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Accumulated absorbed dose rate - T=13.03.2011 - 29.01.2015(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 3794.83
Fukushima I MP8 570942.000 3794.83
Fukushima I MP6 240668.000 3794.83
Yamada Futaba Town 176983.000 2812.61 3351.6
Fukushima I MP2 140420.000 3794.83
Fukushima I MP5 111325.000 3794.83
Fukushima [32] (distance from Fukushima I: 30 km) 101500.000 2407.75 3865.97
Fukushima I MP3 93730.602 3794.83
Fukushima I MP4 86821.500 3794.83
Fukushima [33] (distance from Fukushima I: 30 km) 77197.703 2407.75 3865.97
Fukushima [79] (distance from Fukushima I: 40 km) 54008.602 2356.63 3783.89
Fukushima [31] (distance from Fukushima I: 30 km) 40677.398 2407.75 3865.97
Ono Okuma Town 38610.500 2596.99 3351.6
Shinzan Futaba Town 38332.801 2356.91 3351.6
Fukushima I MP1 31496.801 3794.83
Yonomori Tomioka Town 29815.900 2685.19 3351.6
Fukushima [46] (distance from Fukushima I: 20 km) 28842.500 2407.75 3865.97
Tomioka Tomioka Town 25324.500 2890.99 3351.6
Fukushima [62] (distance from Fukushima I: 40 km) 16464.100 2407.75 3865.97
Fukushima [61] (distance from Fukushima I: 40 km) 13102.800 2407.75 3865.97
Shimo-Kooriyama Tomioka Town 13057.000 2871.41 3351.6
Fukushima [21] (distance from Fukushima I: 30 km) 12103.800 2407.75 3865.97
Fukushima [3] (distance from Fukushima I: 45 km) 11985.000 2407.75 3865.97
Kami-kooriyama Tomioka Town 11803.900 2254.01 3351.6
Fukushima II MP3 11060.600 3794.83
Fukushima II MP1 10903.000 3794.83
Kooriyama Futaba Town 10352.900 2626.39 3351.6
Fukushima II MP4 9696.330 3794.83
Fukushima [34] (distance from Fukushima I: 30 km) 9540.450 2404.34 3860.5
Fukushima II MP5 9382.150 3794.83
Fukushima [2] (distance from Fukushima I: 55 km) 8841.760 2407.75 3865.97
Matsudate Naraha Town 8410.890 3067.39 3351.6
Shigeoka Naraha Town 8115.970 3390.79 3351.6
Fukushima II MP2 7875.320 3794.83
Namie Namie Town 7321.210 2474.51 3351.6
Radiation dose at Shirasawa branch office, Motomiya 7287.920 3811.25
Fukushima II MP6 7062.690 3794.83
Fukushima II MP7 6511.580 3792.1
Fukushima [1] (distance from Fukushima I: 60 km) 5615.310 2407.75 3865.97
Fukushima [11] (distance from Fukushima I: 40 km) 5491.310 2407.75 3865.97
Fukushima [63] (distance from Fukushima I: 45 km) 5448.820 2407.75 3865.97
Fukushima [45] (distance from Fukushima I: 20 km) 3981.200 2407.75 3865.97
Fukushima [42] (distance from Fukushima I: 30 km) 3850.600 2407.75 3865.97
Fukushima [10] (distance from Fukushima I: 40 km) 3734.160 2407.75 3865.97
Fukushima [78] (distance from Fukushima I: 45 km) 3716.820 2402.64 3857.76
Futatsunuma Hirono Town 3520.340 2940 3351.6
Fukushima [4] (distance from Fukushima I: 50 km) 3386.310 2407.75 3865.97
Fukushima [7] (distance from Fukushima I: 45 km) 3313.930 2407.75 3865.97
Radiation dose at Koriyama joint government building, Koriyama 3232.890 3808.51
Fukushima [15] (distance from Fukushima I: 35 km) 3178.670 2407.75 3865.97
Kiyohashi Namie Town 3162.000 2170.69 3351.6
Fukushima [71] (distance from Fukushima I: 25 km) 3161.650 2402.64 3857.76
Radiation dose at Agricultural center, Koriyama 3128.960 3808.51
Fukushima [41] (distance from Fukushima I: 20 km) 3111.490 2407.75 3865.97
Radiation dose at Koriyama city office, Koriyama 2803.520 3808.51
Fukushima [44] (distance from Fukushima I: 30 km) 2535.550 2407.75 3865.97
Fukushima [72] (distance from Fukushima I: 30 km) 2344.620 2402.64 3857.76
Fukushima [43] (distance from Fukushima I: 20 km) 2244.110 2407.75 3865.97
Yamadaoka Naraha Town 2205.340 2606.81 3351.6
Radiation dose at Iwane Fureai Plaza, Motomiya 2169.060 3811.25
Fukushima [22] (distance from Fukushima I: 35 km) 2020.650 2407.75 3865.97
Kuji Hitachi City 1990.890 5985.41 3876.91
Hitachinaka Hitachinaka City 1951.950 2628.08 3874.18
Fukushima [76] (distance from Fukushima I: 25 km) 1945.520 2402.64 3857.76
Fukushima [80] (distance from Fukushima I: 25 km) 1876.860 2402.64 3857.76
Momiyama Hokota City 1837.540 2998.38 3876.91
Fukushima [77] (distance from Fukushima I: 25 km) 1802.490 2402.64 3857.76
Horiguchi Hitachinaka City 1779.410 2620.46 3879.65
Onuma Hitachi City 1776.950 2231.63 3874.18
Fukushima [6] (distance from Fukushima I: 45 km) 1741.180 2407.75 3865.97
Tsukuriya Hokota City 1736.890 2522.27 3876.91
Radiation dose at Big palette Fukushima, Koriyama 1668.540 3808.51
Nemoto Hitachioomiya City 1633.190 2809.36 3874.18
Fukushima [13] (distance from Fukushima I: 40 km) 1624.150 2407.75 3865.97
Fukushima [23] (distance from Fukushima I: 35 km) 1551.750 2407.75 3865.97
Radiation dose at Tsukidatemachi kamitedo, Date 1545.300 3816.72
Fukushima [14] (distance from Fukushima I: 35 km) 1543.460 2407.75 3865.97
Radiation dose at JAEA Oarai (P12) 1512.140 3833.14
Radiation dose at Ose administration center, Koriyama 1494.270 3808.51
Araji Hokota City 1437.760 2527.92 3876.91
Ishigami Tokai Village 1431.690 2301.22 3876.91
Mawatari Hitachinaka City 1422.870 2658.3 3876.91
Radiation dose at JAEA Oarai (P11) 1399.370 3833.14
Onuki Oarai Town 1387.990 2760.33 3876.91
Sawa Hitachinaka City 1353.770 2084.34 3874.18
Toyooka Tokai Village 1321.760 2533.6 3876.91
Ajigaura Hitachinaka City 1313.890 2492.15 3874.18
Fukushima [5] (distance from Fukushima I: 45 km) 1282.090 2407.75 3865.97
Geiger Counter Feeds from Asao Kawasaki 1266.620 3786.62
Radiation dose at Tamokami elementary school, Koriyama 1256.140 3808.51
Isohama Oarai Town 1250.540 2405.49 3871.44
Ebisawa Ibaraki Town 1222.240 6531.73 3874.18
Muramatsu Tokai Village 1203.520 2556.28 3876.91
Kamitoda Hokota City 1184.740 2097.17 3876.91
Yanagisawa Hitachinaka City 1166.970 2135.32 3874.18
Tokushuku Hokota City 1159.730 1893.12 3876.91
Tasaki Hokota City 1153.300 2232.74 3846.82
Fukushima [20] (distance from Fukushima I: 45 km) 1145.390 2407.75 3865.97
Kadobe Naka City 1086.580 5086.28 3874.18
Radiation dose at Date city office, Date 1076.050 3811.25
Oshinobe Tokai Village 1041.340 2386.24 3876.91
Oba Mito City 1037.670 7838.84 3876.91
Godai Naka City 1031.270 2068.81 3876.91
Ishikawa Mito City 1030.810 2438.97 3879.65
Isobe Hitachiota City 1013.130 11766.8 3876.91
Yatabe Ibaraki Town 996.127 2046.16 3876.91
Radiation dose at Motomiya city office, Motomiya 992.703 3811.25
Fukushima [73] (distance from Fukushima I: 35 km) 981.984 2402.64 3857.76
Fukushima [75] (distance from Fukushima I: 45 km) 960.529 2402.64 3857.76
Yokobori Naka City 930.280 2397.56 3876.91
Sugaya Naka City 926.186 3664.12 3879.65
Kounosu Naka City 926.087 1870.44 3876.91
Funaishikawa Tokai Village 900.399 2482.58 3876.91
Nukada Naka City 899.900 2241.36 3871.44
Uridura Naka City 890.113 2139.48 3871.44
Shiraki Tsuruga City 881.330 4543.27 3879.65
Motokomezaki Naka City 880.851 1989.48 3844.08
Shiraki pass Tsuruga City 850.284 4758.8 3879.65
Radiation dose in Yamamoto 846.633 3833.14
Yoshizawa Mito City 837.646 2165.19 3876.91
Radiation dose at JAEA Oarai (P7) 831.135 3833.14
Mayumi Hitachiota City 828.119 2148.18 3876.91
Urasoko Tsuruga City 826.465 3771.87 3879.65
Nemoto Hitachioomiya City 825.588 2418.54 3874.18
Takenami Mihama Town 804.283 3959.04 3879.65
Radiation dose at JAEA Oarai (P15) 780.207 3833.14
Tateishi Tsuruga City 780.092 3136.63 3879.65
Radiation dose at JAEA Oarai (P14) 770.174 3833.14
Radiation dose at JAEA Oarai (P13) 769.612 3833.14
Ukishima Kawasaki Ward 735.475 7401.96 3879.65
Kume Hitachiota City 713.958 2102.82 3876.91
Radiation dose at JAEA Oarai (P2) 712.011 3833.14
Fukushima [74] (distance from Fukushima I: 35 km) 706.552 2402.64 3857.76
Nyuu Mihama Town 674.787 3607.39 3879.65
Fukushima [52] (distance from Fukushima I: 40 km) 672.743 2407.75 3865.97
Radiation dose in Iwanuma 670.242 3833.14
Fukushima [51] (distance from Fukushima I: 40 km) 665.376 2407.75 3865.97
Tsuruga Tsuruga City 655.360 3181.99 3879.65
Shiohama Kawasaki Ward 653.536 2541.07 3879.65
Radiation dose in Kakuda 649.863 3833.14
Sakajiri Mihama Town 649.252 4208.64 3879.65
North point of Kinki University Atomic Energy Research Instirute Station 639.566 2643.16 3879.65
Radiation dose in Onagawa (MP-2) 632.968 3830.4
Kumatori town Nishi primary school Station 631.491 3159.29 3879.65
Oshima Kawasaki Ward 630.402 2421.96 3879.65
Izumisano municipal Oike athletic field Station 629.920 3562.03 3879.65
Atom-kyoudou nursery school Station 625.566 3420.22 3879.65
South point of Kinki University Atomic Energy Research Instirute Station 625.202 3113.93 3879.65
Nakamachi Omaezaki City 623.494 4010.09 3879.65
Uraga Yokosuka City 622.492 1900.11 3879.65
Goritoge Shika Town 622.143 4259.68 3879.65
Kumatori town Minami primary school Station 606.134 3624.41 3879.65
Radiation dose at JAEA Oarai (P1) 603.643 3835.87
Yamanotedai-No.1 Park Station 599.140 3380.5 3879.65
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 595.502 3852.29
Noumi Shika Town 594.021 4214.28 3879.65
Radiation dose in Watari 591.851 3833.14
Hairando Yokosuka City 588.667 2382.24 3879.65
Fukushima [12] (distance from Fukushima I: 40 km) 588.291 2407.75 3865.97
Ningyotoge Kagamino Town 574.857 3380.5 3879.65
Ten-no Kagamino Town 569.960 4049.81 3879.65
Funagura Yokosuka City 563.909 2246.11 3879.65
Chidori Kawasaki Ward 560.211 2172.36 3879.65
Radiation dose at JAEA Oarai (P16) 556.365 3833.14
Shika Shika Town 551.376 4061.14 3879.65
Higashiosaka municipal Kamikosaka primary scool Station 550.277 2637.48 3879.65
Sahara Yokosuka City 547.404 2104.3 3879.65
Kazanashi Shika Town 545.377 3811.58 3879.65
Akasumi Shika Town 544.970 3488.28 3879.65
Kurahashi Maizuru City 540.820 3176.31 3879.65
Obama Obama City 540.809 2841.67 3879.65
Sakuragaike community hall Omaezaki City 540.772 4112.19 3879.65
Shirowa primary school Omaezaki City 535.692 4027.11 3879.65
Radiation dose at JAEA Oarai (P5) 529.759 3833.14
Uenohara Omaezaki City 529.333 4140.57 3879.65
Kumano Shika Town 529.019 3953.4 3879.65
Izumisano municipal Hineno filtration plant Station 527.471 3408.88 3879.65
Nishi-hamasada Matsue City 525.089 3767.23 3863.23
Kouno Minami-Echizen Town 525.028 2858.69 3879.65
Kurihama Yokosuka City 523.708 2274.46 3879.65
Osaka prefectural Kumatori off-site-center Station 522.808 3142.28 3879.65
Ogasa branch Kikugawa City 522.039 4182.47 3865.97
Izumisano municipal Hineno primary scool Station 518.181 2728.24 3879.65
Shirasuna Omaezaki City 499.479 4055.49 3879.65
Jitougata primary school Makinohara City 498.059 3890.98 3879.65
Kataku Matsue City 497.007 3023.16 3879.65
Nishihemi Yokosuka City 496.917 1815.03 3879.65
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 496.721 3852.29
Satsuma-sendai monitoring center Satsuma-sendai City 495.302 2977.8 3879.65
Otomi Takahama Town 494.821 3335.14 3879.65
Otsu Nanao City 493.895 3346.47 3879.65
The Observation point for comparison Tatsunokuchi 493.454 2756.59 3879.65
Hitsuhama Ohi Town 492.630 3102.6 3879.65
Kijiyama Misasa Town 489.284 3147.96 3879.65
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 487.055 3852.29
Hiraba Omaezaki City 485.878 4055.49 3879.65
Tayu Matsue City 484.956 3153.64 3879.65
Hamaokakita primary school Omaezaki City 484.537 4154.22 3865.97
Oitomi Ayabe City 474.670 3998.76 3879.65
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 472.017 3852.29
Kashiwazaki-shigai Kashiwazaki City 470.822 3181.99 3879.65
Mitsu Matsue City 466.897 3017.52 3879.65
Tonomachi Kawasaki Ward 463.967 3822.92 3879.65
Daitou branch Kakegawa City 463.829 4092.06 3865.97
Fukura Shika Town 462.493 3805.9 3879.65
Nagasawa Yokosuka City 462.365 2223.41 3879.65
The athletic field Station of Kinki University 461.661 2512.68 3879.65
Koura Matsue City 461.049 3601.71 3879.65
Sakurasan Ward Omaezaki City 459.434 3925.01 3879.65
Tsuchikawa Nanao City 458.915 3703.8 3879.65
Kumatori Town office Station 457.917 2592.12 3879.65
Shinkango Omaezaki City 449.013 4543.27 3879.65
Ogurui Takahama Town 448.279 2972.12 3879.65
Kusabue Omaezaki City 444.162 4282.35 3879.65
Omaezaki City monitoring center 443.946 4202.95 3879.65
Akawase Kagamino Town 442.246 2592.12 3879.65
Ibaraki 442.139 1901.76 3871.44
Hinode Town Yokosuka City 438.324 1497.41 3879.65
Nishiyama Kashiwazaki City 437.251 4503.56 3879.65
Kariwa Kariwa Village 436.307 3397.52 3879.65
Osaka prefectural Hineno high scool Station 435.745 3028.85 3879.65
Miyagawa Kashiwazaki City 435.245 3352.15 3879.65
Radiation dose in Natori 434.640 3833.14
Kami-koubu Matsue City 433.868 3295.42 3879.65
Shimo-Takamachi Kariwa Village 433.192 3698.16 3879.65
Osaka prefectural Sano supporting school Station 432.398 3301.1 3879.65
Arahama Kashiwazaki City 428.874 3454.25 3879.65
Doai Kashiwazaki City 425.681 3250.06 3879.65
Owashi Matsue City 424.452 3221.71 3879.65
Okayasu Maizuru City 422.568 3794.57 3879.65
Katsuyama Kariwa Village 421.280 3454.25 3879.65
Kita-koubu Matsue City 420.683 3533.64 3879.65
Kichisaka Maizuru City 413.065 4611.34 3879.65
Nagai Ohi Town 410.699 3350.73 3871.44
Shiokumi Maizuru City 407.938 5740.08 3879.65
Miyadome Ohi Town 407.831 2779.29 3879.65
Kariwa Kariwa Village 407.617 3579.04 3879.65
Ueno Satsuma-sendai City 394.248 2597.76 3879.65
Power Station-South 389.191 3783.24 3879.65
Radiation dose at JAEA Oarai (P6) 386.963 3833.14
Power Station- 385.546 3692.47 3879.65
Takae Satsuma-sendai City 379.551 2631.8 3879.65
Hokawaduura Genkai Town 378.015 4007.27 3879.65
Kou Itimatsu Suetsugu 377.929 2892.72 3879.65
Minato Satsuma-sendai City 377.656 2410.59 3879.65
Iwanai Iwanai Town 376.336 3927.92 3876.91
Hattari Kyowa Town 373.047 3820.22 3876.91
Chatsu Tomari Village 371.011 3650.18 3876.91
Oyama Maizuru City 358.223 3323.8 3879.65
Kodaira Satsuma-sendai City 355.545 2438.97 3879.65
Kayanuma Tomari Village 354.809 3247.76 3876.91
Anojiri Obama City 353.215 2722.56 3879.65
Kushi Genkai Town 349.738 5530.2 3879.65
Yamaguchi 348.715 4346.88 3871.44
Sadahongou Matsue City 348.228 3386.18 3879.65
Sakibe Karatsu City 347.801 5240.93 3879.65
Hirao Genkai Town 343.814 5524.52 3879.65
The Meteorological Obsevatory of kyowa Town 343.275 3621.85 3876.91
Minami-Horoni Kyowa Town 335.180 3395.12 3876.91
Kounoura Takahama Town 330.353 2870.02 3879.65
Kyoudomarisaki Karatsu City 328.622 5615.28 3879.65
Horikappu Jinja Tomari Village 328.230 3514.15 3876.91
Hukada-kita Matsue City 327.031 2784.94 3879.65
Radiation dose in KEK, Tsukuba 326.240 3852.29
Herokaruusu Tomari Village 324.242 3644.54 3876.91
Yorita Satsuma-sendai City 323.218 2853 3879.65
Kamoenai Kamoenai Village 322.032 3077.72 3876.91
Radiation dose in Onagawa (MP-6) 316.267 3830.4
Imamura Genkai Town 314.749 47588 3879.65
Yamanaka Takahama Town 314.185 3703.8 3879.65
Sendai (Miyagi) 312.585 1742.15 3871.44
Radiation dose in Onagawa (MP-1) 300.147 3830.4
Gumisaki Satsuma-sendai City 295.693 2302.84 3879.65
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 286.142 3852.29
Aomori Aomori City 285.372 2340.87 3876.91
Misawa City hall Misawa City 283.728 4540.07 3876.91
Kashu Ikata Town 277.173 2376.56 3879.65
Noheji Town Office Noheji Town 272.004 2006.47 3876.91
Takasimamati 271.103 2529.7 3879.65
Radiation dose in Onagawa (MP-3) 270.563 3830.4
Kucho Ikata Town 269.545 2098.65 3879.65
Radiation dose in Marumori 269.436 3833.14
Kawanagata Ikata Town 266.821 2047.6 3879.65
Tochigi 260.733 2275.32 3871.44
Chikagawa Mutu City 256.719 2612.94 3876.91
Yokohama Town Office Yokohama Town 254.846 3202.43 3876.91
Tokyo 251.877 2682.84 3871.44
Hiranuma Rokkasho Village 251.186 2102.82 3876.91
Taisei Ikata Town 246.293 1537.12 3879.65
Chitose-daira Rokkasho Village 245.868 2267.21 3876.91
Gifu 243.951 3735.6 3871.44
Fukkoshi Yokohama Town 243.102 2199.2 3876.91
Shimane 240.651 3735.6 3871.44
Sunagomata Higashidoori Village 238.012 3179.75 3876.91
Obuchi Rokkasho Village 237.506 2527.92 3876.91
Tomari Rokkasho Village 230.636 3536.83 3876.91
kanagawa 226.339 2343.24 3871.44
Saitama 219.770 2037.6 3871.44
Ikatagoshi Ikata Town 217.515 1934.14 3879.65
Touhoku Branch office Touhoku Town 215.416 1830.75 3876.91
Radiation dose at Tohoku University 214.824 3833.14
Odanosawa Higashidoori Village 210.287 2533.6 3876.91
Kagawa 205.829 2614.92 3871.44
Oippe Higashidoori Village 205.182 2182.19 3876.91
Oita 200.921 2886.6 3871.44
Touhoku Town office Touhoku Town 200.811 8467.99 3876.91
Kuchogoshi Ikata Town 198.646 1962.52 3879.65
Minatoura Ikata Town 186.776 1763.98 3879.65
Radiation dose in Koyadori, Ojika 184.905 3827.66
Toyama 184.580 4992.12 3871.44
Fukushima [9] (distance from Fukushima I: 45 km) 184.232 2407.75 3865.97
Radiation dose in Tukahama, Ojika 183.417 3827.66
Chiba 182.407 1494.24 3871.44
Nara 182.387 2716.8 3871.44
Okayama 181.976 3531.84 3871.44
Yamagata 181.598 2784.72 3871.44
Ehime 180.745 2513.04 3871.44
Ishikawa 180.445 4329.9 3871.44
Niigata 177.483 5195.88 3871.44
Hiroshima 176.816 2343.24 3871.44
Mie 174.867 2679.44 3871.44
Fukui 170.045 3294.12 3871.44
Radiation dose in Terama, Ojika 168.036 3827.66
Yamanashi 164.561 2173.44 3871.44
Nagano 162.242 3307.7 3871.44
Saga 161.421 2920.56 3871.44
Tottori 161.392 2682.84 3871.44
Radiation dose in Enoshima, Ojika 160.091 3827.66
Osaka 159.103 2071.56 3871.44
Ibaraki-city Environment 157.249 3786.62
Aichi 149.345 2513.04 3871.44
Toyonoura Ikata Town 149.214 2024.9 3879.65
Shizuoka 148.639 2597.94 3871.44
Kyoto 144.522 2954.52 3871.44
Kagoshima 144.449 3202.43 3871.44
Tokushima 143.627 2275.32 3871.44
Gunma 143.572 1528.2 3871.44
Hyogo 139.710 2580.96 3871.44
Fukuoka 136.511 2682.84 3871.44
Wakayama 133.857 1901.76 3871.44
Radiation at Tamaki-cho Mie Japan 133.138 3786.62
Akita 132.832 2920.56 3871.44
Shiga 124.919 2071.56 3871.44
Nagasaki 109.459 2343.24 3871.44
Hokkaido 109.189 3565.8 3871.44
Kumamoto 103.568 2275.32 3871.44
Aomori 101.819 3463.92 3871.44
Miyazaki 100.354 2254.94 3871.44
Kochi 95.931 2580.96 3871.44
Fukushima [35] (distance from Fukushima I: 35 km) 91.917 2399.23 3852.29
Iwate 90.324 2852.64 3871.44
Environment Feeds from Ohta 83.623 3786.62
Okinawa 82.305 1952.7 3871.44
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