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Accumulated absorbed dose rate - T=13.03.2011 - 24.09.2017(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 6446.02
Fukushima I MP8 570942.000 6446.02
Fukushima I MP6 240668.000 6446.02
Yamada Futaba Town 176983.000 5037.44 6002.78
Fukushima I MP2 140420.000 6446.02
Fukushima I MP5 111325.000 6446.02
Fukushima [32] (distance from Fukushima I: 30 km) 101500.000 4058.93 6517.15
Fukushima I MP3 93730.602 6446.02
Fukushima I MP4 86821.500 6446.02
Fukushima [33] (distance from Fukushima I: 30 km) 77197.703 4058.93 6517.15
Fukushima [79] (distance from Fukushima I: 40 km) 54008.602 4007.81 6435.07
Fukushima [31] (distance from Fukushima I: 30 km) 40677.398 4058.93 6517.15
Ono Okuma Town 38610.500 4651.26 6002.78
Shinzan Futaba Town 38332.801 4221.27 6002.78
Fukushima I MP1 31496.801 6446.02
Yonomori Tomioka Town 29815.900 4809.23 6002.78
Fukushima [46] (distance from Fukushima I: 20 km) 28842.500 4058.93 6517.15
Tomioka Tomioka Town 25324.500 5177.82 6002.78
Fukushima [62] (distance from Fukushima I: 40 km) 16464.100 4058.93 6517.15
Fukushima [61] (distance from Fukushima I: 40 km) 13102.800 4058.93 6517.15
Shimo-Kooriyama Tomioka Town 13057.000 5142.75 6002.78
Fukushima [21] (distance from Fukushima I: 30 km) 12103.800 4058.93 6517.15
Fukushima [3] (distance from Fukushima I: 45 km) 11985.000 4058.93 6517.15
Kami-kooriyama Tomioka Town 11803.900 4036.98 6002.78
Fukushima II MP3 11060.600 6446.02
Fukushima II MP1 10903.000 6446.02
Kooriyama Futaba Town 10352.900 4703.92 6002.78
Fukushima II MP4 9696.330 6446.02
Fukushima [34] (distance from Fukushima I: 30 km) 9540.450 4055.52 6511.68
Fukushima II MP5 9382.150 6446.02
Fukushima [2] (distance from Fukushima I: 55 km) 8841.760 4058.93 6517.15
Matsudate Naraha Town 8410.890 5493.76 6002.78
Shigeoka Naraha Town 8115.970 6072.97 6002.78
Fukushima II MP2 7875.320 6446.02
Namie Namie Town 7321.210 4431.9 6002.78
Radiation dose at Shirasawa branch office, Motomiya 7287.920 6462.43
Fukushima II MP6 7062.690 6446.02
Fukushima II MP7 6511.580 6443.28
Fukushima [1] (distance from Fukushima I: 60 km) 5615.310 4058.93 6517.15
Fukushima [11] (distance from Fukushima I: 40 km) 5491.310 4058.93 6517.15
Fukushima [63] (distance from Fukushima I: 45 km) 5448.820 4058.93 6517.15
Fukushima [45] (distance from Fukushima I: 20 km) 3981.200 4058.93 6517.15
Fukushima [42] (distance from Fukushima I: 30 km) 3850.600 4058.93 6517.15
Fukushima [10] (distance from Fukushima I: 40 km) 3734.160 4058.93 6517.15
Fukushima [78] (distance from Fukushima I: 45 km) 3716.820 4053.82 6508.94
Futatsunuma Hirono Town 3520.340 5265.6 6002.78
Fukushima [4] (distance from Fukushima I: 50 km) 3386.310 4058.93 6517.15
Fukushima [7] (distance from Fukushima I: 45 km) 3313.930 4058.93 6517.15
Radiation dose at Koriyama joint government building, Koriyama 3232.890 6459.7
Fukushima [15] (distance from Fukushima I: 35 km) 3178.670 4058.93 6517.15
Kiyohashi Namie Town 3162.000 3887.75 6002.78
Fukushima [71] (distance from Fukushima I: 25 km) 3161.650 4053.82 6508.94
Radiation dose at Agricultural center, Koriyama 3128.960 6459.7
Fukushima [41] (distance from Fukushima I: 20 km) 3111.490 4058.93 6517.15
Radiation dose at Koriyama city office, Koriyama 2803.520 6459.7
Fukushima [44] (distance from Fukushima I: 30 km) 2535.550 4058.93 6517.15
Fukushima [72] (distance from Fukushima I: 30 km) 2344.620 4053.82 6508.94
Fukushima [43] (distance from Fukushima I: 20 km) 2244.110 4058.93 6517.15
Yamadaoka Naraha Town 2205.340 4668.85 6002.78
Radiation dose at Iwane Fureai Plaza, Motomiya 2169.060 6462.43
Fukushima [22] (distance from Fukushima I: 35 km) 2020.650 4058.93 6517.15
Kuji Hitachi City 1990.890 10078.5 6528.1
Hitachinaka Hitachinaka City 1951.950 4426.54 6525.36
Fukushima [76] (distance from Fukushima I: 25 km) 1945.520 4053.82 6508.94
Fukushima [80] (distance from Fukushima I: 25 km) 1876.860 4053.82 6508.94
Momiyama Hokota City 1837.540 5048.79 6528.1
Fukushima [77] (distance from Fukushima I: 25 km) 1802.490 4053.82 6508.94
Horiguchi Hitachinaka City 1779.410 4411.18 6530.83
Onuma Hitachi City 1776.950 3758.78 6525.36
Fukushima [6] (distance from Fukushima I: 45 km) 1741.180 4058.93 6517.15
Tsukuriya Hokota City 1736.890 4247.1 6528.1
Radiation dose at Big palette Fukushima, Koriyama 1668.540 6459.7
Nemoto Hitachioomiya City 1633.190 4731.86 6525.36
Fukushima [13] (distance from Fukushima I: 40 km) 1624.150 4058.93 6517.15
Fukushima [23] (distance from Fukushima I: 35 km) 1551.750 4058.93 6517.15
Radiation dose at Tsukidatemachi kamitedo, Date 1545.300 6467.9
Fukushima [14] (distance from Fukushima I: 35 km) 1543.460 4058.93 6517.15
Radiation dose at JAEA Oarai (P12) 1512.140 6484.32
Radiation dose at Ose administration center, Koriyama 1494.270 6459.7
Araji Hokota City 1437.760 4256.6 6528.1
Ishigami Tokai Village 1431.690 3874.88 6528.1
Mawatari Hitachinaka City 1422.870 4476.15 6528.1
Radiation dose at JAEA Oarai (P11) 1399.370 6484.32
Onuki Oarai Town 1387.990 4647.95 6528.1
Sawa Hitachinaka City 1353.770 3510.7 6525.36
Toyooka Tokai Village 1321.760 4266.17 6528.1
Ajigaura Hitachinaka City 1313.890 4197.58 6525.36
Fukushima [5] (distance from Fukushima I: 45 km) 1282.090 4058.93 6517.15
Geiger Counter Feeds from Asao Kawasaki 1266.620 6437.81
Radiation dose at Tamokami elementary school, Koriyama 1256.140 6459.7
Isohama Oarai Town 1250.540 4052.78 6522.62
Ebisawa Ibaraki Town 1222.240 11001.5 6525.36
Muramatsu Tokai Village 1203.520 4304.36 6528.1
Kamitoda Hokota City 1184.740 3531.3 6528.1
Yanagisawa Hitachinaka City 1166.970 3596.56 6525.36
Tokushuku Hokota City 1159.730 3187.72 6528.1
Tasaki Hokota City 1153.300 3771.52 6498
Fukushima [20] (distance from Fukushima I: 45 km) 1145.390 4058.93 6517.15
Kadobe Naka City 1086.580 8566.94 6525.36
Radiation dose at Date city office, Date 1076.050 6462.43
Oshinobe Tokai Village 1041.340 4018.04 6528.1
Oba Mito City 1037.670 13199.4 6528.1
Godai Naka City 1031.270 3483.54 6528.1
Ishikawa Mito City 1030.810 4105.66 6530.83
Isobe Hitachiota City 1013.130 19813.3 6528.1
Yatabe Ibaraki Town 996.127 3445.4 6528.1
Radiation dose at Motomiya city office, Motomiya 992.703 6462.43
Fukushima [73] (distance from Fukushima I: 35 km) 981.984 4053.82 6508.94
Fukushima [75] (distance from Fukushima I: 45 km) 960.529 4053.82 6508.94
Yokobori Naka City 930.280 4037.11 6528.1
Sugaya Naka City 926.186 6168.03 6530.83
Kounosu Naka City 926.087 3149.52 6528.1
Funaishikawa Tokai Village 900.399 4180.27 6528.1
Nukada Naka City 899.900 3776.26 6522.62
Uridura Naka City 890.113 3604.61 6522.62
Shiraki Tsuruga City 881.330 7647.95 6530.83
Motokomezaki Naka City 880.851 3361.58 6495.26
Shiraki pass Tsuruga City 850.284 8010.75 6530.83
Radiation dose in Yamamoto 846.633 6484.32
Yoshizawa Mito City 837.646 3645.83 6528.1
Radiation dose at JAEA Oarai (P7) 831.135 6484.32
Mayumi Hitachiota City 828.119 3617.2 6528.1
Urasoko Tsuruga City 826.465 6349.4 6530.83
Nemoto Hitachioomiya City 825.588 4073.6 6525.36
Takenami Mihama Town 804.283 6664.48 6530.83
Radiation dose at JAEA Oarai (P15) 780.207 6484.32
Tateishi Tsuruga City 780.092 5280.06 6530.83
Radiation dose at JAEA Oarai (P14) 770.174 6484.32
Radiation dose at JAEA Oarai (P13) 769.612 6484.32
Ukishima Kawasaki Ward 735.475 12460.1 6530.83
Kume Hitachiota City 713.958 3540.8 6528.1
Radiation dose at JAEA Oarai (P2) 712.011 6484.32
Fukushima [74] (distance from Fukushima I: 35 km) 706.552 4053.82 6508.94
Nyuu Mihama Town 674.787 6072.53 6530.83
Fukushima [52] (distance from Fukushima I: 40 km) 672.743 4058.93 6517.15
Radiation dose in Iwanuma 670.242 6484.32
Fukushima [51] (distance from Fukushima I: 40 km) 665.376 4058.93 6517.15
Tsuruga Tsuruga City 655.360 5356.43 6530.83
Shiohama Kawasaki Ward 653.536 4277.52 6530.83
Radiation dose in Kakuda 649.863 6484.32
Sakajiri Mihama Town 649.252 7084.64 6530.83
North point of Kinki University Atomic Energy Research Instirute Station 639.566 4449.39 6530.83
Radiation dose in Onagawa (MP-2) 632.968 6481.58
Kumatori town Nishi primary school Station 631.491 5318.22 6530.83
Oshima Kawasaki Ward 630.402 4077.02 6530.83
Izumisano municipal Oike athletic field Station 629.920 5996.16 6530.83
Atom-kyoudou nursery school Station 625.566 5757.44 6530.83
South point of Kinki University Atomic Energy Research Instirute Station 625.202 5241.85 6530.83
Nakamachi Omaezaki City 623.494 6750.42 6530.83
Uraga Yokosuka City 622.492 3198.56 6530.83
Goritoge Shika Town 622.143 7170.57 6530.83
Kumatori town Minami primary school Station 606.134 6101.17 6530.83
Radiation dose at JAEA Oarai (P1) 603.643 6487.06
Yamanotedai-No.1 Park Station 599.140 5690.59 6530.83
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 595.502 6503.47
Noumi Shika Town 594.021 7094.15 6530.83
Radiation dose in Watari 591.851 6484.32
Hairando Yokosuka City 588.667 4010.16 6530.83
Fukushima [12] (distance from Fukushima I: 40 km) 588.291 4058.93 6517.15
Ningyotoge Kagamino Town 574.857 5690.59 6530.83
Ten-no Kagamino Town 569.960 6817.27 6530.83
Funagura Yokosuka City 563.909 3781.01 6530.83
Chidori Kawasaki Ward 560.211 3656.86 6530.83
Radiation dose at JAEA Oarai (P16) 556.365 6484.32
Shika Shika Town 551.376 6836.35 6530.83
Higashiosaka municipal Kamikosaka primary scool Station 550.277 4439.82 6530.83
Sahara Yokosuka City 547.404 3542.29 6530.83
Kazanashi Shika Town 545.377 6416.26 6530.83
Akasumi Shika Town 544.970 5872.02 6530.83
Kurahashi Maizuru City 540.820 5346.86 6530.83
Obama Obama City 540.809 4783.55 6530.83
Sakuragaike community hall Omaezaki City 540.772 6922.28 6530.83
Shirowa primary school Omaezaki City 535.692 6779.06 6530.83
Radiation dose at JAEA Oarai (P5) 529.759 6484.32
Uenohara Omaezaki City 529.333 6970.06 6530.83
Kumano Shika Town 529.019 6654.98 6530.83
Izumisano municipal Hineno filtration plant Station 527.471 5738.37 6530.83
Nishi-hamasada Matsue City 525.089 6352.53 6514.42
Kouno Minami-Echizen Town 525.028 4812.19 6530.83
Kurihama Yokosuka City 523.708 3828.73 6530.83
Osaka prefectural Kumatori off-site-center Station 522.808 5289.57 6530.83
Ogasa branch Kikugawa City 522.039 7050.7 6517.15
Izumisano municipal Hineno primary scool Station 518.181 4592.61 6530.83
Shirasuna Omaezaki City 499.479 6826.84 6530.83
Jitougata primary school Makinohara City 498.059 6549.91 6530.83
Kataku Matsue City 497.007 5089.06 6530.83
Nishihemi Yokosuka City 496.917 3055.34 6530.83
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 496.721 6503.47
Satsuma-sendai monitoring center Satsuma-sendai City 495.302 5012.7 6530.83
Otomi Takahama Town 494.821 5614.22 6530.83
Otsu Nanao City 493.895 5633.3 6530.83
The Observation point for comparison Tatsunokuchi 493.454 4640.33 6530.83
Hitsuhama Ohi Town 492.630 5222.78 6530.83
Kijiyama Misasa Town 489.284 5299.14 6530.83
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 487.055 6503.47
Hiraba Omaezaki City 485.878 6826.84 6530.83
Tayu Matsue City 484.956 5308.71 6530.83
Hamaokakita primary school Omaezaki City 484.537 7003.08 6517.15
Oitomi Ayabe City 474.670 6731.34 6530.83
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 472.017 6503.47
Kashiwazaki-shigai Kashiwazaki City 470.822 5356.43 6530.83
Mitsu Matsue City 466.897 5079.56 6530.83
Tonomachi Kawasaki Ward 463.967 6435.33 6530.83
Daitou branch Kakegawa City 463.829 6898.29 6517.15
Fukura Shika Town 462.493 6406.69 6530.83
Nagasawa Yokosuka City 462.365 3742.8 6530.83
The athletic field Station of Kinki University 461.661 4229.75 6530.83
Koura Matsue City 461.049 6062.96 6530.83
Sakurasan Ward Omaezaki City 459.434 6607.2 6530.83
Tsuchikawa Nanao City 458.915 6234.82 6530.83
Kumatori Town office Station 457.917 4363.46 6530.83
Shinkango Omaezaki City 449.013 7647.95 6530.83
Ogurui Takahama Town 448.279 5003.13 6530.83
Kusabue Omaezaki City 444.162 7208.72 6530.83
Omaezaki City monitoring center 443.946 7075.07 6530.83
Akawase Kagamino Town 442.246 4363.46 6530.83
Ibaraki 442.139 3204.1 6522.62
Hinode Town Yokosuka City 438.324 2520.67 6530.83
Nishiyama Kashiwazaki City 437.251 7581.09 6530.83
Kariwa Kariwa Village 436.307 5719.23 6530.83
Osaka prefectural Hineno high scool Station 435.745 5098.63 6530.83
Miyagawa Kashiwazaki City 435.245 5642.87 6530.83
Radiation dose in Natori 434.640 6484.32
Kami-koubu Matsue City 433.868 5547.37 6530.83
Shimo-Takamachi Kariwa Village 433.192 6225.31 6530.83
Osaka prefectural Sano supporting school Station 432.398 5556.94 6530.83
Arahama Kashiwazaki City 428.874 5814.73 6530.83
Doai Kashiwazaki City 425.681 5471 6530.83
Owashi Matsue City 424.452 5423.28 6530.83
Okayasu Maizuru City 422.568 6387.61 6530.83
Katsuyama Kariwa Village 421.280 5814.73 6530.83
Kita-koubu Matsue City 420.683 5948.38 6530.83
Kichisaka Maizuru City 413.065 7762.52 6530.83
Nagai Ohi Town 410.699 5645.33 6522.62
Shiokumi Maizuru City 407.938 9662.6 6530.83
Miyadome Ohi Town 407.831 4678.54 6530.83
Kariwa Kariwa Village 407.617 6024.81 6530.83
Ueno Satsuma-sendai City 394.248 4372.96 6530.83
Power Station-South 389.191 6368.54 6530.83
Radiation dose at JAEA Oarai (P6) 386.963 6484.32
Power Station- 385.546 6215.75 6530.83
Takae Satsuma-sendai City 379.551 4430.25 6530.83
Hokawaduura Genkai Town 378.015 6745.66 6530.83
Kou Itimatsu Suetsugu 377.929 4869.48 6530.83
Minato Satsuma-sendai City 377.656 4057.88 6530.83
Iwanai Iwanai Town 376.336 6613.99 6528.1
Hattari Kyowa Town 373.047 6432.64 6528.1
Chatsu Tomari Village 371.011 6146.32 6528.1
Oyama Maizuru City 358.223 5595.15 6530.83
Kodaira Satsuma-sendai City 355.545 4105.66 6530.83
Kayanuma Tomari Village 354.809 5468.71 6528.1
Anojiri Obama City 353.215 4583.04 6530.83
Kushi Genkai Town 349.738 9309.3 6530.83
Yamaguchi 348.715 7323.65 6522.62
Sadahongou Matsue City 348.228 5700.16 6530.83
Sakibe Karatsu City 347.801 8822.35 6530.83
Hirao Genkai Town 343.814 9299.73 6530.83
The Meteorological Obsevatory of kyowa Town 343.275 6098.62 6528.1
Minami-Horoni Kyowa Town 335.180 5716.84 6528.1
Kounoura Takahama Town 330.353 4831.27 6530.83
Kyoudomarisaki Karatsu City 328.622 9452.52 6530.83
Horikappu Jinja Tomari Village 328.230 5917.26 6528.1
Hukada-kita Matsue City 327.031 4688.05 6530.83
Radiation dose in KEK, Tsukuba 326.240 6503.47
Herokaruusu Tomari Village 324.242 6136.81 6528.1
Yorita Satsuma-sendai City 323.218 4802.62 6530.83
Kamoenai Kamoenai Village 322.032 5182.39 6528.1
Radiation dose in Onagawa (MP-6) 316.267 6481.58
Imamura Genkai Town 314.749 80107.5 6530.83
Yamanaka Takahama Town 314.185 6234.82 6530.83
Sendai (Miyagi) 312.585 2935.18 6522.62
Radiation dose in Onagawa (MP-1) 300.147 6481.58
Gumisaki Satsuma-sendai City 295.693 3876.51 6530.83
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 286.142 6503.47
Aomori Aomori City 285.372 3941.65 6528.1
Misawa City hall Misawa City 283.728 7644.74 6528.1
Kashu Ikata Town 277.173 4000.59 6530.83
Noheji Town Office Noheji Town 272.004 3378.58 6528.1
Takasimamati 271.103 4258.39 6530.83
Radiation dose in Onagawa (MP-3) 270.563 6481.58
Kucho Ikata Town 269.545 3532.78 6530.83
Radiation dose in Marumori 269.436 6484.32
Kawanagata Ikata Town 266.821 3446.85 6530.83
Tochigi 260.733 3833.47 6522.62
Chikagawa Mutu City 256.719 4399.77 6528.1
Yokohama Town Office Yokohama Town 254.846 5392.38 6528.1
Tokyo 251.877 4520.06 6522.62
Hiranuma Rokkasho Village 251.186 3540.8 6528.1
Taisei Ikata Town 246.293 2587.53 6530.83
Chitose-daira Rokkasho Village 245.868 3817.62 6528.1
Gifu 243.951 6293.76 6522.62
Fukkoshi Yokohama Town 243.102 3703.09 6528.1
Shimane 240.651 6293.76 6522.62
Sunagomata Higashidoori Village 238.012 5354.18 6528.1
Obuchi Rokkasho Village 237.506 4256.6 6528.1
Tomari Rokkasho Village 230.636 5955.46 6528.1
kanagawa 226.339 3947.9 6522.62
Saitama 219.770 3432.96 6522.62
Ikatagoshi Ikata Town 217.515 3255.85 6530.83
Touhoku Branch office Touhoku Town 215.416 3082.69 6528.1
Radiation dose at Tohoku University 214.824 6484.32
Odanosawa Higashidoori Village 210.287 4266.17 6528.1
Kagawa 205.829 4405.63 6522.62
Oippe Higashidoori Village 205.182 3674.46 6528.1
Oita 200.921 4863.36 6522.62
Touhoku Town office Touhoku Town 200.811 14258.7 6528.1
Kuchogoshi Ikata Town 198.646 3303.63 6530.83
Minatoura Ikata Town 186.776 2969.41 6530.83
Radiation dose in Koyadori, Ojika 184.905 6478.85
Toyama 184.580 8410.75 6522.62
Fukushima [9] (distance from Fukushima I: 45 km) 184.232 4058.93 6517.15
Radiation dose in Tukahama, Ojika 183.417 6478.85
Chiba 182.407 2517.5 6522.62
Nara 182.387 4577.28 6522.62
Okayama 181.976 5950.46 6522.62
Yamagata 181.598 4691.71 6522.62
Ehime 180.745 4233.98 6522.62
Ishikawa 180.445 7295.04 6522.62
Niigata 177.483 8754.05 6522.62
Hiroshima 176.816 3947.9 6522.62
Mie 174.867 4514.34 6522.62
Fukui 170.045 5549.95 6522.62
Radiation dose in Terama, Ojika 168.036 6478.85
Yamanashi 164.561 3661.82 6522.62
Nagano 162.242 5572.84 6522.62
Saga 161.421 4920.58 6522.62
Tottori 161.392 4520.06 6522.62
Radiation dose in Enoshima, Ojika 160.091 6478.85
Osaka 159.103 3490.18 6522.62
Ibaraki-city Environment 157.249 6437.81
Aichi 149.345 4233.98 6522.62
Toyonoura Ikata Town 149.214 3408.64 6530.83
Shizuoka 148.639 4377.02 6522.62
Kyoto 144.522 4977.79 6522.62
Kagoshima 144.449 5395.47 6522.62
Tokushima 143.627 3833.47 6522.62
Gunma 143.572 2574.72 6522.62
Hyogo 139.710 4348.42 6522.62
Fukuoka 136.511 4520.06 6522.62
Wakayama 133.857 3204.1 6522.62
Radiation at Tamaki-cho Mie Japan 133.138 6437.81
Akita 132.832 4920.58 6522.62
Shiga 124.919 3490.18 6522.62
Nagasaki 109.459 3947.9 6522.62
Hokkaido 109.189 6007.68 6522.62
Kumamoto 103.568 3833.47 6522.62
Aomori 101.819 5836.03 6522.62
Miyazaki 100.354 3799.14 6522.62
Kochi 95.931 4348.42 6522.62
Fukushima [35] (distance from Fukushima I: 35 km) 91.917 4050.41 6503.47
Iwate 90.324 4806.14 6522.62
Environment Feeds from Ohta 83.623 6437.81
Okinawa 82.305 3289.92 6522.62
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