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Accumulated absorbed dose rate - T=13.03.2011 - 28.07.2017(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 6287.33
Fukushima I MP8 570942.000 6287.33
Fukushima I MP6 240668.000 6287.33
Yamada Futaba Town 176983.000 4904.27 5844.1
Fukushima I MP2 140420.000 6287.33
Fukushima I MP5 111325.000 6287.33
Fukushima [32] (distance from Fukushima I: 30 km) 101500.000 3960.1 6358.46
Fukushima I MP3 93730.602 6287.33
Fukushima I MP4 86821.500 6287.33
Fukushima [33] (distance from Fukushima I: 30 km) 77197.703 3960.1 6358.46
Fukushima [79] (distance from Fukushima I: 40 km) 54008.602 3908.98 6276.38
Fukushima [31] (distance from Fukushima I: 30 km) 40677.398 3960.1 6358.46
Ono Okuma Town 38610.500 4528.3 5844.1
Shinzan Futaba Town 38332.801 4109.68 5844.1
Fukushima I MP1 31496.801 6287.33
Yonomori Tomioka Town 29815.900 4682.1 5844.1
Fukushima [46] (distance from Fukushima I: 20 km) 28842.500 3960.1 6358.46
Tomioka Tomioka Town 25324.500 5040.94 5844.1
Fukushima [62] (distance from Fukushima I: 40 km) 16464.100 3960.1 6358.46
Fukushima [61] (distance from Fukushima I: 40 km) 13102.800 3960.1 6358.46
Shimo-Kooriyama Tomioka Town 13057.000 5006.8 5844.1
Fukushima [21] (distance from Fukushima I: 30 km) 12103.800 3960.1 6358.46
Fukushima [3] (distance from Fukushima I: 45 km) 11985.000 3960.1 6358.46
Kami-kooriyama Tomioka Town 11803.900 3930.26 5844.1
Fukushima II MP3 11060.600 6287.33
Fukushima II MP1 10903.000 6287.33
Kooriyama Futaba Town 10352.900 4579.57 5844.1
Fukushima II MP4 9696.330 6287.33
Fukushima [34] (distance from Fukushima I: 30 km) 9540.450 3956.69 6352.99
Fukushima II MP5 9382.150 6287.33
Fukushima [2] (distance from Fukushima I: 55 km) 8841.760 3960.1 6358.46
Matsudate Naraha Town 8410.890 5348.53 5844.1
Shigeoka Naraha Town 8115.970 5912.43 5844.1
Fukushima II MP2 7875.320 6287.33
Namie Namie Town 7321.210 4314.74 5844.1
Radiation dose at Shirasawa branch office, Motomiya 7287.920 6303.74
Fukushima II MP6 7062.690 6287.33
Fukushima II MP7 6511.580 6284.59
Fukushima [1] (distance from Fukushima I: 60 km) 5615.310 3960.1 6358.46
Fukushima [11] (distance from Fukushima I: 40 km) 5491.310 3960.1 6358.46
Fukushima [63] (distance from Fukushima I: 45 km) 5448.820 3960.1 6358.46
Fukushima [45] (distance from Fukushima I: 20 km) 3981.200 3960.1 6358.46
Fukushima [42] (distance from Fukushima I: 30 km) 3850.600 3960.1 6358.46
Fukushima [10] (distance from Fukushima I: 40 km) 3734.160 3960.1 6358.46
Fukushima [78] (distance from Fukushima I: 45 km) 3716.820 3954.98 6350.26
Futatsunuma Hirono Town 3520.340 5126.4 5844.1
Fukushima [4] (distance from Fukushima I: 50 km) 3386.310 3960.1 6358.46
Fukushima [7] (distance from Fukushima I: 45 km) 3313.930 3960.1 6358.46
Radiation dose at Koriyama joint government building, Koriyama 3232.890 6301.01
Fukushima [15] (distance from Fukushima I: 35 km) 3178.670 3960.1 6358.46
Kiyohashi Namie Town 3162.000 3784.98 5844.1
Fukushima [71] (distance from Fukushima I: 25 km) 3161.650 3954.98 6350.26
Radiation dose at Agricultural center, Koriyama 3128.960 6301.01
Fukushima [41] (distance from Fukushima I: 20 km) 3111.490 3960.1 6358.46
Radiation dose at Koriyama city office, Koriyama 2803.520 6301.01
Fukushima [44] (distance from Fukushima I: 30 km) 2535.550 3960.1 6358.46
Fukushima [72] (distance from Fukushima I: 30 km) 2344.620 3954.98 6350.26
Fukushima [43] (distance from Fukushima I: 20 km) 2244.110 3960.1 6358.46
Yamadaoka Naraha Town 2205.340 4545.42 5844.1
Radiation dose at Iwane Fureai Plaza, Motomiya 2169.060 6303.74
Fukushima [22] (distance from Fukushima I: 35 km) 2020.650 3960.1 6358.46
Kuji Hitachi City 1990.890 9833.47 6369.41
Hitachinaka Hitachinaka City 1951.950 4318.89 6366.67
Fukushima [76] (distance from Fukushima I: 25 km) 1945.520 3954.98 6350.26
Fukushima [80] (distance from Fukushima I: 25 km) 1876.860 3954.98 6350.26
Momiyama Hokota City 1837.540 4926.07 6369.41
Fukushima [77] (distance from Fukushima I: 25 km) 1802.490 3954.98 6350.26
Horiguchi Hitachinaka City 1779.410 4303.99 6372.14
Onuma Hitachi City 1776.950 3667.37 6366.67
Fukushima [6] (distance from Fukushima I: 45 km) 1741.180 3960.1 6358.46
Tsukuriya Hokota City 1736.890 4143.86 6369.41
Radiation dose at Big palette Fukushima, Koriyama 1668.540 6301.01
Nemoto Hitachioomiya City 1633.190 4616.79 6366.67
Fukushima [13] (distance from Fukushima I: 40 km) 1624.150 3960.1 6358.46
Fukushima [23] (distance from Fukushima I: 35 km) 1551.750 3960.1 6358.46
Radiation dose at Tsukidatemachi kamitedo, Date 1545.300 6309.22
Fukushima [14] (distance from Fukushima I: 35 km) 1543.460 3960.1 6358.46
Radiation dose at JAEA Oarai (P12) 1512.140 6325.63
Radiation dose at Ose administration center, Koriyama 1494.270 6301.01
Araji Hokota City 1437.760 4153.13 6369.41
Ishigami Tokai Village 1431.690 3780.69 6369.41
Mawatari Hitachinaka City 1422.870 4367.35 6369.41
Radiation dose at JAEA Oarai (P11) 1399.370 6325.63
Onuki Oarai Town 1387.990 4534.96 6369.41
Sawa Hitachinaka City 1353.770 3425.33 6366.67
Toyooka Tokai Village 1321.760 4162.46 6369.41
Ajigaura Hitachinaka City 1313.890 4095.5 6366.67
Fukushima [5] (distance from Fukushima I: 45 km) 1282.090 3960.1 6358.46
Geiger Counter Feeds from Asao Kawasaki 1266.620 6279.12
Radiation dose at Tamokami elementary school, Koriyama 1256.140 6301.01
Isohama Oarai Town 1250.540 3954.18 6363.94
Ebisawa Ibaraki Town 1222.240 10734 6366.67
Muramatsu Tokai Village 1203.520 4199.73 6369.41
Kamitoda Hokota City 1184.740 3445.46 6369.41
Yanagisawa Hitachinaka City 1166.970 3509.1 6366.67
Tokushuku Hokota City 1159.730 3110.23 6369.41
Tasaki Hokota City 1153.300 3679.41 6339.31
Fukushima [20] (distance from Fukushima I: 45 km) 1145.390 3960.1 6358.46
Kadobe Naka City 1086.580 8358.6 6366.67
Radiation dose at Date city office, Date 1076.050 6303.74
Oshinobe Tokai Village 1041.340 3920.37 6369.41
Oba Mito City 1037.670 12878.5 6369.41
Godai Naka City 1031.270 3398.86 6369.41
Ishikawa Mito City 1030.810 4005.9 6372.14
Isobe Hitachiota City 1013.130 19331.7 6369.41
Yatabe Ibaraki Town 996.127 3361.65 6369.41
Radiation dose at Motomiya city office, Motomiya 992.703 6303.74
Fukushima [73] (distance from Fukushima I: 35 km) 981.984 3954.98 6350.26
Fukushima [75] (distance from Fukushima I: 45 km) 960.529 3954.98 6350.26
Yokobori Naka City 930.280 3938.98 6369.41
Sugaya Naka City 926.186 6018.15 6372.14
Kounosu Naka City 926.087 3072.96 6369.41
Funaishikawa Tokai Village 900.399 4078.66 6369.41
Nukada Naka City 899.900 3684.38 6363.94
Uridura Naka City 890.113 3516.91 6363.94
Shiraki Tsuruga City 881.330 7462.12 6372.14
Motokomezaki Naka City 880.851 3279.46 6336.58
Shiraki pass Tsuruga City 850.284 7816.11 6372.14
Radiation dose in Yamamoto 846.633 6325.63
Yoshizawa Mito City 837.646 3557.2 6369.41
Radiation dose at JAEA Oarai (P7) 831.135 6325.63
Mayumi Hitachiota City 828.119 3529.27 6369.41
Urasoko Tsuruga City 826.465 6195.12 6372.14
Nemoto Hitachioomiya City 825.588 3974.53 6366.67
Takenami Mihama Town 804.283 6502.55 6372.14
Radiation dose at JAEA Oarai (P15) 780.207 6325.63
Tateishi Tsuruga City 780.092 5151.77 6372.14
Radiation dose at JAEA Oarai (P14) 770.174 6325.63
Radiation dose at JAEA Oarai (P13) 769.612 6325.63
Ukishima Kawasaki Ward 735.475 12157.4 6372.14
Kume Hitachiota City 713.958 3454.73 6369.41
Radiation dose at JAEA Oarai (P2) 712.011 6325.63
Fukushima [74] (distance from Fukushima I: 35 km) 706.552 3954.98 6350.26
Nyuu Mihama Town 674.787 5924.98 6372.14
Fukushima [52] (distance from Fukushima I: 40 km) 672.743 3960.1 6358.46
Radiation dose in Iwanuma 670.242 6325.63
Fukushima [51] (distance from Fukushima I: 40 km) 665.376 3960.1 6358.46
Tsuruga Tsuruga City 655.360 5226.28 6372.14
Shiohama Kawasaki Ward 653.536 4173.59 6372.14
Radiation dose in Kakuda 649.863 6325.63
Sakajiri Mihama Town 649.252 6912.49 6372.14
North point of Kinki University Atomic Energy Research Instirute Station 639.566 4341.27 6372.14
Radiation dose in Onagawa (MP-2) 632.968 6322.9
Kumatori town Nishi primary school Station 631.491 5188.99 6372.14
Oshima Kawasaki Ward 630.402 3977.95 6372.14
Izumisano municipal Oike athletic field Station 629.920 5850.47 6372.14
Atom-kyoudou nursery school Station 625.566 5617.55 6372.14
South point of Kinki University Atomic Energy Research Instirute Station 625.202 5114.48 6372.14
Nakamachi Omaezaki City 623.494 6586.39 6372.14
Uraga Yokosuka City 622.492 3120.84 6372.14
Goritoge Shika Town 622.143 6996.33 6372.14
Kumatori town Minami primary school Station 606.134 5952.92 6372.14
Radiation dose at JAEA Oarai (P1) 603.643 6328.37
Yamanotedai-No.1 Park Station 599.140 5552.32 6372.14
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 595.502 6344.78
Noumi Shika Town 594.021 6921.77 6372.14
Radiation dose in Watari 591.851 6325.63
Hairando Yokosuka City 588.667 3912.72 6372.14
Fukushima [12] (distance from Fukushima I: 40 km) 588.291 3960.1 6358.46
Ningyotoge Kagamino Town 574.857 5552.32 6372.14
Ten-no Kagamino Town 569.960 6651.62 6372.14
Funagura Yokosuka City 563.909 3689.14 6372.14
Chidori Kawasaki Ward 560.211 3568.01 6372.14
Radiation dose at JAEA Oarai (P16) 556.365 6325.63
Shika Shika Town 551.376 6670.24 6372.14
Higashiosaka municipal Kamikosaka primary scool Station 550.277 4331.94 6372.14
Sahara Yokosuka City 547.404 3456.22 6372.14
Kazanashi Shika Town 545.377 6260.35 6372.14
Akasumi Shika Town 544.970 5729.34 6372.14
Kurahashi Maizuru City 540.820 5216.94 6372.14
Obama Obama City 540.809 4667.32 6372.14
Sakuragaike community hall Omaezaki City 540.772 6754.08 6372.14
Shirowa primary school Omaezaki City 535.692 6614.34 6372.14
Radiation dose at JAEA Oarai (P5) 529.759 6325.63
Uenohara Omaezaki City 529.333 6800.7 6372.14
Kumano Shika Town 529.019 6493.27 6372.14
Izumisano municipal Hineno filtration plant Station 527.471 5598.93 6372.14
Nishi-hamasada Matsue City 525.089 6197.78 6355.73
Kouno Minami-Echizen Town 525.028 4695.26 6372.14
Kurihama Yokosuka City 523.708 3735.7 6372.14
Osaka prefectural Kumatori off-site-center Station 522.808 5161.05 6372.14
Ogasa branch Kikugawa City 522.039 6879.02 6358.46
Izumisano municipal Hineno primary scool Station 518.181 4481.01 6372.14
Shirasuna Omaezaki City 499.479 6660.96 6372.14
Jitougata primary school Makinohara City 498.059 6390.76 6372.14
Kataku Matsue City 497.007 4965.41 6372.14
Nishihemi Yokosuka City 496.917 2981.1 6372.14
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 496.721 6344.78
Satsuma-sendai monitoring center Satsuma-sendai City 495.302 4890.9 6372.14
Otomi Takahama Town 494.821 5477.81 6372.14
Otsu Nanao City 493.895 5496.42 6372.14
The Observation point for comparison Tatsunokuchi 493.454 4527.58 6372.14
Hitsuhama Ohi Town 492.630 5095.87 6372.14
Kijiyama Misasa Town 489.284 5170.38 6372.14
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 487.055 6344.78
Hiraba Omaezaki City 485.878 6660.96 6372.14
Tayu Matsue City 484.956 5179.71 6372.14
Hamaokakita primary school Omaezaki City 484.537 6832.56 6358.46
Oitomi Ayabe City 474.670 6567.78 6372.14
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 472.017 6344.78
Kashiwazaki-shigai Kashiwazaki City 470.822 5226.28 6372.14
Mitsu Matsue City 466.897 4956.13 6372.14
Tonomachi Kawasaki Ward 463.967 6278.97 6372.14
Daitou branch Kakegawa City 463.829 6730.32 6358.46
Fukura Shika Town 462.493 6251.02 6372.14
Nagasawa Yokosuka City 462.365 3651.85 6372.14
The athletic field Station of Kinki University 461.661 4126.97 6372.14
Koura Matsue City 461.049 5915.64 6372.14
Sakurasan Ward Omaezaki City 459.434 6446.65 6372.14
Tsuchikawa Nanao City 458.915 6083.33 6372.14
Kumatori Town office Station 457.917 4257.43 6372.14
Shinkango Omaezaki City 449.013 7462.12 6372.14
Ogurui Takahama Town 448.279 4881.57 6372.14
Kusabue Omaezaki City 444.162 7033.56 6372.14
Omaezaki City monitoring center 443.946 6903.16 6372.14
Akawase Kagamino Town 442.246 4257.43 6372.14
Ibaraki 442.139 3126.14 6363.94
Hinode Town Yokosuka City 438.324 2459.42 6372.14
Nishiyama Kashiwazaki City 437.251 7396.89 6372.14
Kariwa Kariwa Village 436.307 5580.27 6372.14
Osaka prefectural Hineno high scool Station 435.745 4974.74 6372.14
Miyagawa Kashiwazaki City 435.245 5505.76 6372.14
Radiation dose in Natori 434.640 6325.63
Kami-koubu Matsue City 433.868 5412.58 6372.14
Shimo-Takamachi Kariwa Village 433.192 6074.05 6372.14
Osaka prefectural Sano supporting school Station 432.398 5421.91 6372.14
Arahama Kashiwazaki City 428.874 5673.44 6372.14
Doai Kashiwazaki City 425.681 5338.07 6372.14
Owashi Matsue City 424.452 5291.51 6372.14
Okayasu Maizuru City 422.568 6232.4 6372.14
Katsuyama Kariwa Village 421.280 5673.44 6372.14
Kita-koubu Matsue City 420.683 5803.85 6372.14
Kichisaka Maizuru City 413.065 7573.91 6372.14
Nagai Ohi Town 410.699 5507.99 6363.94
Shiokumi Maizuru City 407.938 9427.81 6372.14
Miyadome Ohi Town 407.831 4564.86 6372.14
Kariwa Kariwa Village 407.617 5878.41 6372.14
Ueno Satsuma-sendai City 394.248 4266.71 6372.14
Power Station-South 389.191 6213.79 6372.14
Radiation dose at JAEA Oarai (P6) 386.963 6325.63
Power Station- 385.546 6064.72 6372.14
Takae Satsuma-sendai City 379.551 4322.61 6372.14
Hokawaduura Genkai Town 378.015 6581.75 6372.14
Kou Itimatsu Suetsugu 377.929 4751.16 6372.14
Minato Satsuma-sendai City 377.656 3959.28 6372.14
Iwanai Iwanai Town 376.336 6453.22 6369.41
Hattari Kyowa Town 373.047 6276.27 6369.41
Chatsu Tomari Village 371.011 5996.91 6369.41
Oyama Maizuru City 358.223 5459.19 6372.14
Kodaira Satsuma-sendai City 355.545 4005.9 6372.14
Kayanuma Tomari Village 354.809 5335.78 6369.41
Anojiri Obama City 353.215 4471.68 6372.14
Kushi Genkai Town 349.738 9083.1 6372.14
Yamaguchi 348.715 7145.47 6363.94
Sadahongou Matsue City 348.228 5561.65 6372.14
Sakibe Karatsu City 347.801 8607.98 6372.14
Hirao Genkai Town 343.814 9073.77 6372.14
The Meteorological Obsevatory of kyowa Town 343.275 5950.37 6369.41
Minami-Horoni Kyowa Town 335.180 5577.87 6369.41
Kounoura Takahama Town 330.353 4713.88 6372.14
Kyoudomarisaki Karatsu City 328.622 9222.84 6372.14
Horikappu Jinja Tomari Village 328.230 5773.42 6369.41
Hukada-kita Matsue City 327.031 4574.14 6372.14
Radiation dose in KEK, Tsukuba 326.240 6344.78
Herokaruusu Tomari Village 324.242 5987.63 6369.41
Yorita Satsuma-sendai City 323.218 4685.93 6372.14
Kamoenai Kamoenai Village 322.032 5056.42 6369.41
Radiation dose in Onagawa (MP-6) 316.267 6322.9
Imamura Genkai Town 314.749 78161.1 6372.14
Yamanaka Takahama Town 314.185 6083.33 6372.14
Sendai (Miyagi) 312.585 2863.77 6363.94
Radiation dose in Onagawa (MP-1) 300.147 6322.9
Gumisaki Satsuma-sendai City 295.693 3782.31 6372.14
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 286.142 6344.78
Aomori Aomori City 285.372 3845.84 6369.41
Misawa City hall Misawa City 283.728 7458.91 6369.41
Kashu Ikata Town 277.173 3903.39 6372.14
Noheji Town Office Noheji Town 272.004 3296.45 6369.41
Takasimamati 271.103 4154.92 6372.14
Radiation dose in Onagawa (MP-3) 270.563 6322.9
Kucho Ikata Town 269.545 3446.94 6372.14
Radiation dose in Marumori 269.436 6325.63
Kawanagata Ikata Town 266.821 3363.09 6372.14
Tochigi 260.733 3740.21 6363.94
Chikagawa Mutu City 256.719 4292.81 6369.41
Yokohama Town Office Yokohama Town 254.846 5261.3 6369.41
Tokyo 251.877 4410.1 6363.94
Hiranuma Rokkasho Village 251.186 3454.73 6369.41
Taisei Ikata Town 246.293 2524.65 6372.14
Chitose-daira Rokkasho Village 245.868 3724.82 6369.41
Gifu 243.951 6140.64 6363.94
Fukkoshi Yokohama Town 243.102 3613.07 6369.41
Shimane 240.651 6140.64 6363.94
Sunagomata Higashidoori Village 238.012 5224.03 6369.41
Obuchi Rokkasho Village 237.506 4153.13 6369.41
Tomari Rokkasho Village 230.636 5810.69 6369.41
kanagawa 226.339 3851.86 6363.94
Saitama 219.770 3349.44 6363.94
Ikatagoshi Ikata Town 217.515 3176.74 6372.14
Touhoku Branch office Touhoku Town 215.416 3007.76 6369.41
Radiation dose at Tohoku University 214.824 6325.63
Odanosawa Higashidoori Village 210.287 4162.46 6369.41
Kagawa 205.829 4298.45 6363.94
Oippe Higashidoori Village 205.182 3585.14 6369.41
Oita 200.921 4745.04 6363.94
Touhoku Town office Touhoku Town 200.811 13912.1 6369.41
Kuchogoshi Ikata Town 198.646 3223.35 6372.14
Minatoura Ikata Town 186.776 2897.26 6372.14
Radiation dose in Koyadori, Ojika 184.905 6320.16
Toyama 184.580 8206.13 6363.94
Fukushima [9] (distance from Fukushima I: 45 km) 184.232 3960.1 6358.46
Radiation dose in Tukahama, Ojika 183.417 6320.16
Chiba 182.407 2456.26 6363.94
Nara 182.387 4465.92 6363.94
Okayama 181.976 5805.7 6363.94
Yamagata 181.598 4577.57 6363.94
Ehime 180.745 4130.98 6363.94
Ishikawa 180.445 7117.56 6363.94
Niigata 177.483 8541.07 6363.94
Hiroshima 176.816 3851.86 6363.94
Mie 174.867 4404.51 6363.94
Fukui 170.045 5414.93 6363.94
Radiation dose in Terama, Ojika 168.036 6320.16
Yamanashi 164.561 3572.74 6363.94
Nagano 162.242 5437.26 6363.94
Saga 161.421 4800.86 6363.94
Tottori 161.392 4410.1 6363.94
Radiation dose in Enoshima, Ojika 160.091 6320.16
Osaka 159.103 3405.26 6363.94
Ibaraki-city Environment 157.249 6279.12
Aichi 149.345 4130.98 6363.94
Toyonoura Ikata Town 149.214 3325.81 6372.14
Shizuoka 148.639 4270.54 6363.94
Kyoto 144.522 4856.69 6363.94
Kagoshima 144.449 5264.2 6363.94
Tokushima 143.627 3740.21 6363.94
Gunma 143.572 2512.08 6363.94
Hyogo 139.710 4242.62 6363.94
Fukuoka 136.511 4410.1 6363.94
Wakayama 133.857 3126.14 6363.94
Radiation at Tamaki-cho Mie Japan 133.138 6279.12
Akita 132.832 4800.86 6363.94
Shiga 124.919 3405.26 6363.94
Nagasaki 109.459 3851.86 6363.94
Hokkaido 109.189 5861.52 6363.94
Kumamoto 103.568 3740.21 6363.94
Aomori 101.819 5694.05 6363.94
Miyazaki 100.354 3706.71 6363.94
Kochi 95.931 4242.62 6363.94
Fukushima [35] (distance from Fukushima I: 35 km) 91.917 3951.58 6344.78
Iwate 90.324 4689.22 6363.94
Environment Feeds from Ohta 83.623 6279.12
Okinawa 82.305 3209.88 6363.94
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