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Accumulated absorbed dose rate - T=13.03.2011 - 21.09.2014(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 3439.15
Fukushima I MP8 570942.000 3439.15
Fukushima I MP6 240668.000 3439.15
Yamada Futaba Town 176983.000 2514.13 2995.92
Fukushima I MP2 140420.000 3439.15
Fukushima I MP5 111325.000 3439.15
Fukushima [32] (distance from Fukushima I: 30 km) 101500.000 2186.23 3510.29
Fukushima I MP3 93730.602 3439.15
Fukushima I MP4 86821.500 3439.15
Fukushima [33] (distance from Fukushima I: 30 km) 77197.703 2186.23 3510.29
Fukushima [79] (distance from Fukushima I: 40 km) 54008.602 2135.11 3428.21
Fukushima [31] (distance from Fukushima I: 30 km) 40677.398 2186.23 3510.29
Ono Okuma Town 38610.500 2321.39 2995.92
Shinzan Futaba Town 38332.801 2106.79 2995.92
Fukushima I MP1 31496.801 3439.15
Yonomori Tomioka Town 29815.900 2400.23 2995.92
Fukushima [46] (distance from Fukushima I: 20 km) 28842.500 2186.23 3510.29
Tomioka Tomioka Town 25324.500 2584.19 2995.92
Fukushima [62] (distance from Fukushima I: 40 km) 16464.100 2186.23 3510.29
Fukushima [61] (distance from Fukushima I: 40 km) 13102.800 2186.23 3510.29
Shimo-Kooriyama Tomioka Town 13057.000 2566.69 2995.92
Fukushima [21] (distance from Fukushima I: 30 km) 12103.800 2186.23 3510.29
Fukushima [3] (distance from Fukushima I: 45 km) 11985.000 2186.23 3510.29
Kami-kooriyama Tomioka Town 11803.900 2014.81 2995.92
Fukushima II MP3 11060.600 3439.15
Fukushima II MP1 10903.000 3439.15
Kooriyama Futaba Town 10352.900 2347.67 2995.92
Fukushima II MP4 9696.330 3439.15
Fukushima [34] (distance from Fukushima I: 30 km) 9540.450 2182.82 3504.82
Fukushima II MP5 9382.150 3439.15
Fukushima [2] (distance from Fukushima I: 55 km) 8841.760 2186.23 3510.29
Matsudate Naraha Town 8410.890 2741.87 2995.92
Shigeoka Naraha Town 8115.970 3030.95 2995.92
Fukushima II MP2 7875.320 3439.15
Namie Namie Town 7321.210 2211.91 2995.92
Radiation dose at Shirasawa branch office, Motomiya 7287.920 3455.57
Fukushima II MP6 7062.690 3439.15
Fukushima II MP7 6511.580 3436.42
Fukushima [1] (distance from Fukushima I: 60 km) 5615.310 2186.23 3510.29
Fukushima [11] (distance from Fukushima I: 40 km) 5491.310 2186.23 3510.29
Fukushima [63] (distance from Fukushima I: 45 km) 5448.820 2186.23 3510.29
Fukushima [45] (distance from Fukushima I: 20 km) 3981.200 2186.23 3510.29
Fukushima [42] (distance from Fukushima I: 30 km) 3850.600 2186.23 3510.29
Fukushima [10] (distance from Fukushima I: 40 km) 3734.160 2186.23 3510.29
Fukushima [78] (distance from Fukushima I: 45 km) 3716.820 2181.12 3502.08
Futatsunuma Hirono Town 3520.340 2628 2995.92
Fukushima [4] (distance from Fukushima I: 50 km) 3386.310 2186.23 3510.29
Fukushima [7] (distance from Fukushima I: 45 km) 3313.930 2186.23 3510.29
Radiation dose at Koriyama joint government building, Koriyama 3232.890 3452.83
Fukushima [15] (distance from Fukushima I: 35 km) 3178.670 2186.23 3510.29
Kiyohashi Namie Town 3162.000 1940.33 2995.92
Fukushima [71] (distance from Fukushima I: 25 km) 3161.650 2181.12 3502.08
Radiation dose at Agricultural center, Koriyama 3128.960 3452.83
Fukushima [41] (distance from Fukushima I: 20 km) 3111.490 2186.23 3510.29
Radiation dose at Koriyama city office, Koriyama 2803.520 3452.83
Fukushima [44] (distance from Fukushima I: 30 km) 2535.550 2186.23 3510.29
Fukushima [72] (distance from Fukushima I: 30 km) 2344.620 2181.12 3502.08
Fukushima [43] (distance from Fukushima I: 20 km) 2244.110 2186.23 3510.29
Yamadaoka Naraha Town 2205.340 2330.17 2995.92
Radiation dose at Iwane Fureai Plaza, Motomiya 2169.060 3455.57
Fukushima [22] (distance from Fukushima I: 35 km) 2020.650 2186.23 3510.29
Kuji Hitachi City 1990.890 5436.29 3521.23
Hitachinaka Hitachinaka City 1951.950 2386.81 3518.5
Fukushima [76] (distance from Fukushima I: 25 km) 1945.520 2181.12 3502.08
Fukushima [80] (distance from Fukushima I: 25 km) 1876.860 2181.12 3502.08
Momiyama Hokota City 1837.540 2723.3 3521.23
Fukushima [77] (distance from Fukushima I: 25 km) 1802.490 2181.12 3502.08
Horiguchi Hitachinaka City 1779.410 2380.22 3523.97
Onuma Hitachi City 1776.950 2026.75 3518.5
Fukushima [6] (distance from Fukushima I: 45 km) 1741.180 2186.23 3510.29
Tsukuriya Hokota City 1736.890 2290.87 3521.23
Radiation dose at Big palette Fukushima, Koriyama 1668.540 3452.83
Nemoto Hitachioomiya City 1633.190 2551.43 3518.5
Fukushima [13] (distance from Fukushima I: 40 km) 1624.150 2186.23 3510.29
Fukushima [23] (distance from Fukushima I: 35 km) 1551.750 2186.23 3510.29
Radiation dose at Tsukidatemachi kamitedo, Date 1545.300 3461.04
Fukushima [14] (distance from Fukushima I: 35 km) 1543.460 2186.23 3510.29
Radiation dose at JAEA Oarai (P12) 1512.140 3477.46
Radiation dose at Ose administration center, Koriyama 1494.270 3452.83
Araji Hokota City 1437.760 2296 3521.23
Ishigami Tokai Village 1431.690 2090.1 3521.23
Mawatari Hitachinaka City 1422.870 2414.42 3521.23
Radiation dose at JAEA Oarai (P11) 1399.370 3477.46
Onuki Oarai Town 1387.990 2507.09 3521.23
Sawa Hitachinaka City 1353.770 1892.98 3518.5
Toyooka Tokai Village 1321.760 2301.16 3521.23
Ajigaura Hitachinaka City 1313.890 2263.35 3518.5
Fukushima [5] (distance from Fukushima I: 45 km) 1282.090 2186.23 3510.29
Geiger Counter Feeds from Asao Kawasaki 1266.620 3430.94
Radiation dose at Tamokami elementary school, Koriyama 1256.140 3452.83
Isohama Oarai Town 1250.540 2184.49 3515.76
Ebisawa Ibaraki Town 1222.240 5932.06 3518.5
Muramatsu Tokai Village 1203.520 2321.76 3521.23
Kamitoda Hokota City 1184.740 1904.77 3521.23
Yanagisawa Hitachinaka City 1166.970 1939.28 3518.5
Tokushuku Hokota City 1159.730 1719.44 3521.23
Tasaki Hokota City 1153.300 2026.3 3491.14
Fukushima [20] (distance from Fukushima I: 45 km) 1145.390 2186.23 3510.29
Kadobe Naka City 1086.580 4619.32 3518.5
Radiation dose at Date city office, Date 1076.050 3455.57
Oshinobe Tokai Village 1041.340 2167.32 3521.23
Oba Mito City 1037.670 7119.68 3521.23
Godai Naka City 1031.270 1879.01 3521.23
Ishikawa Mito City 1030.810 2215.37 3523.97
Isobe Hitachiota City 1013.130 10687.2 3521.23
Yatabe Ibaraki Town 996.127 1858.44 3521.23
Radiation dose at Motomiya city office, Motomiya 992.703 3455.57
Fukushima [73] (distance from Fukushima I: 35 km) 981.984 2181.12 3502.08
Fukushima [75] (distance from Fukushima I: 45 km) 960.529 2181.12 3502.08
Yokobori Naka City 930.280 2177.6 3521.23
Sugaya Naka City 926.186 3328.2 3523.97
Kounosu Naka City 926.087 1698.84 3521.23
Funaishikawa Tokai Village 900.399 2254.82 3521.23
Nukada Naka City 899.900 2035.44 3515.76
Uridura Naka City 890.113 1942.92 3515.76
Shiraki Tsuruga City 881.330 4126.75 3523.97
Motokomezaki Naka City 880.851 1805.4 3488.4
Shiraki pass Tsuruga City 850.284 4322.52 3523.97
Radiation dose in Yamamoto 846.633 3477.46
Yoshizawa Mito City 837.646 1966.55 3521.23
Radiation dose at JAEA Oarai (P7) 831.135 3477.46
Mayumi Hitachiota City 828.119 1951.1 3521.23
Urasoko Tsuruga City 826.465 3426.07 3523.97
Nemoto Hitachioomiya City 825.588 2196.5 3518.5
Takenami Mihama Town 804.283 3596.09 3523.97
Radiation dose at JAEA Oarai (P15) 780.207 3477.46
Tateishi Tsuruga City 780.092 2849.07 3523.97
Radiation dose at JAEA Oarai (P14) 770.174 3477.46
Radiation dose at JAEA Oarai (P13) 769.612 3477.46
Ukishima Kawasaki Ward 735.475 6723.36 3523.97
Kume Hitachiota City 713.958 1909.9 3521.23
Radiation dose at JAEA Oarai (P2) 712.011 3477.46
Fukushima [74] (distance from Fukushima I: 35 km) 706.552 2181.12 3502.08
Nyuu Mihama Town 674.787 3276.67 3523.97
Fukushima [52] (distance from Fukushima I: 40 km) 672.743 2186.23 3510.29
Radiation dose in Iwanuma 670.242 3477.46
Fukushima [51] (distance from Fukushima I: 40 km) 665.376 2186.23 3510.29
Tsuruga Tsuruga City 655.360 2890.27 3523.97
Shiohama Kawasaki Ward 653.536 2308.11 3523.97
Radiation dose in Kakuda 649.863 3477.46
Sakajiri Mihama Town 649.252 3822.79 3523.97
North point of Kinki University Atomic Energy Research Instirute Station 639.566 2400.84 3523.97
Radiation dose in Onagawa (MP-2) 632.968 3474.72
Kumatori town Nishi primary school Station 631.491 2869.65 3523.97
Oshima Kawasaki Ward 630.402 2199.91 3523.97
Izumisano municipal Oike athletic field Station 629.920 3235.47 3523.97
Atom-kyoudou nursery school Station 625.566 3106.66 3523.97
South point of Kinki University Atomic Energy Research Instirute Station 625.202 2828.45 3523.97
Nakamachi Omaezaki City 623.494 3642.45 3523.97
Uraga Yokosuka City 622.492 1725.91 3523.97
Goritoge Shika Town 622.143 3869.16 3523.97
Kumatori town Minami primary school Station 606.134 3292.13 3523.97
Radiation dose at JAEA Oarai (P1) 603.643 3480.19
Yamanotedai-No.1 Park Station 599.140 3070.58 3523.97
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 595.502 3496.61
Noumi Shika Town 594.021 3827.93 3523.97
Radiation dose in Watari 591.851 3477.46
Hairando Yokosuka City 588.667 2163.84 3523.97
Fukushima [12] (distance from Fukushima I: 40 km) 588.291 2186.23 3510.29
Ningyotoge Kagamino Town 574.857 3070.58 3523.97
Ten-no Kagamino Town 569.960 3678.53 3523.97
Funagura Yokosuka City 563.909 2040.19 3523.97
Chidori Kawasaki Ward 560.211 1973.21 3523.97
Radiation dose at JAEA Oarai (P16) 556.365 3477.46
Shika Shika Town 551.376 3688.82 3523.97
Higashiosaka municipal Kamikosaka primary scool Station 550.277 2395.68 3523.97
Sahara Yokosuka City 547.404 1911.38 3523.97
Kazanashi Shika Town 545.377 3462.14 3523.97
Akasumi Shika Town 544.970 3168.48 3523.97
Kurahashi Maizuru City 540.820 2885.11 3523.97
Obama Obama City 540.809 2581.15 3523.97
Sakuragaike community hall Omaezaki City 540.772 3735.19 3523.97
Shirowa primary school Omaezaki City 535.692 3657.91 3523.97
Radiation dose at JAEA Oarai (P5) 529.759 3477.46
Uenohara Omaezaki City 529.333 3760.97 3523.97
Kumano Shika Town 529.019 3590.95 3523.97
Izumisano municipal Hineno filtration plant Station 527.471 3096.36 3523.97
Nishi-hamasada Matsue City 525.089 3420.39 3507.55
Kouno Minami-Echizen Town 525.028 2596.61 3523.97
Kurihama Yokosuka City 523.708 2065.94 3523.97
Osaka prefectural Kumatori off-site-center Station 522.808 2854.2 3523.97
Ogasa branch Kikugawa City 522.039 3797.67 3510.29
Izumisano municipal Hineno primary scool Station 518.181 2478.12 3523.97
Shirasuna Omaezaki City 499.479 3683.69 3523.97
Jitougata primary school Makinohara City 498.059 3534.26 3523.97
Kataku Matsue City 497.007 2746.01 3523.97
Nishihemi Yokosuka City 496.917 1648.63 3523.97
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 496.721 3496.61
Satsuma-sendai monitoring center Satsuma-sendai City 495.302 2704.8 3523.97
Otomi Takahama Town 494.821 3029.38 3523.97
Otsu Nanao City 493.895 3039.67 3523.97
The Observation point for comparison Tatsunokuchi 493.454 2503.87 3523.97
Hitsuhama Ohi Town 492.630 2818.15 3523.97
Kijiyama Misasa Town 489.284 2859.36 3523.97
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 487.055 3496.61
Hiraba Omaezaki City 485.878 3683.69 3523.97
Tayu Matsue City 484.956 2864.52 3523.97
Hamaokakita primary school Omaezaki City 484.537 3772.02 3510.29
Oitomi Ayabe City 474.670 3632.16 3523.97
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 472.017 3496.61
Kashiwazaki-shigai Kashiwazaki City 470.822 2890.27 3523.97
Mitsu Matsue City 466.897 2740.87 3523.97
Tonomachi Kawasaki Ward 463.967 3472.44 3523.97
Daitou branch Kakegawa City 463.829 3715.58 3510.29
Fukura Shika Town 462.493 3456.98 3523.97
Nagasawa Yokosuka City 462.365 2019.57 3523.97
The athletic field Station of Kinki University 461.661 2282.33 3523.97
Koura Matsue City 461.049 3271.51 3523.97
Sakurasan Ward Omaezaki City 459.434 3565.17 3523.97
Tsuchikawa Nanao City 458.915 3364.25 3523.97
Kumatori Town office Station 457.917 2354.47 3523.97
Shinkango Omaezaki City 449.013 4126.75 3523.97
Ogurui Takahama Town 448.279 2699.64 3523.97
Kusabue Omaezaki City 444.162 3889.75 3523.97
Omaezaki City monitoring center 443.946 3817.63 3523.97
Akawase Kagamino Town 442.246 2354.47 3523.97
Ibaraki 442.139 1727.04 3515.76
Hinode Town Yokosuka City 438.324 1360.13 3523.97
Nishiyama Kashiwazaki City 437.251 4090.68 3523.97
Kariwa Kariwa Village 436.307 3086.04 3523.97
Osaka prefectural Hineno high scool Station 435.745 2751.17 3523.97
Miyagawa Kashiwazaki City 435.245 3044.83 3523.97
Radiation dose in Natori 434.640 3477.46
Kami-koubu Matsue City 433.868 2993.3 3523.97
Shimo-Takamachi Kariwa Village 433.192 3359.11 3523.97
Osaka prefectural Sano supporting school Station 432.398 2998.46 3523.97
Arahama Kashiwazaki City 428.874 3137.57 3523.97
Doai Kashiwazaki City 425.681 2952.1 3523.97
Owashi Matsue City 424.452 2926.35 3523.97
Okayasu Maizuru City 422.568 3446.69 3523.97
Katsuyama Kariwa Village 421.280 3137.57 3523.97
Kita-koubu Matsue City 420.683 3209.69 3523.97
Kichisaka Maizuru City 413.065 4188.58 3523.97
Nagai Ohi Town 410.699 3042.89 3515.76
Shiokumi Maizuru City 407.938 5213.83 3523.97
Miyadome Ohi Town 407.831 2524.49 3523.97
Kariwa Kariwa Village 407.617 3250.92 3523.97
Ueno Satsuma-sendai City 394.248 2359.61 3523.97
Power Station-South 389.191 3436.39 3523.97
Radiation dose at JAEA Oarai (P6) 386.963 3477.46
Power Station- 385.546 3353.95 3523.97
Takae Satsuma-sendai City 379.551 2390.52 3523.97
Hokawaduura Genkai Town 378.015 3639.89 3523.97
Kou Itimatsu Suetsugu 377.929 2627.52 3523.97
Minato Satsuma-sendai City 377.656 2189.59 3523.97
Iwanai Iwanai Town 376.336 3567.56 3521.23
Hattari Kyowa Town 373.047 3469.74 3521.23
Chatsu Tomari Village 371.011 3315.3 3521.23
Oyama Maizuru City 358.223 3019.08 3523.97
Kodaira Satsuma-sendai City 355.545 2215.37 3523.97
Kayanuma Tomari Village 354.809 2949.8 3521.23
Anojiri Obama City 353.215 2472.96 3523.97
Kushi Genkai Town 349.738 5023.2 3523.97
Yamaguchi 348.715 3947.52 3515.76
Sadahongou Matsue City 348.228 3075.74 3523.97
Sakibe Karatsu City 347.801 4760.45 3523.97
Hirao Genkai Town 343.814 5018.04 3523.97
The Meteorological Obsevatory of kyowa Town 343.275 3289.57 3521.23
Minami-Horoni Kyowa Town 335.180 3083.64 3521.23
Kounoura Takahama Town 330.353 2606.9 3523.97
Kyoudomarisaki Karatsu City 328.622 5100.48 3523.97
Horikappu Jinja Tomari Village 328.230 3191.75 3521.23
Hukada-kita Matsue City 327.031 2529.62 3523.97
Radiation dose in KEK, Tsukuba 326.240 3496.61
Herokaruusu Tomari Village 324.242 3310.17 3521.23
Yorita Satsuma-sendai City 323.218 2591.45 3523.97
Kamoenai Kamoenai Village 322.032 2795.36 3521.23
Radiation dose in Onagawa (MP-6) 316.267 3474.72
Imamura Genkai Town 314.749 43225.2 3523.97
Yamanaka Takahama Town 314.185 3364.25 3523.97
Sendai (Miyagi) 312.585 1582.09 3515.76
Radiation dose in Onagawa (MP-1) 300.147 3474.72
Gumisaki Satsuma-sendai City 295.693 2091.72 3523.97
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 286.142 3496.61
Aomori Aomori City 285.372 2126.11 3521.23
Misawa City hall Misawa City 283.728 4123.55 3521.23
Kashu Ikata Town 277.173 2158.68 3523.97
Noheji Town Office Noheji Town 272.004 1822.39 3521.23
Takasimamati 271.103 2297.78 3523.97
Radiation dose in Onagawa (MP-3) 270.563 3474.72
Kucho Ikata Town 269.545 1906.25 3523.97
Radiation dose in Marumori 269.436 3477.46
Kawanagata Ikata Town 266.821 1859.88 3523.97
Tochigi 260.733 2066.28 3515.76
Chikagawa Mutu City 256.719 2373.22 3521.23
Yokohama Town Office Yokohama Town 254.846 2908.63 3521.23
Tokyo 251.877 2436.36 3515.76
Hiranuma Rokkasho Village 251.186 1909.9 3521.23
Taisei Ikata Town 246.293 1396.2 3523.97
Chitose-daira Rokkasho Village 245.868 2059.21 3521.23
Gifu 243.951 3392.4 3515.76
Fukkoshi Yokohama Town 243.102 1997.43 3521.23
Shimane 240.651 3392.4 3515.76
Sunagomata Higashidoori Village 238.012 2888.03 3521.23
Obuchi Rokkasho Village 237.506 2296 3521.23
Tomari Rokkasho Village 230.636 3212.35 3521.23
kanagawa 226.339 2127.96 3515.76
Saitama 219.770 1850.4 3515.76
Ikatagoshi Ikata Town 217.515 1756.82 3523.97
Touhoku Branch office Touhoku Town 215.416 1662.79 3521.23
Radiation dose at Tohoku University 214.824 3477.46
Odanosawa Higashidoori Village 210.287 2301.16 3521.23
Kagawa 205.829 2374.68 3515.76
Oippe Higashidoori Village 205.182 1981.99 3521.23
Oita 200.921 2621.4 3515.76
Touhoku Town office Touhoku Town 200.811 7691.11 3521.23
Kuchogoshi Ikata Town 198.646 1782.6 3523.97
Minatoura Ikata Town 186.776 1602.26 3523.97
Radiation dose in Koyadori, Ojika 184.905 3471.98
Toyama 184.580 4533.48 3515.76
Fukushima [9] (distance from Fukushima I: 45 km) 184.232 2186.23 3510.29
Radiation dose in Tukahama, Ojika 183.417 3471.98
Chiba 182.407 1356.96 3515.76
Nara 182.387 2467.2 3515.76
Okayama 181.976 3207.36 3515.76
Yamagata 181.598 2528.88 3515.76
Ehime 180.745 2282.16 3515.76
Ishikawa 180.445 3932.1 3515.76
Niigata 177.483 4718.52 3515.76
Hiroshima 176.816 2127.96 3515.76
Mie 174.867 2433.28 3515.76
Fukui 170.045 2991.48 3515.76
Radiation dose in Terama, Ojika 168.036 3471.98
Yamanashi 164.561 1973.76 3515.76
Nagano 162.242 3003.82 3515.76
Saga 161.421 2652.24 3515.76
Tottori 161.392 2436.36 3515.76
Radiation dose in Enoshima, Ojika 160.091 3471.98
Osaka 159.103 1881.24 3515.76
Ibaraki-city Environment 157.249 3430.94
Aichi 149.345 2282.16 3515.76
Toyonoura Ikata Town 149.214 1839.26 3523.97
Shizuoka 148.639 2359.26 3515.76
Kyoto 144.522 2683.08 3515.76
Kagoshima 144.449 2908.21 3515.76
Tokushima 143.627 2066.28 3515.76
Gunma 143.572 1387.8 3515.76
Hyogo 139.710 2343.84 3515.76
Fukuoka 136.511 2436.36 3515.76
Wakayama 133.857 1727.04 3515.76
Radiation at Tamaki-cho Mie Japan 133.138 3430.94
Akita 132.832 2652.24 3515.76
Shiga 124.919 1881.24 3515.76
Nagasaki 109.459 2127.96 3515.76
Hokkaido 109.189 3238.2 3515.76
Kumamoto 103.568 2066.28 3515.76
Aomori 101.819 3145.68 3515.76
Miyazaki 100.354 2047.78 3515.76
Kochi 95.931 2343.84 3515.76
Fukushima [35] (distance from Fukushima I: 35 km) 91.917 2177.71 3496.61
Iwate 90.324 2590.56 3515.76
Environment Feeds from Ohta 83.623 3430.94
Okinawa 82.305 1773.3 3515.76
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