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Accumulated absorbed dose rate - T=13.03.2011 - 21.02.2017(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 5857.78
Fukushima I MP8 570942.000 5857.78
Fukushima I MP6 240668.000 5857.78
Yamada Futaba Town 176983.000 4543.8 5414.54
Fukushima I MP2 140420.000 5857.78
Fukushima I MP5 111325.000 5857.78
Fukushima [32] (distance from Fukushima I: 30 km) 101500.000 3692.57 5928.91
Fukushima I MP3 93730.602 5857.78
Fukushima I MP4 86821.500 5857.78
Fukushima [33] (distance from Fukushima I: 30 km) 77197.703 3692.57 5928.91
Fukushima [79] (distance from Fukushima I: 40 km) 54008.602 3641.45 5846.83
Fukushima [31] (distance from Fukushima I: 30 km) 40677.398 3692.57 5928.91
Ono Okuma Town 38610.500 4195.46 5414.54
Shinzan Futaba Town 38332.801 3807.61 5414.54
Fukushima I MP1 31496.801 5857.78
Yonomori Tomioka Town 29815.900 4337.95 5414.54
Fukushima [46] (distance from Fukushima I: 20 km) 28842.500 3692.57 5928.91
Tomioka Tomioka Town 25324.500 4670.42 5414.54
Fukushima [62] (distance from Fukushima I: 40 km) 16464.100 3692.57 5928.91
Fukushima [61] (distance from Fukushima I: 40 km) 13102.800 3692.57 5928.91
Shimo-Kooriyama Tomioka Town 13057.000 4638.79 5414.54
Fukushima [21] (distance from Fukushima I: 30 km) 12103.800 3692.57 5928.91
Fukushima [3] (distance from Fukushima I: 45 km) 11985.000 3692.57 5928.91
Kami-kooriyama Tomioka Town 11803.900 3641.38 5414.54
Fukushima II MP3 11060.600 5857.78
Fukushima II MP1 10903.000 5857.78
Kooriyama Futaba Town 10352.900 4242.96 5414.54
Fukushima II MP4 9696.330 5857.78
Fukushima [34] (distance from Fukushima I: 30 km) 9540.450 3689.16 5923.44
Fukushima II MP5 9382.150 5857.78
Fukushima [2] (distance from Fukushima I: 55 km) 8841.760 3692.57 5928.91
Matsudate Naraha Town 8410.890 4955.4 5414.54
Shigeoka Naraha Town 8115.970 5477.86 5414.54
Fukushima II MP2 7875.320 5857.78
Namie Namie Town 7321.210 3997.6 5414.54
Radiation dose at Shirasawa branch office, Motomiya 7287.920 5874.19
Fukushima II MP6 7062.690 5857.78
Fukushima II MP7 6511.580 5855.04
Fukushima [1] (distance from Fukushima I: 60 km) 5615.310 3692.57 5928.91
Fukushima [11] (distance from Fukushima I: 40 km) 5491.310 3692.57 5928.91
Fukushima [63] (distance from Fukushima I: 45 km) 5448.820 3692.57 5928.91
Fukushima [45] (distance from Fukushima I: 20 km) 3981.200 3692.57 5928.91
Fukushima [42] (distance from Fukushima I: 30 km) 3850.600 3692.57 5928.91
Fukushima [10] (distance from Fukushima I: 40 km) 3734.160 3692.57 5928.91
Fukushima [78] (distance from Fukushima I: 45 km) 3716.820 3687.46 5920.7
Futatsunuma Hirono Town 3520.340 4749.6 5414.54
Fukushima [4] (distance from Fukushima I: 50 km) 3386.310 3692.57 5928.91
Fukushima [7] (distance from Fukushima I: 45 km) 3313.930 3692.57 5928.91
Radiation dose at Koriyama joint government building, Koriyama 3232.890 5871.46
Fukushima [15] (distance from Fukushima I: 35 km) 3178.670 3692.57 5928.91
Kiyohashi Namie Town 3162.000 3506.77 5414.54
Fukushima [71] (distance from Fukushima I: 25 km) 3161.650 3687.46 5920.7
Radiation dose at Agricultural center, Koriyama 3128.960 5871.46
Fukushima [41] (distance from Fukushima I: 20 km) 3111.490 3692.57 5928.91
Radiation dose at Koriyama city office, Koriyama 2803.520 5871.46
Fukushima [44] (distance from Fukushima I: 30 km) 2535.550 3692.57 5928.91
Fukushima [72] (distance from Fukushima I: 30 km) 2344.620 3687.46 5920.7
Fukushima [43] (distance from Fukushima I: 20 km) 2244.110 3692.57 5928.91
Yamadaoka Naraha Town 2205.340 4211.33 5414.54
Radiation dose at Iwane Fureai Plaza, Motomiya 2169.060 5874.19
Fukushima [22] (distance from Fukushima I: 35 km) 2020.650 3692.57 5928.91
Kuji Hitachi City 1990.890 9170.3 5939.86
Hitachinaka Hitachinaka City 1951.950 4027.5 5937.12
Fukushima [76] (distance from Fukushima I: 25 km) 1945.520 3687.46 5920.7
Fukushima [80] (distance from Fukushima I: 25 km) 1876.860 3687.46 5920.7
Momiyama Hokota City 1837.540 4593.85 5939.86
Fukushima [77] (distance from Fukushima I: 25 km) 1802.490 3687.46 5920.7
Horiguchi Hitachinaka City 1779.410 4013.86 5942.59
Onuma Hitachi City 1776.950 3419.94 5937.12
Fukushima [6] (distance from Fukushima I: 45 km) 1741.180 3692.57 5928.91
Tsukuriya Hokota City 1736.890 3864.4 5939.86
Radiation dose at Big palette Fukushima, Koriyama 1668.540 5871.46
Nemoto Hitachioomiya City 1633.190 4305.3 5937.12
Fukushima [13] (distance from Fukushima I: 40 km) 1624.150 3692.57 5928.91
Fukushima [23] (distance from Fukushima I: 35 km) 1551.750 3692.57 5928.91
Radiation dose at Tsukidatemachi kamitedo, Date 1545.300 5879.66
Fukushima [14] (distance from Fukushima I: 35 km) 1543.460 3692.57 5928.91
Radiation dose at JAEA Oarai (P12) 1512.140 5896.08
Radiation dose at Ose administration center, Koriyama 1494.270 5871.46
Araji Hokota City 1437.760 3873.05 5939.86
Ishigami Tokai Village 1431.690 3525.72 5939.86
Mawatari Hitachinaka City 1422.870 4072.81 5939.86
Radiation dose at JAEA Oarai (P11) 1399.370 5896.08
Onuki Oarai Town 1387.990 4229.12 5939.86
Sawa Hitachinaka City 1353.770 3194.22 5937.12
Toyooka Tokai Village 1321.760 3881.75 5939.86
Ajigaura Hitachinaka City 1313.890 3819.18 5937.12
Fukushima [5] (distance from Fukushima I: 45 km) 1282.090 3692.57 5928.91
Geiger Counter Feeds from Asao Kawasaki 1266.620 5849.57
Radiation dose at Tamokami elementary school, Koriyama 1256.140 5871.46
Isohama Oarai Town 1250.540 3687.28 5934.38
Ebisawa Ibaraki Town 1222.240 10009.8 5937.12
Muramatsu Tokai Village 1203.520 3916.5 5939.86
Kamitoda Hokota City 1184.740 3213.1 5939.86
Yanagisawa Hitachinaka City 1166.970 3272.34 5937.12
Tokushuku Hokota City 1159.730 2900.47 5939.86
Tasaki Hokota City 1153.300 3430.1 5909.76
Fukushima [20] (distance from Fukushima I: 45 km) 1145.390 3692.57 5928.91
Kadobe Naka City 1086.580 7794.66 5937.12
Radiation dose at Date city office, Date 1076.050 5874.19
Oshinobe Tokai Village 1041.340 3655.98 5939.86
Oba Mito City 1037.670 12010 5939.86
Godai Naka City 1031.270 3169.64 5939.86
Ishikawa Mito City 1030.810 3735.86 5942.59
Isobe Hitachiota City 1013.130 18028 5939.86
Yatabe Ibaraki Town 996.127 3134.94 5939.86
Radiation dose at Motomiya city office, Motomiya 992.703 5874.19
Fukushima [73] (distance from Fukushima I: 35 km) 981.984 3687.46 5920.7
Fukushima [75] (distance from Fukushima I: 45 km) 960.529 3687.46 5920.7
Yokobori Naka City 930.280 3673.33 5939.86
Sugaya Naka City 926.186 5612.47 5942.59
Kounosu Naka City 926.087 2865.72 5939.86
Funaishikawa Tokai Village 900.399 3803.59 5939.86
Nukada Naka City 899.900 3435.7 5934.38
Uridura Naka City 890.113 3279.53 5934.38
Shiraki Tsuruga City 881.330 6959.09 5942.59
Motokomezaki Naka City 880.851 3057.14 5907.02
Shiraki pass Tsuruga City 850.284 7289.21 5942.59
Radiation dose in Yamamoto 846.633 5896.08
Yoshizawa Mito City 837.646 3317.31 5939.86
Radiation dose at JAEA Oarai (P7) 831.135 5896.08
Mayumi Hitachiota City 828.119 3291.25 5939.86
Urasoko Tsuruga City 826.465 5777.5 5942.59
Nemoto Hitachioomiya City 825.588 3706.38 5937.12
Takenami Mihama Town 804.283 6064.21 5942.59
Radiation dose at JAEA Oarai (P15) 780.207 5896.08
Tateishi Tsuruga City 780.092 4804.48 5942.59
Radiation dose at JAEA Oarai (P14) 770.174 5896.08
Radiation dose at JAEA Oarai (P13) 769.612 5896.08
Ukishima Kawasaki Ward 735.475 11337.8 5942.59
Kume Hitachiota City 713.958 3221.75 5939.86
Radiation dose at JAEA Oarai (P2) 712.011 5896.08
Fukushima [74] (distance from Fukushima I: 35 km) 706.552 3687.46 5920.7
Nyuu Mihama Town 674.787 5525.57 5942.59
Fukushima [52] (distance from Fukushima I: 40 km) 672.743 3692.57 5928.91
Radiation dose in Iwanuma 670.242 5896.08
Fukushima [51] (distance from Fukushima I: 40 km) 665.376 3692.57 5928.91
Tsuruga Tsuruga City 655.360 4873.97 5942.59
Shiohama Kawasaki Ward 653.536 3892.24 5942.59
Radiation dose in Kakuda 649.863 5896.08
Sakajiri Mihama Town 649.252 6446.51 5942.59
North point of Kinki University Atomic Energy Research Instirute Station 639.566 4048.63 5942.59
Radiation dose in Onagawa (MP-2) 632.968 5893.34
Kumatori town Nishi primary school Station 631.491 4839.2 5942.59
Oshima Kawasaki Ward 630.402 3709.79 5942.59
Izumisano municipal Oike athletic field Station 629.920 5456.08 5942.59
Atom-kyoudou nursery school Station 625.566 5238.86 5942.59
South point of Kinki University Atomic Energy Research Instirute Station 625.202 4769.71 5942.59
Nakamachi Omaezaki City 623.494 6142.4 5942.59
Uraga Yokosuka City 622.492 2910.46 5942.59
Goritoge Shika Town 622.143 6524.71 5942.59
Kumatori town Minami primary school Station 606.134 5551.63 5942.59
Radiation dose at JAEA Oarai (P1) 603.643 5898.82
Yamanotedai-No.1 Park Station 599.140 5178.03 5942.59
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 595.502 5915.23
Noumi Shika Town 594.021 6455.17 5942.59
Radiation dose in Watari 591.851 5896.08
Hairando Yokosuka City 588.667 3648.96 5942.59
Fukushima [12] (distance from Fukushima I: 40 km) 588.291 3692.57 5928.91
Ningyotoge Kagamino Town 574.857 5178.03 5942.59
Ten-no Kagamino Town 569.960 6203.23 5942.59
Funagura Yokosuka City 563.909 3440.45 5942.59
Chidori Kawasaki Ward 560.211 3327.49 5942.59
Radiation dose at JAEA Oarai (P16) 556.365 5896.08
Shika Shika Town 551.376 6220.59 5942.59
Higashiosaka municipal Kamikosaka primary scool Station 550.277 4039.92 5942.59
Sahara Yokosuka City 547.404 3223.23 5942.59
Kazanashi Shika Town 545.377 5838.34 5942.59
Akasumi Shika Town 544.970 5343.12 5942.59
Kurahashi Maizuru City 540.820 4865.26 5942.59
Obama Obama City 540.809 4352.69 5942.59
Sakuragaike community hall Omaezaki City 540.772 6298.78 5942.59
Shirowa primary school Omaezaki City 535.692 6168.46 5942.59
Radiation dose at JAEA Oarai (P5) 529.759 5896.08
Uenohara Omaezaki City 529.333 6342.26 5942.59
Kumano Shika Town 529.019 6055.55 5942.59
Izumisano municipal Hineno filtration plant Station 527.471 5221.51 5942.59
Nishi-hamasada Matsue City 525.089 5778.91 5926.18
Kouno Minami-Echizen Town 525.028 4378.75 5942.59
Kurihama Yokosuka City 523.708 3483.87 5942.59
Osaka prefectural Kumatori off-site-center Station 522.808 4813.13 5942.59
Ogasa branch Kikugawa City 522.039 6414.3 5928.91
Izumisano municipal Hineno primary scool Station 518.181 4178.95 5942.59
Shirasuna Omaezaki City 499.479 6211.94 5942.59
Jitougata primary school Makinohara City 498.059 5959.95 5942.59
Kataku Matsue City 497.007 4630.69 5942.59
Nishihemi Yokosuka City 496.917 2780.14 5942.59
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 496.721 5915.23
Satsuma-sendai monitoring center Satsuma-sendai City 495.302 4561.2 5942.59
Otomi Takahama Town 494.821 5108.54 5942.59
Otsu Nanao City 493.895 5125.9 5942.59
The Observation point for comparison Tatsunokuchi 493.454 4222.37 5942.59
Hitsuhama Ohi Town 492.630 4752.35 5942.59
Kijiyama Misasa Town 489.284 4821.84 5942.59
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 487.055 5915.23
Hiraba Omaezaki City 485.878 6211.94 5942.59
Tayu Matsue City 484.956 4830.55 5942.59
Hamaokakita primary school Omaezaki City 484.537 6370.98 5928.91
Oitomi Ayabe City 474.670 6125.04 5942.59
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 472.017 5915.23
Kashiwazaki-shigai Kashiwazaki City 470.822 4873.97 5942.59
Mitsu Matsue City 466.897 4622.03 5942.59
Tonomachi Kawasaki Ward 463.967 5855.69 5942.59
Daitou branch Kakegawa City 463.829 6275.65 5928.91
Fukura Shika Town 462.493 5829.63 5942.59
Nagasawa Yokosuka City 462.365 3405.68 5942.59
The athletic field Station of Kinki University 461.661 3848.77 5942.59
Koura Matsue City 461.049 5516.86 5942.59
Sakurasan Ward Omaezaki City 459.434 6012.08 5942.59
Tsuchikawa Nanao City 458.915 5673.25 5942.59
Kumatori Town office Station 457.917 3970.43 5942.59
Shinkango Omaezaki City 449.013 6959.09 5942.59
Ogurui Takahama Town 448.279 4552.49 5942.59
Kusabue Omaezaki City 444.162 6559.42 5942.59
Omaezaki City monitoring center 443.946 6437.81 5942.59
Akawase Kagamino Town 442.246 3970.43 5942.59
Ibaraki 442.139 2915.14 5934.38
Hinode Town Yokosuka City 438.324 2293.63 5942.59
Nishiyama Kashiwazaki City 437.251 6898.25 5942.59
Kariwa Kariwa Village 436.307 5204.09 5942.59
Osaka prefectural Hineno high scool Station 435.745 4639.39 5942.59
Miyagawa Kashiwazaki City 435.245 5134.61 5942.59
Radiation dose in Natori 434.640 5896.08
Kami-koubu Matsue City 433.868 5047.71 5942.59
Shimo-Takamachi Kariwa Village 433.192 5664.59 5942.59
Osaka prefectural Sano supporting school Station 432.398 5056.42 5942.59
Arahama Kashiwazaki City 428.874 5290.99 5942.59
Doai Kashiwazaki City 425.681 4978.22 5942.59
Owashi Matsue City 424.452 4934.8 5942.59
Okayasu Maizuru City 422.568 5812.27 5942.59
Katsuyama Kariwa Village 421.280 5290.99 5942.59
Kita-koubu Matsue City 420.683 5412.61 5942.59
Kichisaka Maizuru City 413.065 7063.34 5942.59
Nagai Ohi Town 410.699 5136.21 5934.38
Shiokumi Maizuru City 407.938 8792.27 5942.59
Miyadome Ohi Town 407.831 4257.14 5942.59
Kariwa Kariwa Village 407.617 5482.15 5942.59
Ueno Satsuma-sendai City 394.248 3979.09 5942.59
Power Station-South 389.191 5794.91 5942.59
Radiation dose at JAEA Oarai (P6) 386.963 5896.08
Power Station- 385.546 5655.89 5942.59
Takae Satsuma-sendai City 379.551 4031.21 5942.59
Hokawaduura Genkai Town 378.015 6138.07 5942.59
Kou Itimatsu Suetsugu 377.929 4430.88 5942.59
Minato Satsuma-sendai City 377.656 3692.38 5942.59
Iwanai Iwanai Town 376.336 6018.01 5939.86
Hattari Kyowa Town 373.047 5853 5939.86
Chatsu Tomari Village 371.011 5592.48 5939.86
Oyama Maizuru City 358.223 5091.19 5942.59
Kodaira Satsuma-sendai City 355.545 3735.86 5942.59
Kayanuma Tomari Village 354.809 4975.93 5939.86
Anojiri Obama City 353.215 4170.24 5942.59
Kushi Genkai Town 349.738 8470.8 5942.59
Yamaguchi 348.715 6663.17 5934.38
Sadahongou Matsue City 348.228 5186.74 5942.59
Sakibe Karatsu City 347.801 8027.71 5942.59
Hirao Genkai Town 343.814 8462.09 5942.59
The Meteorological Obsevatory of kyowa Town 343.275 5549.08 5939.86
Minami-Horoni Kyowa Town 335.180 5201.7 5939.86
Kounoura Takahama Town 330.353 4396.11 5942.59
Kyoudomarisaki Karatsu City 328.622 8601.12 5942.59
Horikappu Jinja Tomari Village 328.230 5384.06 5939.86
Hukada-kita Matsue City 327.031 4265.79 5942.59
Radiation dose in KEK, Tsukuba 326.240 5915.23
Herokaruusu Tomari Village 324.242 5583.83 5939.86
Yorita Satsuma-sendai City 323.218 4370.05 5942.59
Kamoenai Kamoenai Village 322.032 4715.41 5939.86
Radiation dose in Onagawa (MP-6) 316.267 5893.34
Imamura Genkai Town 314.749 72892.1 5942.59
Yamanaka Takahama Town 314.185 5673.25 5942.59
Sendai (Miyagi) 312.585 2670.47 5934.38
Radiation dose in Onagawa (MP-1) 300.147 5893.34
Gumisaki Satsuma-sendai City 295.693 3527.35 5942.59
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 286.142 5915.23
Aomori Aomori City 285.372 3586.47 5939.86
Misawa City hall Misawa City 283.728 6955.88 5939.86
Kashu Ikata Town 277.173 3640.25 5942.59
Noheji Town Office Noheji Town 272.004 3074.14 5939.86
Takasimamati 271.103 3874.83 5942.59
Radiation dose in Onagawa (MP-3) 270.563 5893.34
Kucho Ikata Town 269.545 3214.58 5942.59
Radiation dose in Marumori 269.436 5896.08
Kawanagata Ikata Town 266.821 3136.39 5942.59
Tochigi 260.733 3487.75 5934.38
Chikagawa Mutu City 256.719 4003.31 5939.86
Yokohama Town Office Yokohama Town 254.846 4906.48 5939.86
Tokyo 251.877 4112.42 5934.38
Hiranuma Rokkasho Village 251.186 3221.75 5939.86
Taisei Ikata Town 246.293 2354.47 5942.59
Chitose-daira Rokkasho Village 245.868 3473.62 5939.86
Gifu 243.951 5726.16 5934.38
Fukkoshi Yokohama Town 243.102 3369.41 5939.86
Shimane 240.651 5726.16 5934.38
Sunagomata Higashidoori Village 238.012 4871.72 5939.86
Obuchi Rokkasho Village 237.506 3873.05 5939.86
Tomari Rokkasho Village 230.636 5418.82 5939.86
kanagawa 226.339 3591.86 5934.38
Saitama 219.770 3123.36 5934.38
Ikatagoshi Ikata Town 217.515 2962.59 5942.59
Touhoku Branch office Touhoku Town 215.416 2804.91 5939.86
Radiation dose at Tohoku University 214.824 5896.08
Odanosawa Higashidoori Village 210.287 3881.75 5939.86
Kagawa 205.829 4008.31 5934.38
Oippe Higashidoori Village 205.182 3343.36 5939.86
Oita 200.921 4424.76 5934.38
Touhoku Town office Touhoku Town 200.811 12973.9 5939.86
Kuchogoshi Ikata Town 198.646 3006.07 5942.59
Minatoura Ikata Town 186.776 2701.95 5942.59
Radiation dose in Koyadori, Ojika 184.905 5890.61
Toyama 184.580 7652.23 5934.38
Fukushima [9] (distance from Fukushima I: 45 km) 184.232 3692.57 5928.91
Radiation dose in Tukahama, Ojika 183.417 5890.61
Chiba 182.407 2290.46 5934.38
Nara 182.387 4164.48 5934.38
Okayama 181.976 5413.82 5934.38
Yamagata 181.598 4268.59 5934.38
Ehime 180.745 3852.14 5934.38
Ishikawa 180.445 6637.14 5934.38
Niigata 177.483 7964.57 5934.38
Hiroshima 176.816 3591.86 5934.38
Mie 174.867 4107.22 5934.38
Fukui 170.045 5049.43 5934.38
Radiation dose in Terama, Ojika 168.036 5890.61
Yamanashi 164.561 3331.58 5934.38
Nagano 162.242 5070.25 5934.38
Saga 161.421 4476.82 5934.38
Tottori 161.392 4112.42 5934.38
Radiation dose in Enoshima, Ojika 160.091 5890.61
Osaka 159.103 3175.42 5934.38
Ibaraki-city Environment 157.249 5849.57
Aichi 149.345 3852.14 5934.38
Toyonoura Ikata Town 149.214 3101.62 5942.59
Shizuoka 148.639 3982.28 5934.38
Kyoto 144.522 4528.87 5934.38
Kagoshima 144.449 4908.88 5934.38
Tokushima 143.627 3487.75 5934.38
Gunma 143.572 2342.52 5934.38
Hyogo 139.710 3956.26 5934.38
Fukuoka 136.511 4112.42 5934.38
Wakayama 133.857 2915.14 5934.38
Radiation at Tamaki-cho Mie Japan 133.138 5849.57
Akita 132.832 4476.82 5934.38
Shiga 124.919 3175.42 5934.38
Nagasaki 109.459 3591.86 5934.38
Hokkaido 109.189 5465.88 5934.38
Kumamoto 103.568 3487.75 5934.38
Aomori 101.819 5309.71 5934.38
Miyazaki 100.354 3456.52 5934.38
Kochi 95.931 3956.26 5934.38
Fukushima [35] (distance from Fukushima I: 35 km) 91.917 3684.05 5915.23
Iwate 90.324 4372.7 5934.38
Environment Feeds from Ohta 83.623 5849.57
Okinawa 82.305 2993.22 5934.38
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