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Accumulated absorbed dose rate - T=13.03.2011 - 22.01.2017(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 5775.7
Fukushima I MP8 570942.000 5775.7
Fukushima I MP6 240668.000 5775.7
Yamada Futaba Town 176983.000 4474.92 5332.46
Fukushima I MP2 140420.000 5775.7
Fukushima I MP5 111325.000 5775.7
Fukushima [32] (distance from Fukushima I: 30 km) 101500.000 3641.45 5846.83
Fukushima I MP3 93730.602 5775.7
Fukushima I MP4 86821.500 5775.7
Fukushima [33] (distance from Fukushima I: 30 km) 77197.703 3641.45 5846.83
Fukushima [79] (distance from Fukushima I: 40 km) 54008.602 3590.33 5764.75
Fukushima [31] (distance from Fukushima I: 30 km) 40677.398 3641.45 5846.83
Ono Okuma Town 38610.500 4131.86 5332.46
Shinzan Futaba Town 38332.801 3749.89 5332.46
Fukushima I MP1 31496.801 5775.7
Yonomori Tomioka Town 29815.900 4272.19 5332.46
Fukushima [46] (distance from Fukushima I: 20 km) 28842.500 3641.45 5846.83
Tomioka Tomioka Town 25324.500 4599.62 5332.46
Fukushima [62] (distance from Fukushima I: 40 km) 16464.100 3641.45 5846.83
Fukushima [61] (distance from Fukushima I: 40 km) 13102.800 3641.45 5846.83
Shimo-Kooriyama Tomioka Town 13057.000 4568.47 5332.46
Fukushima [21] (distance from Fukushima I: 30 km) 12103.800 3641.45 5846.83
Fukushima [3] (distance from Fukushima I: 45 km) 11985.000 3641.45 5846.83
Kami-kooriyama Tomioka Town 11803.900 3586.18 5332.46
Fukushima II MP3 11060.600 5775.7
Fukushima II MP1 10903.000 5775.7
Kooriyama Futaba Town 10352.900 4178.64 5332.46
Fukushima II MP4 9696.330 5775.7
Fukushima [34] (distance from Fukushima I: 30 km) 9540.450 3638.04 5841.36
Fukushima II MP5 9382.150 5775.7
Fukushima [2] (distance from Fukushima I: 55 km) 8841.760 3641.45 5846.83
Matsudate Naraha Town 8410.890 4880.28 5332.46
Shigeoka Naraha Town 8115.970 5394.82 5332.46
Fukushima II MP2 7875.320 5775.7
Namie Namie Town 7321.210 3937 5332.46
Radiation dose at Shirasawa branch office, Motomiya 7287.920 5792.11
Fukushima II MP6 7062.690 5775.7
Fukushima II MP7 6511.580 5772.96
Fukushima [1] (distance from Fukushima I: 60 km) 5615.310 3641.45 5846.83
Fukushima [11] (distance from Fukushima I: 40 km) 5491.310 3641.45 5846.83
Fukushima [63] (distance from Fukushima I: 45 km) 5448.820 3641.45 5846.83
Fukushima [45] (distance from Fukushima I: 20 km) 3981.200 3641.45 5846.83
Fukushima [42] (distance from Fukushima I: 30 km) 3850.600 3641.45 5846.83
Fukushima [10] (distance from Fukushima I: 40 km) 3734.160 3641.45 5846.83
Fukushima [78] (distance from Fukushima I: 45 km) 3716.820 3636.34 5838.62
Futatsunuma Hirono Town 3520.340 4677.6 5332.46
Fukushima [4] (distance from Fukushima I: 50 km) 3386.310 3641.45 5846.83
Fukushima [7] (distance from Fukushima I: 45 km) 3313.930 3641.45 5846.83
Radiation dose at Koriyama joint government building, Koriyama 3232.890 5789.38
Fukushima [15] (distance from Fukushima I: 35 km) 3178.670 3641.45 5846.83
Kiyohashi Namie Town 3162.000 3453.61 5332.46
Fukushima [71] (distance from Fukushima I: 25 km) 3161.650 3636.34 5838.62
Radiation dose at Agricultural center, Koriyama 3128.960 5789.38
Fukushima [41] (distance from Fukushima I: 20 km) 3111.490 3641.45 5846.83
Radiation dose at Koriyama city office, Koriyama 2803.520 5789.38
Fukushima [44] (distance from Fukushima I: 30 km) 2535.550 3641.45 5846.83
Fukushima [72] (distance from Fukushima I: 30 km) 2344.620 3636.34 5838.62
Fukushima [43] (distance from Fukushima I: 20 km) 2244.110 3641.45 5846.83
Yamadaoka Naraha Town 2205.340 4147.49 5332.46
Radiation dose at Iwane Fureai Plaza, Motomiya 2169.060 5792.11
Fukushima [22] (distance from Fukushima I: 35 km) 2020.650 3641.45 5846.83
Kuji Hitachi City 1990.890 9043.58 5857.78
Hitachinaka Hitachinaka City 1951.950 3971.82 5855.04
Fukushima [76] (distance from Fukushima I: 25 km) 1945.520 3636.34 5838.62
Fukushima [80] (distance from Fukushima I: 25 km) 1876.860 3636.34 5838.62
Momiyama Hokota City 1837.540 4530.37 5857.78
Fukushima [77] (distance from Fukushima I: 25 km) 1802.490 3636.34 5838.62
Horiguchi Hitachinaka City 1779.410 3958.42 5860.51
Onuma Hitachi City 1776.950 3372.66 5855.04
Fukushima [6] (distance from Fukushima I: 45 km) 1741.180 3641.45 5846.83
Tsukuriya Hokota City 1736.890 3811 5857.78
Radiation dose at Big palette Fukushima, Koriyama 1668.540 5789.38
Nemoto Hitachioomiya City 1633.190 4245.78 5855.04
Fukushima [13] (distance from Fukushima I: 40 km) 1624.150 3641.45 5846.83
Fukushima [23] (distance from Fukushima I: 35 km) 1551.750 3641.45 5846.83
Radiation dose at Tsukidatemachi kamitedo, Date 1545.300 5797.58
Fukushima [14] (distance from Fukushima I: 35 km) 1543.460 3641.45 5846.83
Radiation dose at JAEA Oarai (P12) 1512.140 5814
Radiation dose at Ose administration center, Koriyama 1494.270 5789.38
Araji Hokota City 1437.760 3819.53 5857.78
Ishigami Tokai Village 1431.690 3477 5857.78
Mawatari Hitachinaka City 1422.870 4016.53 5857.78
Radiation dose at JAEA Oarai (P11) 1399.370 5814
Onuki Oarai Town 1387.990 4170.69 5857.78
Sawa Hitachinaka City 1353.770 3150.06 5855.04
Toyooka Tokai Village 1321.760 3828.11 5857.78
Ajigaura Hitachinaka City 1313.890 3766.38 5855.04
Fukushima [5] (distance from Fukushima I: 45 km) 1282.090 3641.45 5846.83
Geiger Counter Feeds from Asao Kawasaki 1266.620 5767.49
Radiation dose at Tamokami elementary school, Koriyama 1256.140 5789.38
Isohama Oarai Town 1250.540 3636.28 5852.3
Ebisawa Ibaraki Town 1222.240 9871.39 5855.04
Muramatsu Tokai Village 1203.520 3862.38 5857.78
Kamitoda Hokota City 1184.740 3168.7 5857.78
Yanagisawa Hitachinaka City 1166.970 3227.1 5855.04
Tokushuku Hokota City 1159.730 2860.39 5857.78
Tasaki Hokota City 1153.300 3382.46 5827.68
Fukushima [20] (distance from Fukushima I: 45 km) 1145.390 3641.45 5846.83
Kadobe Naka City 1086.580 7686.9 5855.04
Radiation dose at Date city office, Date 1076.050 5792.11
Oshinobe Tokai Village 1041.340 3605.46 5857.78
Oba Mito City 1037.670 11844 5857.78
Godai Naka City 1031.270 3125.84 5857.78
Ishikawa Mito City 1030.810 3684.26 5860.51
Isobe Hitachiota City 1013.130 17778.9 5857.78
Yatabe Ibaraki Town 996.127 3091.62 5857.78
Radiation dose at Motomiya city office, Motomiya 992.703 5792.11
Fukushima [73] (distance from Fukushima I: 35 km) 981.984 3636.34 5838.62
Fukushima [75] (distance from Fukushima I: 45 km) 960.529 3636.34 5838.62
Yokobori Naka City 930.280 3622.57 5857.78
Sugaya Naka City 926.186 5534.95 5860.51
Kounosu Naka City 926.087 2826.12 5857.78
Funaishikawa Tokai Village 900.399 3751.03 5857.78
Nukada Naka City 899.900 3388.18 5852.3
Uridura Naka City 890.113 3234.17 5852.3
Shiraki Tsuruga City 881.330 6862.97 5860.51
Motokomezaki Naka City 880.851 3014.66 5824.94
Shiraki pass Tsuruga City 850.284 7188.54 5860.51
Radiation dose in Yamamoto 846.633 5814
Yoshizawa Mito City 837.646 3271.47 5857.78
Radiation dose at JAEA Oarai (P7) 831.135 5814
Mayumi Hitachiota City 828.119 3245.77 5857.78
Urasoko Tsuruga City 826.465 5697.7 5860.51
Nemoto Hitachioomiya City 825.588 3655.14 5855.04
Takenami Mihama Town 804.283 5980.45 5860.51
Radiation dose at JAEA Oarai (P15) 780.207 5814
Tateishi Tsuruga City 780.092 4738.12 5860.51
Radiation dose at JAEA Oarai (P14) 770.174 5814
Radiation dose at JAEA Oarai (P13) 769.612 5814
Ukishima Kawasaki Ward 735.475 11181.2 5860.51
Kume Hitachiota City 713.958 3177.23 5857.78
Radiation dose at JAEA Oarai (P2) 712.011 5814
Fukushima [74] (distance from Fukushima I: 35 km) 706.552 3636.34 5838.62
Nyuu Mihama Town 674.787 5449.25 5860.51
Fukushima [52] (distance from Fukushima I: 40 km) 672.743 3641.45 5846.83
Radiation dose in Iwanuma 670.242 5814
Fukushima [51] (distance from Fukushima I: 40 km) 665.376 3641.45 5846.83
Tsuruga Tsuruga City 655.360 4806.65 5860.51
Shiohama Kawasaki Ward 653.536 3838.48 5860.51
Radiation dose in Kakuda 649.863 5814
Sakajiri Mihama Town 649.252 6357.47 5860.51
North point of Kinki University Atomic Energy Research Instirute Station 639.566 3992.71 5860.51
Radiation dose in Onagawa (MP-2) 632.968 5811.26
Kumatori town Nishi primary school Station 631.491 4772.36 5860.51
Oshima Kawasaki Ward 630.402 3658.55 5860.51
Izumisano municipal Oike athletic field Station 629.920 5380.72 5860.51
Atom-kyoudou nursery school Station 625.566 5166.5 5860.51
South point of Kinki University Atomic Energy Research Instirute Station 625.202 4703.83 5860.51
Nakamachi Omaezaki City 623.494 6057.56 5860.51
Uraga Yokosuka City 622.492 2870.26 5860.51
Goritoge Shika Town 622.143 6434.58 5860.51
Kumatori town Minami primary school Station 606.134 5474.95 5860.51
Radiation dose at JAEA Oarai (P1) 603.643 5816.74
Yamanotedai-No.1 Park Station 599.140 5106.51 5860.51
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 595.502 5833.15
Noumi Shika Town 594.021 6366.01 5860.51
Radiation dose in Watari 591.851 5814
Hairando Yokosuka City 588.667 3598.56 5860.51
Fukushima [12] (distance from Fukushima I: 40 km) 588.291 3641.45 5846.83
Ningyotoge Kagamino Town 574.857 5106.51 5860.51
Ten-no Kagamino Town 569.960 6117.55 5860.51
Funagura Yokosuka City 563.909 3392.93 5860.51
Chidori Kawasaki Ward 560.211 3281.53 5860.51
Radiation dose at JAEA Oarai (P16) 556.365 5814
Shika Shika Town 551.376 6134.67 5860.51
Higashiosaka municipal Kamikosaka primary scool Station 550.277 3984.12 5860.51
Sahara Yokosuka City 547.404 3178.71 5860.51
Kazanashi Shika Town 545.377 5757.7 5860.51
Akasumi Shika Town 544.970 5269.32 5860.51
Kurahashi Maizuru City 540.820 4798.06 5860.51
Obama Obama City 540.809 4292.57 5860.51
Sakuragaike community hall Omaezaki City 540.772 6211.78 5860.51
Shirowa primary school Omaezaki City 535.692 6083.26 5860.51
Radiation dose at JAEA Oarai (P5) 529.759 5814
Uenohara Omaezaki City 529.333 6254.66 5860.51
Kumano Shika Town 529.019 5971.91 5860.51
Izumisano municipal Hineno filtration plant Station 527.471 5149.39 5860.51
Nishi-hamasada Matsue City 525.089 5698.87 5844.1
Kouno Minami-Echizen Town 525.028 4318.27 5860.51
Kurihama Yokosuka City 523.708 3435.75 5860.51
Osaka prefectural Kumatori off-site-center Station 522.808 4746.65 5860.51
Ogasa branch Kikugawa City 522.039 6325.5 5846.83
Izumisano municipal Hineno primary scool Station 518.181 4121.23 5860.51
Shirasuna Omaezaki City 499.479 6126.14 5860.51
Jitougata primary school Makinohara City 498.059 5877.63 5860.51
Kataku Matsue City 497.007 4566.73 5860.51
Nishihemi Yokosuka City 496.917 2741.74 5860.51
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 496.721 5833.15
Satsuma-sendai monitoring center Satsuma-sendai City 495.302 4498.2 5860.51
Otomi Takahama Town 494.821 5037.98 5860.51
Otsu Nanao City 493.895 5055.1 5860.51
The Observation point for comparison Tatsunokuchi 493.454 4164.05 5860.51
Hitsuhama Ohi Town 492.630 4686.71 5860.51
Kijiyama Misasa Town 489.284 4755.24 5860.51
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 487.055 5833.15
Hiraba Omaezaki City 485.878 6126.14 5860.51
Tayu Matsue City 484.956 4763.83 5860.51
Hamaokakita primary school Omaezaki City 484.537 6282.78 5846.83
Oitomi Ayabe City 474.670 6040.44 5860.51
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 472.017 5833.15
Kashiwazaki-shigai Kashiwazaki City 470.822 4806.65 5860.51
Mitsu Matsue City 466.897 4558.19 5860.51
Tonomachi Kawasaki Ward 463.967 5774.81 5860.51
Daitou branch Kakegawa City 463.829 6188.77 5846.83
Fukura Shika Town 462.493 5749.11 5860.51
Nagasawa Yokosuka City 462.365 3358.64 5860.51
The athletic field Station of Kinki University 461.661 3795.61 5860.51
Koura Matsue City 461.049 5440.66 5860.51
Sakurasan Ward Omaezaki City 459.434 5929.04 5860.51
Tsuchikawa Nanao City 458.915 5594.89 5860.51
Kumatori Town office Station 457.917 3915.59 5860.51
Shinkango Omaezaki City 449.013 6862.97 5860.51
Ogurui Takahama Town 448.279 4489.61 5860.51
Kusabue Omaezaki City 444.162 6468.82 5860.51
Omaezaki City monitoring center 443.946 6348.89 5860.51
Akawase Kagamino Town 442.246 3915.59 5860.51
Ibaraki 442.139 2874.82 5852.3
Hinode Town Yokosuka City 438.324 2261.95 5860.51
Nishiyama Kashiwazaki City 437.251 6802.97 5860.51
Kariwa Kariwa Village 436.307 5132.21 5860.51
Osaka prefectural Hineno high scool Station 435.745 4575.31 5860.51
Miyagawa Kashiwazaki City 435.245 5063.69 5860.51
Radiation dose in Natori 434.640 5814
Kami-koubu Matsue City 433.868 4977.99 5860.51
Shimo-Takamachi Kariwa Village 433.192 5586.35 5860.51
Osaka prefectural Sano supporting school Station 432.398 4986.58 5860.51
Arahama Kashiwazaki City 428.874 5217.91 5860.51
Doai Kashiwazaki City 425.681 4909.46 5860.51
Owashi Matsue City 424.452 4866.64 5860.51
Okayasu Maizuru City 422.568 5731.99 5860.51
Katsuyama Kariwa Village 421.280 5217.91 5860.51
Kita-koubu Matsue City 420.683 5337.85 5860.51
Kichisaka Maizuru City 413.065 6965.78 5860.51
Nagai Ohi Town 410.699 5065.17 5852.3
Shiokumi Maizuru City 407.938 8670.83 5860.51
Miyadome Ohi Town 407.831 4198.34 5860.51
Kariwa Kariwa Village 407.617 5406.43 5860.51
Ueno Satsuma-sendai City 394.248 3924.13 5860.51
Power Station-South 389.191 5714.87 5860.51
Radiation dose at JAEA Oarai (P6) 386.963 5814
Power Station- 385.546 5577.77 5860.51
Takae Satsuma-sendai City 379.551 3975.53 5860.51
Hokawaduura Genkai Town 378.015 6053.29 5860.51
Kou Itimatsu Suetsugu 377.929 4369.68 5860.51
Minato Satsuma-sendai City 377.656 3641.38 5860.51
Iwanai Iwanai Town 376.336 5934.85 5857.78
Hattari Kyowa Town 373.047 5772.12 5857.78
Chatsu Tomari Village 371.011 5515.2 5857.78
Oyama Maizuru City 358.223 5020.87 5860.51
Kodaira Satsuma-sendai City 355.545 3684.26 5860.51
Kayanuma Tomari Village 354.809 4907.17 5857.78
Anojiri Obama City 353.215 4112.64 5860.51
Kushi Genkai Town 349.738 8353.8 5860.51
Yamaguchi 348.715 6571.01 5852.3
Sadahongou Matsue City 348.228 5115.1 5860.51
Sakibe Karatsu City 347.801 7916.83 5860.51
Hirao Genkai Town 343.814 8345.21 5860.51
The Meteorological Obsevatory of kyowa Town 343.275 5472.4 5857.78
Minami-Horoni Kyowa Town 335.180 5129.82 5857.78
Kounoura Takahama Town 330.353 4335.39 5860.51
Kyoudomarisaki Karatsu City 328.622 8482.32 5860.51
Horikappu Jinja Tomari Village 328.230 5309.66 5857.78
Hukada-kita Matsue City 327.031 4206.87 5860.51
Radiation dose in KEK, Tsukuba 326.240 5833.15
Herokaruusu Tomari Village 324.242 5506.67 5857.78
Yorita Satsuma-sendai City 323.218 4309.69 5860.51
Kamoenai Kamoenai Village 322.032 4650.25 5857.78
Radiation dose in Onagawa (MP-6) 316.267 5811.26
Imamura Genkai Town 314.749 71885.3 5860.51
Yamanaka Takahama Town 314.185 5594.89 5860.51
Sendai (Miyagi) 312.585 2633.54 5852.3
Radiation dose in Onagawa (MP-1) 300.147 5811.26
Gumisaki Satsuma-sendai City 295.693 3478.63 5860.51
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 286.142 5833.15
Aomori Aomori City 285.372 3536.92 5857.78
Misawa City hall Misawa City 283.728 6859.76 5857.78
Kashu Ikata Town 277.173 3589.98 5860.51
Noheji Town Office Noheji Town 272.004 3031.66 5857.78
Takasimamati 271.103 3821.31 5860.51
Radiation dose in Onagawa (MP-3) 270.563 5811.26
Kucho Ikata Town 269.545 3170.18 5860.51
Radiation dose in Marumori 269.436 5814
Kawanagata Ikata Town 266.821 3093.07 5860.51
Tochigi 260.733 3439.51 5852.3
Chikagawa Mutu City 256.719 3947.99 5857.78
Yokohama Town Office Yokohama Town 254.846 4838.68 5857.78
Tokyo 251.877 4055.54 5852.3
Hiranuma Rokkasho Village 251.186 3177.23 5857.78
Taisei Ikata Town 246.293 2321.95 5860.51
Chitose-daira Rokkasho Village 245.868 3425.62 5857.78
Gifu 243.951 5646.96 5852.3
Fukkoshi Yokohama Town 243.102 3322.85 5857.78
Shimane 240.651 5646.96 5852.3
Sunagomata Higashidoori Village 238.012 4804.4 5857.78
Obuchi Rokkasho Village 237.506 3819.53 5857.78
Tomari Rokkasho Village 230.636 5343.94 5857.78
kanagawa 226.339 3542.18 5852.3
Saitama 219.770 3080.16 5852.3
Ikatagoshi Ikata Town 217.515 2921.67 5860.51
Touhoku Branch office Touhoku Town 215.416 2766.15 5857.78
Radiation dose at Tohoku University 214.824 5814
Odanosawa Higashidoori Village 210.287 3828.11 5857.78
Kagawa 205.829 3952.87 5852.3
Oippe Higashidoori Village 205.182 3297.16 5857.78
Oita 200.921 4363.56 5852.3
Touhoku Town office Touhoku Town 200.811 12794.6 5857.78
Kuchogoshi Ikata Town 198.646 2964.55 5860.51
Minatoura Ikata Town 186.776 2664.63 5860.51
Radiation dose in Koyadori, Ojika 184.905 5808.53
Toyama 184.580 7546.39 5852.3
Fukushima [9] (distance from Fukushima I: 45 km) 184.232 3641.45 5846.83
Radiation dose in Tukahama, Ojika 183.417 5808.53
Chiba 182.407 2258.78 5852.3
Nara 182.387 4106.88 5852.3
Okayama 181.976 5338.94 5852.3
Yamagata 181.598 4209.55 5852.3
Ehime 180.745 3798.86 5852.3
Ishikawa 180.445 6545.34 5852.3
Niigata 177.483 7854.41 5852.3
Hiroshima 176.816 3542.18 5852.3
Mie 174.867 4050.41 5852.3
Fukui 170.045 4979.59 5852.3
Radiation dose in Terama, Ojika 168.036 5808.53
Yamanashi 164.561 3285.5 5852.3
Nagano 162.242 5000.13 5852.3
Saga 161.421 4414.9 5852.3
Tottori 161.392 4055.54 5852.3
Radiation dose in Enoshima, Ojika 160.091 5808.53
Osaka 159.103 3131.5 5852.3
Ibaraki-city Environment 157.249 5767.49
Aichi 149.345 3798.86 5852.3
Toyonoura Ikata Town 149.214 3058.78 5860.51
Shizuoka 148.639 3927.2 5852.3
Kyoto 144.522 4466.23 5852.3
Kagoshima 144.449 4840.98 5852.3
Tokushima 143.627 3439.51 5852.3
Gunma 143.572 2310.12 5852.3
Hyogo 139.710 3901.54 5852.3
Fukuoka 136.511 4055.54 5852.3
Wakayama 133.857 2874.82 5852.3
Radiation at Tamaki-cho Mie Japan 133.138 5767.49
Akita 132.832 4414.9 5852.3
Shiga 124.919 3131.5 5852.3
Nagasaki 109.459 3542.18 5852.3
Hokkaido 109.189 5390.28 5852.3
Kumamoto 103.568 3439.51 5852.3
Aomori 101.819 5236.27 5852.3
Miyazaki 100.354 3408.71 5852.3
Kochi 95.931 3901.54 5852.3
Fukushima [35] (distance from Fukushima I: 35 km) 91.917 3632.93 5833.15
Iwate 90.324 4312.22 5852.3
Environment Feeds from Ohta 83.623 5767.49
Okinawa 82.305 2951.82 5852.3
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