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Accumulated absorbed dose rate - T=13.03.2011 - 24.05.2015(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 4109.47
Fukushima I MP8 570942.000 4109.47
Fukushima I MP6 240668.000 4109.47
Yamada Futaba Town 176983.000 3076.65 3666.24
Fukushima I MP2 140420.000 4109.47
Fukushima I MP5 111325.000 4109.47
Fukushima [32] (distance from Fukushima I: 30 km) 101500.000 2603.71 4180.61
Fukushima I MP3 93730.602 4109.47
Fukushima I MP4 86821.500 4109.47
Fukushima [33] (distance from Fukushima I: 30 km) 77197.703 2603.71 4180.61
Fukushima [79] (distance from Fukushima I: 40 km) 54008.602 2552.59 4098.53
Fukushima [31] (distance from Fukushima I: 30 km) 40677.398 2603.71 4180.61
Ono Okuma Town 38610.500 2840.79 3666.24
Shinzan Futaba Town 38332.801 2578.17 3666.24
Fukushima I MP1 31496.801 4109.47
Yonomori Tomioka Town 29815.900 2937.27 3666.24
Fukushima [46] (distance from Fukushima I: 20 km) 28842.500 2603.71 4180.61
Tomioka Tomioka Town 25324.500 3162.39 3666.24
Fukushima [62] (distance from Fukushima I: 40 km) 16464.100 2603.71 4180.61
Fukushima [61] (distance from Fukushima I: 40 km) 13102.800 2603.71 4180.61
Shimo-Kooriyama Tomioka Town 13057.000 3140.97 3666.24
Fukushima [21] (distance from Fukushima I: 30 km) 12103.800 2603.71 4180.61
Fukushima [3] (distance from Fukushima I: 45 km) 11985.000 2603.71 4180.61
Kami-kooriyama Tomioka Town 11803.900 2465.61 3666.24
Fukushima II MP3 11060.600 4109.47
Fukushima II MP1 10903.000 4109.47
Kooriyama Futaba Town 10352.900 2872.95 3666.24
Fukushima II MP4 9696.330 4109.47
Fukushima [34] (distance from Fukushima I: 30 km) 9540.450 2600.3 4175.14
Fukushima II MP5 9382.150 4109.47
Fukushima [2] (distance from Fukushima I: 55 km) 8841.760 2603.71 4180.61
Matsudate Naraha Town 8410.890 3355.35 3666.24
Shigeoka Naraha Town 8115.970 3709.11 3666.24
Fukushima II MP2 7875.320 4109.47
Namie Namie Town 7321.210 2706.81 3666.24
Radiation dose at Shirasawa branch office, Motomiya 7287.920 4125.89
Fukushima II MP6 7062.690 4109.47
Fukushima II MP7 6511.580 4106.74
Fukushima [1] (distance from Fukushima I: 60 km) 5615.310 2603.71 4180.61
Fukushima [11] (distance from Fukushima I: 40 km) 5491.310 2603.71 4180.61
Fukushima [63] (distance from Fukushima I: 45 km) 5448.820 2603.71 4180.61
Fukushima [45] (distance from Fukushima I: 20 km) 3981.200 2603.71 4180.61
Fukushima [42] (distance from Fukushima I: 30 km) 3850.600 2603.71 4180.61
Fukushima [10] (distance from Fukushima I: 40 km) 3734.160 2603.71 4180.61
Fukushima [78] (distance from Fukushima I: 45 km) 3716.820 2598.6 4172.4
Futatsunuma Hirono Town 3520.340 3216 3666.24
Fukushima [4] (distance from Fukushima I: 50 km) 3386.310 2603.71 4180.61
Fukushima [7] (distance from Fukushima I: 45 km) 3313.930 2603.71 4180.61
Radiation dose at Koriyama joint government building, Koriyama 3232.890 4123.15
Fukushima [15] (distance from Fukushima I: 35 km) 3178.670 2603.71 4180.61
Kiyohashi Namie Town 3162.000 2374.47 3666.24
Fukushima [71] (distance from Fukushima I: 25 km) 3161.650 2598.6 4172.4
Radiation dose at Agricultural center, Koriyama 3128.960 4123.15
Fukushima [41] (distance from Fukushima I: 20 km) 3111.490 2603.71 4180.61
Radiation dose at Koriyama city office, Koriyama 2803.520 4123.15
Fukushima [44] (distance from Fukushima I: 30 km) 2535.550 2603.71 4180.61
Fukushima [72] (distance from Fukushima I: 30 km) 2344.620 2598.6 4172.4
Fukushima [43] (distance from Fukushima I: 20 km) 2244.110 2603.71 4180.61
Yamadaoka Naraha Town 2205.340 2851.53 3666.24
Radiation dose at Iwane Fureai Plaza, Motomiya 2169.060 4125.89
Fukushima [22] (distance from Fukushima I: 35 km) 2020.650 2603.71 4180.61
Kuji Hitachi City 1990.890 6471.17 4191.55
Hitachinaka Hitachinaka City 1951.950 2841.52 4188.82
Fukushima [76] (distance from Fukushima I: 25 km) 1945.520 2598.6 4172.4
Fukushima [80] (distance from Fukushima I: 25 km) 1876.860 2598.6 4172.4
Momiyama Hokota City 1837.540 3241.72 4191.55
Fukushima [77] (distance from Fukushima I: 25 km) 1802.490 2598.6 4172.4
Horiguchi Hitachinaka City 1779.410 2832.98 4194.29
Onuma Hitachi City 1776.950 2412.87 4188.82
Fukushima [6] (distance from Fukushima I: 45 km) 1741.180 2603.71 4180.61
Tsukuriya Hokota City 1736.890 2726.97 4191.55
Radiation dose at Big palette Fukushima, Koriyama 1668.540 4123.15
Nemoto Hitachioomiya City 1633.190 3037.52 4188.82
Fukushima [13] (distance from Fukushima I: 40 km) 1624.150 2603.71 4180.61
Fukushima [23] (distance from Fukushima I: 35 km) 1551.750 2603.71 4180.61
Radiation dose at Tsukidatemachi kamitedo, Date 1545.300 4131.36
Fukushima [14] (distance from Fukushima I: 35 km) 1543.460 2603.71 4180.61
Radiation dose at JAEA Oarai (P12) 1512.140 4147.78
Radiation dose at Ose administration center, Koriyama 1494.270 4123.15
Araji Hokota City 1437.760 2733.08 4191.55
Ishigami Tokai Village 1431.690 2487.98 4191.55
Mawatari Hitachinaka City 1422.870 2874.04 4191.55
Radiation dose at JAEA Oarai (P11) 1399.370 4147.78
Onuki Oarai Town 1387.990 2984.35 4191.55
Sawa Hitachinaka City 1353.770 2253.62 4188.82
Toyooka Tokai Village 1321.760 2739.22 4191.55
Ajigaura Hitachinaka City 1313.890 2694.55 4188.82
Fukushima [5] (distance from Fukushima I: 45 km) 1282.090 2603.71 4180.61
Geiger Counter Feeds from Asao Kawasaki 1266.620 4101.26
Radiation dose at Tamokami elementary school, Koriyama 1256.140 4123.15
Isohama Oarai Town 1250.540 2600.99 4186.08
Ebisawa Ibaraki Town 1222.240 7062.2 4188.82
Muramatsu Tokai Village 1203.520 2763.74 4191.55
Kamitoda Hokota City 1184.740 2267.37 4191.55
Yanagisawa Hitachinaka City 1166.970 2308.74 4188.82
Tokushuku Hokota City 1159.730 2046.76 4191.55
Tasaki Hokota City 1153.300 2415.36 4161.46
Fukushima [20] (distance from Fukushima I: 45 km) 1145.390 2603.71 4180.61
Kadobe Naka City 1086.580 5499.36 4188.82
Radiation dose at Date city office, Date 1076.050 4125.89
Oshinobe Tokai Village 1041.340 2579.9 4191.55
Oba Mito City 1037.670 8475.02 4191.55
Godai Naka City 1031.270 2236.71 4191.55
Ishikawa Mito City 1030.810 2636.77 4194.29
Isobe Hitachiota City 1013.130 12721.7 4191.55
Yatabe Ibaraki Town 996.127 2212.22 4191.55
Radiation dose at Motomiya city office, Motomiya 992.703 4125.89
Fukushima [73] (distance from Fukushima I: 35 km) 981.984 2598.6 4172.4
Fukushima [75] (distance from Fukushima I: 45 km) 960.529 2598.6 4172.4
Yokobori Naka City 930.280 2592.14 4191.55
Sugaya Naka City 926.186 3961.28 4194.29
Kounosu Naka City 926.087 2022.24 4191.55
Funaishikawa Tokai Village 900.399 2684.06 4191.55
Nukada Naka City 899.900 2423.52 4186.08
Uridura Naka City 890.113 2313.36 4186.08
Shiraki Tsuruga City 881.330 4911.73 4194.29
Motokomezaki Naka City 880.851 2152.32 4158.72
Shiraki pass Tsuruga City 850.284 5144.74 4194.29
Radiation dose in Yamamoto 846.633 4147.78
Yoshizawa Mito City 837.646 2340.91 4191.55
Radiation dose at JAEA Oarai (P7) 831.135 4147.78
Mayumi Hitachiota City 828.119 2322.52 4191.55
Urasoko Tsuruga City 826.465 4077.77 4194.29
Nemoto Hitachioomiya City 825.588 2614.96 4188.82
Takenami Mihama Town 804.283 4280.12 4194.29
Radiation dose at JAEA Oarai (P15) 780.207 4147.78
Tateishi Tsuruga City 780.092 3391.01 4194.29
Radiation dose at JAEA Oarai (P14) 770.174 4147.78
Radiation dose at JAEA Oarai (P13) 769.612 4147.78
Ukishima Kawasaki Ward 735.475 8002.26 4194.29
Kume Hitachiota City 713.958 2273.48 4191.55
Radiation dose at JAEA Oarai (P2) 712.011 4147.78
Fukushima [74] (distance from Fukushima I: 35 km) 706.552 2598.6 4172.4
Nyuu Mihama Town 674.787 3899.95 4194.29
Fukushima [52] (distance from Fukushima I: 40 km) 672.743 2603.71 4180.61
Radiation dose in Iwanuma 670.242 4147.78
Fukushima [51] (distance from Fukushima I: 40 km) 665.376 2603.71 4180.61
Tsuruga Tsuruga City 655.360 3440.05 4194.29
Shiohama Kawasaki Ward 653.536 2747.15 4194.29
Radiation dose in Kakuda 649.863 4147.78
Sakajiri Mihama Town 649.252 4549.96 4194.29
North point of Kinki University Atomic Energy Research Instirute Station 639.566 2857.52 4194.29
Radiation dose in Onagawa (MP-2) 632.968 4145.04
Kumatori town Nishi primary school Station 631.491 3415.51 4194.29
Oshima Kawasaki Ward 630.402 2618.38 4194.29
Izumisano municipal Oike athletic field Station 629.920 3850.91 4194.29
Atom-kyoudou nursery school Station 625.566 3697.6 4194.29
South point of Kinki University Atomic Energy Research Instirute Station 625.202 3366.47 4194.29
Nakamachi Omaezaki City 623.494 4335.31 4194.29
Uraga Yokosuka City 622.492 2054.21 4194.29
Goritoge Shika Town 622.143 4605.14 4194.29
Kumatori town Minami primary school Station 606.134 3918.35 4194.29
Radiation dose at JAEA Oarai (P1) 603.643 4150.51
Yamanotedai-No.1 Park Station 599.140 3654.66 4194.29
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 595.502 4166.93
Noumi Shika Town 594.021 4556.06 4194.29
Radiation dose in Watari 591.851 4147.78
Hairando Yokosuka City 588.667 2575.44 4194.29
Fukushima [12] (distance from Fukushima I: 40 km) 588.291 2603.71 4180.61
Ningyotoge Kagamino Town 574.857 3654.66 4194.29
Ten-no Kagamino Town 569.960 4378.25 4194.29
Funagura Yokosuka City 563.909 2428.27 4194.29
Chidori Kawasaki Ward 560.211 2348.54 4194.29
Radiation dose at JAEA Oarai (P16) 556.365 4147.78
Shika Shika Town 551.376 4390.5 4194.29
Higashiosaka municipal Kamikosaka primary scool Station 550.277 2851.38 4194.29
Sahara Yokosuka City 547.404 2274.96 4194.29
Kazanashi Shika Town 545.377 4120.7 4194.29
Akasumi Shika Town 544.970 3771.18 4194.29
Kurahashi Maizuru City 540.820 3433.91 4194.29
Obama Obama City 540.809 3072.13 4194.29
Sakuragaike community hall Omaezaki City 540.772 4445.69 4194.29
Shirowa primary school Omaezaki City 535.692 4353.71 4194.29
Radiation dose at JAEA Oarai (P5) 529.759 4147.78
Uenohara Omaezaki City 529.333 4476.37 4194.29
Kumano Shika Town 529.019 4274.02 4194.29
Izumisano municipal Hineno filtration plant Station 527.471 3685.34 4194.29
Nishi-hamasada Matsue City 525.089 4074.05 4177.87
Kouno Minami-Echizen Town 525.028 3090.53 4194.29
Kurihama Yokosuka City 523.708 2458.92 4194.29
Osaka prefectural Kumatori off-site-center Station 522.808 3397.12 4194.29
Ogasa branch Kikugawa City 522.039 4522.87 4180.61
Izumisano municipal Hineno primary scool Station 518.181 2949.5 4194.29
Shirasuna Omaezaki City 499.479 4384.39 4194.29
Jitougata primary school Makinohara City 498.059 4206.54 4194.29
Kataku Matsue City 497.007 3268.34 4194.29
Nishihemi Yokosuka City 496.917 1962.23 4194.29
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 496.721 4166.93
Satsuma-sendai monitoring center Satsuma-sendai City 495.302 3219.3 4194.29
Otomi Takahama Town 494.821 3605.62 4194.29
Otsu Nanao City 493.895 3617.87 4194.29
The Observation point for comparison Tatsunokuchi 493.454 2980.15 4194.29
Hitsuhama Ohi Town 492.630 3354.22 4194.29
Kijiyama Misasa Town 489.284 3403.26 4194.29
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 487.055 4166.93
Hiraba Omaezaki City 485.878 4384.39 4194.29
Tayu Matsue City 484.956 3409.4 4194.29
Hamaokakita primary school Omaezaki City 484.537 4492.32 4180.61
Oitomi Ayabe City 474.670 4323.06 4194.29
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 472.017 4166.93
Kashiwazaki-shigai Kashiwazaki City 470.822 3440.05 4194.29
Mitsu Matsue City 466.897 3262.24 4194.29
Tonomachi Kawasaki Ward 463.967 4132.96 4194.29
Daitou branch Kakegawa City 463.829 4425.1 4180.61
Fukura Shika Town 462.493 4114.56 4194.29
Nagasawa Yokosuka City 462.365 2403.73 4194.29
The athletic field Station of Kinki University 461.661 2716.46 4194.29
Koura Matsue City 461.049 3893.81 4194.29
Sakurasan Ward Omaezaki City 459.434 4243.33 4194.29
Tsuchikawa Nanao City 458.915 4004.18 4194.29
Kumatori Town office Station 457.917 2802.34 4194.29
Shinkango Omaezaki City 449.013 4911.73 4194.29
Ogurui Takahama Town 448.279 3213.16 4194.29
Kusabue Omaezaki City 444.162 4629.65 4194.29
Omaezaki City monitoring center 443.946 4543.81 4194.29
Akawase Kagamino Town 442.246 2802.34 4194.29
Ibaraki 442.139 2056.32 4186.08
Hinode Town Yokosuka City 438.324 1618.85 4194.29
Nishiyama Kashiwazaki City 437.251 4868.8 4194.29
Kariwa Kariwa Village 436.307 3673.06 4194.29
Osaka prefectural Hineno high scool Station 435.745 3274.49 4194.29
Miyagawa Kashiwazaki City 435.245 3624.01 4194.29
Radiation dose in Natori 434.640 4147.78
Kami-koubu Matsue City 433.868 3562.68 4194.29
Shimo-Takamachi Kariwa Village 433.192 3998.08 4194.29
Osaka prefectural Sano supporting school Station 432.398 3568.82 4194.29
Arahama Kashiwazaki City 428.874 3734.39 4194.29
Doai Kashiwazaki City 425.681 3513.64 4194.29
Owashi Matsue City 424.452 3482.99 4194.29
Okayasu Maizuru City 422.568 4102.31 4194.29
Katsuyama Kariwa Village 421.280 3734.39 4194.29
Kita-koubu Matsue City 420.683 3820.22 4194.29
Kichisaka Maizuru City 413.065 4985.32 4194.29
Nagai Ohi Town 410.699 3623.05 4186.08
Shiokumi Maizuru City 407.938 6205.6 4194.29
Miyadome Ohi Town 407.831 3004.69 4194.29
Kariwa Kariwa Village 407.617 3869.3 4194.29
Ueno Satsuma-sendai City 394.248 2808.44 4194.29
Power Station-South 389.191 4090.06 4194.29
Radiation dose at JAEA Oarai (P6) 386.963 4147.78
Power Station- 385.546 3991.93 4194.29
Takae Satsuma-sendai City 379.551 2845.24 4194.29
Hokawaduura Genkai Town 378.015 4332.26 4194.29
Kou Itimatsu Suetsugu 377.929 3127.32 4194.29
Minato Satsuma-sendai City 377.656 2606.09 4194.29
Iwanai Iwanai Town 376.336 4246.7 4191.55
Hattari Kyowa Town 373.047 4130.26 4191.55
Chatsu Tomari Village 371.011 3946.42 4191.55
Oyama Maizuru City 358.223 3593.36 4194.29
Kodaira Satsuma-sendai City 355.545 2636.77 4194.29
Kayanuma Tomari Village 354.809 3511.34 4191.55
Anojiri Obama City 353.215 2943.36 4194.29
Kushi Genkai Town 349.738 5978.7 4194.29
Yamaguchi 348.715 4700.16 4186.08
Sadahongou Matsue City 348.228 3660.8 4194.29
Sakibe Karatsu City 347.801 5665.97 4194.29
Hirao Genkai Town 343.814 5972.56 4194.29
The Meteorological Obsevatory of kyowa Town 343.275 3915.79 4191.55
Minami-Horoni Kyowa Town 335.180 3670.66 4191.55
Kounoura Takahama Town 330.353 3102.78 4194.29
Kyoudomarisaki Karatsu City 328.622 6070.68 4194.29
Horikappu Jinja Tomari Village 328.230 3799.35 4191.55
Hukada-kita Matsue City 327.031 3010.8 4194.29
Radiation dose in KEK, Tsukuba 326.240 4166.93
Herokaruusu Tomari Village 324.242 3940.32 4191.55
Yorita Satsuma-sendai City 323.218 3084.38 4194.29
Kamoenai Kamoenai Village 322.032 3327.5 4191.55
Radiation dose in Onagawa (MP-6) 316.267 4145.04
Imamura Genkai Town 314.749 51447.4 4194.29
Yamanaka Takahama Town 314.185 4004.18 4194.29
Sendai (Miyagi) 312.585 1883.74 4186.08
Radiation dose in Onagawa (MP-1) 300.147 4145.04
Gumisaki Satsuma-sendai City 295.693 2489.6 4194.29
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 286.142 4166.93
Aomori Aomori City 285.372 2530.85 4191.55
Misawa City hall Misawa City 283.728 4908.53 4191.55
Kashu Ikata Town 277.173 2569.3 4194.29
Noheji Town Office Noheji Town 272.004 2169.31 4191.55
Takasimamati 271.103 2734.86 4194.29
Radiation dose in Onagawa (MP-3) 270.563 4145.04
Kucho Ikata Town 269.545 2268.85 4194.29
Radiation dose in Marumori 269.436 4147.78
Kawanagata Ikata Town 266.821 2213.66 4194.29
Tochigi 260.733 2460.24 4186.08
Chikagawa Mutu City 256.719 2825 4191.55
Yokohama Town Office Yokohama Town 254.846 3462.33 4191.55
Tokyo 251.877 2900.88 4186.08
Hiranuma Rokkasho Village 251.186 2273.48 4191.55
Taisei Ikata Town 246.293 1661.78 4194.29
Chitose-daira Rokkasho Village 245.868 2451.21 4191.55
Gifu 243.951 4039.2 4186.08
Fukkoshi Yokohama Town 243.102 2377.68 4191.55
Shimane 240.651 4039.2 4186.08
Sunagomata Higashidoori Village 238.012 3437.81 4191.55
Obuchi Rokkasho Village 237.506 2733.08 4191.55
Tomari Rokkasho Village 230.636 3823.87 4191.55
kanagawa 226.339 2533.68 4186.08
Saitama 219.770 2203.2 4186.08
Ikatagoshi Ikata Town 217.515 2091 4194.29
Touhoku Branch office Touhoku Town 215.416 1979.33 4191.55
Radiation dose at Tohoku University 214.824 4147.78
Odanosawa Higashidoori Village 210.287 2739.22 4191.55
Kagawa 205.829 2827.44 4186.08
Oippe Higashidoori Village 205.182 2359.29 4191.55
Oita 200.921 3121.2 4186.08
Touhoku Town office Touhoku Town 200.811 9155.23 4191.55
Kuchogoshi Ikata Town 198.646 2121.68 4194.29
Minatoura Ikata Town 186.776 1907.04 4194.29
Radiation dose in Koyadori, Ojika 184.905 4142.3
Toyama 184.580 5397.84 4186.08
Fukushima [9] (distance from Fukushima I: 45 km) 184.232 2603.71 4180.61
Radiation dose in Tukahama, Ojika 183.417 4142.3
Chiba 182.407 1615.68 4186.08
Nara 182.387 2937.6 4186.08
Okayama 181.976 3818.88 4186.08
Yamagata 181.598 3011.04 4186.08
Ehime 180.745 2717.28 4186.08
Ishikawa 180.445 4681.8 4186.08
Niigata 177.483 5618.16 4186.08
Hiroshima 176.816 2533.68 4186.08
Mie 174.867 2897.21 4186.08
Fukui 170.045 3561.84 4186.08
Radiation dose in Terama, Ojika 168.036 4142.3
Yamanashi 164.561 2350.08 4186.08
Nagano 162.242 3576.53 4186.08
Saga 161.421 3157.92 4186.08
Tottori 161.392 2900.88 4186.08
Radiation dose in Enoshima, Ojika 160.091 4142.3
Osaka 159.103 2239.92 4186.08
Ibaraki-city Environment 157.249 4101.26
Aichi 149.345 2717.28 4186.08
Toyonoura Ikata Town 149.214 2189.12 4194.29
Shizuoka 148.639 2809.08 4186.08
Kyoto 144.522 3194.64 4186.08
Kagoshima 144.449 3462.7 4186.08
Tokushima 143.627 2460.24 4186.08
Gunma 143.572 1652.4 4186.08
Hyogo 139.710 2790.72 4186.08
Fukuoka 136.511 2900.88 4186.08
Wakayama 133.857 2056.32 4186.08
Radiation at Tamaki-cho Mie Japan 133.138 4101.26
Akita 132.832 3157.92 4186.08
Shiga 124.919 2239.92 4186.08
Nagasaki 109.459 2533.68 4186.08
Hokkaido 109.189 3855.6 4186.08
Kumamoto 103.568 2460.24 4186.08
Aomori 101.819 3745.44 4186.08
Miyazaki 100.354 2438.21 4186.08
Kochi 95.931 2790.72 4186.08
Fukushima [35] (distance from Fukushima I: 35 km) 91.917 2595.19 4166.93
Iwate 90.324 3084.48 4186.08
Environment Feeds from Ohta 83.623 4101.26
Okinawa 82.305 2111.4 4186.08
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