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Accumulated absorbed dose rate - T=13.03.2011 - 22.12.2014(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 3690.86
Fukushima I MP8 570942.000 3690.86
Fukushima I MP6 240668.000 3690.86
Yamada Futaba Town 176983.000 2725.36 3247.63
Fukushima I MP2 140420.000 3690.86
Fukushima I MP5 111325.000 3690.86
Fukushima [32] (distance from Fukushima I: 30 km) 101500.000 2343 3762
Fukushima I MP3 93730.602 3690.86
Fukushima I MP4 86821.500 3690.86
Fukushima [33] (distance from Fukushima I: 30 km) 77197.703 2343 3762
Fukushima [79] (distance from Fukushima I: 40 km) 54008.602 2291.88 3679.92
Fukushima [31] (distance from Fukushima I: 30 km) 40677.398 2343 3762
Ono Okuma Town 38610.500 2516.43 3247.63
Shinzan Futaba Town 38332.801 2283.8 3247.63
Fukushima I MP1 31496.801 3690.86
Yonomori Tomioka Town 29815.900 2601.89 3247.63
Fukushima [46] (distance from Fukushima I: 20 km) 28842.500 2343 3762
Tomioka Tomioka Town 25324.500 2801.31 3247.63
Fukushima [62] (distance from Fukushima I: 40 km) 16464.100 2343 3762
Fukushima [61] (distance from Fukushima I: 40 km) 13102.800 2343 3762
Shimo-Kooriyama Tomioka Town 13057.000 2782.34 3247.63
Fukushima [21] (distance from Fukushima I: 30 km) 12103.800 2343 3762
Fukushima [3] (distance from Fukushima I: 45 km) 11985.000 2343 3762
Kami-kooriyama Tomioka Town 11803.900 2184.09 3247.63
Fukushima II MP3 11060.600 3690.86
Fukushima II MP1 10903.000 3690.86
Kooriyama Futaba Town 10352.900 2544.92 3247.63
Fukushima II MP4 9696.330 3690.86
Fukushima [34] (distance from Fukushima I: 30 km) 9540.450 2339.59 3756.53
Fukushima II MP5 9382.150 3690.86
Fukushima [2] (distance from Fukushima I: 55 km) 8841.760 2343 3762
Matsudate Naraha Town 8410.890 2972.24 3247.63
Shigeoka Naraha Town 8115.970 3285.61 3247.63
Fukushima II MP2 7875.320 3690.86
Namie Namie Town 7321.210 2397.75 3247.63
Radiation dose at Shirasawa branch office, Motomiya 7287.920 3707.28
Fukushima II MP6 7062.690 3690.86
Fukushima II MP7 6511.580 3688.13
Fukushima [1] (distance from Fukushima I: 60 km) 5615.310 2343 3762
Fukushima [11] (distance from Fukushima I: 40 km) 5491.310 2343 3762
Fukushima [63] (distance from Fukushima I: 45 km) 5448.820 2343 3762
Fukushima [45] (distance from Fukushima I: 20 km) 3981.200 2343 3762
Fukushima [42] (distance from Fukushima I: 30 km) 3850.600 2343 3762
Fukushima [10] (distance from Fukushima I: 40 km) 3734.160 2343 3762
Fukushima [78] (distance from Fukushima I: 45 km) 3716.820 2337.89 3753.79
Futatsunuma Hirono Town 3520.340 2848.8 3247.63
Fukushima [4] (distance from Fukushima I: 50 km) 3386.310 2343 3762
Fukushima [7] (distance from Fukushima I: 45 km) 3313.930 2343 3762
Radiation dose at Koriyama joint government building, Koriyama 3232.890 3704.54
Fukushima [15] (distance from Fukushima I: 35 km) 3178.670 2343 3762
Kiyohashi Namie Town 3162.000 2103.35 3247.63
Fukushima [71] (distance from Fukushima I: 25 km) 3161.650 2337.89 3753.79
Radiation dose at Agricultural center, Koriyama 3128.960 3704.54
Fukushima [41] (distance from Fukushima I: 20 km) 3111.490 2343 3762
Radiation dose at Koriyama city office, Koriyama 2803.520 3704.54
Fukushima [44] (distance from Fukushima I: 30 km) 2535.550 2343 3762
Fukushima [72] (distance from Fukushima I: 30 km) 2344.620 2337.89 3753.79
Fukushima [43] (distance from Fukushima I: 20 km) 2244.110 2343 3762
Yamadaoka Naraha Town 2205.340 2525.95 3247.63
Radiation dose at Iwane Fureai Plaza, Motomiya 2169.060 3707.28
Fukushima [22] (distance from Fukushima I: 35 km) 2020.650 2343 3762
Kuji Hitachi City 1990.890 5824.9 3772.94
Hitachinaka Hitachinaka City 1951.950 2557.56 3770.21
Fukushima [76] (distance from Fukushima I: 25 km) 1945.520 2337.89 3753.79
Fukushima [80] (distance from Fukushima I: 25 km) 1876.860 2337.89 3753.79
Momiyama Hokota City 1837.540 2917.97 3772.94
Fukushima [77] (distance from Fukushima I: 25 km) 1802.490 2337.89 3753.79
Horiguchi Hitachinaka City 1779.410 2550.24 3775.68
Onuma Hitachi City 1776.950 2171.74 3770.21
Fukushima [6] (distance from Fukushima I: 45 km) 1741.180 2343 3762
Tsukuriya Hokota City 1736.890 2454.63 3772.94
Radiation dose at Big palette Fukushima, Koriyama 1668.540 3704.54
Nemoto Hitachioomiya City 1633.190 2733.96 3770.21
Fukushima [13] (distance from Fukushima I: 40 km) 1624.150 2343 3762
Fukushima [23] (distance from Fukushima I: 35 km) 1551.750 2343 3762
Radiation dose at Tsukidatemachi kamitedo, Date 1545.300 3712.75
Fukushima [14] (distance from Fukushima I: 35 km) 1543.460 2343 3762
Radiation dose at JAEA Oarai (P12) 1512.140 3729.17
Radiation dose at Ose administration center, Koriyama 1494.270 3704.54
Araji Hokota City 1437.760 2460.12 3772.94
Ishigami Tokai Village 1431.690 2239.51 3772.94
Mawatari Hitachinaka City 1422.870 2587.01 3772.94
Radiation dose at JAEA Oarai (P11) 1399.370 3729.17
Onuki Oarai Town 1387.990 2686.3 3772.94
Sawa Hitachinaka City 1353.770 2028.41 3770.21
Toyooka Tokai Village 1321.760 2465.65 3772.94
Ajigaura Hitachinaka City 1313.890 2425.27 3770.21
Fukushima [5] (distance from Fukushima I: 45 km) 1282.090 2343 3762
Geiger Counter Feeds from Asao Kawasaki 1266.620 3682.66
Radiation dose at Tamokami elementary school, Koriyama 1256.140 3704.54
Isohama Oarai Town 1250.540 2340.89 3767.47
Ebisawa Ibaraki Town 1222.240 6356.44 3770.21
Muramatsu Tokai Village 1203.520 2487.73 3772.94
Kamitoda Hokota City 1184.740 2040.93 3772.94
Yanagisawa Hitachinaka City 1166.970 2078.01 3770.21
Tokushuku Hokota City 1159.730 1842.36 3772.94
Tasaki Hokota City 1153.300 2172.39 3742.85
Fukushima [20] (distance from Fukushima I: 45 km) 1145.390 2343 3762
Kadobe Naka City 1086.580 4949.79 3770.21
Radiation dose at Date city office, Date 1076.050 3707.28
Oshinobe Tokai Village 1041.340 2322.25 3772.94
Oba Mito City 1037.670 7628.63 3772.94
Godai Naka City 1031.270 2013.33 3772.94
Ishikawa Mito City 1030.810 2373.61 3775.68
Isobe Hitachiota City 1013.130 11451.2 3772.94
Yatabe Ibaraki Town 996.127 1991.29 3772.94
Radiation dose at Motomiya city office, Motomiya 992.703 3707.28
Fukushima [73] (distance from Fukushima I: 35 km) 981.984 2337.89 3753.79
Fukushima [75] (distance from Fukushima I: 45 km) 960.529 2337.89 3753.79
Yokobori Naka City 930.280 2333.27 3772.94
Sugaya Naka City 926.186 3565.93 3775.68
Kounosu Naka City 926.087 1820.28 3772.94
Funaishikawa Tokai Village 900.399 2416.01 3772.94
Nukada Naka City 899.900 2181.17 3767.47
Uridura Naka City 890.113 2082.02 3767.47
Shiraki Tsuruga City 881.330 4421.52 3775.68
Motokomezaki Naka City 880.851 1935.67 3740.11
Shiraki pass Tsuruga City 850.284 4631.27 3775.68
Radiation dose in Yamamoto 846.633 3729.17
Yoshizawa Mito City 837.646 2107.12 3772.94
Radiation dose at JAEA Oarai (P7) 831.135 3729.17
Mayumi Hitachiota City 828.119 2090.57 3772.94
Urasoko Tsuruga City 826.465 3670.79 3775.68
Nemoto Hitachioomiya City 825.588 2353.64 3770.21
Takenami Mihama Town 804.283 3852.95 3775.68
Radiation dose at JAEA Oarai (P15) 780.207 3729.17
Tateishi Tsuruga City 780.092 3052.57 3775.68
Radiation dose at JAEA Oarai (P14) 770.174 3729.17
Radiation dose at JAEA Oarai (P13) 769.612 3729.17
Ukishima Kawasaki Ward 735.475 7203.6 3775.68
Kume Hitachiota City 713.958 2046.43 3772.94
Radiation dose at JAEA Oarai (P2) 712.011 3729.17
Fukushima [74] (distance from Fukushima I: 35 km) 706.552 2337.89 3753.79
Nyuu Mihama Town 674.787 3510.72 3775.68
Fukushima [52] (distance from Fukushima I: 40 km) 672.743 2343 3762
Radiation dose in Iwanuma 670.242 3729.17
Fukushima [51] (distance from Fukushima I: 40 km) 665.376 2343 3762
Tsuruga Tsuruga City 655.360 3096.72 3775.68
Shiohama Kawasaki Ward 653.536 2472.97 3775.68
Radiation dose in Kakuda 649.863 3729.17
Sakajiri Mihama Town 649.252 4095.85 3775.68
North point of Kinki University Atomic Energy Research Instirute Station 639.566 2572.33 3775.68
Radiation dose in Onagawa (MP-2) 632.968 3726.43
Kumatori town Nishi primary school Station 631.491 3074.63 3775.68
Oshima Kawasaki Ward 630.402 2357.05 3775.68
Izumisano municipal Oike athletic field Station 629.920 3466.57 3775.68
Atom-kyoudou nursery school Station 625.566 3328.56 3775.68
South point of Kinki University Atomic Energy Research Instirute Station 625.202 3030.48 3775.68
Nakamachi Omaezaki City 623.494 3902.63 3775.68
Uraga Yokosuka City 622.492 1849.19 3775.68
Goritoge Shika Town 622.143 4145.53 3775.68
Kumatori town Minami primary school Station 606.134 3527.28 3775.68
Radiation dose at JAEA Oarai (P1) 603.643 3731.9
Yamanotedai-No.1 Park Station 599.140 3289.91 3775.68
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 595.502 3748.32
Noumi Shika Town 594.021 4101.35 3775.68
Radiation dose in Watari 591.851 3729.17
Hairando Yokosuka City 588.667 2318.4 3775.68
Fukushima [12] (distance from Fukushima I: 40 km) 588.291 2343 3762
Ningyotoge Kagamino Town 574.857 3289.91 3775.68
Ten-no Kagamino Town 569.960 3941.28 3775.68
Funagura Yokosuka City 563.909 2185.92 3775.68
Chidori Kawasaki Ward 560.211 2114.15 3775.68
Radiation dose at JAEA Oarai (P16) 556.365 3729.17
Shika Shika Town 551.376 3952.31 3775.68
Higashiosaka municipal Kamikosaka primary scool Station 550.277 2566.8 3775.68
Sahara Yokosuka City 547.404 2047.91 3775.68
Kazanashi Shika Town 545.377 3709.44 3775.68
Akasumi Shika Town 544.970 3394.8 3775.68
Kurahashi Maizuru City 540.820 3091.19 3775.68
Obama Obama City 540.809 2765.52 3775.68
Sakuragaike community hall Omaezaki City 540.772 4001.99 3775.68
Shirowa primary school Omaezaki City 535.692 3919.19 3775.68
Radiation dose at JAEA Oarai (P5) 529.759 3729.17
Uenohara Omaezaki City 529.333 4029.61 3775.68
Kumano Shika Town 529.019 3847.45 3775.68
Izumisano municipal Hineno filtration plant Station 527.471 3317.53 3775.68
Nishi-hamasada Matsue City 525.089 3665.84 3759.26
Kouno Minami-Echizen Town 525.028 2782.08 3775.68
Kurihama Yokosuka City 523.708 2213.51 3775.68
Osaka prefectural Kumatori off-site-center Station 522.808 3058.07 3775.68
Ogasa branch Kikugawa City 522.039 4069.99 3762
Izumisano municipal Hineno primary scool Station 518.181 2655.13 3775.68
Shirasuna Omaezaki City 499.479 3946.81 3775.68
Jitougata primary school Makinohara City 498.059 3786.71 3775.68
Kataku Matsue City 497.007 2942.15 3775.68
Nishihemi Yokosuka City 496.917 1766.39 3775.68
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 496.721 3748.32
Satsuma-sendai monitoring center Satsuma-sendai City 495.302 2898 3775.68
Otomi Takahama Town 494.821 3245.76 3775.68
Otsu Nanao City 493.895 3256.79 3775.68
The Observation point for comparison Tatsunokuchi 493.454 2682.72 3775.68
Hitsuhama Ohi Town 492.630 3019.45 3775.68
Kijiyama Misasa Town 489.284 3063.6 3775.68
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 487.055 3748.32
Hiraba Omaezaki City 485.878 3946.81 3775.68
Tayu Matsue City 484.956 3069.13 3775.68
Hamaokakita primary school Omaezaki City 484.537 4042.5 3762
Oitomi Ayabe City 474.670 3891.6 3775.68
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 472.017 3748.32
Kashiwazaki-shigai Kashiwazaki City 470.822 3096.72 3775.68
Mitsu Matsue City 466.897 2936.65 3775.68
Tonomachi Kawasaki Ward 463.967 3720.47 3775.68
Daitou branch Kakegawa City 463.829 3982.01 3762
Fukura Shika Town 462.493 3703.91 3775.68
Nagasawa Yokosuka City 462.365 2163.83 3775.68
The athletic field Station of Kinki University 461.661 2445.35 3775.68
Koura Matsue City 461.049 3505.19 3775.68
Sakurasan Ward Omaezaki City 459.434 3819.83 3775.68
Tsuchikawa Nanao City 458.915 3604.55 3775.68
Kumatori Town office Station 457.917 2522.65 3775.68
Shinkango Omaezaki City 449.013 4421.52 3775.68
Ogurui Takahama Town 448.279 2892.47 3775.68
Kusabue Omaezaki City 444.162 4167.59 3775.68
Omaezaki City monitoring center 443.946 4090.32 3775.68
Akawase Kagamino Town 442.246 2522.65 3775.68
Ibaraki 442.139 1850.69 3767.47
Hinode Town Yokosuka City 438.324 1457.28 3775.68
Nishiyama Kashiwazaki City 437.251 4382.87 3775.68
Kariwa Kariwa Village 436.307 3306.47 3775.68
Osaka prefectural Hineno high scool Station 435.745 2947.68 3775.68
Miyagawa Kashiwazaki City 435.245 3262.32 3775.68
Radiation dose in Natori 434.640 3729.17
Kami-koubu Matsue City 433.868 3207.11 3775.68
Shimo-Takamachi Kariwa Village 433.192 3599.05 3775.68
Osaka prefectural Sano supporting school Station 432.398 3212.64 3775.68
Arahama Kashiwazaki City 428.874 3361.68 3775.68
Doai Kashiwazaki City 425.681 3162.96 3775.68
Owashi Matsue City 424.452 3135.37 3775.68
Okayasu Maizuru City 422.568 3692.88 3775.68
Katsuyama Kariwa Village 421.280 3361.68 3775.68
Kita-koubu Matsue City 420.683 3438.95 3775.68
Kichisaka Maizuru City 413.065 4487.76 3775.68
Nagai Ohi Town 410.699 3260.75 3767.47
Shiokumi Maizuru City 407.938 5586.25 3775.68
Miyadome Ohi Town 407.831 2704.81 3775.68
Kariwa Kariwa Village 407.617 3483.13 3775.68
Ueno Satsuma-sendai City 394.248 2528.15 3775.68
Power Station-South 389.191 3681.85 3775.68
Radiation dose at JAEA Oarai (P6) 386.963 3729.17
Power Station- 385.546 3593.52 3775.68
Takae Satsuma-sendai City 379.551 2561.27 3775.68
Hokawaduura Genkai Town 378.015 3899.88 3775.68
Kou Itimatsu Suetsugu 377.929 2815.2 3775.68
Minato Satsuma-sendai City 377.656 2345.99 3775.68
Iwanai Iwanai Town 376.336 3822.59 3772.94
Hattari Kyowa Town 373.047 3717.77 3772.94
Chatsu Tomari Village 371.011 3552.29 3772.94
Oyama Maizuru City 358.223 3234.73 3775.68
Kodaira Satsuma-sendai City 355.545 2373.61 3775.68
Kayanuma Tomari Village 354.809 3160.67 3772.94
Anojiri Obama City 353.215 2649.6 3775.68
Kushi Genkai Town 349.738 5382 3775.68
Yamaguchi 348.715 4230.14 3767.47
Sadahongou Matsue City 348.228 3295.44 3775.68
Sakibe Karatsu City 347.801 5100.48 3775.68
Hirao Genkai Town 343.814 5376.47 3775.68
The Meteorological Obsevatory of kyowa Town 343.275 3524.72 3772.94
Minami-Horoni Kyowa Town 335.180 3304.07 3772.94
Kounoura Takahama Town 330.353 2793.11 3775.68
Kyoudomarisaki Karatsu City 328.622 5464.8 3775.68
Horikappu Jinja Tomari Village 328.230 3419.91 3772.94
Hukada-kita Matsue City 327.031 2710.31 3775.68
Radiation dose in KEK, Tsukuba 326.240 3748.32
Herokaruusu Tomari Village 324.242 3546.8 3772.94
Yorita Satsuma-sendai City 323.218 2776.55 3775.68
Kamoenai Kamoenai Village 322.032 2995.19 3772.94
Radiation dose in Onagawa (MP-6) 316.267 3726.43
Imamura Genkai Town 314.749 46312.7 3775.68
Yamanaka Takahama Town 314.185 3604.55 3775.68
Sendai (Miyagi) 312.585 1695.36 3767.47
Radiation dose in Onagawa (MP-1) 300.147 3726.43
Gumisaki Satsuma-sendai City 295.693 2241.13 3775.68
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 286.142 3748.32
Aomori Aomori City 285.372 2278.1 3772.94
Misawa City hall Misawa City 283.728 4418.32 3772.94
Kashu Ikata Town 277.173 2312.87 3775.68
Noheji Town Office Noheji Town 272.004 1952.66 3772.94
Takasimamati 271.103 2461.91 3775.68
Radiation dose in Onagawa (MP-3) 270.563 3726.43
Kucho Ikata Town 269.545 2042.41 3775.68
Radiation dose in Marumori 269.436 3729.17
Kawanagata Ikata Town 266.821 1992.73 3775.68
Tochigi 260.733 2214.22 3767.47
Chikagawa Mutu City 256.719 2542.86 3772.94
Yokohama Town Office Yokohama Town 254.846 3116.55 3772.94
Tokyo 251.877 2610.79 3767.47
Hiranuma Rokkasho Village 251.186 2046.43 3772.94
Taisei Ikata Town 246.293 1495.93 3775.68
Chitose-daira Rokkasho Village 245.868 2206.41 3772.94
Gifu 243.951 3635.28 3767.47
Fukkoshi Yokohama Town 243.102 2140.22 3772.94
Shimane 240.651 3635.28 3767.47
Sunagomata Higashidoori Village 238.012 3094.48 3772.94
Obuchi Rokkasho Village 237.506 2460.12 3772.94
Tomari Rokkasho Village 230.636 3441.98 3772.94
kanagawa 226.339 2280.31 3767.47
Saitama 219.770 1982.88 3767.47
Ikatagoshi Ikata Town 217.515 1882.31 3775.68
Touhoku Branch office Touhoku Town 215.416 1781.66 3772.94
Radiation dose at Tohoku University 214.824 3729.17
Odanosawa Higashidoori Village 210.287 2465.65 3772.94
Kagawa 205.829 2544.7 3767.47
Oippe Higashidoori Village 205.182 2123.67 3772.94
Oita 200.921 2809.08 3767.47
Touhoku Town office Touhoku Town 200.811 8240.9 3772.94
Kuchogoshi Ikata Town 198.646 1909.93 3775.68
Minatoura Ikata Town 186.776 1716.71 3775.68
Radiation dose in Koyadori, Ojika 184.905 3723.7
Toyama 184.580 4858.06 3767.47
Fukushima [9] (distance from Fukushima I: 45 km) 184.232 2343 3762
Radiation dose in Tukahama, Ojika 183.417 3723.7
Chiba 182.407 1454.11 3767.47
Nara 182.387 2643.84 3767.47
Okayama 181.976 3436.99 3767.47
Yamagata 181.598 2709.94 3767.47
Ehime 180.745 2445.55 3767.47
Ishikawa 180.445 4213.62 3767.47
Niigata 177.483 5056.34 3767.47
Hiroshima 176.816 2280.31 3767.47
Mie 174.867 2607.49 3767.47
Fukui 170.045 3205.66 3767.47
Radiation dose in Terama, Ojika 168.036 3723.7
Yamanashi 164.561 2115.07 3767.47
Nagano 162.242 3218.88 3767.47
Saga 161.421 2842.13 3767.47
Tottori 161.392 2610.79 3767.47
Radiation dose in Enoshima, Ojika 160.091 3723.7
Osaka 159.103 2015.93 3767.47
Ibaraki-city Environment 157.249 3682.66
Aichi 149.345 2445.55 3767.47
Toyonoura Ikata Town 149.214 1970.64 3775.68
Shizuoka 148.639 2528.17 3767.47
Kyoto 144.522 2875.18 3767.47
Kagoshima 144.449 3116.43 3767.47
Tokushima 143.627 2214.22 3767.47
Gunma 143.572 1487.16 3767.47
Hyogo 139.710 2511.65 3767.47
Fukuoka 136.511 2610.79 3767.47
Wakayama 133.857 1850.69 3767.47
Radiation at Tamaki-cho Mie Japan 133.138 3682.66
Akita 132.832 2842.13 3767.47
Shiga 124.919 2015.93 3767.47
Nagasaki 109.459 2280.31 3767.47
Hokkaido 109.189 3470.04 3767.47
Kumamoto 103.568 2214.22 3767.47
Aomori 101.819 3370.9 3767.47
Miyazaki 100.354 2194.39 3767.47
Kochi 95.931 2511.65 3767.47
Fukushima [35] (distance from Fukushima I: 35 km) 91.917 2334.48 3748.32
Iwate 90.324 2776.03 3767.47
Environment Feeds from Ohta 83.623 3682.66
Okinawa 82.305 1900.26 3767.47
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