy Research Instirute Station 639.566 3608.72 5296.9
Radiation dose in Onagawa (MP-2) 632.968 5247.65
Kumatori town Nishi primary school Station 631.491 4313.39 5296.9
Oshima Kawasaki Ward 630.402 3306.7 5296.9
Izumisano municipal Oike athletic field Station 629.920 4863.25 5296.9
Atom-kyoudou nursery school Station 625.566 4669.63 5296.9
South point of Kinki University Atomic Energy Research Instirute Station 625.202 4251.46 5296.9
Nakamachi Omaezaki City 623.494 5474.99 5296.9
Uraga Yokosuka City 622.492 2594.22 5296.9
Goritoge Shika Town 622.143 5815.76 5296.9
Kumatori town Minami primary school Station 606.134 4948.42 5296.9
Radiation dose at JAEA Oarai (P1) 603.643 5253.12
Yamanotedai-No.1 Park Station 599.140 4615.41 5296.9
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 595.502 5269.54
Noumi Shika Town 594.021 5753.78 5296.9
Radiation dose in Watari 591.851 5250.38
Hairando Yokosuka City 588.667 3252.48 5296.9
Fukushima [12] (distance from Fukushima I: 40 km) 588.291 3290.42 5283.22
Ningyotoge Kagamino Town 574.857 4615.41 5296.9
Ten-no Kagamino Town 569.960 5529.22 5296.9
Funagura Yokosuka City 563.909 3066.62 5296.9
Chidori Kawasaki Ward 560.211 2965.94 5296.9
Radiation dose at JAEA Oarai (P16) 556.365 5250.38
Shika Shika Town 551.376 5544.69 5296.9
Higashiosaka municipal Kamikosaka primary scool Station 550.277 3600.96 5296.9
Sahara Yokosuka City 547.404 2873.01 5296.9
Kazanashi Shika Town 545.377 5203.97 5296.9
Akasumi Shika Town 544.970 4762.56 5296.9
Kurahashi Maizuru City 540.820 4336.62 5296.9
Obama Obama City 540.809 3879.74 5296.9
Sakuragaike community hall Omaezaki City 540.772 5614.38 5296.9
Shirowa primary school Omaezaki City 535.692 5498.22 5296.9
Radiation dose at JAEA Oarai (P5) 529.759 5250.38
Uenohara Omaezaki City 529.333 5653.14 5296.9
Kumano Shika Town 529.019 5397.58 5296.9
Izumisano municipal Hineno filtration plant Station 527.471 4654.16 5296.9
Nishi-hamasada Matsue City 525.089 5149.26 5280.48
Kouno Minami-Echizen Town 525.028 3902.98 5296.9
Kurihama Yokosuka City 523.708 3105.33 5296.9
Osaka prefectural Kumatori off-site-center Station 522.808 4290.16 5296.9
Ogasa branch Kikugawa City 522.039 5715.74 5283.22
Izumisano municipal Hineno primary scool Station 518.181 3724.88 5296.9
Shirasuna Omaezaki City 499.479 5536.98 5296.9
Jitougata primary school Makinohara City 498.059 5312.37 5296.9
Kataku Matsue City 497.007 4127.54 5296.9
Nishihemi Yokosuka City 496.917 2478.06 5296.9
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 496.721 5269.54
Satsuma-sendai monitoring center Satsuma-sendai City 495.302 4065.6 5296.9
Otomi Takahama Town 494.821 4553.47 5296.9
Otsu Nanao City 493.895 4568.94 5296.9
The Observation point for comparison Tatsunokuchi 493.454 3763.58 5296.9
Hitsuhama Ohi Town 492.630 4235.98 5296.9
Kijiyama Misasa Town 489.284 4297.92 5296.9
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 487.055 5269.54
Hiraba Omaezaki City 485.878 5536.98 5296.9
Tayu Matsue City 484.956 4305.68 5296.9
Hamaokakita primary school Omaezaki City 484.537 5677.14 5283.22
Oitomi Ayabe City 474.670 5459.52 5296.9
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 472.017 5269.54
Kashiwazaki-shigai Kashiwazaki City 470.822 4344.38 5296.9
Mitsu Matsue City 466.897 4119.82 5296.9
Tonomachi Kawasaki Ward 463.967 5219.44 5296.9
Daitou branch Kakegawa City 463.829 5592.19 5283.22
Fukura Shika Town 462.493 5196.21 5296.9
Nagasawa Yokosuka City 462.365 3035.63 5296.9
The athletic field Station of Kinki University 461.661 3430.58 5296.9
Koura Matsue City 461.049 4917.42 5296.9
Sakurasan Ward Omaezaki City 459.434 5358.83 5296.9
Tsuchikawa Nanao City 458.915 5056.82 5296.9
Kumatori Town office Station 457.917 3539.02 5296.9
Shinkango Omaezaki City 449.013 6202.94 5296.9
Ogurui Takahama Town 448.279 4057.84 5296.9
Kusabue Omaezaki City 444.162 5846.7 5296.9
Omaezaki City monitoring center 443.946 5738.3 5296.9
Akawase Kagamino Town 442.246 3539.02 5296.9
Ibaraki 442.139 2597.95 5288.69
Hinode Town Yokosuka City 438.324 2044.42 5296.9
Nishiyama Kashiwazaki City 437.251 6148.72 5296.9
Kariwa Kariwa Village 436.307 4638.64 5296.9
Osaka prefectural Hineno high scool Station 435.745 4135.3 5296.9
Miyagawa Kashiwazaki City 435.245 4576.7 5296.9
Radiation dose in Natori 434.640 5250.38
Kami-koubu Matsue City 433.868 4499.25 5296.9
Shimo-Takamachi Kariwa Village 433.192 5049.1 5296.9
Osaka prefectural Sano supporting school Station 432.398 4507.01 5296.9
Arahama Kashiwazaki City 428.874 4716.1 5296.9
Doai Kashiwazaki City 425.681 4437.31 5296.9
Owashi Matsue City 424.452 4398.61 5296.9
Okayasu Maizuru City 422.568 5180.74 5296.9
Katsuyama Kariwa Village 421.280 4716.1 5296.9
Kita-koubu Matsue City 420.683 4824.5 5296.9
Kichisaka Maizuru City 413.065 6295.87 5296.9
Nagai Ohi Town 410.699 4577.36 5288.69
Shiokumi Maizuru City 407.938 7836.94 5296.9
Miyadome Ohi Town 407.831 3794.58 5296.9
Kariwa Kariwa Village 407.617 4886.48 5296.9
Ueno Satsuma-sendai City 394.248 3546.74 5296.9
Power Station-South 389.191 5165.26 5296.9
Radiation dose at JAEA Oarai (P6) 386.963 5250.38
Power Station- 385.546 5041.34 5296.9
Takae Satsuma-sendai City 379.551 3593.2 5296.9
Hokawaduura Genkai Town 378.015 5471.14 5296.9
Kou Itimatsu Suetsugu 377.929 3949.44 5296.9
Minato Satsuma-sendai City 377.656 3291.18 5296.9
Iwanai Iwanai Town 376.336 5363.82 5294.16
Hattari Kyowa Town 373.047 5216.74 5294.16
Chatsu Tomari Village 371.011 4984.54 5294.16
Oyama Maizuru City 358.223 4538 5296.9
Kodaira Satsuma-sendai City 355.545 3329.94 5296.9
Kayanuma Tomari Village 354.809 4435.02 5294.16
Anojiri Obama City 353.215 3717.12 5296.9
Kushi Genkai Town 349.738 7550.4 5296.9
Yamaguchi 348.715 5938.18 5288.69
Sadahongou Matsue City 348.228 4623.17 5296.9
Sakibe Karatsu City 347.801 7155.46 5296.9
Hirao Genkai Town 343.814 7542.64 5296.9
The Meteorological Obsevatory of kyowa Town 343.275 4945.86 5294.16
Minami-Horoni Kyowa Town 335.180 4636.24 5294.16
Kounoura Takahama Town 330.353 3918.45 5296.9
Kyoudomarisaki Karatsu City 328.622 7666.56 5296.9
Horikappu Jinja Tomari Village 328.230 4798.78 5294.16
Hukada-kita Matsue City 327.031 3802.29 5296.9
Radiation dose in KEK, Tsukuba 326.240 5269.54
Herokaruusu Tomari Village 324.242 4976.84 5294.16
Yorita Satsuma-sendai City 323.218 3895.22 5296.9
Kamoenai Kamoenai Village 322.032 4202.82 5294.16
Radiation dose in Onagawa (MP-6) 316.267 5247.65
Imamura Genkai Town 314.749 64972 5296.9
Yamanaka Takahama Town 314.185 5056.82 5296.9
Sendai (Miyagi) 312.585 2379.91 5288.69
Radiation dose in Onagawa (MP-1) 300.147 5247.65
Gumisaki Satsuma-sendai City 295.693 3144.08 5296.9
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 286.142 5269.54
Aomori Aomori City 285.372 3196.6 5294.16
Misawa City hall Misawa City 283.728 6199.74 5294.16
Kashu Ikata Town 277.173 3244.72 5296.9
Noheji Town Office Noheji Town 272.004 2739.96 5294.16
Takasimamati 271.103 3453.81 5296.9
Radiation dose in Onagawa (MP-3) 270.563 5247.65
Kucho Ikata Town 269.545 2865.3 5296.9
Radiation dose in Marumori 269.436 5250.38
Kawanagata Ikata Town 266.821 2795.6 5296.9
Tochigi 260.733 3108.26 5288.69
Chikagawa Mutu City 256.719 3568.12 5294.16
Yokohama Town Office Yokohama Town 254.846 4373.12 5294.16
Tokyo 251.877 3664.97 5288.69
Hiranuma Rokkasho Village 251.186 2871.52 5294.16
Taisei Ikata Town 246.293 2098.64 5296.9
Chitose-daira Rokkasho Village 245.868 3096.02 5294.16
Gifu 243.951 5103.12 5288.69
Fukkoshi Yokohama Town 243.102 3003.14 5294.16
Shimane 240.651 5103.12 5288.69
Sunagomata Higashidoori Village 238.012 4342.14 5294.16
Obuchi Rokkasho Village 237.506 3452.02 5294.16
Tomari Rokkasho Village 230.636 4829.76 5294.16
kanagawa 226.339 3201.05 5288.69
Saitama 219.770 2783.52 5288.69
Ikatagoshi Ikata Town 217.515 2640.69 5296.9
Touhoku Branch office Touhoku Town 215.416 2500 5294.16
Radiation dose at Tohoku University 214.824 5250.38
Odanosawa Higashidoori Village 210.287 3459.78 5294.16
Kagawa 205.829 3572.18 5288.69
Oippe Higashidoori Village 205.182 2979.92 5294.16
Oita 200.921 3943.32 5288.69
Touhoku Town office Touhoku Town 200.811 11563.6 5294.16
Kuchogoshi Ikata Town 198.646 2679.44 5296.9
Minatoura Ikata Town 186.776 2408.37 5296.9
Radiation dose in Koyadori, Ojika 184.905 5244.91
Toyama 184.580 6819.62 5288.69
Fukushima [9] (distance from Fukushima I: 45 km) 184.232 3290.42 5283.22
Radiation dose in Tukahama, Ojika 183.417 5244.91
Chiba 182.407 2041.25 5288.69
Nara 182.387 3711.36 5288.69
Okayama 181.976 4824.77 5288.69
Yamagata 181.598 3804.14 5288.69
Ehime 180.745 3433.01 5288.69
Ishikawa 180.445 5914.98 5288.69
Niigata 177.483 7097.98 5288.69
Hiroshima 176.816 3201.05 5288.69
Mie 174.867 3660.33 5288.69
Fukui 170.045 4500.02 5288.69
Radiation dose in Terama, Ojika 168.036 5244.91
Yamanashi 164.561 2969.09 5288.69
Nagano 162.242 4518.58 5288.69
Saga 161.421 3989.71 5288.69
Tottori 161.392 3664.97 5288.69
Radiation dose in Enoshima, Ojika 160.091 5244.91
Osaka 159.103 2829.91 5288.69
Ibaraki-city Environment 157.249 5203.87
Aichi 149.345 3433.01 5288.69
Toyonoura Ikata Town 149.214 2764.61 5296.9
Shizuoka 148.639 3548.99 5288.69
Kyoto 144.522 4036.1 5288.69
Kagoshima 144.449 4374.77 5288.69
Tokushima 143.627 3108.26 5288.69
Gunma 143.572 2087.64 5288.69
Hyogo 139.710 3525.79 5288.69
Fukuoka 136.511 3664.97 5288.69
Wakayama 133.857 2597.95 5288.69
Radiation at Tamaki-cho Mie Japan 133.138 5203.87
Akita 132.832 3989.71 5288.69
Shiga 124.919 2829.91 5288.69
Nagasaki 109.459 3201.05 5288.69
Hokkaido 109.189 4871.16 5288.69
Kumamoto 103.568 3108.26 5288.69
Aomori 101.819 4731.98 5288.69
Miyazaki 100.354 3080.43 5288.69
Kochi 95.931 3525.79 5288.69
Fukushima [35] (distance from Fukushima I: 35 km) 91.917 3281.9 5269.54
Iwate 90.324 3896.93 5288.69
Environment Feeds from Ohta 83.623 5203.87
Okinawa 82.305 2667.54 5288.69
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