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Accumulated absorbed dose rate - T=13.03.2011 - 18.11.2017(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 6596.5
Fukushima I MP8 570942.000 6596.5
Fukushima I MP6 240668.000 6596.5
Yamada Futaba Town 176983.000 5163.72 6153.26
Fukushima I MP2 140420.000 6596.5
Fukushima I MP5 111325.000 6596.5
Fukushima [32] (distance from Fukushima I: 30 km) 101500.000 4152.65 6667.63
Fukushima I MP3 93730.602 6596.5
Fukushima I MP4 86821.500 6596.5
Fukushima [33] (distance from Fukushima I: 30 km) 77197.703 4152.65 6667.63
Fukushima [79] (distance from Fukushima I: 40 km) 54008.602 4101.53 6585.55
Fukushima [31] (distance from Fukushima I: 30 km) 40677.398 4152.65 6667.63
Ono Okuma Town 38610.500 4767.86 6153.26
Shinzan Futaba Town 38332.801 4327.09 6153.26
Fukushima I MP1 31496.801 6596.5
Yonomori Tomioka Town 29815.900 4929.79 6153.26
Fukushima [46] (distance from Fukushima I: 20 km) 28842.500 4152.65 6667.63
Tomioka Tomioka Town 25324.500 5307.62 6153.26
Fukushima [62] (distance from Fukushima I: 40 km) 16464.100 4152.65 6667.63
Fukushima [61] (distance from Fukushima I: 40 km) 13102.800 4152.65 6667.63
Shimo-Kooriyama Tomioka Town 13057.000 5271.67 6153.26
Fukushima [21] (distance from Fukushima I: 30 km) 12103.800 4152.65 6667.63
Fukushima [3] (distance from Fukushima I: 45 km) 11985.000 4152.65 6667.63
Kami-kooriyama Tomioka Town 11803.900 4138.18 6153.26
Fukushima II MP3 11060.600 6596.5
Fukushima II MP1 10903.000 6596.5
Kooriyama Futaba Town 10352.900 4821.84 6153.26
Fukushima II MP4 9696.330 6596.5
Fukushima [34] (distance from Fukushima I: 30 km) 9540.450 4149.24 6662.16
Fukushima II MP5 9382.150 6596.5
Fukushima [2] (distance from Fukushima I: 55 km) 8841.760 4152.65 6667.63
Matsudate Naraha Town 8410.890 5631.48 6153.26
Shigeoka Naraha Town 8115.970 6225.21 6153.26
Fukushima II MP2 7875.320 6596.5
Namie Namie Town 7321.210 4543 6153.26
Radiation dose at Shirasawa branch office, Motomiya 7287.920 6612.91
Fukushima II MP6 7062.690 6596.5
Fukushima II MP7 6511.580 6593.76
Fukushima [1] (distance from Fukushima I: 60 km) 5615.310 4152.65 6667.63
Fukushima [11] (distance from Fukushima I: 40 km) 5491.310 4152.65 6667.63
Fukushima [63] (distance from Fukushima I: 45 km) 5448.820 4152.65 6667.63
Fukushima [45] (distance from Fukushima I: 20 km) 3981.200 4152.65 6667.63
Fukushima [42] (distance from Fukushima I: 30 km) 3850.600 4152.65 6667.63
Fukushima [10] (distance from Fukushima I: 40 km) 3734.160 4152.65 6667.63
Fukushima [78] (distance from Fukushima I: 45 km) 3716.820 4147.54 6659.42
Futatsunuma Hirono Town 3520.340 5397.6 6153.26
Fukushima [4] (distance from Fukushima I: 50 km) 3386.310 4152.65 6667.63
Fukushima [7] (distance from Fukushima I: 45 km) 3313.930 4152.65 6667.63
Radiation dose at Koriyama joint government building, Koriyama 3232.890 6610.18
Fukushima [15] (distance from Fukushima I: 35 km) 3178.670 4152.65 6667.63
Kiyohashi Namie Town 3162.000 3985.21 6153.26
Fukushima [71] (distance from Fukushima I: 25 km) 3161.650 4147.54 6659.42
Radiation dose at Agricultural center, Koriyama 3128.960 6610.18
Fukushima [41] (distance from Fukushima I: 20 km) 3111.490 4152.65 6667.63
Radiation dose at Koriyama city office, Koriyama 2803.520 6610.18
Fukushima [44] (distance from Fukushima I: 30 km) 2535.550 4152.65 6667.63
Fukushima [72] (distance from Fukushima I: 30 km) 2344.620 4147.54 6659.42
Fukushima [43] (distance from Fukushima I: 20 km) 2244.110 4152.65 6667.63
Yamadaoka Naraha Town 2205.340 4785.89 6153.26
Radiation dose at Iwane Fureai Plaza, Motomiya 2169.060 6612.91
Fukushima [22] (distance from Fukushima I: 35 km) 2020.650 4152.65 6667.63
Kuji Hitachi City 1990.890 10310.8 6678.58
Hitachinaka Hitachinaka City 1951.950 4528.62 6675.84
Fukushima [76] (distance from Fukushima I: 25 km) 1945.520 4147.54 6659.42
Fukushima [80] (distance from Fukushima I: 25 km) 1876.860 4147.54 6659.42
Momiyama Hokota City 1837.540 5165.18 6678.58
Fukushima [77] (distance from Fukushima I: 25 km) 1802.490 4147.54 6659.42
Horiguchi Hitachinaka City 1779.410 4512.82 6681.31
Onuma Hitachi City 1776.950 3845.46 6675.84
Fukushima [6] (distance from Fukushima I: 45 km) 1741.180 4152.65 6667.63
Tsukuriya Hokota City 1736.890 4345 6678.58
Radiation dose at Big palette Fukushima, Koriyama 1668.540 6610.18
Nemoto Hitachioomiya City 1633.190 4840.98 6675.84
Fukushima [13] (distance from Fukushima I: 40 km) 1624.150 4152.65 6667.63
Fukushima [23] (distance from Fukushima I: 35 km) 1551.750 4152.65 6667.63
Radiation dose at Tsukidatemachi kamitedo, Date 1545.300 6618.38
Fukushima [14] (distance from Fukushima I: 35 km) 1543.460 4152.65 6667.63
Radiation dose at JAEA Oarai (P12) 1512.140 6634.8
Radiation dose at Ose administration center, Koriyama 1494.270 6610.18
Araji Hokota City 1437.760 4354.72 6678.58
Ishigami Tokai Village 1431.690 3964.2 6678.58
Mawatari Hitachinaka City 1422.870 4579.34 6678.58
Radiation dose at JAEA Oarai (P11) 1399.370 6634.8
Onuki Oarai Town 1387.990 4755.09 6678.58
Sawa Hitachinaka City 1353.770 3591.66 6675.84
Toyooka Tokai Village 1321.760 4364.51 6678.58
Ajigaura Hitachinaka City 1313.890 4294.38 6675.84
Fukushima [5] (distance from Fukushima I: 45 km) 1282.090 4152.65 6667.63
Geiger Counter Feeds from Asao Kawasaki 1266.620 6588.29
Radiation dose at Tamokami elementary school, Koriyama 1256.140 6610.18
Isohama Oarai Town 1250.540 4146.28 6673.1
Ebisawa Ibaraki Town 1222.240 11255.2 6675.84
Muramatsu Tokai Village 1203.520 4403.58 6678.58
Kamitoda Hokota City 1184.740 3612.7 6678.58
Yanagisawa Hitachinaka City 1166.970 3679.5 6675.84
Tokushuku Hokota City 1159.730 3261.2 6678.58
Tasaki Hokota City 1153.300 3858.86 6648.48
Fukushima [20] (distance from Fukushima I: 45 km) 1145.390 4152.65 6667.63
Kadobe Naka City 1086.580 8764.5 6675.84
Radiation dose at Date city office, Date 1076.050 6612.91
Oshinobe Tokai Village 1041.340 4110.66 6678.58
Oba Mito City 1037.670 13503.6 6678.58
Godai Naka City 1031.270 3563.84 6678.58
Ishikawa Mito City 1030.810 4200.26 6681.31
Isobe Hitachiota City 1013.130 20270.1 6678.58
Yatabe Ibaraki Town 996.127 3524.82 6678.58
Radiation dose at Motomiya city office, Motomiya 992.703 6612.91
Fukushima [73] (distance from Fukushima I: 35 km) 981.984 4147.54 6659.42
Fukushima [75] (distance from Fukushima I: 45 km) 960.529 4147.54 6659.42
Yokobori Naka City 930.280 4130.17 6678.58
Sugaya Naka City 926.186 6310.15 6681.31
Kounosu Naka City 926.087 3222.12 6678.58
Funaishikawa Tokai Village 900.399 4276.63 6678.58
Nukada Naka City 899.900 3863.38 6673.1
Uridura Naka City 890.113 3687.77 6673.1
Shiraki Tsuruga City 881.330 7824.17 6681.31
Motokomezaki Naka City 880.851 3439.46 6645.74
Shiraki pass Tsuruga City 850.284 8195.33 6681.31
Radiation dose in Yamamoto 846.633 6634.8
Yoshizawa Mito City 837.646 3729.87 6678.58
Radiation dose at JAEA Oarai (P7) 831.135 6634.8
Mayumi Hitachiota City 828.119 3700.58 6678.58
Urasoko Tsuruga City 826.465 6495.7 6681.31
Nemoto Hitachioomiya City 825.588 4167.54 6675.84
Takenami Mihama Town 804.283 6818.04 6681.31
Radiation dose at JAEA Oarai (P15) 780.207 6634.8
Tateishi Tsuruga City 780.092 5401.72 6681.31
Radiation dose at JAEA Oarai (P14) 770.174 6634.8
Radiation dose at JAEA Oarai (P13) 769.612 6634.8
Ukishima Kawasaki Ward 735.475 12747.2 6681.31
Kume Hitachiota City 713.958 3622.42 6678.58
Radiation dose at JAEA Oarai (P2) 712.011 6634.8
Fukushima [74] (distance from Fukushima I: 35 km) 706.552 4147.54 6659.42
Nyuu Mihama Town 674.787 6212.45 6681.31
Fukushima [52] (distance from Fukushima I: 40 km) 672.743 4152.65 6667.63
Radiation dose in Iwanuma 670.242 6634.8
Fukushima [51] (distance from Fukushima I: 40 km) 665.376 4152.65 6667.63
Tsuruga Tsuruga City 655.360 5479.85 6681.31
Shiohama Kawasaki Ward 653.536 4376.08 6681.31
Radiation dose in Kakuda 649.863 6634.8
Sakajiri Mihama Town 649.252 7247.88 6681.31
North point of Kinki University Atomic Energy Research Instirute Station 639.566 4551.91 6681.31
Radiation dose in Onagawa (MP-2) 632.968 6632.06
Kumatori town Nishi primary school Station 631.491 5440.76 6681.31
Oshima Kawasaki Ward 630.402 4170.96 6681.31
Izumisano municipal Oike athletic field Station 629.920 6134.32 6681.31
Atom-kyoudou nursery school Station 625.566 5890.1 6681.31
South point of Kinki University Atomic Energy Research Instirute Station 625.202 5362.63 6681.31
Nakamachi Omaezaki City 623.494 6905.96 6681.31
Uraga Yokosuka City 622.492 3272.26 6681.31
Goritoge Shika Town 622.143 7335.79 6681.31
Kumatori town Minami primary school Station 606.134 6241.75 6681.31
Radiation dose at JAEA Oarai (P1) 603.643 6637.54
Yamanotedai-No.1 Park Station 599.140 5821.71 6681.31
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 595.502 6653.95
Noumi Shika Town 594.021 7257.6 6681.31
Radiation dose in Watari 591.851 6634.8
Hairando Yokosuka City 588.667 4102.56 6681.31
Fukushima [12] (distance from Fukushima I: 40 km) 588.291 4152.65 6667.63
Ningyotoge Kagamino Town 574.857 5821.71 6681.31
Ten-no Kagamino Town 569.960 6974.35 6681.31
Funagura Yokosuka City 563.909 3868.13 6681.31
Chidori Kawasaki Ward 560.211 3741.12 6681.31
Radiation dose at JAEA Oarai (P16) 556.365 6634.8
Shika Shika Town 551.376 6993.87 6681.31
Higashiosaka municipal Kamikosaka primary scool Station 550.277 4542.12 6681.31
Sahara Yokosuka City 547.404 3623.91 6681.31
Kazanashi Shika Town 545.377 6564.1 6681.31
Akasumi Shika Town 544.970 6007.32 6681.31
Kurahashi Maizuru City 540.820 5470.06 6681.31
Obama Obama City 540.809 4893.77 6681.31
Sakuragaike community hall Omaezaki City 540.772 7081.78 6681.31
Shirowa primary school Omaezaki City 535.692 6935.26 6681.31
Radiation dose at JAEA Oarai (P5) 529.759 6634.8
Uenohara Omaezaki City 529.333 7130.66 6681.31
Kumano Shika Town 529.019 6808.32 6681.31
Izumisano municipal Hineno filtration plant Station 527.471 5870.59 6681.31
Nishi-hamasada Matsue City 525.089 6499.27 6664.9
Kouno Minami-Echizen Town 525.028 4923.07 6681.31
Kurihama Yokosuka City 523.708 3916.95 6681.31
Osaka prefectural Kumatori off-site-center Station 522.808 5411.45 6681.31
Ogasa branch Kikugawa City 522.039 7213.5 6667.63
Izumisano municipal Hineno primary scool Station 518.181 4698.43 6681.31
Shirasuna Omaezaki City 499.479 6984.14 6681.31
Jitougata primary school Makinohara City 498.059 6700.83 6681.31
Kataku Matsue City 497.007 5206.32 6681.31
Nishihemi Yokosuka City 496.917 3125.74 6681.31
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 496.721 6653.95
Satsuma-sendai monitoring center Satsuma-sendai City 495.302 5128.2 6681.31
Otomi Takahama Town 494.821 5743.58 6681.31
Otsu Nanao City 493.895 5763.1 6681.31
The Observation point for comparison Tatsunokuchi 493.454 4747.25 6681.31
Hitsuhama Ohi Town 492.630 5343.12 6681.31
Kijiyama Misasa Town 489.284 5421.24 6681.31
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 487.055 6653.95
Hiraba Omaezaki City 485.878 6984.14 6681.31
Tayu Matsue City 484.956 5431.03 6681.31
Hamaokakita primary school Omaezaki City 484.537 7164.78 6667.63
Oitomi Ayabe City 474.670 6886.44 6681.31
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 472.017 6653.95
Kashiwazaki-shigai Kashiwazaki City 470.822 5479.85 6681.31
Mitsu Matsue City 466.897 5196.6 6681.31
Tonomachi Kawasaki Ward 463.967 6583.61 6681.31
Daitou branch Kakegawa City 463.829 7057.57 6667.63
Fukura Shika Town 462.493 6554.31 6681.31
Nagasawa Yokosuka City 462.365 3829.04 6681.31
The athletic field Station of Kinki University 461.661 4327.2 6681.31
Koura Matsue City 461.049 6202.66 6681.31
Sakurasan Ward Omaezaki City 459.434 6759.44 6681.31
Tsuchikawa Nanao City 458.915 6378.48 6681.31
Kumatori Town office Station 457.917 4464 6681.31
Shinkango Omaezaki City 449.013 7824.17 6681.31
Ogurui Takahama Town 448.279 5118.41 6681.31
Kusabue Omaezaki City 444.162 7374.82 6681.31
Omaezaki City monitoring center 443.946 7238.09 6681.31
Akawase Kagamino Town 442.246 4464 6681.31
Ibaraki 442.139 3278.02 6673.1
Hinode Town Yokosuka City 438.324 2578.75 6681.31
Nishiyama Kashiwazaki City 437.251 7755.77 6681.31
Kariwa Kariwa Village 436.307 5851.01 6681.31
Osaka prefectural Hineno high scool Station 435.745 5216.11 6681.31
Miyagawa Kashiwazaki City 435.245 5772.89 6681.31
Radiation dose in Natori 434.640 6634.8
Kami-koubu Matsue City 433.868 5675.19 6681.31
Shimo-Takamachi Kariwa Village 433.192 6368.76 6681.31
Osaka prefectural Sano supporting school Station 432.398 5684.98 6681.31
Arahama Kashiwazaki City 428.874 5948.71 6681.31
Doai Kashiwazaki City 425.681 5597.06 6681.31
Owashi Matsue City 424.452 5548.24 6681.31
Okayasu Maizuru City 422.568 6534.79 6681.31
Katsuyama Kariwa Village 421.280 5948.71 6681.31
Kita-koubu Matsue City 420.683 6085.44 6681.31
Kichisaka Maizuru City 413.065 7941.38 6681.31
Nagai Ohi Town 410.699 5775.57 6673.1
Shiokumi Maizuru City 407.938 9885.24 6681.31
Miyadome Ohi Town 407.831 4786.34 6681.31
Kariwa Kariwa Village 407.617 6163.63 6681.31
Ueno Satsuma-sendai City 394.248 4473.72 6681.31
Power Station-South 389.191 6515.28 6681.31
Radiation dose at JAEA Oarai (P6) 386.963 6634.8
Power Station- 385.546 6358.97 6681.31
Takae Satsuma-sendai City 379.551 4532.33 6681.31
Hokawaduura Genkai Town 378.015 6901.09 6681.31
Kou Itimatsu Suetsugu 377.929 4981.68 6681.31
Minato Satsuma-sendai City 377.656 4151.38 6681.31
Iwanai Iwanai Town 376.336 6766.45 6678.58
Hattari Kyowa Town 373.047 6580.92 6678.58
Chatsu Tomari Village 371.011 6288 6678.58
Oyama Maizuru City 358.223 5724.07 6681.31
Kodaira Satsuma-sendai City 355.545 4200.26 6681.31
Kayanuma Tomari Village 354.809 5594.77 6678.58
Anojiri Obama City 353.215 4688.64 6681.31
Kushi Genkai Town 349.738 9523.8 6681.31
Yamaguchi 348.715 7492.61 6673.1
Sadahongou Matsue City 348.228 5831.5 6681.31
Sakibe Karatsu City 347.801 9025.63 6681.31
Hirao Genkai Town 343.814 9514.01 6681.31
The Meteorological Obsevatory of kyowa Town 343.275 6239.2 6678.58
Minami-Horoni Kyowa Town 335.180 5848.62 6678.58
Kounoura Takahama Town 330.353 4942.59 6681.31
Kyoudomarisaki Karatsu City 328.622 9670.32 6681.31
Horikappu Jinja Tomari Village 328.230 6053.66 6678.58
Hukada-kita Matsue City 327.031 4796.07 6681.31
Radiation dose in KEK, Tsukuba 326.240 6653.95
Herokaruusu Tomari Village 324.242 6278.27 6678.58
Yorita Satsuma-sendai City 323.218 4913.28 6681.31
Kamoenai Kamoenai Village 322.032 5301.85 6678.58
Radiation dose in Onagawa (MP-6) 316.267 6632.06
Imamura Genkai Town 314.749 81953.3 6681.31
Yamanaka Takahama Town 314.185 6378.48 6681.31
Sendai (Miyagi) 312.585 3002.9 6673.1
Radiation dose in Onagawa (MP-1) 300.147 6632.06
Gumisaki Satsuma-sendai City 295.693 3965.83 6681.31
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 286.142 6653.95
Aomori Aomori City 285.372 4032.51 6678.58
Misawa City hall Misawa City 283.728 7820.96 6678.58
Kashu Ikata Town 277.173 4092.77 6681.31
Noheji Town Office Noheji Town 272.004 3456.46 6678.58
Takasimamati 271.103 4356.51 6681.31
Radiation dose in Onagawa (MP-3) 270.563 6632.06
Kucho Ikata Town 269.545 3614.18 6681.31
Radiation dose in Marumori 269.436 6634.8
Kawanagata Ikata Town 266.821 3526.27 6681.31
Tochigi 260.733 3921.91 6673.1
Chikagawa Mutu City 256.719 4501.18 6678.58
Yokohama Town Office Yokohama Town 254.846 5516.68 6678.58
Tokyo 251.877 4624.34 6673.1
Hiranuma Rokkasho Village 251.186 3622.42 6678.58
Taisei Ikata Town 246.293 2647.15 6681.31
Chitose-daira Rokkasho Village 245.868 3905.62 6678.58
Gifu 243.951 6438.96 6673.1
Fukkoshi Yokohama Town 243.102 3788.45 6678.58
Shimane 240.651 6438.96 6673.1
Sunagomata Higashidoori Village 238.012 5477.6 6678.58
Obuchi Rokkasho Village 237.506 4354.72 6678.58
Tomari Rokkasho Village 230.636 6092.74 6678.58
kanagawa 226.339 4038.98 6673.1
Saitama 219.770 3512.16 6673.1
Ikatagoshi Ikata Town 217.515 3330.87 6681.31
Touhoku Branch office Touhoku Town 215.416 3153.75 6678.58
Radiation dose at Tohoku University 214.824 6634.8
Odanosawa Higashidoori Village 210.287 4364.51 6678.58
Kagawa 205.829 4507.27 6673.1
Oippe Higashidoori Village 205.182 3759.16 6678.58
Oita 200.921 4975.56 6673.1
Touhoku Town office Touhoku Town 200.811 14587.4 6678.58
Kuchogoshi Ikata Town 198.646 3379.75 6681.31
Minatoura Ikata Town 186.776 3037.83 6681.31
Radiation dose in Koyadori, Ojika 184.905 6629.33
Toyama 184.580 8604.79 6673.1
Fukushima [9] (distance from Fukushima I: 45 km) 184.232 4152.65 6667.63
Radiation dose in Tukahama, Ojika 183.417 6629.33
Chiba 182.407 2575.58 6673.1
Nara 182.387 4682.88 6673.1
Okayama 181.976 6087.74 6673.1
Yamagata 181.598 4799.95 6673.1
Ehime 180.745 4331.66 6673.1
Ishikawa 180.445 7463.34 6673.1
Niigata 177.483 8956.01 6673.1
Hiroshima 176.816 4038.98 6673.1
Mie 174.867 4618.49 6673.1
Fukui 170.045 5677.99 6673.1
Radiation dose in Terama, Ojika 168.036 6629.33
Yamanashi 164.561 3746.3 6673.1
Nagano 162.242 5701.41 6673.1
Saga 161.421 5034.1 6673.1
Tottori 161.392 4624.34 6673.1
Radiation dose in Enoshima, Ojika 160.091 6629.33
Osaka 159.103 3570.7 6673.1
Ibaraki-city Environment 157.249 6588.29
Aichi 149.345 4331.66 6673.1
Toyonoura Ikata Town 149.214 3487.18 6681.31
Shizuoka 148.639 4478 6673.1
Kyoto 144.522 5092.63 6673.1
Kagoshima 144.449 5519.94 6673.1
Tokushima 143.627 3921.91 6673.1
Gunma 143.572 2634.12 6673.1
Hyogo 139.710 4448.74 6673.1
Fukuoka 136.511 4624.34 6673.1
Wakayama 133.857 3278.02 6673.1
Radiation at Tamaki-cho Mie Japan 133.138 6588.29
Akita 132.832 5034.1 6673.1
Shiga 124.919 3570.7 6673.1
Nagasaki 109.459 4038.98 6673.1
Hokkaido 109.189 6146.28 6673.1
Kumamoto 103.568 3921.91 6673.1
Aomori 101.819 5970.67 6673.1
Miyazaki 100.354 3886.79 6673.1
Kochi 95.931 4448.74 6673.1
Fukushima [35] (distance from Fukushima I: 35 km) 91.917 4144.13 6653.95
Iwate 90.324 4917.02 6673.1
Environment Feeds from Ohta 83.623 6588.29
Okinawa 82.305 3365.82 6673.1
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