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Accumulated absorbed dose rate - T=13.03.2011 - 31.07.2015(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 4295.52
Fukushima I MP8 570942.000 4295.52
Fukushima I MP6 240668.000 4295.52
Yamada Futaba Town 176983.000 3232.78 3852.29
Fukushima I MP2 140420.000 4295.52
Fukushima I MP5 111325.000 4295.52
Fukushima [32] (distance from Fukushima I: 30 km) 101500.000 2719.58 4366.66
Fukushima I MP3 93730.602 4295.52
Fukushima I MP4 86821.500 4295.52
Fukushima [33] (distance from Fukushima I: 30 km) 77197.703 2719.58 4366.66
Fukushima [79] (distance from Fukushima I: 40 km) 54008.602 2668.46 4284.58
Fukushima [31] (distance from Fukushima I: 30 km) 40677.398 2719.58 4366.66
Ono Okuma Town 38610.500 2984.95 3852.29
Shinzan Futaba Town 38332.801 2709 3852.29
Fukushima I MP1 31496.801 4295.52
Yonomori Tomioka Town 29815.900 3086.32 3852.29
Fukushima [46] (distance from Fukushima I: 20 km) 28842.500 2719.58 4366.66
Tomioka Tomioka Town 25324.500 3322.87 3852.29
Fukushima [62] (distance from Fukushima I: 40 km) 16464.100 2719.58 4366.66
Fukushima [61] (distance from Fukushima I: 40 km) 13102.800 2719.58 4366.66
Shimo-Kooriyama Tomioka Town 13057.000 3300.36 3852.29
Fukushima [21] (distance from Fukushima I: 30 km) 12103.800 2719.58 4366.66
Fukushima [3] (distance from Fukushima I: 45 km) 11985.000 2719.58 4366.66
Kami-kooriyama Tomioka Town 11803.900 2590.73 3852.29
Fukushima II MP3 11060.600 4295.52
Fukushima II MP1 10903.000 4295.52
Kooriyama Futaba Town 10352.900 3018.74 3852.29
Fukushima II MP4 9696.330 4295.52
Fukushima [34] (distance from Fukushima I: 30 km) 9540.450 2716.18 4361.18
Fukushima II MP5 9382.150 4295.52
Fukushima [2] (distance from Fukushima I: 55 km) 8841.760 2719.58 4366.66
Matsudate Naraha Town 8410.890 3525.62 3852.29
Shigeoka Naraha Town 8115.970 3897.33 3852.29
Fukushima II MP2 7875.320 4295.52
Namie Namie Town 7321.210 2844.17 3852.29
Radiation dose at Shirasawa branch office, Motomiya 7287.920 4311.94
Fukushima II MP6 7062.690 4295.52
Fukushima II MP7 6511.580 4292.78
Fukushima [1] (distance from Fukushima I: 60 km) 5615.310 2719.58 4366.66
Fukushima [11] (distance from Fukushima I: 40 km) 5491.310 2719.58 4366.66
Fukushima [63] (distance from Fukushima I: 45 km) 5448.820 2719.58 4366.66
Fukushima [45] (distance from Fukushima I: 20 km) 3981.200 2719.58 4366.66
Fukushima [42] (distance from Fukushima I: 30 km) 3850.600 2719.58 4366.66
Fukushima [10] (distance from Fukushima I: 40 km) 3734.160 2719.58 4366.66
Fukushima [78] (distance from Fukushima I: 45 km) 3716.820 2714.47 4358.45
Futatsunuma Hirono Town 3520.340 3379.2 3852.29
Fukushima [4] (distance from Fukushima I: 50 km) 3386.310 2719.58 4366.66
Fukushima [7] (distance from Fukushima I: 45 km) 3313.930 2719.58 4366.66
Radiation dose at Koriyama joint government building, Koriyama 3232.890 4309.2
Fukushima [15] (distance from Fukushima I: 35 km) 3178.670 2719.58 4366.66
Kiyohashi Namie Town 3162.000 2494.96 3852.29
Fukushima [71] (distance from Fukushima I: 25 km) 3161.650 2714.47 4358.45
Radiation dose at Agricultural center, Koriyama 3128.960 4309.2
Fukushima [41] (distance from Fukushima I: 20 km) 3111.490 2719.58 4366.66
Radiation dose at Koriyama city office, Koriyama 2803.520 4309.2
Fukushima [44] (distance from Fukushima I: 30 km) 2535.550 2719.58 4366.66
Fukushima [72] (distance from Fukushima I: 30 km) 2344.620 2714.47 4358.45
Fukushima [43] (distance from Fukushima I: 20 km) 2244.110 2719.58 4366.66
Yamadaoka Naraha Town 2205.340 2996.24 3852.29
Radiation dose at Iwane Fureai Plaza, Motomiya 2169.060 4311.94
Fukushima [22] (distance from Fukushima I: 35 km) 2020.650 2719.58 4366.66
Kuji Hitachi City 1990.890 6758.4 4377.6
Hitachinaka Hitachinaka City 1951.950 2967.73 4374.86
Fukushima [76] (distance from Fukushima I: 25 km) 1945.520 2714.47 4358.45
Fukushima [80] (distance from Fukushima I: 25 km) 1876.860 2714.47 4358.45
Momiyama Hokota City 1837.540 3385.61 4377.6
Fukushima [77] (distance from Fukushima I: 25 km) 1802.490 2714.47 4358.45
Horiguchi Hitachinaka City 1779.410 2958.65 4380.34
Onuma Hitachi City 1776.950 2520.04 4374.86
Fukushima [6] (distance from Fukushima I: 45 km) 1741.180 2719.58 4366.66
Tsukuriya Hokota City 1736.890 2848.01 4377.6
Radiation dose at Big palette Fukushima, Koriyama 1668.540 4309.2
Nemoto Hitachioomiya City 1633.190 3172.43 4374.86
Fukushima [13] (distance from Fukushima I: 40 km) 1624.150 2719.58 4366.66
Fukushima [23] (distance from Fukushima I: 35 km) 1551.750 2719.58 4366.66
Radiation dose at Tsukidatemachi kamitedo, Date 1545.300 4317.41
Fukushima [14] (distance from Fukushima I: 35 km) 1543.460 2719.58 4366.66
Radiation dose at JAEA Oarai (P12) 1512.140 4333.82
Radiation dose at Ose administration center, Koriyama 1494.270 4309.2
Araji Hokota City 1437.760 2854.39 4377.6
Ishigami Tokai Village 1431.690 2598.41 4377.6
Mawatari Hitachinaka City 1422.870 3001.61 4377.6
Radiation dose at JAEA Oarai (P11) 1399.370 4333.82
Onuki Oarai Town 1387.990 3116.81 4377.6
Sawa Hitachinaka City 1353.770 2353.72 4374.86
Toyooka Tokai Village 1321.760 2860.8 4377.6
Ajigaura Hitachinaka City 1313.890 2814.23 4374.86
Fukushima [5] (distance from Fukushima I: 45 km) 1282.090 2719.58 4366.66
Geiger Counter Feeds from Asao Kawasaki 1266.620 4287.31
Radiation dose at Tamokami elementary school, Koriyama 1256.140 4309.2
Isohama Oarai Town 1250.540 2716.59 4372.13
Ebisawa Ibaraki Town 1222.240 7375.87 4374.86
Muramatsu Tokai Village 1203.520 2886.41 4377.6
Kamitoda Hokota City 1184.740 2368.01 4377.6
Yanagisawa Hitachinaka City 1166.970 2411.28 4374.86
Tokushuku Hokota City 1159.730 2137.61 4377.6
Tasaki Hokota City 1153.300 2523.34 4347.5
Fukushima [20] (distance from Fukushima I: 45 km) 1145.390 2719.58 4366.66
Kadobe Naka City 1086.580 5743.62 4374.86
Radiation dose at Date city office, Date 1076.050 4311.94
Oshinobe Tokai Village 1041.340 2694.41 4377.6
Oba Mito City 1037.670 8851.2 4377.6
Godai Naka City 1031.270 2335.99 4377.6
Ishikawa Mito City 1030.810 2753.73 4380.34
Isobe Hitachiota City 1013.130 13286.4 4377.6
Yatabe Ibaraki Town 996.127 2310.41 4377.6
Radiation dose at Motomiya city office, Motomiya 992.703 4311.94
Fukushima [73] (distance from Fukushima I: 35 km) 981.984 2714.47 4358.45
Fukushima [75] (distance from Fukushima I: 45 km) 960.529 2714.47 4358.45
Yokobori Naka City 930.280 2707.2 4377.6
Sugaya Naka City 926.186 4137 4380.34
Kounosu Naka City 926.087 2112 4377.6
Funaishikawa Tokai Village 900.399 2803.2 4377.6
Nukada Naka City 899.900 2531.23 4372.13
Uridura Naka City 890.113 2416.18 4372.13
Shiraki Tsuruga City 881.330 5129.6 4380.34
Motokomezaki Naka City 880.851 2248.61 4344.77
Shiraki pass Tsuruga City 850.284 5372.94 4380.34
Radiation dose in Yamamoto 846.633 4333.82
Yoshizawa Mito City 837.646 2444.81 4377.6
Radiation dose at JAEA Oarai (P7) 831.135 4333.82
Mayumi Hitachiota City 828.119 2425.61 4377.6
Urasoko Tsuruga City 826.465 4258.65 4380.34
Nemoto Hitachioomiya City 825.588 2731.1 4374.86
Takenami Mihama Town 804.283 4469.98 4380.34
Radiation dose at JAEA Oarai (P15) 780.207 4333.82
Tateishi Tsuruga City 780.092 3541.42 4380.34
Radiation dose at JAEA Oarai (P14) 770.174 4333.82
Radiation dose at JAEA Oarai (P13) 769.612 4333.82
Ukishima Kawasaki Ward 735.475 8357.22 4380.34
Kume Hitachiota City 713.958 2374.39 4377.6
Radiation dose at JAEA Oarai (P2) 712.011 4333.82
Fukushima [74] (distance from Fukushima I: 35 km) 706.552 2714.47 4358.45
Nyuu Mihama Town 674.787 4072.94 4380.34
Fukushima [52] (distance from Fukushima I: 40 km) 672.743 2719.58 4366.66
Radiation dose in Iwanuma 670.242 4333.82
Fukushima [51] (distance from Fukushima I: 40 km) 665.376 2719.58 4366.66
Tsuruga Tsuruga City 655.360 3592.64 4380.34
Shiohama Kawasaki Ward 653.536 2869 4380.34
Radiation dose in Kakuda 649.863 4333.82
Sakajiri Mihama Town 649.252 4751.78 4380.34
North point of Kinki University Atomic Energy Research Instirute Station 639.566 2984.28 4380.34
Radiation dose in Onagawa (MP-2) 632.968 4331.09
Kumatori town Nishi primary school Station 631.491 3567.02 4380.34
Oshima Kawasaki Ward 630.402 2734.52 4380.34
Izumisano municipal Oike athletic field Station 629.920 4021.72 4380.34
Atom-kyoudou nursery school Station 625.566 3861.61 4380.34
South point of Kinki University Atomic Energy Research Instirute Station 625.202 3515.8 4380.34
Nakamachi Omaezaki City 623.494 4527.62 4380.34
Uraga Yokosuka City 622.492 2145.33 4380.34
Goritoge Shika Town 622.143 4809.42 4380.34
Kumatori town Minami primary school Station 606.134 4092.16 4380.34
Radiation dose at JAEA Oarai (P1) 603.643 4336.56
Yamanotedai-No.1 Park Station 599.140 3816.77 4380.34
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 595.502 4352.98
Noumi Shika Town 594.021 4758.16 4380.34
Radiation dose in Watari 591.851 4333.82
Hairando Yokosuka City 588.667 2689.68 4380.34
Fukushima [12] (distance from Fukushima I: 40 km) 588.291 2719.58 4366.66
Ningyotoge Kagamino Town 574.857 3816.77 4380.34
Ten-no Kagamino Town 569.960 4572.46 4380.34
Funagura Yokosuka City 563.909 2535.98 4380.34
Chidori Kawasaki Ward 560.211 2452.72 4380.34
Radiation dose at JAEA Oarai (P16) 556.365 4333.82
Shika Shika Town 551.376 4585.25 4380.34
Higashiosaka municipal Kamikosaka primary scool Station 550.277 2977.86 4380.34
Sahara Yokosuka City 547.404 2375.87 4380.34
Kazanashi Shika Town 545.377 4303.49 4380.34
Akasumi Shika Town 544.970 3938.46 4380.34
Kurahashi Maizuru City 540.820 3586.23 4380.34
Obama Obama City 540.809 3208.4 4380.34
Sakuragaike community hall Omaezaki City 540.772 4642.89 4380.34
Shirowa primary school Omaezaki City 535.692 4546.83 4380.34
Radiation dose at JAEA Oarai (P5) 529.759 4333.82
Uenohara Omaezaki City 529.333 4674.93 4380.34
Kumano Shika Town 529.019 4463.6 4380.34
Izumisano municipal Hineno filtration plant Station 527.471 3848.82 4380.34
Nishi-hamasada Matsue City 525.089 4255.47 4363.92
Kouno Minami-Echizen Town 525.028 3227.62 4380.34
Kurihama Yokosuka City 523.708 2567.99 4380.34
Osaka prefectural Kumatori off-site-center Station 522.808 3547.8 4380.34
Ogasa branch Kikugawa City 522.039 4724.15 4366.66
Izumisano municipal Hineno primary scool Station 518.181 3080.34 4380.34
Shirasuna Omaezaki City 499.479 4578.87 4380.34
Jitougata primary school Makinohara City 498.059 4393.13 4380.34
Kataku Matsue City 497.007 3413.32 4380.34
Nishihemi Yokosuka City 496.917 2049.27 4380.34
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 496.721 4352.98
Satsuma-sendai monitoring center Satsuma-sendai City 495.302 3362.1 4380.34
Otomi Takahama Town 494.821 3765.55 4380.34
Otsu Nanao City 493.895 3778.35 4380.34
The Observation point for comparison Tatsunokuchi 493.454 3112.34 4380.34
Hitsuhama Ohi Town 492.630 3503 4380.34
Kijiyama Misasa Town 489.284 3554.22 4380.34
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 487.055 4352.98
Hiraba Omaezaki City 485.878 4578.87 4380.34
Tayu Matsue City 484.956 3560.64 4380.34
Hamaokakita primary school Omaezaki City 484.537 4692.24 4366.66
Oitomi Ayabe City 474.670 4514.82 4380.34
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 472.017 4352.98
Kashiwazaki-shigai Kashiwazaki City 470.822 3592.64 4380.34
Mitsu Matsue City 466.897 3406.94 4380.34
Tonomachi Kawasaki Ward 463.967 4316.28 4380.34
Daitou branch Kakegawa City 463.829 4622.03 4366.66
Fukura Shika Town 462.493 4297.07 4380.34
Nagasawa Yokosuka City 462.365 2510.36 4380.34
The athletic field Station of Kinki University 461.661 2836.96 4380.34
Koura Matsue City 461.049 4066.53 4380.34
Sakurasan Ward Omaezaki City 459.434 4431.56 4380.34
Tsuchikawa Nanao City 458.915 4181.8 4380.34
Kumatori Town office Station 457.917 2926.64 4380.34
Shinkango Omaezaki City 449.013 5129.6 4380.34
Ogurui Takahama Town 448.279 3355.68 4380.34
Kusabue Omaezaki City 444.162 4835.01 4380.34
Omaezaki City monitoring center 443.946 4745.36 4380.34
Akawase Kagamino Town 442.246 2926.64 4380.34
Ibaraki 442.139 2147.71 4372.13
Hinode Town Yokosuka City 438.324 1690.66 4380.34
Nishiyama Kashiwazaki City 437.251 5084.76 4380.34
Kariwa Kariwa Village 436.307 3835.98 4380.34
Osaka prefectural Hineno high scool Station 435.745 3419.74 4380.34
Miyagawa Kashiwazaki City 435.245 3784.76 4380.34
Radiation dose in Natori 434.640 4333.82
Kami-koubu Matsue City 433.868 3720.71 4380.34
Shimo-Takamachi Kariwa Village 433.192 4175.42 4380.34
Osaka prefectural Sano supporting school Station 432.398 3727.13 4380.34
Arahama Kashiwazaki City 428.874 3900.04 4380.34
Doai Kashiwazaki City 425.681 3669.49 4380.34
Owashi Matsue City 424.452 3637.48 4380.34
Okayasu Maizuru City 422.568 4284.28 4380.34
Katsuyama Kariwa Village 421.280 3900.04 4380.34
Kita-koubu Matsue City 420.683 3989.68 4380.34
Kichisaka Maizuru City 413.065 5206.45 4380.34
Nagai Ohi Town 410.699 3784.08 4372.13
Shiokumi Maizuru City 407.938 6480.86 4380.34
Miyadome Ohi Town 407.831 3137.97 4380.34
Kariwa Kariwa Village 407.617 4040.94 4380.34
Ueno Satsuma-sendai City 394.248 2933.02 4380.34
Power Station-South 389.191 4271.48 4380.34
Radiation dose at JAEA Oarai (P6) 386.963 4333.82
Power Station- 385.546 4169 4380.34
Takae Satsuma-sendai City 379.551 2971.44 4380.34
Hokawaduura Genkai Town 378.015 4524.43 4380.34
Kou Itimatsu Suetsugu 377.929 3266.04 4380.34
Minato Satsuma-sendai City 377.656 2721.69 4380.34
Iwanai Iwanai Town 376.336 4435.2 4377.6
Hattari Kyowa Town 373.047 4313.59 4377.6
Chatsu Tomari Village 371.011 4121.59 4377.6
Oyama Maizuru City 358.223 3752.76 4380.34
Kodaira Satsuma-sendai City 355.545 2753.73 4380.34
Kayanuma Tomari Village 354.809 3667.2 4377.6
Anojiri Obama City 353.215 3073.92 4380.34
Kushi Genkai Town 349.738 6243.9 4380.34
Yamaguchi 348.715 4909.06 4372.13
Sadahongou Matsue City 348.228 3823.19 4380.34
Sakibe Karatsu City 347.801 5917.3 4380.34
Hirao Genkai Town 343.814 6237.48 4380.34
The Meteorological Obsevatory of kyowa Town 343.275 4089.6 4377.6
Minami-Horoni Kyowa Town 335.180 3833.59 4377.6
Kounoura Takahama Town 330.353 3240.41 4380.34
Kyoudomarisaki Karatsu City 328.622 6339.96 4380.34
Horikappu Jinja Tomari Village 328.230 3967.99 4377.6
Hukada-kita Matsue City 327.031 3144.35 4380.34
Radiation dose in KEK, Tsukuba 326.240 4352.98
Herokaruusu Tomari Village 324.242 4115.21 4377.6
Yorita Satsuma-sendai City 323.218 3221.2 4380.34
Kamoenai Kamoenai Village 322.032 3475.2 4377.6
Radiation dose in Onagawa (MP-6) 316.267 4331.09
Imamura Genkai Town 314.749 53729.4 4380.34
Yamanaka Takahama Town 314.185 4181.8 4380.34
Sendai (Miyagi) 312.585 1967.46 4372.13
Radiation dose in Onagawa (MP-1) 300.147 4331.09
Gumisaki Satsuma-sendai City 295.693 2600.04 4380.34
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 286.142 4352.98
Aomori Aomori City 285.372 2643.19 4377.6
Misawa City hall Misawa City 283.728 5126.4 4377.6
Kashu Ikata Town 277.173 2683.26 4380.34
Noheji Town Office Noheji Town 272.004 2265.6 4377.6
Takasimamati 271.103 2856.17 4380.34
Radiation dose in Onagawa (MP-3) 270.563 4331.09
Kucho Ikata Town 269.545 2369.49 4380.34
Radiation dose in Marumori 269.436 4333.82
Kawanagata Ikata Town 266.821 2311.86 4380.34
Tochigi 260.733 2569.58 4372.13
Chikagawa Mutu City 256.719 2950.39 4377.6
Yokohama Town Office Yokohama Town 254.846 3616.01 4377.6
Tokyo 251.877 3029.81 4372.13
Hiranuma Rokkasho Village 251.186 2374.39 4377.6
Taisei Ikata Town 246.293 1735.5 4380.34
Chitose-daira Rokkasho Village 245.868 2560.01 4377.6
Gifu 243.951 4218.72 4372.13
Fukkoshi Yokohama Town 243.102 2483.21 4377.6
Shimane 240.651 4218.72 4372.13
Sunagomata Higashidoori Village 238.012 3590.4 4377.6
Obuchi Rokkasho Village 237.506 2854.39 4377.6
Tomari Rokkasho Village 230.636 3993.6 4377.6
kanagawa 226.339 2646.29 4372.13
Saitama 219.770 2301.12 4372.13
Ikatagoshi Ikata Town 217.515 2183.75 4380.34
Touhoku Branch office Touhoku Town 215.416 2067.19 4377.6
Radiation dose at Tohoku University 214.824 4333.82
Odanosawa Higashidoori Village 210.287 2860.8 4377.6
Kagawa 205.829 2953.1 4372.13
Oippe Higashidoori Village 205.182 2464.01 4377.6
Oita 200.921 3259.92 4372.13
Touhoku Town office Touhoku Town 200.811 9561.6 4377.6
Kuchogoshi Ikata Town 198.646 2215.8 4380.34
Minatoura Ikata Town 186.776 1991.63 4380.34
Radiation dose in Koyadori, Ojika 184.905 4328.35
Toyama 184.580 5637.74 4372.13
Fukushima [9] (distance from Fukushima I: 45 km) 184.232 2719.58 4366.66
Radiation dose in Tukahama, Ojika 183.417 4328.35
Chiba 182.407 1687.49 4372.13
Nara 182.387 3068.16 4372.13
Okayama 181.976 3988.61 4372.13
Yamagata 181.598 3144.86 4372.13
Ehime 180.745 2838.05 4372.13
Ishikawa 180.445 4889.88 4372.13
Niigata 177.483 5867.86 4372.13
Hiroshima 176.816 2646.29 4372.13
Mie 174.867 3025.97 4372.13
Fukui 170.045 3720.14 4372.13
Radiation dose in Terama, Ojika 168.036 4328.35
Yamanashi 164.561 2454.53 4372.13
Nagano 162.242 3735.48 4372.13
Saga 161.421 3298.27 4372.13
Tottori 161.392 3029.81 4372.13
Radiation dose in Enoshima, Ojika 160.091 4328.35
Osaka 159.103 2339.47 4372.13
Ibaraki-city Environment 157.249 4287.31
Aichi 149.345 2838.05 4372.13
Toyonoura Ikata Town 149.214 2286.23 4380.34
Shizuoka 148.639 2933.93 4372.13
Kyoto 144.522 3336.62 4372.13
Kagoshima 144.449 3616.59 4372.13
Tokushima 143.627 2569.58 4372.13
Gunma 143.572 1725.84 4372.13
Hyogo 139.710 2914.75 4372.13
Fukuoka 136.511 3029.81 4372.13
Wakayama 133.857 2147.71 4372.13
Radiation at Tamaki-cho Mie Japan 133.138 4287.31
Akita 132.832 3298.27 4372.13
Shiga 124.919 2339.47 4372.13
Nagasaki 109.459 2646.29 4372.13
Hokkaido 109.189 4026.96 4372.13
Kumamoto 103.568 2569.58 4372.13
Aomori 101.819 3911.9 4372.13
Miyazaki 100.354 2546.57 4372.13
Kochi 95.931 2914.75 4372.13
Fukushima [35] (distance from Fukushima I: 35 km) 91.917 2711.06 4352.98
Iwate 90.324 3221.57 4372.13
Environment Feeds from Ohta 83.623 4287.31
Okinawa 82.305 2205.24 4372.13
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