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Accumulated absorbed dose rate - T=13.03.2011 - 21.04.2015(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 4019.18
Fukushima I MP8 570942.000 4019.18
Fukushima I MP6 240668.000 4019.18
Yamada Futaba Town 176983.000 3000.88 3575.95
Fukushima I MP2 140420.000 4019.18
Fukushima I MP5 111325.000 4019.18
Fukushima [32] (distance from Fukushima I: 30 km) 101500.000 2547.48 4090.32
Fukushima I MP3 93730.602 4019.18
Fukushima I MP4 86821.500 4019.18
Fukushima [33] (distance from Fukushima I: 30 km) 77197.703 2547.48 4090.32
Fukushima [79] (distance from Fukushima I: 40 km) 54008.602 2496.36 4008.24
Fukushima [31] (distance from Fukushima I: 30 km) 40677.398 2547.48 4090.32
Ono Okuma Town 38610.500 2770.83 3575.95
Shinzan Futaba Town 38332.801 2514.68 3575.95
Fukushima I MP1 31496.801 4019.18
Yonomori Tomioka Town 29815.900 2864.93 3575.95
Fukushima [46] (distance from Fukushima I: 20 km) 28842.500 2547.48 4090.32
Tomioka Tomioka Town 25324.500 3084.51 3575.95
Fukushima [62] (distance from Fukushima I: 40 km) 16464.100 2547.48 4090.32
Fukushima [61] (distance from Fukushima I: 40 km) 13102.800 2547.48 4090.32
Shimo-Kooriyama Tomioka Town 13057.000 3063.62 3575.95
Fukushima [21] (distance from Fukushima I: 30 km) 12103.800 2547.48 4090.32
Fukushima [3] (distance from Fukushima I: 45 km) 11985.000 2547.48 4090.32
Kami-kooriyama Tomioka Town 11803.900 2404.89 3575.95
Fukushima II MP3 11060.600 4019.18
Fukushima II MP1 10903.000 4019.18
Kooriyama Futaba Town 10352.900 2802.2 3575.95
Fukushima II MP4 9696.330 4019.18
Fukushima [34] (distance from Fukushima I: 30 km) 9540.450 2544.07 4084.85
Fukushima II MP5 9382.150 4019.18
Fukushima [2] (distance from Fukushima I: 55 km) 8841.760 2547.48 4090.32
Matsudate Naraha Town 8410.890 3272.72 3575.95
Shigeoka Naraha Town 8115.970 3617.77 3575.95
Fukushima II MP2 7875.320 4019.18
Namie Namie Town 7321.210 2640.15 3575.95
Radiation dose at Shirasawa branch office, Motomiya 7287.920 4035.6
Fukushima II MP6 7062.690 4019.18
Fukushima II MP7 6511.580 4016.45
Fukushima [1] (distance from Fukushima I: 60 km) 5615.310 2547.48 4090.32
Fukushima [11] (distance from Fukushima I: 40 km) 5491.310 2547.48 4090.32
Fukushima [63] (distance from Fukushima I: 45 km) 5448.820 2547.48 4090.32
Fukushima [45] (distance from Fukushima I: 20 km) 3981.200 2547.48 4090.32
Fukushima [42] (distance from Fukushima I: 30 km) 3850.600 2547.48 4090.32
Fukushima [10] (distance from Fukushima I: 40 km) 3734.160 2547.48 4090.32
Fukushima [78] (distance from Fukushima I: 45 km) 3716.820 2542.37 4082.11
Futatsunuma Hirono Town 3520.340 3136.8 3575.95
Fukushima [4] (distance from Fukushima I: 50 km) 3386.310 2547.48 4090.32
Fukushima [7] (distance from Fukushima I: 45 km) 3313.930 2547.48 4090.32
Radiation dose at Koriyama joint government building, Koriyama 3232.890 4032.86
Fukushima [15] (distance from Fukushima I: 35 km) 3178.670 2547.48 4090.32
Kiyohashi Namie Town 3162.000 2315.99 3575.95
Fukushima [71] (distance from Fukushima I: 25 km) 3161.650 2542.37 4082.11
Radiation dose at Agricultural center, Koriyama 3128.960 4032.86
Fukushima [41] (distance from Fukushima I: 20 km) 3111.490 2547.48 4090.32
Radiation dose at Koriyama city office, Koriyama 2803.520 4032.86
Fukushima [44] (distance from Fukushima I: 30 km) 2535.550 2547.48 4090.32
Fukushima [72] (distance from Fukushima I: 30 km) 2344.620 2542.37 4082.11
Fukushima [43] (distance from Fukushima I: 20 km) 2244.110 2547.48 4090.32
Yamadaoka Naraha Town 2205.340 2781.31 3575.95
Radiation dose at Iwane Fureai Plaza, Motomiya 2169.060 4035.6
Fukushima [22] (distance from Fukushima I: 35 km) 2020.650 2547.48 4090.32
Kuji Hitachi City 1990.890 6331.78 4101.26
Hitachinaka Hitachinaka City 1951.950 2780.28 4098.53
Fukushima [76] (distance from Fukushima I: 25 km) 1945.520 2542.37 4082.11
Fukushima [80] (distance from Fukushima I: 25 km) 1876.860 2542.37 4082.11
Momiyama Hokota City 1837.540 3171.9 4101.26
Fukushima [77] (distance from Fukushima I: 25 km) 1802.490 2542.37 4082.11
Horiguchi Hitachinaka City 1779.410 2772 4104
Onuma Hitachi City 1776.950 2360.86 4098.53
Fukushima [6] (distance from Fukushima I: 45 km) 1741.180 2547.48 4090.32
Tsukuriya Hokota City 1736.890 2668.23 4101.26
Radiation dose at Big palette Fukushima, Koriyama 1668.540 4032.86
Nemoto Hitachioomiya City 1633.190 2972.04 4098.53
Fukushima [13] (distance from Fukushima I: 40 km) 1624.150 2547.48 4090.32
Fukushima [23] (distance from Fukushima I: 35 km) 1551.750 2547.48 4090.32
Radiation dose at Tsukidatemachi kamitedo, Date 1545.300 4041.07
Fukushima [14] (distance from Fukushima I: 35 km) 1543.460 2547.48 4090.32
Radiation dose at JAEA Oarai (P12) 1512.140 4057.49
Radiation dose at Ose administration center, Koriyama 1494.270 4032.86
Araji Hokota City 1437.760 2674.2 4101.26
Ishigami Tokai Village 1431.690 2434.39 4101.26
Mawatari Hitachinaka City 1422.870 2812.14 4101.26
Radiation dose at JAEA Oarai (P11) 1399.370 4057.49
Onuki Oarai Town 1387.990 2920.06 4101.26
Sawa Hitachinaka City 1353.770 2205.04 4098.53
Toyooka Tokai Village 1321.760 2680.21 4101.26
Ajigaura Hitachinaka City 1313.890 2636.47 4098.53
Fukushima [5] (distance from Fukushima I: 45 km) 1282.090 2547.48 4090.32
Geiger Counter Feeds from Asao Kawasaki 1266.620 4010.98
Radiation dose at Tamokami elementary school, Koriyama 1256.140 4032.86
Isohama Oarai Town 1250.540 2544.89 4095.79
Ebisawa Ibaraki Town 1222.240 6909.97 4098.53
Muramatsu Tokai Village 1203.520 2704.21 4101.26
Kamitoda Hokota City 1184.740 2218.53 4101.26
Yanagisawa Hitachinaka City 1166.970 2258.97 4098.53
Tokushuku Hokota City 1159.730 2002.68 4101.26
Tasaki Hokota City 1153.300 2362.96 4071.17
Fukushima [20] (distance from Fukushima I: 45 km) 1145.390 2547.48 4090.32
Kadobe Naka City 1086.580 5380.83 4098.53
Radiation dose at Date city office, Date 1076.050 4035.6
Oshinobe Tokai Village 1041.340 2524.33 4101.26
Oba Mito City 1037.670 8292.47 4101.26
Godai Naka City 1031.270 2188.53 4101.26
Ishikawa Mito City 1030.810 2580.01 4104
Isobe Hitachiota City 1013.130 12447.7 4101.26
Yatabe Ibaraki Town 996.127 2164.57 4101.26
Radiation dose at Motomiya city office, Motomiya 992.703 4035.6
Fukushima [73] (distance from Fukushima I: 35 km) 981.984 2542.37 4082.11
Fukushima [75] (distance from Fukushima I: 45 km) 960.529 2542.37 4082.11
Yokobori Naka City 930.280 2536.31 4101.26
Sugaya Naka City 926.186 3876.01 4104
Kounosu Naka City 926.087 1978.68 4101.26
Funaishikawa Tokai Village 900.399 2626.25 4101.26
Nukada Naka City 899.900 2371.25 4095.79
Uridura Naka City 890.113 2263.46 4095.79
Shiraki Tsuruga City 881.330 4806 4104
Motokomezaki Naka City 880.851 2105.59 4068.43
Shiraki pass Tsuruga City 850.284 5033.99 4104
Radiation dose in Yamamoto 846.633 4057.49
Yoshizawa Mito City 837.646 2290.48 4101.26
Radiation dose at JAEA Oarai (P7) 831.135 4057.49
Mayumi Hitachiota City 828.119 2272.5 4101.26
Urasoko Tsuruga City 826.465 3989.99 4104
Nemoto Hitachioomiya City 825.588 2558.6 4098.53
Takenami Mihama Town 804.283 4187.99 4104
Radiation dose at JAEA Oarai (P15) 780.207 4057.49
Tateishi Tsuruga City 780.092 3318.01 4104
Radiation dose at JAEA Oarai (P14) 770.174 4057.49
Radiation dose at JAEA Oarai (P13) 769.612 4057.49
Ukishima Kawasaki Ward 735.475 7830 4104
Kume Hitachiota City 713.958 2224.5 4101.26
Radiation dose at JAEA Oarai (P2) 712.011 4057.49
Fukushima [74] (distance from Fukushima I: 35 km) 706.552 2542.37 4082.11
Nyuu Mihama Town 674.787 3816 4104
Fukushima [52] (distance from Fukushima I: 40 km) 672.743 2547.48 4090.32
Radiation dose in Iwanuma 670.242 4057.49
Fukushima [51] (distance from Fukushima I: 40 km) 665.376 2547.48 4090.32
Tsuruga Tsuruga City 655.360 3366 4104
Shiohama Kawasaki Ward 653.536 2688.01 4104
Radiation dose in Kakuda 649.863 4057.49
Sakajiri Mihama Town 649.252 4452.01 4104
North point of Kinki University Atomic Energy Research Instirute Station 639.566 2796.01 4104
Radiation dose in Onagawa (MP-2) 632.968 4054.75
Kumatori town Nishi primary school Station 631.491 3341.99 4104
Oshima Kawasaki Ward 630.402 2562.01 4104
Izumisano municipal Oike athletic field Station 629.920 3768.01 4104
Atom-kyoudou nursery school Station 625.566 3618 4104
South point of Kinki University Atomic Energy Research Instirute Station 625.202 3294 4104
Nakamachi Omaezaki City 623.494 4241.99 4104
Uraga Yokosuka City 622.492 2009.99 4104
Goritoge Shika Town 622.143 4506.01 4104
Kumatori town Minami primary school Station 606.134 3834 4104
Radiation dose at JAEA Oarai (P1) 603.643 4060.22
Yamanotedai-No.1 Park Station 599.140 3575.99 4104
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 595.502 4076.64
Noumi Shika Town 594.021 4457.99 4104
Radiation dose in Watari 591.851 4057.49
Hairando Yokosuka City 588.667 2520 4104
Fukushima [12] (distance from Fukushima I: 40 km) 588.291 2547.48 4090.32
Ningyotoge Kagamino Town 574.857 3575.99 4104
Ten-no Kagamino Town 569.960 4284 4104
Funagura Yokosuka City 563.909 2376 4104
Chidori Kawasaki Ward 560.211 2297.99 4104
Radiation dose at JAEA Oarai (P16) 556.365 4057.49
Shika Shika Town 551.376 4295.99 4104
Higashiosaka municipal Kamikosaka primary scool Station 550.277 2790 4104
Sahara Yokosuka City 547.404 2225.99 4104
Kazanashi Shika Town 545.377 4032 4104
Akasumi Shika Town 544.970 3690 4104
Kurahashi Maizuru City 540.820 3359.99 4104
Obama Obama City 540.809 3006 4104
Sakuragaike community hall Omaezaki City 540.772 4349.99 4104
Shirowa primary school Omaezaki City 535.692 4259.99 4104
Radiation dose at JAEA Oarai (P5) 529.759 4057.49
Uenohara Omaezaki City 529.333 4380.01 4104
Kumano Shika Town 529.019 4182.01 4104
Izumisano municipal Hineno filtration plant Station 527.471 3606.01 4104
Nishi-hamasada Matsue City 525.089 3986 4087.58
Kouno Minami-Echizen Town 525.028 3024 4104
Kurihama Yokosuka City 523.708 2405.99 4104
Osaka prefectural Kumatori off-site-center Station 522.808 3323.99 4104
Ogasa branch Kikugawa City 522.039 4425.19 4090.32
Izumisano municipal Hineno primary scool Station 518.181 2886.01 4104
Shirasuna Omaezaki City 499.479 4290.01 4104
Jitougata primary school Makinohara City 498.059 4115.99 4104
Kataku Matsue City 497.007 3197.99 4104
Nishihemi Yokosuka City 496.917 1919.99 4104
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 496.721 4076.64
Satsuma-sendai monitoring center Satsuma-sendai City 495.302 3150 4104
Otomi Takahama Town 494.821 3528 4104
Otsu Nanao City 493.895 3539.99 4104
The Observation point for comparison Tatsunokuchi 493.454 2916 4104
Hitsuhama Ohi Town 492.630 3282.01 4104
Kijiyama Misasa Town 489.284 3330 4104
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 487.055 4076.64
Hiraba Omaezaki City 485.878 4290.01 4104
Tayu Matsue City 484.956 3336.01 4104
Hamaokakita primary school Omaezaki City 484.537 4395.3 4090.32
Oitomi Ayabe City 474.670 4230 4104
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 472.017 4076.64
Kashiwazaki-shigai Kashiwazaki City 470.822 3366 4104
Mitsu Matsue City 466.897 3192.01 4104
Tonomachi Kawasaki Ward 463.967 4043.99 4104
Daitou branch Kakegawa City 463.829 4329.53 4090.32
Fukura Shika Town 462.493 4025.99 4104
Nagasawa Yokosuka City 462.365 2351.99 4104
The athletic field Station of Kinki University 461.661 2657.99 4104
Koura Matsue City 461.049 3809.99 4104
Sakurasan Ward Omaezaki City 459.434 4151.99 4104
Tsuchikawa Nanao City 458.915 3917.99 4104
Kumatori Town office Station 457.917 2742.01 4104
Shinkango Omaezaki City 449.013 4806 4104
Ogurui Takahama Town 448.279 3143.99 4104
Kusabue Omaezaki City 444.162 4529.99 4104
Omaezaki City monitoring center 443.946 4446 4104
Akawase Kagamino Town 442.246 2742.01 4104
Ibaraki 442.139 2011.97 4095.79
Hinode Town Yokosuka City 438.324 1584 4104
Nishiyama Kashiwazaki City 437.251 4763.99 4104
Kariwa Kariwa Village 436.307 3593.99 4104
Osaka prefectural Hineno high scool Station 435.745 3204 4104
Miyagawa Kashiwazaki City 435.245 3546 4104
Radiation dose in Natori 434.640 4057.49
Kami-koubu Matsue City 433.868 3485.99 4104
Shimo-Takamachi Kariwa Village 433.192 3912.01 4104
Osaka prefectural Sano supporting school Station 432.398 3492 4104
Arahama Kashiwazaki City 428.874 3654 4104
Doai Kashiwazaki City 425.681 3438 4104
Owashi Matsue City 424.452 3408.01 4104
Okayasu Maizuru City 422.568 4014 4104
Katsuyama Kariwa Village 421.280 3654 4104
Kita-koubu Matsue City 420.683 3737.99 4104
Kichisaka Maizuru City 413.065 4878 4104
Nagai Ohi Town 410.699 3544.91 4095.79
Shiokumi Maizuru City 407.938 6072.01 4104
Miyadome Ohi Town 407.831 2940.01 4104
Kariwa Kariwa Village 407.617 3786.01 4104
Ueno Satsuma-sendai City 394.248 2747.99 4104
Power Station-South 389.191 4002.01 4104
Radiation dose at JAEA Oarai (P6) 386.963 4057.49
Power Station- 385.546 3906 4104
Takae Satsuma-sendai City 379.551 2783.99 4104
Hokawaduura Genkai Town 378.015 4239 4104
Kou Itimatsu Suetsugu 377.929 3060 4104
Minato Satsuma-sendai City 377.656 2549.99 4104
Iwanai Iwanai Town 376.336 4155.23 4101.26
Hattari Kyowa Town 373.047 4041.29 4101.26
Chatsu Tomari Village 371.011 3861.41 4101.26
Oyama Maizuru City 358.223 3516.01 4104
Kodaira Satsuma-sendai City 355.545 2580.01 4104
Kayanuma Tomari Village 354.809 3435.71 4101.26
Anojiri Obama City 353.215 2880 4104
Kushi Genkai Town 349.738 5850 4104
Yamaguchi 348.715 4598.78 4095.79
Sadahongou Matsue City 348.228 3582 4104
Sakibe Karatsu City 347.801 5544 4104
Hirao Genkai Town 343.814 5843.99 4104
The Meteorological Obsevatory of kyowa Town 343.275 3831.44 4101.26
Minami-Horoni Kyowa Town 335.180 3591.59 4101.26
Kounoura Takahama Town 330.353 3035.99 4104
Kyoudomarisaki Karatsu City 328.622 5940 4104
Horikappu Jinja Tomari Village 328.230 3717.51 4101.26
Hukada-kita Matsue City 327.031 2945.99 4104
Radiation dose in KEK, Tsukuba 326.240 4076.64
Herokaruusu Tomari Village 324.242 3855.44 4101.26
Yorita Satsuma-sendai City 323.218 3017.99 4104
Kamoenai Kamoenai Village 322.032 3255.83 4101.26
Radiation dose in Onagawa (MP-6) 316.267 4054.75
Imamura Genkai Town 314.749 50339.9 4104
Yamanaka Takahama Town 314.185 3917.99 4104
Sendai (Miyagi) 312.585 1843.11 4095.79
Radiation dose in Onagawa (MP-1) 300.147 4054.75
Gumisaki Satsuma-sendai City 295.693 2436.01 4104
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 286.142 4076.64
Aomori Aomori City 285.372 2476.34 4101.26
Misawa City hall Misawa City 283.728 4802.8 4101.26
Kashu Ikata Town 277.173 2513.99 4104
Noheji Town Office Noheji Town 272.004 2122.58 4101.26
Takasimamati 271.103 2675.99 4104
Radiation dose in Onagawa (MP-3) 270.563 4054.75
Kucho Ikata Town 269.545 2220.01 4104
Radiation dose in Marumori 269.436 4057.49
Kawanagata Ikata Town 266.821 2166.01 4104
Tochigi 260.733 2407.18 4095.79
Chikagawa Mutu City 256.719 2764.14 4101.26
Yokohama Town Office Yokohama Town 254.846 3387.75 4101.26
Tokyo 251.877 2838.31 4095.79
Hiranuma Rokkasho Village 251.186 2224.5 4101.26
Taisei Ikata Town 246.293 1626.01 4104
Chitose-daira Rokkasho Village 245.868 2398.41 4101.26
Gifu 243.951 3952.08 4095.79
Fukkoshi Yokohama Town 243.102 2326.46 4101.26
Shimane 240.651 3952.08 4095.79
Sunagomata Higashidoori Village 238.012 3363.76 4101.26
Obuchi Rokkasho Village 237.506 2674.2 4101.26
Tomari Rokkasho Village 230.636 3741.5 4101.26
kanagawa 226.339 2479.03 4095.79
Saitama 219.770 2155.68 4095.79
Ikatagoshi Ikata Town 217.515 2045.99 4104
Touhoku Branch office Touhoku Town 215.416 1936.7 4101.26
Radiation dose at Tohoku University 214.824 4057.49
Odanosawa Higashidoori Village 210.287 2680.21 4101.26
Kagawa 205.829 2766.46 4095.79
Oippe Higashidoori Village 205.182 2308.47 4101.26
Oita 200.921 3053.88 4095.79
Touhoku Town office Touhoku Town 200.811 8958.02 4101.26
Kuchogoshi Ikata Town 198.646 2076.01 4104
Minatoura Ikata Town 186.776 1865.99 4104
Radiation dose in Koyadori, Ojika 184.905 4052.02
Toyama 184.580 5281.42 4095.79
Fukushima [9] (distance from Fukushima I: 45 km) 184.232 2547.48 4090.32
Radiation dose in Tukahama, Ojika 183.417 4052.02
Chiba 182.407 1580.83 4095.79
Nara 182.387 2874.24 4095.79
Okayama 181.976 3736.51 4095.79
Yamagata 181.598 2946.1 4095.79
Ehime 180.745 2658.67 4095.79
Ishikawa 180.445 4580.82 4095.79
Niigata 177.483 5496.98 4095.79
Hiroshima 176.816 2479.03 4095.79
Mie 174.867 2834.72 4095.79
Fukui 170.045 3485.02 4095.79
Radiation dose in Terama, Ojika 168.036 4052.02
Yamanashi 164.561 2299.39 4095.79
Nagano 162.242 3499.39 4095.79
Saga 161.421 3089.81 4095.79
Tottori 161.392 2838.31 4095.79
Radiation dose in Enoshima, Ojika 160.091 4052.02
Osaka 159.103 2191.61 4095.79
Ibaraki-city Environment 157.249 4010.98
Aichi 149.345 2658.67 4095.79
Toyonoura Ikata Town 149.214 2142 4104
Shizuoka 148.639 2748.49 4095.79
Kyoto 144.522 3125.74 4095.79
Kagoshima 144.449 3388.01 4095.79
Tokushima 143.627 2407.18 4095.79
Gunma 143.572 1616.76 4095.79
Hyogo 139.710 2730.53 4095.79
Fukuoka 136.511 2838.31 4095.79
Wakayama 133.857 2011.97 4095.79
Radiation at Tamaki-cho Mie Japan 133.138 4010.98
Akita 132.832 3089.81 4095.79
Shiga 124.919 2191.61 4095.79
Nagasaki 109.459 2479.03 4095.79
Hokkaido 109.189 3772.44 4095.79
Kumamoto 103.568 2407.18 4095.79
Aomori 101.819 3664.66 4095.79
Miyazaki 100.354 2385.62 4095.79
Kochi 95.931 2730.53 4095.79
Fukushima [35] (distance from Fukushima I: 35 km) 91.917 2538.96 4076.64
Iwate 90.324 3017.95 4095.79
Environment Feeds from Ohta 83.623 4010.98
Okinawa 82.305 2065.86 4095.79
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
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Summary

Japan nuclear accident