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Accumulated absorbed dose rate - T=13.03.2011 - 29.05.2017(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 6123.17
Fukushima I MP8 570942.000 6123.17
Fukushima I MP6 240668.000 6123.17
Yamada Futaba Town 176983.000 4766.51 5679.94
Fukushima I MP2 140420.000 6123.17
Fukushima I MP5 111325.000 6123.17
Fukushima [32] (distance from Fukushima I: 30 km) 101500.000 3857.86 6194.3
Fukushima I MP3 93730.602 6123.17
Fukushima I MP4 86821.500 6123.17
Fukushima [33] (distance from Fukushima I: 30 km) 77197.703 3857.86 6194.3
Fukushima [79] (distance from Fukushima I: 40 km) 54008.602 3806.74 6112.22
Fukushima [31] (distance from Fukushima I: 30 km) 40677.398 3857.86 6194.3
Ono Okuma Town 38610.500 4401.1 5679.94
Shinzan Futaba Town 38332.801 3994.24 5679.94
Fukushima I MP1 31496.801 6123.17
Yonomori Tomioka Town 29815.900 4550.58 5679.94
Fukushima [46] (distance from Fukushima I: 20 km) 28842.500 3857.86 6194.3
Tomioka Tomioka Town 25324.500 4899.34 5679.94
Fukushima [62] (distance from Fukushima I: 40 km) 16464.100 3857.86 6194.3
Fukushima [61] (distance from Fukushima I: 40 km) 13102.800 3857.86 6194.3
Shimo-Kooriyama Tomioka Town 13057.000 4866.16 5679.94
Fukushima [21] (distance from Fukushima I: 30 km) 12103.800 3857.86 6194.3
Fukushima [3] (distance from Fukushima I: 45 km) 11985.000 3857.86 6194.3
Kami-kooriyama Tomioka Town 11803.900 3819.86 5679.94
Fukushima II MP3 11060.600 6123.17
Fukushima II MP1 10903.000 6123.17
Kooriyama Futaba Town 10352.900 4450.93 5679.94
Fukushima II MP4 9696.330 6123.17
Fukushima [34] (distance from Fukushima I: 30 km) 9540.450 3854.45 6188.83
Fukushima II MP5 9382.150 6123.17
Fukushima [2] (distance from Fukushima I: 55 km) 8841.760 3857.86 6194.3
Matsudate Naraha Town 8410.890 5198.29 5679.94
Shigeoka Naraha Town 8115.970 5746.35 5679.94
Fukushima II MP2 7875.320 6123.17
Namie Namie Town 7321.210 4193.54 5679.94
Radiation dose at Shirasawa branch office, Motomiya 7287.920 6139.58
Fukushima II MP6 7062.690 6123.17
Fukushima II MP7 6511.580 6120.43
Fukushima [1] (distance from Fukushima I: 60 km) 5615.310 3857.86 6194.3
Fukushima [11] (distance from Fukushima I: 40 km) 5491.310 3857.86 6194.3
Fukushima [63] (distance from Fukushima I: 45 km) 5448.820 3857.86 6194.3
Fukushima [45] (distance from Fukushima I: 20 km) 3981.200 3857.86 6194.3
Fukushima [42] (distance from Fukushima I: 30 km) 3850.600 3857.86 6194.3
Fukushima [10] (distance from Fukushima I: 40 km) 3734.160 3857.86 6194.3
Fukushima [78] (distance from Fukushima I: 45 km) 3716.820 3852.74 6186.1
Futatsunuma Hirono Town 3520.340 4982.4 5679.94
Fukushima [4] (distance from Fukushima I: 50 km) 3386.310 3857.86 6194.3
Fukushima [7] (distance from Fukushima I: 45 km) 3313.930 3857.86 6194.3
Radiation dose at Koriyama joint government building, Koriyama 3232.890 6136.85
Fukushima [15] (distance from Fukushima I: 35 km) 3178.670 3857.86 6194.3
Kiyohashi Namie Town 3162.000 3678.66 5679.94
Fukushima [71] (distance from Fukushima I: 25 km) 3161.650 3852.74 6186.1
Radiation dose at Agricultural center, Koriyama 3128.960 6136.85
Fukushima [41] (distance from Fukushima I: 20 km) 3111.490 3857.86 6194.3
Radiation dose at Koriyama city office, Koriyama 2803.520 6136.85
Fukushima [44] (distance from Fukushima I: 30 km) 2535.550 3857.86 6194.3
Fukushima [72] (distance from Fukushima I: 30 km) 2344.620 3852.74 6186.1
Fukushima [43] (distance from Fukushima I: 20 km) 2244.110 3857.86 6194.3
Yamadaoka Naraha Town 2205.340 4417.74 5679.94
Radiation dose at Iwane Fureai Plaza, Motomiya 2169.060 6139.58
Fukushima [22] (distance from Fukushima I: 35 km) 2020.650 3857.86 6194.3
Kuji Hitachi City 1990.890 9580.03 6205.25
Hitachinaka Hitachinaka City 1951.950 4207.53 6202.51
Fukushima [76] (distance from Fukushima I: 25 km) 1945.520 3852.74 6186.1
Fukushima [80] (distance from Fukushima I: 25 km) 1876.860 3852.74 6186.1
Momiyama Hokota City 1837.540 4799.11 6205.25
Fukushima [77] (distance from Fukushima I: 25 km) 1802.490 3852.74 6186.1
Horiguchi Hitachinaka City 1779.410 4193.11 6207.98
Onuma Hitachi City 1776.950 3572.81 6202.51
Fukushima [6] (distance from Fukushima I: 45 km) 1741.180 3857.86 6194.3
Tsukuriya Hokota City 1736.890 4037.06 6205.25
Radiation dose at Big palette Fukushima, Koriyama 1668.540 6136.85
Nemoto Hitachioomiya City 1633.190 4497.75 6202.51
Fukushima [13] (distance from Fukushima I: 40 km) 1624.150 3857.86 6194.3
Fukushima [23] (distance from Fukushima I: 35 km) 1551.750 3857.86 6194.3
Radiation dose at Tsukidatemachi kamitedo, Date 1545.300 6145.06
Fukushima [14] (distance from Fukushima I: 35 km) 1543.460 3857.86 6194.3
Radiation dose at JAEA Oarai (P12) 1512.140 6161.47
Radiation dose at Ose administration center, Koriyama 1494.270 6136.85
Araji Hokota City 1437.760 4046.09 6205.25
Ishigami Tokai Village 1431.690 3683.25 6205.25
Mawatari Hitachinaka City 1422.870 4254.79 6205.25
Radiation dose at JAEA Oarai (P11) 1399.370 6161.47
Onuki Oarai Town 1387.990 4418.08 6205.25
Sawa Hitachinaka City 1353.770 3337.01 6202.51
Toyooka Tokai Village 1321.760 4055.18 6205.25
Ajigaura Hitachinaka City 1313.890 3989.9 6202.51
Fukushima [5] (distance from Fukushima I: 45 km) 1282.090 3857.86 6194.3
Geiger Counter Feeds from Asao Kawasaki 1266.620 6114.96
Radiation dose at Tamokami elementary school, Koriyama 1256.140 6136.85
Isohama Oarai Town 1250.540 3852.18 6199.78
Ebisawa Ibaraki Town 1222.240 10457.2 6202.51
Muramatsu Tokai Village 1203.520 4091.49 6205.25
Kamitoda Hokota City 1184.740 3356.66 6205.25
Yanagisawa Hitachinaka City 1166.970 3418.62 6202.51
Tokushuku Hokota City 1159.730 3030.07 6205.25
Tasaki Hokota City 1153.300 3584.13 6175.15
Fukushima [20] (distance from Fukushima I: 45 km) 1145.390 3857.86 6194.3
Kadobe Naka City 1086.580 8143.08 6202.51
Radiation dose at Date city office, Date 1076.050 6139.58
Oshinobe Tokai Village 1041.340 3819.33 6205.25
Oba Mito City 1037.670 12546.6 6205.25
Godai Naka City 1031.270 3311.26 6205.25
Ishikawa Mito City 1030.810 3902.7 6207.98
Isobe Hitachiota City 1013.130 18833.5 6205.25
Yatabe Ibaraki Town 996.127 3275.01 6205.25
Radiation dose at Motomiya city office, Motomiya 992.703 6139.58
Fukushima [73] (distance from Fukushima I: 35 km) 981.984 3852.74 6186.1
Fukushima [75] (distance from Fukushima I: 45 km) 960.529 3852.74 6186.1
Yokobori Naka City 930.280 3837.46 6205.25
Sugaya Naka City 926.186 5863.11 6207.98
Kounosu Naka City 926.087 2993.76 6205.25
Funaishikawa Tokai Village 900.399 3973.54 6205.25
Nukada Naka City 899.900 3589.34 6199.78
Uridura Naka City 890.113 3426.19 6199.78
Shiraki Tsuruga City 881.330 7269.88 6207.98
Motokomezaki Naka City 880.851 3194.5 6172.42
Shiraki pass Tsuruga City 850.284 7614.75 6207.98
Radiation dose in Yamamoto 846.633 6161.47
Yoshizawa Mito City 837.646 3465.52 6205.25
Radiation dose at JAEA Oarai (P7) 831.135 6161.47
Mayumi Hitachiota City 828.119 3438.31 6205.25
Urasoko Tsuruga City 826.465 6035.52 6207.98
Nemoto Hitachioomiya City 825.588 3872.05 6202.51
Takenami Mihama Town 804.283 6335.03 6207.98
Radiation dose at JAEA Oarai (P15) 780.207 6161.47
Tateishi Tsuruga City 780.092 5019.05 6207.98
Radiation dose at JAEA Oarai (P14) 770.174 6161.47
Radiation dose at JAEA Oarai (P13) 769.612 6161.47
Ukishima Kawasaki Ward 735.475 11844.2 6207.98
Kume Hitachiota City 713.958 3365.69 6205.25
Radiation dose at JAEA Oarai (P2) 712.011 6161.47
Fukushima [74] (distance from Fukushima I: 35 km) 706.552 3852.74 6186.1
Nyuu Mihama Town 674.787 5772.34 6207.98
Fukushima [52] (distance from Fukushima I: 40 km) 672.743 3857.86 6194.3
Radiation dose in Iwanuma 670.242 6161.47
Fukushima [51] (distance from Fukushima I: 40 km) 665.376 3857.86 6194.3
Tsuruga Tsuruga City 655.360 5091.64 6207.98
Shiohama Kawasaki Ward 653.536 4066.07 6207.98
Radiation dose in Kakuda 649.863 6161.47
Sakajiri Mihama Town 649.252 6734.41 6207.98
North point of Kinki University Atomic Energy Research Instirute Station 639.566 4229.43 6207.98
Radiation dose in Onagawa (MP-2) 632.968 6158.74
Kumatori town Nishi primary school Station 631.491 5055.31 6207.98
Oshima Kawasaki Ward 630.402 3875.47 6207.98
Izumisano municipal Oike athletic field Station 629.920 5699.75 6207.98
Atom-kyoudou nursery school Station 625.566 5472.83 6207.98
South point of Kinki University Atomic Energy Research Instirute Station 625.202 4982.72 6207.98
Nakamachi Omaezaki City 623.494 6416.71 6207.98
Uraga Yokosuka City 622.492 3040.44 6207.98
Goritoge Shika Town 622.143 6816.09 6207.98
Kumatori town Minami primary school Station 606.134 5799.56 6207.98
Radiation dose at JAEA Oarai (P1) 603.643 6164.21
Yamanotedai-No.1 Park Station 599.140 5409.28 6207.98
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 595.502 6180.62
Noumi Shika Town 594.021 6743.45 6207.98
Radiation dose in Watari 591.851 6161.47
Hairando Yokosuka City 588.667 3811.92 6207.98
Fukushima [12] (distance from Fukushima I: 40 km) 588.291 3857.86 6194.3
Ningyotoge Kagamino Town 574.857 5409.28 6207.98
Ten-no Kagamino Town 569.960 6480.26 6207.98
Funagura Yokosuka City 563.909 3594.1 6207.98
Chidori Kawasaki Ward 560.211 3476.09 6207.98
Radiation dose at JAEA Oarai (P16) 556.365 6161.47
Shika Shika Town 551.376 6498.4 6207.98
Higashiosaka municipal Kamikosaka primary scool Station 550.277 4220.34 6207.98
Sahara Yokosuka City 547.404 3367.18 6207.98
Kazanashi Shika Town 545.377 6099.07 6207.98
Akasumi Shika Town 544.970 5581.74 6207.98
Kurahashi Maizuru City 540.820 5082.54 6207.98
Obama Obama City 540.809 4547.08 6207.98
Sakuragaike community hall Omaezaki City 540.772 6580.08 6207.98
Shirowa primary school Omaezaki City 535.692 6443.94 6207.98
Radiation dose at JAEA Oarai (P5) 529.759 6161.47
Uenohara Omaezaki City 529.333 6625.5 6207.98
Kumano Shika Town 529.019 6325.99 6207.98
Izumisano municipal Hineno filtration plant Station 527.471 5454.69 6207.98
Nishi-hamasada Matsue City 525.089 6037.7 6191.57
Kouno Minami-Echizen Town 525.028 4574.3 6207.98
Kurihama Yokosuka City 523.708 3639.46 6207.98
Osaka prefectural Kumatori off-site-center Station 522.808 5028.09 6207.98
Ogasa branch Kikugawa City 522.039 6701.42 6194.3
Izumisano municipal Hineno primary scool Station 518.181 4365.57 6207.98
Shirasuna Omaezaki City 499.479 6489.36 6207.98
Jitougata primary school Makinohara City 498.059 6226.12 6207.98
Kataku Matsue City 497.007 4837.49 6207.98
Nishihemi Yokosuka City 496.917 2904.3 6207.98
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 496.721 6180.62
Satsuma-sendai monitoring center Satsuma-sendai City 495.302 4764.9 6207.98
Otomi Takahama Town 494.821 5336.69 6207.98
Otsu Nanao City 493.895 5354.82 6207.98
The Observation point for comparison Tatsunokuchi 493.454 4410.94 6207.98
Hitsuhama Ohi Town 492.630 4964.59 6207.98
Kijiyama Misasa Town 489.284 5037.18 6207.98
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 487.055 6180.62
Hiraba Omaezaki City 485.878 6489.36 6207.98
Tayu Matsue City 484.956 5046.27 6207.98
Hamaokakita primary school Omaezaki City 484.537 6656.16 6194.3
Oitomi Ayabe City 474.670 6398.58 6207.98
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 472.017 6180.62
Kashiwazaki-shigai Kashiwazaki City 470.822 5091.64 6207.98
Mitsu Matsue City 466.897 4828.45 6207.98
Tonomachi Kawasaki Ward 463.967 6117.21 6207.98
Daitou branch Kakegawa City 463.829 6556.56 6194.3
Fukura Shika Town 462.493 6089.98 6207.98
Nagasawa Yokosuka City 462.365 3557.77 6207.98
The athletic field Station of Kinki University 461.661 4020.65 6207.98
Koura Matsue City 461.049 5763.24 6207.98
Sakurasan Ward Omaezaki City 459.434 6280.57 6207.98
Tsuchikawa Nanao City 458.915 5926.61 6207.98
Kumatori Town office Station 457.917 4147.75 6207.98
Shinkango Omaezaki City 449.013 7269.88 6207.98
Ogurui Takahama Town 448.279 4755.81 6207.98
Kusabue Omaezaki City 444.162 6852.36 6207.98
Omaezaki City monitoring center 443.946 6725.32 6207.98
Akawase Kagamino Town 442.246 4147.75 6207.98
Ibaraki 442.139 3045.5 6199.78
Hinode Town Yokosuka City 438.324 2396.06 6207.98
Nishiyama Kashiwazaki City 437.251 7206.33 6207.98
Kariwa Kariwa Village 436.307 5436.51 6207.98
Osaka prefectural Hineno high scool Station 435.745 4846.58 6207.98
Miyagawa Kashiwazaki City 435.245 5363.92 6207.98
Radiation dose in Natori 434.640 6161.47
Kami-koubu Matsue City 433.868 5273.14 6207.98
Shimo-Takamachi Kariwa Village 433.192 5917.57 6207.98
Osaka prefectural Sano supporting school Station 432.398 5282.23 6207.98
Arahama Kashiwazaki City 428.874 5527.28 6207.98
Doai Kashiwazaki City 425.681 5200.55 6207.98
Owashi Matsue City 424.452 5155.19 6207.98
Okayasu Maizuru City 422.568 6071.84 6207.98
Katsuyama Kariwa Village 421.280 5527.28 6207.98
Kita-koubu Matsue City 420.683 5654.33 6207.98
Kichisaka Maizuru City 413.065 7378.79 6207.98
Nagai Ohi Town 410.699 5365.91 6199.78
Shiokumi Maizuru City 407.938 9184.93 6207.98
Miyadome Ohi Town 407.831 4447.26 6207.98
Kariwa Kariwa Village 407.617 5726.97 6207.98
Ueno Satsuma-sendai City 394.248 4156.79 6207.98
Power Station-South 389.191 6053.71 6207.98
Radiation dose at JAEA Oarai (P6) 386.963 6161.47
Power Station- 385.546 5908.48 6207.98
Takae Satsuma-sendai City 379.551 4211.25 6207.98
Hokawaduura Genkai Town 378.015 6412.19 6207.98
Kou Itimatsu Suetsugu 377.929 4628.76 6207.98
Minato Satsuma-sendai City 377.656 3857.28 6207.98
Iwanai Iwanai Town 376.336 6286.9 6205.25
Hattari Kyowa Town 373.047 6114.51 6205.25
Chatsu Tomari Village 371.011 5842.35 6205.25
Oyama Maizuru City 358.223 5318.55 6207.98
Kodaira Satsuma-sendai City 355.545 3902.7 6207.98
Kayanuma Tomari Village 354.809 5198.26 6205.25
Anojiri Obama City 353.215 4356.48 6207.98
Kushi Genkai Town 349.738 8849.1 6207.98
Yamaguchi 348.715 6961.15 6199.78
Sadahongou Matsue City 348.228 5418.37 6207.98
Sakibe Karatsu City 347.801 8386.22 6207.98
Hirao Genkai Town 343.814 8840.01 6207.98
The Meteorological Obsevatory of kyowa Town 343.275 5797.01 6205.25
Minami-Horoni Kyowa Town 335.180 5434.11 6205.25
Kounoura Takahama Town 330.353 4592.44 6207.98
Kyoudomarisaki Karatsu City 328.622 8985.24 6207.98
Horikappu Jinja Tomari Village 328.230 5624.62 6205.25
Hukada-kita Matsue City 327.031 4456.3 6207.98
Radiation dose in KEK, Tsukuba 326.240 6180.62
Herokaruusu Tomari Village 324.242 5833.31 6205.25
Yorita Satsuma-sendai City 323.218 4565.21 6207.98
Kamoenai Kamoenai Village 322.032 4926.1 6205.25
Radiation dose in Onagawa (MP-6) 316.267 6158.74
Imamura Genkai Town 314.749 76147.5 6207.98
Yamanaka Takahama Town 314.185 5926.61 6207.98
Sendai (Miyagi) 312.585 2789.9 6199.78
Radiation dose in Onagawa (MP-1) 300.147 6158.74
Gumisaki Satsuma-sendai City 295.693 3684.87 6207.98
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 286.142 6180.62
Aomori Aomori City 285.372 3746.72 6205.25
Misawa City hall Misawa City 283.728 7266.67 6205.25
Kashu Ikata Town 277.173 3802.83 6207.98
Noheji Town Office Noheji Town 272.004 3211.49 6205.25
Takasimamati 271.103 4047.88 6207.98
Radiation dose in Onagawa (MP-3) 270.563 6158.74
Kucho Ikata Town 269.545 3358.14 6207.98
Radiation dose in Marumori 269.436 6161.47
Kawanagata Ikata Town 266.821 3276.45 6207.98
Tochigi 260.733 3643.73 6199.78
Chikagawa Mutu City 256.719 4182.17 6205.25
Yokohama Town Office Yokohama Town 254.846 5125.7 6205.25
Tokyo 251.877 4296.34 6199.78
Hiranuma Rokkasho Village 251.186 3365.69 6205.25
Taisei Ikata Town 246.293 2459.61 6207.98
Chitose-daira Rokkasho Village 245.868 3628.82 6205.25
Gifu 243.951 5982.24 6199.78
Fukkoshi Yokohama Town 243.102 3519.95 6205.25
Shimane 240.651 5982.24 6199.78
Sunagomata Higashidoori Village 238.012 5089.39 6205.25
Obuchi Rokkasho Village 237.506 4046.09 6205.25
Tomari Rokkasho Village 230.636 5660.93 6205.25
kanagawa 226.339 3752.5 6199.78
Saitama 219.770 3263.04 6199.78
Ikatagoshi Ikata Town 217.515 3094.9 6207.98
Touhoku Branch office Touhoku Town 215.416 2930.24 6205.25
Radiation dose at Tohoku University 214.824 6161.47
Odanosawa Higashidoori Village 210.287 4055.18 6205.25
Kagawa 205.829 4187.57 6199.78
Oippe Higashidoori Village 205.182 3492.74 6205.25
Oita 200.921 4622.64 6199.78
Touhoku Town office Touhoku Town 200.811 13553.6 6205.25
Kuchogoshi Ikata Town 198.646 3140.31 6207.98
Minatoura Ikata Town 186.776 2822.62 6207.98
Radiation dose in Koyadori, Ojika 184.905 6156
Toyama 184.580 7994.45 6199.78
Fukushima [9] (distance from Fukushima I: 45 km) 184.232 3857.86 6194.3
Radiation dose in Tukahama, Ojika 183.417 6156
Chiba 182.407 2392.9 6199.78
Nara 182.387 4350.72 6199.78
Okayama 181.976 5655.94 6199.78
Yamagata 181.598 4459.49 6199.78
Ehime 180.745 4024.42 6199.78
Ishikawa 180.445 6933.96 6199.78
Niigata 177.483 8320.75 6199.78
Hiroshima 176.816 3752.5 6199.78
Mie 174.867 4290.9 6199.78
Fukui 170.045 5275.25 6199.78
Radiation dose in Terama, Ojika 168.036 6156
Yamanashi 164.561 3480.58 6199.78
Nagano 162.242 5297 6199.78
Saga 161.421 4677.02 6199.78
Tottori 161.392 4296.34 6199.78
Radiation dose in Enoshima, Ojika 160.091 6156
Osaka 159.103 3317.42 6199.78
Ibaraki-city Environment 157.249 6114.96
Aichi 149.345 4024.42 6199.78
Toyonoura Ikata Town 149.214 3240.13 6207.98
Shizuoka 148.639 4160.38 6199.78
Kyoto 144.522 4731.41 6199.78
Kagoshima 144.449 5128.41 6199.78
Tokushima 143.627 3643.73 6199.78
Gunma 143.572 2447.28 6199.78
Hyogo 139.710 4133.18 6199.78
Fukuoka 136.511 4296.34 6199.78
Wakayama 133.857 3045.5 6199.78
Radiation at Tamaki-cho Mie Japan 133.138 6114.96
Akita 132.832 4677.02 6199.78
Shiga 124.919 3317.42 6199.78
Nagasaki 109.459 3752.5 6199.78
Hokkaido 109.189 5710.32 6199.78
Kumamoto 103.568 3643.73 6199.78
Aomori 101.819 5547.17 6199.78
Miyazaki 100.354 3611.1 6199.78
Kochi 95.931 4133.18 6199.78
Fukushima [35] (distance from Fukushima I: 35 km) 91.917 3849.34 6180.62
Iwate 90.324 4568.26 6199.78
Environment Feeds from Ohta 83.623 6114.96
Okinawa 82.305 3127.08 6199.78
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