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Accumulated absorbed dose rate - T=13.03.2011 - 30.09.2014(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 3463.78
Fukushima I MP8 570942.000 3463.78
Fukushima I MP6 240668.000 3463.78
Yamada Futaba Town 176983.000 2534.79 3020.54
Fukushima I MP2 140420.000 3463.78
Fukushima I MP5 111325.000 3463.78
Fukushima [32] (distance from Fukushima I: 30 km) 101500.000 2201.57 3534.91
Fukushima I MP3 93730.602 3463.78
Fukushima I MP4 86821.500 3463.78
Fukushima [33] (distance from Fukushima I: 30 km) 77197.703 2201.57 3534.91
Fukushima [79] (distance from Fukushima I: 40 km) 54008.602 2150.45 3452.83
Fukushima [31] (distance from Fukushima I: 30 km) 40677.398 2201.57 3534.91
Ono Okuma Town 38610.500 2340.47 3020.54
Shinzan Futaba Town 38332.801 2124.1 3020.54
Fukushima I MP1 31496.801 3463.78
Yonomori Tomioka Town 29815.900 2419.96 3020.54
Fukushima [46] (distance from Fukushima I: 20 km) 28842.500 2201.57 3534.91
Tomioka Tomioka Town 25324.500 2605.43 3020.54
Fukushima [62] (distance from Fukushima I: 40 km) 16464.100 2201.57 3534.91
Fukushima [61] (distance from Fukushima I: 40 km) 13102.800 2201.57 3534.91
Shimo-Kooriyama Tomioka Town 13057.000 2587.78 3020.54
Fukushima [21] (distance from Fukushima I: 30 km) 12103.800 2201.57 3534.91
Fukushima [3] (distance from Fukushima I: 45 km) 11985.000 2201.57 3534.91
Kami-kooriyama Tomioka Town 11803.900 2031.37 3020.54
Fukushima II MP3 11060.600 3463.78
Fukushima II MP1 10903.000 3463.78
Kooriyama Futaba Town 10352.900 2366.97 3020.54
Fukushima II MP4 9696.330 3463.78
Fukushima [34] (distance from Fukushima I: 30 km) 9540.450 2198.16 3529.44
Fukushima II MP5 9382.150 3463.78
Fukushima [2] (distance from Fukushima I: 55 km) 8841.760 2201.57 3534.91
Matsudate Naraha Town 8410.890 2764.41 3020.54
Shigeoka Naraha Town 8115.970 3055.86 3020.54
Fukushima II MP2 7875.320 3463.78
Namie Namie Town 7321.210 2230.09 3020.54
Radiation dose at Shirasawa branch office, Motomiya 7287.920 3480.19
Fukushima II MP6 7062.690 3463.78
Fukushima II MP7 6511.580 3461.04
Fukushima [1] (distance from Fukushima I: 60 km) 5615.310 2201.57 3534.91
Fukushima [11] (distance from Fukushima I: 40 km) 5491.310 2201.57 3534.91
Fukushima [63] (distance from Fukushima I: 45 km) 5448.820 2201.57 3534.91
Fukushima [45] (distance from Fukushima I: 20 km) 3981.200 2201.57 3534.91
Fukushima [42] (distance from Fukushima I: 30 km) 3850.600 2201.57 3534.91
Fukushima [10] (distance from Fukushima I: 40 km) 3734.160 2201.57 3534.91
Fukushima [78] (distance from Fukushima I: 45 km) 3716.820 2196.46 3526.7
Futatsunuma Hirono Town 3520.340 2649.6 3020.54
Fukushima [4] (distance from Fukushima I: 50 km) 3386.310 2201.57 3534.91
Fukushima [7] (distance from Fukushima I: 45 km) 3313.930 2201.57 3534.91
Radiation dose at Koriyama joint government building, Koriyama 3232.890 3477.46
Fukushima [15] (distance from Fukushima I: 35 km) 3178.670 2201.57 3534.91
Kiyohashi Namie Town 3162.000 1956.28 3020.54
Fukushima [71] (distance from Fukushima I: 25 km) 3161.650 2196.46 3526.7
Radiation dose at Agricultural center, Koriyama 3128.960 3477.46
Fukushima [41] (distance from Fukushima I: 20 km) 3111.490 2201.57 3534.91
Radiation dose at Koriyama city office, Koriyama 2803.520 3477.46
Fukushima [44] (distance from Fukushima I: 30 km) 2535.550 2201.57 3534.91
Fukushima [72] (distance from Fukushima I: 30 km) 2344.620 2196.46 3526.7
Fukushima [43] (distance from Fukushima I: 20 km) 2244.110 2201.57 3534.91
Yamadaoka Naraha Town 2205.340 2349.32 3020.54
Radiation dose at Iwane Fureai Plaza, Motomiya 2169.060 3480.19
Fukushima [22] (distance from Fukushima I: 35 km) 2020.650 2201.57 3534.91
Kuji Hitachi City 1990.890 5474.3 3545.86
Hitachinaka Hitachinaka City 1951.950 2403.51 3543.12
Fukushima [76] (distance from Fukushima I: 25 km) 1945.520 2196.46 3526.7
Fukushima [80] (distance from Fukushima I: 25 km) 1876.860 2196.46 3526.7
Momiyama Hokota City 1837.540 2742.35 3545.86
Fukushima [77] (distance from Fukushima I: 25 km) 1802.490 2196.46 3526.7
Horiguchi Hitachinaka City 1779.410 2396.86 3548.59
Onuma Hitachi City 1776.950 2040.93 3543.12
Fukushima [6] (distance from Fukushima I: 45 km) 1741.180 2201.57 3534.91
Tsukuriya Hokota City 1736.890 2306.89 3545.86
Radiation dose at Big palette Fukushima, Koriyama 1668.540 3477.46
Nemoto Hitachioomiya City 1633.190 2569.29 3543.12
Fukushima [13] (distance from Fukushima I: 40 km) 1624.150 2201.57 3534.91
Fukushima [23] (distance from Fukushima I: 35 km) 1551.750 2201.57 3534.91
Radiation dose at Tsukidatemachi kamitedo, Date 1545.300 3485.66
Fukushima [14] (distance from Fukushima I: 35 km) 1543.460 2201.57 3534.91
Radiation dose at JAEA Oarai (P12) 1512.140 3502.08
Radiation dose at Ose administration center, Koriyama 1494.270 3477.46
Araji Hokota City 1437.760 2312.05 3545.86
Ishigami Tokai Village 1431.690 2104.71 3545.86
Mawatari Hitachinaka City 1422.870 2431.31 3545.86
Radiation dose at JAEA Oarai (P11) 1399.370 3502.08
Onuki Oarai Town 1387.990 2524.62 3545.86
Sawa Hitachinaka City 1353.770 1906.23 3543.12
Toyooka Tokai Village 1321.760 2317.25 3545.86
Ajigaura Hitachinaka City 1313.890 2279.19 3543.12
Fukushima [5] (distance from Fukushima I: 45 km) 1282.090 2201.57 3534.91
Geiger Counter Feeds from Asao Kawasaki 1266.620 3455.57
Radiation dose at Tamokami elementary school, Koriyama 1256.140 3477.46
Isohama Oarai Town 1250.540 2199.79 3540.38
Ebisawa Ibaraki Town 1222.240 5973.58 3543.12
Muramatsu Tokai Village 1203.520 2337.99 3545.86
Kamitoda Hokota City 1184.740 1918.09 3545.86
Yanagisawa Hitachinaka City 1166.970 1952.85 3543.12
Tokushuku Hokota City 1159.730 1731.47 3545.86
Tasaki Hokota City 1153.300 2040.59 3515.76
Fukushima [20] (distance from Fukushima I: 45 km) 1145.390 2201.57 3534.91
Kadobe Naka City 1086.580 4651.65 3543.12
Radiation dose at Date city office, Date 1076.050 3480.19
Oshinobe Tokai Village 1041.340 2182.47 3545.86
Oba Mito City 1037.670 7169.47 3545.86
Godai Naka City 1031.270 1892.15 3545.86
Ishikawa Mito City 1030.810 2230.85 3548.59
Isobe Hitachiota City 1013.130 10762 3545.86
Yatabe Ibaraki Town 996.127 1871.43 3545.86
Radiation dose at Motomiya city office, Motomiya 992.703 3480.19
Fukushima [73] (distance from Fukushima I: 35 km) 981.984 2196.46 3526.7
Fukushima [75] (distance from Fukushima I: 45 km) 960.529 2196.46 3526.7
Yokobori Naka City 930.280 2192.83 3545.86
Sugaya Naka City 926.186 3351.46 3548.59
Kounosu Naka City 926.087 1710.72 3545.86
Funaishikawa Tokai Village 900.399 2270.59 3545.86
Nukada Naka City 899.900 2049.7 3540.38
Uridura Naka City 890.113 1956.53 3540.38
Shiraki Tsuruga City 881.330 4155.59 3548.59
Motokomezaki Naka City 880.851 1818.14 3513.02
Shiraki pass Tsuruga City 850.284 4352.72 3548.59
Radiation dose in Yamamoto 846.633 3502.08
Yoshizawa Mito City 837.646 1980.3 3545.86
Radiation dose at JAEA Oarai (P7) 831.135 3502.08
Mayumi Hitachiota City 828.119 1964.75 3545.86
Urasoko Tsuruga City 826.465 3450.01 3548.59
Nemoto Hitachioomiya City 825.588 2211.87 3543.12
Takenami Mihama Town 804.283 3621.21 3548.59
Radiation dose at JAEA Oarai (P15) 780.207 3502.08
Tateishi Tsuruga City 780.092 2868.97 3548.59
Radiation dose at JAEA Oarai (P14) 770.174 3502.08
Radiation dose at JAEA Oarai (P13) 769.612 3502.08
Ukishima Kawasaki Ward 735.475 6770.34 3548.59
Kume Hitachiota City 713.958 1923.25 3545.86
Radiation dose at JAEA Oarai (P2) 712.011 3502.08
Fukushima [74] (distance from Fukushima I: 35 km) 706.552 2196.46 3526.7
Nyuu Mihama Town 674.787 3299.57 3548.59
Fukushima [52] (distance from Fukushima I: 40 km) 672.743 2201.57 3534.91
Radiation dose in Iwanuma 670.242 3502.08
Fukushima [51] (distance from Fukushima I: 40 km) 665.376 2201.57 3534.91
Tsuruga Tsuruga City 655.360 2910.47 3548.59
Shiohama Kawasaki Ward 653.536 2324.23 3548.59
Radiation dose in Kakuda 649.863 3502.08
Sakajiri Mihama Town 649.252 3849.51 3548.59
North point of Kinki University Atomic Energy Research Instirute Station 639.566 2417.62 3548.59
Radiation dose in Onagawa (MP-2) 632.968 3499.34
Kumatori town Nishi primary school Station 631.491 2889.71 3548.59
Oshima Kawasaki Ward 630.402 2215.29 3548.59
Izumisano municipal Oike athletic field Station 629.920 3258.07 3548.59
Atom-kyoudou nursery school Station 625.566 3128.36 3548.59
South point of Kinki University Atomic Energy Research Instirute Station 625.202 2848.21 3548.59
Nakamachi Omaezaki City 623.494 3667.91 3548.59
Uraga Yokosuka City 622.492 1737.97 3548.59
Goritoge Shika Town 622.143 3896.2 3548.59
Kumatori town Minami primary school Station 606.134 3315.13 3548.59
Radiation dose at JAEA Oarai (P1) 603.643 3504.82
Yamanotedai-No.1 Park Station 599.140 3092.04 3548.59
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 595.502 3521.23
Noumi Shika Town 594.021 3854.67 3548.59
Radiation dose in Watari 591.851 3502.08
Hairando Yokosuka City 588.667 2178.96 3548.59
Fukushima [12] (distance from Fukushima I: 40 km) 588.291 2201.57 3534.91
Ningyotoge Kagamino Town 574.857 3092.04 3548.59
Ten-no Kagamino Town 569.960 3704.23 3548.59
Funagura Yokosuka City 563.909 2054.45 3548.59
Chidori Kawasaki Ward 560.211 1986.99 3548.59
Radiation dose at JAEA Oarai (P16) 556.365 3502.08
Shika Shika Town 551.376 3714.6 3548.59
Higashiosaka municipal Kamikosaka primary scool Station 550.277 2412.42 3548.59
Sahara Yokosuka City 547.404 1924.74 3548.59
Kazanashi Shika Town 545.377 3486.34 3548.59
Akasumi Shika Town 544.970 3190.62 3548.59
Kurahashi Maizuru City 540.820 2905.27 3548.59
Obama Obama City 540.809 2599.19 3548.59
Sakuragaike community hall Omaezaki City 540.772 3761.29 3548.59
Shirowa primary school Omaezaki City 535.692 3683.47 3548.59
Radiation dose at JAEA Oarai (P5) 529.759 3502.08
Uenohara Omaezaki City 529.333 3787.25 3548.59
Kumano Shika Town 529.019 3616.05 3548.59
Izumisano municipal Hineno filtration plant Station 527.471 3118 3548.59
Nishi-hamasada Matsue City 525.089 3444.4 3532.18
Kouno Minami-Echizen Town 525.028 2614.75 3548.59
Kurihama Yokosuka City 523.708 2080.38 3548.59
Osaka prefectural Kumatori off-site-center Station 522.808 2874.14 3548.59
Ogasa branch Kikugawa City 522.039 3824.31 3534.91
Izumisano municipal Hineno primary scool Station 518.181 2495.44 3548.59
Shirasuna Omaezaki City 499.479 3709.43 3548.59
Jitougata primary school Makinohara City 498.059 3558.96 3548.59
Kataku Matsue City 497.007 2765.19 3548.59
Nishihemi Yokosuka City 496.917 1660.15 3548.59
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 496.721 3521.23
Satsuma-sendai monitoring center Satsuma-sendai City 495.302 2723.7 3548.59
Otomi Takahama Town 494.821 3050.54 3548.59
Otsu Nanao City 493.895 3060.91 3548.59
The Observation point for comparison Tatsunokuchi 493.454 2521.37 3548.59
Hitsuhama Ohi Town 492.630 2837.85 3548.59
Kijiyama Misasa Town 489.284 2879.34 3548.59
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 487.055 3521.23
Hiraba Omaezaki City 485.878 3709.43 3548.59
Tayu Matsue City 484.956 2884.54 3548.59
Hamaokakita primary school Omaezaki City 484.537 3798.48 3534.91
Oitomi Ayabe City 474.670 3657.54 3548.59
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 472.017 3521.23
Kashiwazaki-shigai Kashiwazaki City 470.822 2910.47 3548.59
Mitsu Matsue City 466.897 2760.03 3548.59
Tonomachi Kawasaki Ward 463.967 3496.7 3548.59
Daitou branch Kakegawa City 463.829 3741.64 3534.91
Fukura Shika Town 462.493 3481.14 3548.59
Nagasawa Yokosuka City 462.365 2033.69 3548.59
The athletic field Station of Kinki University 461.661 2298.27 3548.59
Koura Matsue City 461.049 3294.37 3548.59
Sakurasan Ward Omaezaki City 459.434 3590.09 3548.59
Tsuchikawa Nanao City 458.915 3387.75 3548.59
Kumatori Town office Station 457.917 2370.93 3548.59
Shinkango Omaezaki City 449.013 4155.59 3548.59
Ogurui Takahama Town 448.279 2718.5 3548.59
Kusabue Omaezaki City 444.162 3916.93 3548.59
Omaezaki City monitoring center 443.946 3844.31 3548.59
Akawase Kagamino Town 442.246 2370.93 3548.59
Ibaraki 442.139 1739.14 3540.38
Hinode Town Yokosuka City 438.324 1369.63 3548.59
Nishiyama Kashiwazaki City 437.251 4119.26 3548.59
Kariwa Kariwa Village 436.307 3107.6 3548.59
Osaka prefectural Hineno high scool Station 435.745 2770.39 3548.59
Miyagawa Kashiwazaki City 435.245 3066.11 3548.59
Radiation dose in Natori 434.640 3502.08
Kami-koubu Matsue City 433.868 3014.22 3548.59
Shimo-Takamachi Kariwa Village 433.192 3382.59 3548.59
Osaka prefectural Sano supporting school Station 432.398 3019.42 3548.59
Arahama Kashiwazaki City 428.874 3159.49 3548.59
Doai Kashiwazaki City 425.681 2972.72 3548.59
Owashi Matsue City 424.452 2946.79 3548.59
Okayasu Maizuru City 422.568 3470.77 3548.59
Katsuyama Kariwa Village 421.280 3159.49 3548.59
Kita-koubu Matsue City 420.683 3232.11 3548.59
Kichisaka Maizuru City 413.065 4217.84 3548.59
Nagai Ohi Town 410.699 3064.2 3540.38
Shiokumi Maizuru City 407.938 5250.27 3548.59
Miyadome Ohi Town 407.831 2542.13 3548.59
Kariwa Kariwa Village 407.617 3273.64 3548.59
Ueno Satsuma-sendai City 394.248 2376.09 3548.59
Power Station-South 389.191 3460.41 3548.59
Radiation dose at JAEA Oarai (P6) 386.963 3502.08
Power Station- 385.546 3377.39 3548.59
Takae Satsuma-sendai City 379.551 2407.22 3548.59
Hokawaduura Genkai Town 378.015 3665.32 3548.59
Kou Itimatsu Suetsugu 377.929 2645.88 3548.59
Minato Satsuma-sendai City 377.656 2204.89 3548.59
Iwanai Iwanai Town 376.336 3592.51 3545.86
Hattari Kyowa Town 373.047 3494.01 3545.86
Chatsu Tomari Village 371.011 3338.49 3545.86
Oyama Maizuru City 358.223 3040.18 3548.59
Kodaira Satsuma-sendai City 355.545 2230.85 3548.59
Kayanuma Tomari Village 354.809 2970.43 3545.86
Anojiri Obama City 353.215 2490.24 3548.59
Kushi Genkai Town 349.738 5058.3 3548.59
Yamaguchi 348.715 3975.17 3540.38
Sadahongou Matsue City 348.228 3097.24 3548.59
Sakibe Karatsu City 347.801 4793.71 3548.59
Hirao Genkai Town 343.814 5053.1 3548.59
The Meteorological Obsevatory of kyowa Town 343.275 3312.58 3545.86
Minami-Horoni Kyowa Town 335.180 3105.21 3545.86
Kounoura Takahama Town 330.353 2625.12 3548.59
Kyoudomarisaki Karatsu City 328.622 5136.12 3548.59
Horikappu Jinja Tomari Village 328.230 3214.07 3545.86
Hukada-kita Matsue City 327.031 2547.3 3548.59
Radiation dose in KEK, Tsukuba 326.240 3521.23
Herokaruusu Tomari Village 324.242 3333.32 3545.86
Yorita Satsuma-sendai City 323.218 2609.55 3548.59
Kamoenai Kamoenai Village 322.032 2814.91 3545.86
Radiation dose in Onagawa (MP-6) 316.267 3499.34
Imamura Genkai Town 314.749 43527.2 3548.59
Yamanaka Takahama Town 314.185 3387.75 3548.59
Sendai (Miyagi) 312.585 1593.17 3540.38
Radiation dose in Onagawa (MP-1) 300.147 3499.34
Gumisaki Satsuma-sendai City 295.693 2106.34 3548.59
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 286.142 3521.23
Aomori Aomori City 285.372 2140.98 3545.86
Misawa City hall Misawa City 283.728 4152.38 3545.86
Kashu Ikata Town 277.173 2173.76 3548.59
Noheji Town Office Noheji Town 272.004 1835.14 3545.86
Takasimamati 271.103 2313.84 3548.59
Radiation dose in Onagawa (MP-3) 270.563 3499.34
Kucho Ikata Town 269.545 1919.57 3548.59
Radiation dose in Marumori 269.436 3502.08
Kawanagata Ikata Town 266.821 1872.88 3548.59
Tochigi 260.733 2080.75 3540.38
Chikagawa Mutu City 256.719 2389.81 3545.86
Yokohama Town Office Yokohama Town 254.846 2928.97 3545.86
Tokyo 251.877 2453.42 3540.38
Hiranuma Rokkasho Village 251.186 1923.25 3545.86
Taisei Ikata Town 246.293 1405.96 3548.59
Chitose-daira Rokkasho Village 245.868 2073.61 3545.86
Gifu 243.951 3416.16 3540.38
Fukkoshi Yokohama Town 243.102 2011.4 3545.86
Shimane 240.651 3416.16 3540.38
Sunagomata Higashidoori Village 238.012 2908.22 3545.86
Obuchi Rokkasho Village 237.506 2312.05 3545.86
Tomari Rokkasho Village 230.636 3234.82 3545.86
kanagawa 226.339 2142.86 3540.38
Saitama 219.770 1863.36 3540.38
Ikatagoshi Ikata Town 217.515 1769.1 3548.59
Touhoku Branch office Touhoku Town 215.416 1674.42 3545.86
Radiation dose at Tohoku University 214.824 3502.08
Odanosawa Higashidoori Village 210.287 2317.25 3545.86
Kagawa 205.829 2391.31 3540.38
Oippe Higashidoori Village 205.182 1995.85 3545.86
Oita 200.921 2639.76 3540.38
Touhoku Town office Touhoku Town 200.811 7744.9 3545.86
Kuchogoshi Ikata Town 198.646 1795.06 3548.59
Minatoura Ikata Town 186.776 1613.46 3548.59
Radiation dose in Koyadori, Ojika 184.905 3496.61
Toyama 184.580 4565.23 3540.38
Fukushima [9] (distance from Fukushima I: 45 km) 184.232 2201.57 3534.91
Radiation dose in Tukahama, Ojika 183.417 3496.61
Chiba 182.407 1366.46 3540.38
Nara 182.387 2484.48 3540.38
Okayama 181.976 3229.82 3540.38
Yamagata 181.598 2546.59 3540.38
Ehime 180.745 2298.14 3540.38
Ishikawa 180.445 3959.64 3540.38
Niigata 177.483 4751.57 3540.38
Hiroshima 176.816 2142.86 3540.38
Mie 174.867 2450.32 3540.38
Fukui 170.045 3012.43 3540.38
Radiation dose in Terama, Ojika 168.036 3496.61
Yamanashi 164.561 1987.58 3540.38
Nagano 162.242 3024.85 3540.38
Saga 161.421 2670.82 3540.38
Tottori 161.392 2453.42 3540.38
Radiation dose in Enoshima, Ojika 160.091 3496.61
Osaka 159.103 1894.42 3540.38
Ibaraki-city Environment 157.249 3455.57
Aichi 149.345 2298.14 3540.38
Toyonoura Ikata Town 149.214 1852.12 3548.59
Shizuoka 148.639 2375.78 3540.38
Kyoto 144.522 2701.87 3540.38
Kagoshima 144.449 2928.58 3540.38
Tokushima 143.627 2080.75 3540.38
Gunma 143.572 1397.52 3540.38
Hyogo 139.710 2360.26 3540.38
Fukuoka 136.511 2453.42 3540.38
Wakayama 133.857 1739.14 3540.38
Radiation at Tamaki-cho Mie Japan 133.138 3455.57
Akita 132.832 2670.82 3540.38
Shiga 124.919 1894.42 3540.38
Nagasaki 109.459 2142.86 3540.38
Hokkaido 109.189 3260.88 3540.38
Kumamoto 103.568 2080.75 3540.38
Aomori 101.819 3167.71 3540.38
Miyazaki 100.354 2062.12 3540.38
Kochi 95.931 2360.26 3540.38
Fukushima [35] (distance from Fukushima I: 35 km) 91.917 2193.05 3521.23
Iwate 90.324 2608.7 3540.38
Environment Feeds from Ohta 83.623 3455.57
Okinawa 82.305 1785.72 3540.38
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