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Accumulated absorbed dose rate - T=13.03.2011 - 23.07.2014(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 3274.99
Fukushima I MP8 570942.000 3274.99
Fukushima I MP6 240668.000 3274.99
Yamada Futaba Town 176983.000 2376.37 2831.76
Fukushima I MP2 140420.000 3274.99
Fukushima I MP5 111325.000 3274.99
Fukushima [32] (distance from Fukushima I: 30 km) 101500.000 2083.99 3346.13
Fukushima I MP3 93730.602 3274.99
Fukushima I MP4 86821.500 3274.99
Fukushima [33] (distance from Fukushima I: 30 km) 77197.703 2083.99 3346.13
Fukushima [79] (distance from Fukushima I: 40 km) 54008.602 2032.87 3264.05
Fukushima [31] (distance from Fukushima I: 30 km) 40677.398 2083.99 3346.13
Ono Okuma Town 38610.500 2194.19 2831.76
Shinzan Futaba Town 38332.801 1991.35 2831.76
Fukushima I MP1 31496.801 3274.99
Yonomori Tomioka Town 29815.900 2268.71 2831.76
Fukushima [46] (distance from Fukushima I: 20 km) 28842.500 2083.99 3346.13
Tomioka Tomioka Town 25324.500 2442.59 2831.76
Fukushima [62] (distance from Fukushima I: 40 km) 16464.100 2083.99 3346.13
Fukushima [61] (distance from Fukushima I: 40 km) 13102.800 2083.99 3346.13
Shimo-Kooriyama Tomioka Town 13057.000 2426.05 2831.76
Fukushima [21] (distance from Fukushima I: 30 km) 12103.800 2083.99 3346.13
Fukushima [3] (distance from Fukushima I: 45 km) 11985.000 2083.99 3346.13
Kami-kooriyama Tomioka Town 11803.900 1904.41 2831.76
Fukushima II MP3 11060.600 3274.99
Fukushima II MP1 10903.000 3274.99
Kooriyama Futaba Town 10352.900 2219.03 2831.76
Fukushima II MP4 9696.330 3274.99
Fukushima [34] (distance from Fukushima I: 30 km) 9540.450 2080.58 3340.66
Fukushima II MP5 9382.150 3274.99
Fukushima [2] (distance from Fukushima I: 55 km) 8841.760 2083.99 3346.13
Matsudate Naraha Town 8410.890 2591.63 2831.76
Shigeoka Naraha Town 8115.970 2864.87 2831.76
Fukushima II MP2 7875.320 3274.99
Namie Namie Town 7321.210 2090.71 2831.76
Radiation dose at Shirasawa branch office, Motomiya 7287.920 3291.41
Fukushima II MP6 7062.690 3274.99
Fukushima II MP7 6511.580 3272.26
Fukushima [1] (distance from Fukushima I: 60 km) 5615.310 2083.99 3346.13
Fukushima [11] (distance from Fukushima I: 40 km) 5491.310 2083.99 3346.13
Fukushima [63] (distance from Fukushima I: 45 km) 5448.820 2083.99 3346.13
Fukushima [45] (distance from Fukushima I: 20 km) 3981.200 2083.99 3346.13
Fukushima [42] (distance from Fukushima I: 30 km) 3850.600 2083.99 3346.13
Fukushima [10] (distance from Fukushima I: 40 km) 3734.160 2083.99 3346.13
Fukushima [78] (distance from Fukushima I: 45 km) 3716.820 2078.88 3337.92
Futatsunuma Hirono Town 3520.340 2484 2831.76
Fukushima [4] (distance from Fukushima I: 50 km) 3386.310 2083.99 3346.13
Fukushima [7] (distance from Fukushima I: 45 km) 3313.930 2083.99 3346.13
Radiation dose at Koriyama joint government building, Koriyama 3232.890 3288.67
Fukushima [15] (distance from Fukushima I: 35 km) 3178.670 2083.99 3346.13
Kiyohashi Namie Town 3162.000 1834.01 2831.76
Fukushima [71] (distance from Fukushima I: 25 km) 3161.650 2078.88 3337.92
Radiation dose at Agricultural center, Koriyama 3128.960 3288.67
Fukushima [41] (distance from Fukushima I: 20 km) 3111.490 2083.99 3346.13
Radiation dose at Koriyama city office, Koriyama 2803.520 3288.67
Fukushima [44] (distance from Fukushima I: 30 km) 2535.550 2083.99 3346.13
Fukushima [72] (distance from Fukushima I: 30 km) 2344.620 2078.88 3337.92
Fukushima [43] (distance from Fukushima I: 20 km) 2244.110 2083.99 3346.13
Yamadaoka Naraha Town 2205.340 2202.49 2831.76
Radiation dose at Iwane Fureai Plaza, Motomiya 2169.060 3291.41
Fukushima [22] (distance from Fukushima I: 35 km) 2020.650 2083.99 3346.13
Kuji Hitachi City 1990.890 5182.85 3357.07
Hitachinaka Hitachinaka City 1951.950 2275.45 3354.34
Fukushima [76] (distance from Fukushima I: 25 km) 1945.520 2078.88 3337.92
Fukushima [80] (distance from Fukushima I: 25 km) 1876.860 2078.88 3337.92
Momiyama Hokota City 1837.540 2596.34 3357.07
Fukushima [77] (distance from Fukushima I: 25 km) 1802.490 2078.88 3337.92
Horiguchi Hitachinaka City 1779.410 2269.34 3359.81
Onuma Hitachi City 1776.950 1932.19 3354.34
Fukushima [6] (distance from Fukushima I: 45 km) 1741.180 2083.99 3346.13
Tsukuriya Hokota City 1736.890 2184.07 3357.07
Radiation dose at Big palette Fukushima, Koriyama 1668.540 3288.67
Nemoto Hitachioomiya City 1633.190 2432.39 3354.34
Fukushima [13] (distance from Fukushima I: 40 km) 1624.150 2083.99 3346.13
Fukushima [23] (distance from Fukushima I: 35 km) 1551.750 2083.99 3346.13
Radiation dose at Tsukidatemachi kamitedo, Date 1545.300 3296.88
Fukushima [14] (distance from Fukushima I: 35 km) 1543.460 2083.99 3346.13
Radiation dose at JAEA Oarai (P12) 1512.140 3313.3
Radiation dose at Ose administration center, Koriyama 1494.270 3288.67
Araji Hokota City 1437.760 2188.96 3357.07
Ishigami Tokai Village 1431.690 1992.66 3357.07
Mawatari Hitachinaka City 1422.870 2301.86 3357.07
Radiation dose at JAEA Oarai (P11) 1399.370 3313.3
Onuki Oarai Town 1387.990 2390.21 3357.07
Sawa Hitachinaka City 1353.770 1804.66 3354.34
Toyooka Tokai Village 1321.760 2193.88 3357.07
Ajigaura Hitachinaka City 1313.890 2157.75 3354.34
Fukushima [5] (distance from Fukushima I: 45 km) 1282.090 2083.99 3346.13
Geiger Counter Feeds from Asao Kawasaki 1266.620 3266.78
Radiation dose at Tamokami elementary school, Koriyama 1256.140 3288.67
Isohama Oarai Town 1250.540 2082.49 3351.6
Ebisawa Ibaraki Town 1222.240 5655.29 3354.34
Muramatsu Tokai Village 1203.520 2213.52 3357.07
Kamitoda Hokota City 1184.740 1815.97 3357.07
Yanagisawa Hitachinaka City 1166.970 1848.8 3354.34
Tokushuku Hokota City 1159.730 1639.28 3357.07
Tasaki Hokota City 1153.300 1931.02 3326.98
Fukushima [20] (distance from Fukushima I: 45 km) 1145.390 2083.99 3346.13
Kadobe Naka City 1086.580 4403.8 3354.34
Radiation dose at Date city office, Date 1076.050 3291.41
Oshinobe Tokai Village 1041.340 2066.28 3357.07
Oba Mito City 1037.670 6787.76 3357.07
Godai Naka City 1031.270 1791.41 3357.07
Ishikawa Mito City 1030.810 2112.17 3359.81
Isobe Hitachiota City 1013.130 10189 3357.07
Yatabe Ibaraki Town 996.127 1771.8 3357.07
Radiation dose at Motomiya city office, Motomiya 992.703 3291.41
Fukushima [73] (distance from Fukushima I: 35 km) 981.984 2078.88 3337.92
Fukushima [75] (distance from Fukushima I: 45 km) 960.529 2078.88 3337.92
Yokobori Naka City 930.280 2076.08 3357.07
Sugaya Naka City 926.186 3173.16 3359.81
Kounosu Naka City 926.087 1619.64 3357.07
Funaishikawa Tokai Village 900.399 2149.7 3357.07
Nukada Naka City 899.900 1940.4 3351.6
Uridura Naka City 890.113 1852.2 3351.6
Shiraki Tsuruga City 881.330 3934.51 3359.81
Motokomezaki Naka City 880.851 1720.44 3324.24
Shiraki pass Tsuruga City 850.284 4121.16 3359.81
Radiation dose in Yamamoto 846.633 3313.3
Yoshizawa Mito City 837.646 1874.87 3357.07
Radiation dose at JAEA Oarai (P7) 831.135 3313.3
Mayumi Hitachiota City 828.119 1860.14 3357.07
Urasoko Tsuruga City 826.465 3266.47 3359.81
Nemoto Hitachioomiya City 825.588 2094.02 3354.34
Takenami Mihama Town 804.283 3428.57 3359.81
Radiation dose at JAEA Oarai (P15) 780.207 3313.3
Tateishi Tsuruga City 780.092 2716.35 3359.81
Radiation dose at JAEA Oarai (P14) 770.174 3313.3
Radiation dose at JAEA Oarai (P13) 769.612 3313.3
Ukishima Kawasaki Ward 735.475 6410.16 3359.81
Kume Hitachiota City 713.958 1820.86 3357.07
Radiation dose at JAEA Oarai (P2) 712.011 3313.3
Fukushima [74] (distance from Fukushima I: 35 km) 706.552 2078.88 3337.92
Nyuu Mihama Town 674.787 3124.03 3359.81
Fukushima [52] (distance from Fukushima I: 40 km) 672.743 2083.99 3346.13
Radiation dose in Iwanuma 670.242 3313.3
Fukushima [51] (distance from Fukushima I: 40 km) 665.376 2083.99 3346.13
Tsuruga Tsuruga City 655.360 2755.63 3359.81
Shiohama Kawasaki Ward 653.536 2200.59 3359.81
Radiation dose in Kakuda 649.863 3313.3
Sakajiri Mihama Town 649.252 3644.71 3359.81
North point of Kinki University Atomic Energy Research Instirute Station 639.566 2289 3359.81
Radiation dose in Onagawa (MP-2) 632.968 3310.56
Kumatori town Nishi primary school Station 631.491 2735.97 3359.81
Oshima Kawasaki Ward 630.402 2097.43 3359.81
Izumisano municipal Oike athletic field Station 629.920 3084.75 3359.81
Atom-kyoudou nursery school Station 625.566 2961.94 3359.81
South point of Kinki University Atomic Energy Research Instirute Station 625.202 2696.69 3359.81
Nakamachi Omaezaki City 623.494 3472.77 3359.81
Uraga Yokosuka City 622.492 1645.51 3359.81
Goritoge Shika Town 622.143 3688.92 3359.81
Kumatori town Minami primary school Station 606.134 3138.77 3359.81
Radiation dose at JAEA Oarai (P1) 603.643 3316.03
Yamanotedai-No.1 Park Station 599.140 2927.54 3359.81
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 595.502 3332.45
Noumi Shika Town 594.021 3649.61 3359.81
Radiation dose in Watari 591.851 3313.3
Hairando Yokosuka City 588.667 2063.04 3359.81
Fukushima [12] (distance from Fukushima I: 40 km) 588.291 2083.99 3346.13
Ningyotoge Kagamino Town 574.857 2927.54 3359.81
Ten-no Kagamino Town 569.960 3507.17 3359.81
Funagura Yokosuka City 563.909 1945.15 3359.81
Chidori Kawasaki Ward 560.211 1881.29 3359.81
Radiation dose at JAEA Oarai (P16) 556.365 3313.3
Shika Shika Town 551.376 3516.98 3359.81
Higashiosaka municipal Kamikosaka primary scool Station 550.277 2284.08 3359.81
Sahara Yokosuka City 547.404 1822.34 3359.81
Kazanashi Shika Town 545.377 3300.86 3359.81
Akasumi Shika Town 544.970 3020.88 3359.81
Kurahashi Maizuru City 540.820 2750.71 3359.81
Obama Obama City 540.809 2460.91 3359.81
Sakuragaike community hall Omaezaki City 540.772 3561.19 3359.81
Shirowa primary school Omaezaki City 535.692 3487.51 3359.81
Radiation dose at JAEA Oarai (P5) 529.759 3313.3
Uenohara Omaezaki City 529.333 3585.77 3359.81
Kumano Shika Town 529.019 3423.67 3359.81
Izumisano municipal Hineno filtration plant Station 527.471 2952.12 3359.81
Nishi-hamasada Matsue City 525.089 3260.31 3343.39
Kouno Minami-Echizen Town 525.028 2475.65 3359.81
Kurihama Yokosuka City 523.708 1969.7 3359.81
Osaka prefectural Kumatori off-site-center Station 522.808 2721.24 3359.81
Ogasa branch Kikugawa City 522.039 3620.07 3346.13
Izumisano municipal Hineno primary scool Station 518.181 2362.68 3359.81
Shirasuna Omaezaki City 499.479 3512.09 3359.81
Jitougata primary school Makinohara City 498.059 3369.62 3359.81
Kataku Matsue City 497.007 2618.09 3359.81
Nishihemi Yokosuka City 496.917 1571.83 3359.81
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 496.721 3332.45
Satsuma-sendai monitoring center Satsuma-sendai City 495.302 2578.8 3359.81
Otomi Takahama Town 494.821 2888.26 3359.81
Otsu Nanao City 493.895 2898.07 3359.81
The Observation point for comparison Tatsunokuchi 493.454 2387.23 3359.81
Hitsuhama Ohi Town 492.630 2686.87 3359.81
Kijiyama Misasa Town 489.284 2726.16 3359.81
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 487.055 3332.45
Hiraba Omaezaki City 485.878 3512.09 3359.81
Tayu Matsue City 484.956 2731.08 3359.81
Hamaokakita primary school Omaezaki City 484.537 3595.62 3346.13
Oitomi Ayabe City 474.670 3462.96 3359.81
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 472.017 3332.45
Kashiwazaki-shigai Kashiwazaki City 470.822 2755.63 3359.81
Mitsu Matsue City 466.897 2613.19 3359.81
Tonomachi Kawasaki Ward 463.967 3310.68 3359.81
Daitou branch Kakegawa City 463.829 3541.82 3346.13
Fukura Shika Town 462.493 3295.94 3359.81
Nagasawa Yokosuka City 462.365 1925.49 3359.81
The athletic field Station of Kinki University 461.661 2176.01 3359.81
Koura Matsue City 461.049 3119.11 3359.81
Sakurasan Ward Omaezaki City 459.434 3399.09 3359.81
Tsuchikawa Nanao City 458.915 3207.53 3359.81
Kumatori Town office Station 457.917 2244.79 3359.81
Shinkango Omaezaki City 449.013 3934.51 3359.81
Ogurui Takahama Town 448.279 2573.88 3359.81
Kusabue Omaezaki City 444.162 3708.55 3359.81
Omaezaki City monitoring center 443.946 3639.79 3359.81
Akawase Kagamino Town 442.246 2244.79 3359.81
Ibaraki 442.139 1646.4 3351.6
Hinode Town Yokosuka City 438.324 1296.77 3359.81
Nishiyama Kashiwazaki City 437.251 3900.12 3359.81
Kariwa Kariwa Village 436.307 2942.28 3359.81
Osaka prefectural Hineno high scool Station 435.745 2623.01 3359.81
Miyagawa Kashiwazaki City 435.245 2902.99 3359.81
Radiation dose in Natori 434.640 3313.3
Kami-koubu Matsue City 433.868 2853.86 3359.81
Shimo-Takamachi Kariwa Village 433.192 3202.63 3359.81
Osaka prefectural Sano supporting school Station 432.398 2858.78 3359.81
Arahama Kashiwazaki City 428.874 2991.41 3359.81
Doai Kashiwazaki City 425.681 2814.58 3359.81
Owashi Matsue City 424.452 2790.03 3359.81
Okayasu Maizuru City 422.568 3286.13 3359.81
Katsuyama Kariwa Village 421.280 2991.41 3359.81
Kita-koubu Matsue City 420.683 3060.17 3359.81
Kichisaka Maizuru City 413.065 3993.46 3359.81
Nagai Ohi Town 410.699 2900.81 3351.6
Shiokumi Maizuru City 407.938 4970.95 3359.81
Miyadome Ohi Town 407.831 2406.89 3359.81
Kariwa Kariwa Village 407.617 3099.48 3359.81
Ueno Satsuma-sendai City 394.248 2249.69 3359.81
Power Station-South 389.191 3276.31 3359.81
Radiation dose at JAEA Oarai (P6) 386.963 3313.3
Power Station- 385.546 3197.71 3359.81
Takae Satsuma-sendai City 379.551 2279.16 3359.81
Hokawaduura Genkai Town 378.015 3470.33 3359.81
Kou Itimatsu Suetsugu 377.929 2505.12 3359.81
Minato Satsuma-sendai City 377.656 2087.59 3359.81
Iwanai Iwanai Town 376.336 3401.24 3357.07
Hattari Kyowa Town 373.047 3307.98 3357.07
Chatsu Tomari Village 371.011 3160.74 3357.07
Oyama Maizuru City 358.223 2878.44 3359.81
Kodaira Satsuma-sendai City 355.545 2112.17 3359.81
Kayanuma Tomari Village 354.809 2812.28 3357.07
Anojiri Obama City 353.215 2357.76 3359.81
Kushi Genkai Town 349.738 4789.2 3359.81
Yamaguchi 348.715 3763.2 3351.6
Sadahongou Matsue City 348.228 2932.46 3359.81
Sakibe Karatsu City 347.801 4538.69 3359.81
Hirao Genkai Town 343.814 4784.28 3359.81
The Meteorological Obsevatory of kyowa Town 343.275 3136.21 3357.07
Minami-Horoni Kyowa Town 335.180 2939.88 3357.07
Kounoura Takahama Town 330.353 2485.46 3359.81
Kyoudomarisaki Karatsu City 328.622 4862.88 3359.81
Horikappu Jinja Tomari Village 328.230 3042.95 3357.07
Hukada-kita Matsue City 327.031 2411.78 3359.81
Radiation dose in KEK, Tsukuba 326.240 3332.45
Herokaruusu Tomari Village 324.242 3155.85 3357.07
Yorita Satsuma-sendai City 323.218 2470.73 3359.81
Kamoenai Kamoenai Village 322.032 2665.04 3357.07
Radiation dose in Onagawa (MP-6) 316.267 3310.56
Imamura Genkai Town 314.749 41211.6 3359.81
Yamanaka Takahama Town 314.185 3207.53 3359.81
Sendai (Miyagi) 312.585 1508.22 3351.6
Radiation dose in Onagawa (MP-1) 300.147 3310.56
Gumisaki Satsuma-sendai City 295.693 1994.28 3359.81
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 286.142 3332.45
Aomori Aomori City 285.372 2026.99 3357.07
Misawa City hall Misawa City 283.728 3931.31 3357.07
Kashu Ikata Town 277.173 2058.12 3359.81
Noheji Town Office Noheji Town 272.004 1737.43 3357.07
Takasimamati 271.103 2190.74 3359.81
Radiation dose in Onagawa (MP-3) 270.563 3310.56
Kucho Ikata Town 269.545 1817.45 3359.81
Radiation dose in Marumori 269.436 3313.3
Kawanagata Ikata Town 266.821 1773.24 3359.81
Tochigi 260.733 1969.8 3351.6
Chikagawa Mutu City 256.719 2262.58 3357.07
Yokohama Town Office Yokohama Town 254.846 2773.03 3357.07
Tokyo 251.877 2322.6 3351.6
Hiranuma Rokkasho Village 251.186 1820.86 3357.07
Taisei Ikata Town 246.293 1331.16 3359.81
Chitose-daira Rokkasho Village 245.868 1963.21 3357.07
Gifu 243.951 3234 3351.6
Fukkoshi Yokohama Town 243.102 1904.31 3357.07
Shimane 240.651 3234 3351.6
Sunagomata Higashidoori Village 238.012 2753.39 3357.07
Obuchi Rokkasho Village 237.506 2188.96 3357.07
Tomari Rokkasho Village 230.636 3062.59 3357.07
kanagawa 226.339 2028.6 3351.6
Saitama 219.770 1764 3351.6
Ikatagoshi Ikata Town 217.515 1674.98 3359.81
Touhoku Branch office Touhoku Town 215.416 1585.27 3357.07
Radiation dose at Tohoku University 214.824 3313.3
Odanosawa Higashidoori Village 210.287 2193.88 3357.07
Kagawa 205.829 2263.8 3351.6
Oippe Higashidoori Village 205.182 1889.59 3357.07
Oita 200.921 2499 3351.6
Touhoku Town office Touhoku Town 200.811 7332.55 3357.07
Kuchogoshi Ikata Town 198.646 1699.56 3359.81
Minatoura Ikata Town 186.776 1527.62 3359.81
Radiation dose in Koyadori, Ojika 184.905 3307.82
Toyama 184.580 4321.8 3351.6
Fukushima [9] (distance from Fukushima I: 45 km) 184.232 2083.99 3346.13
Radiation dose in Tukahama, Ojika 183.417 3307.82
Chiba 182.407 1293.6 3351.6
Nara 182.387 2352 3351.6
Okayama 181.976 3057.6 3351.6
Yamagata 181.598 2410.8 3351.6
Ehime 180.745 2175.6 3351.6
Ishikawa 180.445 3748.5 3351.6
Niigata 177.483 4498.2 3351.6
Hiroshima 176.816 2028.6 3351.6
Mie 174.867 2319.66 3351.6
Fukui 170.045 2851.8 3351.6
Radiation dose in Terama, Ojika 168.036 3307.82
Yamanashi 164.561 1881.6 3351.6
Nagano 162.242 2863.56 3351.6
Saga 161.421 2528.4 3351.6
Tottori 161.392 2322.6 3351.6
Radiation dose in Enoshima, Ojika 160.091 3307.82
Osaka 159.103 1793.4 3351.6
Ibaraki-city Environment 157.249 3266.78
Aichi 149.345 2175.6 3351.6
Toyonoura Ikata Town 149.214 1753.58 3359.81
Shizuoka 148.639 2249.1 3351.6
Kyoto 144.522 2557.8 3351.6
Kagoshima 144.449 2772.42 3351.6
Tokushima 143.627 1969.8 3351.6
Gunma 143.572 1323 3351.6
Hyogo 139.710 2234.4 3351.6
Fukuoka 136.511 2322.6 3351.6
Wakayama 133.857 1646.4 3351.6
Radiation at Tamaki-cho Mie Japan 133.138 3266.78
Akita 132.832 2528.4 3351.6
Shiga 124.919 1793.4 3351.6
Nagasaki 109.459 2028.6 3351.6
Hokkaido 109.189 3087 3351.6
Kumamoto 103.568 1969.8 3351.6
Aomori 101.819 2998.8 3351.6
Miyazaki 100.354 1952.16 3351.6
Kochi 95.931 2234.4 3351.6
Fukushima [35] (distance from Fukushima I: 35 km) 91.917 2075.47 3332.45
Iwate 90.324 2469.6 3351.6
Environment Feeds from Ohta 83.623 3266.78
Okinawa 82.305 1690.5 3351.6
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