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Accumulated absorbed dose rate - T=13.03.2011 - 27.03.2017(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 5950.8
Fukushima I MP8 570942.000 5950.8
Fukushima I MP6 240668.000 5950.8
Yamada Futaba Town 176983.000 4621.86 5507.57
Fukushima I MP2 140420.000 5950.8
Fukushima I MP5 111325.000 5950.8
Fukushima [32] (distance from Fukushima I: 30 km) 101500.000 3750.5 6021.94
Fukushima I MP3 93730.602 5950.8
Fukushima I MP4 86821.500 5950.8
Fukushima [33] (distance from Fukushima I: 30 km) 77197.703 3750.5 6021.94
Fukushima [79] (distance from Fukushima I: 40 km) 54008.602 3699.38 5939.86
Fukushima [31] (distance from Fukushima I: 30 km) 40677.398 3750.5 6021.94
Ono Okuma Town 38610.500 4267.54 5507.57
Shinzan Futaba Town 38332.801 3873.03 5507.57
Fukushima I MP1 31496.801 5950.8
Yonomori Tomioka Town 29815.900 4412.48 5507.57
Fukushima [46] (distance from Fukushima I: 20 km) 28842.500 3750.5 6021.94
Tomioka Tomioka Town 25324.500 4750.66 5507.57
Fukushima [62] (distance from Fukushima I: 40 km) 16464.100 3750.5 6021.94
Fukushima [61] (distance from Fukushima I: 40 km) 13102.800 3750.5 6021.94
Shimo-Kooriyama Tomioka Town 13057.000 4718.49 5507.57
Fukushima [21] (distance from Fukushima I: 30 km) 12103.800 3750.5 6021.94
Fukushima [3] (distance from Fukushima I: 45 km) 11985.000 3750.5 6021.94
Kami-kooriyama Tomioka Town 11803.900 3703.94 5507.57
Fukushima II MP3 11060.600 5950.8
Fukushima II MP1 10903.000 5950.8
Kooriyama Futaba Town 10352.900 4315.86 5507.57
Fukushima II MP4 9696.330 5950.8
Fukushima [34] (distance from Fukushima I: 30 km) 9540.450 3747.1 6016.46
Fukushima II MP5 9382.150 5950.8
Fukushima [2] (distance from Fukushima I: 55 km) 8841.760 3750.5 6021.94
Matsudate Naraha Town 8410.890 5040.54 5507.57
Shigeoka Naraha Town 8115.970 5571.97 5507.57
Fukushima II MP2 7875.320 5950.8
Namie Namie Town 7321.210 4066.28 5507.57
Radiation dose at Shirasawa branch office, Motomiya 7287.920 5967.22
Fukushima II MP6 7062.690 5950.8
Fukushima II MP7 6511.580 5948.06
Fukushima [1] (distance from Fukushima I: 60 km) 5615.310 3750.5 6021.94
Fukushima [11] (distance from Fukushima I: 40 km) 5491.310 3750.5 6021.94
Fukushima [63] (distance from Fukushima I: 45 km) 5448.820 3750.5 6021.94
Fukushima [45] (distance from Fukushima I: 20 km) 3981.200 3750.5 6021.94
Fukushima [42] (distance from Fukushima I: 30 km) 3850.600 3750.5 6021.94
Fukushima [10] (distance from Fukushima I: 40 km) 3734.160 3750.5 6021.94
Fukushima [78] (distance from Fukushima I: 45 km) 3716.820 3745.39 6013.73
Futatsunuma Hirono Town 3520.340 4831.2 5507.57
Fukushima [4] (distance from Fukushima I: 50 km) 3386.310 3750.5 6021.94
Fukushima [7] (distance from Fukushima I: 45 km) 3313.930 3750.5 6021.94
Radiation dose at Koriyama joint government building, Koriyama 3232.890 5964.48
Fukushima [15] (distance from Fukushima I: 35 km) 3178.670 3750.5 6021.94
Kiyohashi Namie Town 3162.000 3567.02 5507.57
Fukushima [71] (distance from Fukushima I: 25 km) 3161.650 3745.39 6013.73
Radiation dose at Agricultural center, Koriyama 3128.960 5964.48
Fukushima [41] (distance from Fukushima I: 20 km) 3111.490 3750.5 6021.94
Radiation dose at Koriyama city office, Koriyama 2803.520 5964.48
Fukushima [44] (distance from Fukushima I: 30 km) 2535.550 3750.5 6021.94
Fukushima [72] (distance from Fukushima I: 30 km) 2344.620 3745.39 6013.73
Fukushima [43] (distance from Fukushima I: 20 km) 2244.110 3750.5 6021.94
Yamadaoka Naraha Town 2205.340 4283.68 5507.57
Radiation dose at Iwane Fureai Plaza, Motomiya 2169.060 5967.22
Fukushima [22] (distance from Fukushima I: 35 km) 2020.650 3750.5 6021.94
Kuji Hitachi City 1990.890 9313.92 6032.88
Hitachinaka Hitachinaka City 1951.950 4090.61 6030.14
Fukushima [76] (distance from Fukushima I: 25 km) 1945.520 3745.39 6013.73
Fukushima [80] (distance from Fukushima I: 25 km) 1876.860 3745.39 6013.73
Momiyama Hokota City 1837.540 4665.8 6032.88
Fukushima [77] (distance from Fukushima I: 25 km) 1802.490 3745.39 6013.73
Horiguchi Hitachinaka City 1779.410 4076.69 6035.62
Onuma Hitachi City 1776.950 3473.52 6030.14
Fukushima [6] (distance from Fukushima I: 45 km) 1741.180 3750.5 6021.94
Tsukuriya Hokota City 1736.890 3924.92 6032.88
Radiation dose at Big palette Fukushima, Koriyama 1668.540 5964.48
Nemoto Hitachioomiya City 1633.190 4372.75 6030.14
Fukushima [13] (distance from Fukushima I: 40 km) 1624.150 3750.5 6021.94
Fukushima [23] (distance from Fukushima I: 35 km) 1551.750 3750.5 6021.94
Radiation dose at Tsukidatemachi kamitedo, Date 1545.300 5972.69
Fukushima [14] (distance from Fukushima I: 35 km) 1543.460 3750.5 6021.94
Radiation dose at JAEA Oarai (P12) 1512.140 5989.1
Radiation dose at Ose administration center, Koriyama 1494.270 5964.48
Araji Hokota City 1437.760 3933.7 6032.88
Ishigami Tokai Village 1431.690 3580.94 6032.88
Mawatari Hitachinaka City 1422.870 4136.6 6032.88
Radiation dose at JAEA Oarai (P11) 1399.370 5989.1
Onuki Oarai Town 1387.990 4295.36 6032.88
Sawa Hitachinaka City 1353.770 3244.27 6030.14
Toyooka Tokai Village 1321.760 3942.54 6032.88
Ajigaura Hitachinaka City 1313.890 3879.02 6030.14
Fukushima [5] (distance from Fukushima I: 45 km) 1282.090 3750.5 6021.94
Geiger Counter Feeds from Asao Kawasaki 1266.620 5942.59
Radiation dose at Tamokami elementary school, Koriyama 1256.140 5964.48
Isohama Oarai Town 1250.540 3745.08 6027.41
Ebisawa Ibaraki Town 1222.240 10166.6 6030.14
Muramatsu Tokai Village 1203.520 3977.84 6032.88
Kamitoda Hokota City 1184.740 3263.42 6032.88
Yanagisawa Hitachinaka City 1166.970 3323.61 6030.14
Tokushuku Hokota City 1159.730 2945.9 6032.88
Tasaki Hokota City 1153.300 3484.09 6002.78
Fukushima [20] (distance from Fukushima I: 45 km) 1145.390 3750.5 6021.94
Kadobe Naka City 1086.580 7916.79 6030.14
Radiation dose at Date city office, Date 1076.050 5967.22
Oshinobe Tokai Village 1041.340 3713.24 6032.88
Oba Mito City 1037.670 12198.1 6032.88
Godai Naka City 1031.270 3219.28 6032.88
Ishikawa Mito City 1030.810 3794.34 6035.62
Isobe Hitachiota City 1013.130 18310.3 6032.88
Yatabe Ibaraki Town 996.127 3184.04 6032.88
Radiation dose at Motomiya city office, Motomiya 992.703 5967.22
Fukushima [73] (distance from Fukushima I: 35 km) 981.984 3745.39 6013.73
Fukushima [75] (distance from Fukushima I: 45 km) 960.529 3745.39 6013.73
Yokobori Naka City 930.280 3730.86 6032.88
Sugaya Naka City 926.186 5700.32 6035.62
Kounosu Naka City 926.087 2910.6 6032.88
Funaishikawa Tokai Village 900.399 3863.16 6032.88
Nukada Naka City 899.900 3489.55 6027.41
Uridura Naka City 890.113 3330.94 6027.41
Shiraki Tsuruga City 881.330 7068.02 6035.62
Motokomezaki Naka City 880.851 3105.29 6000.05
Shiraki pass Tsuruga City 850.284 7403.32 6035.62
Radiation dose in Yamamoto 846.633 5989.1
Yoshizawa Mito City 837.646 3369.26 6032.88
Radiation dose at JAEA Oarai (P7) 831.135 5989.1
Mayumi Hitachiota City 828.119 3342.8 6032.88
Urasoko Tsuruga City 826.465 5867.94 6035.62
Nemoto Hitachioomiya City 825.588 3764.45 6030.14
Takenami Mihama Town 804.283 6159.13 6035.62
Radiation dose at JAEA Oarai (P15) 780.207 5989.1
Tateishi Tsuruga City 780.092 4879.69 6035.62
Radiation dose at JAEA Oarai (P14) 770.174 5989.1
Radiation dose at JAEA Oarai (P13) 769.612 5989.1
Ukishima Kawasaki Ward 735.475 11515.3 6035.62
Kume Hitachiota City 713.958 3272.2 6032.88
Radiation dose at JAEA Oarai (P2) 712.011 5989.1
Fukushima [74] (distance from Fukushima I: 35 km) 706.552 3745.39 6013.73
Nyuu Mihama Town 674.787 5612.06 6035.62
Fukushima [52] (distance from Fukushima I: 40 km) 672.743 3750.5 6021.94
Radiation dose in Iwanuma 670.242 5989.1
Fukushima [51] (distance from Fukushima I: 40 km) 665.376 3750.5 6021.94
Tsuruga Tsuruga City 655.360 4950.26 6035.62
Shiohama Kawasaki Ward 653.536 3953.17 6035.62
Radiation dose in Kakuda 649.863 5989.1
Sakajiri Mihama Town 649.252 6547.43 6035.62
North point of Kinki University Atomic Energy Research Instirute Station 639.566 4112 6035.62
Radiation dose in Onagawa (MP-2) 632.968 5986.37
Kumatori town Nishi primary school Station 631.491 4914.95 6035.62
Oshima Kawasaki Ward 630.402 3767.87 6035.62
Izumisano municipal Oike athletic field Station 629.920 5541.49 6035.62
Atom-kyoudou nursery school Station 625.566 5320.87 6035.62
South point of Kinki University Atomic Energy Research Instirute Station 625.202 4844.38 6035.62
Nakamachi Omaezaki City 623.494 6238.55 6035.62
Uraga Yokosuka City 622.492 2956.02 6035.62
Goritoge Shika Town 622.143 6626.84 6035.62
Kumatori town Minami primary school Station 606.134 5638.54 6035.62
Radiation dose at JAEA Oarai (P1) 603.643 5991.84
Yamanotedai-No.1 Park Station 599.140 5259.09 6035.62
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 595.502 6008.26
Noumi Shika Town 594.021 6556.21 6035.62
Radiation dose in Watari 591.851 5989.1
Hairando Yokosuka City 588.667 3706.08 6035.62
Fukushima [12] (distance from Fukushima I: 40 km) 588.291 3750.5 6021.94
Ningyotoge Kagamino Town 574.857 5259.09 6035.62
Ten-no Kagamino Town 569.960 6300.34 6035.62
Funagura Yokosuka City 563.909 3494.3 6035.62
Chidori Kawasaki Ward 560.211 3379.57 6035.62
Radiation dose at JAEA Oarai (P16) 556.365 5989.1
Shika Shika Town 551.376 6317.97 6035.62
Higashiosaka municipal Kamikosaka primary scool Station 550.277 4103.16 6035.62
Sahara Yokosuka City 547.404 3273.69 6035.62
Kazanashi Shika Town 545.377 5929.73 6035.62
Akasumi Shika Town 544.970 5426.76 6035.62
Kurahashi Maizuru City 540.820 4941.42 6035.62
Obama Obama City 540.809 4420.82 6035.62
Sakuragaike community hall Omaezaki City 540.772 6397.38 6035.62
Shirowa primary school Omaezaki City 535.692 6265.02 6035.62
Radiation dose at JAEA Oarai (P5) 529.759 5989.1
Uenohara Omaezaki City 529.333 6441.54 6035.62
Kumano Shika Town 529.019 6150.35 6035.62
Izumisano municipal Hineno filtration plant Station 527.471 5303.24 6035.62
Nishi-hamasada Matsue City 525.089 5869.62 6019.2
Kouno Minami-Echizen Town 525.028 4447.3 6035.62
Kurihama Yokosuka City 523.708 3538.41 6035.62
Osaka prefectural Kumatori off-site-center Station 522.808 4888.48 6035.62
Ogasa branch Kikugawa City 522.039 6514.94 6021.94
Izumisano municipal Hineno primary scool Station 518.181 4244.36 6035.62
Shirasuna Omaezaki City 499.479 6309.18 6035.62
Jitougata primary school Makinohara City 498.059 6053.25 6035.62
Kataku Matsue City 497.007 4703.17 6035.62
Nishihemi Yokosuka City 496.917 2823.66 6035.62
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 496.721 6008.26
Satsuma-sendai monitoring center Satsuma-sendai City 495.302 4632.6 6035.62
Otomi Takahama Town 494.821 5188.51 6035.62
Otsu Nanao City 493.895 5206.14 6035.62
The Observation point for comparison Tatsunokuchi 493.454 4288.46 6035.62
Hitsuhama Ohi Town 492.630 4826.75 6035.62
Kijiyama Misasa Town 489.284 4897.32 6035.62
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 487.055 6008.26
Hiraba Omaezaki City 485.878 6309.18 6035.62
Tayu Matsue City 484.956 4906.16 6035.62
Hamaokakita primary school Omaezaki City 484.537 6470.94 6021.94
Oitomi Ayabe City 474.670 6220.92 6035.62
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 472.017 6008.26
Kashiwazaki-shigai Kashiwazaki City 470.822 4950.26 6035.62
Mitsu Matsue City 466.897 4694.39 6035.62
Tonomachi Kawasaki Ward 463.967 5947.36 6035.62
Daitou branch Kakegawa City 463.829 6374.11 6021.94
Fukura Shika Town 462.493 5920.89 6035.62
Nagasawa Yokosuka City 462.365 3458.99 6035.62
The athletic field Station of Kinki University 461.661 3909.01 6035.62
Koura Matsue City 461.049 5603.22 6035.62
Sakurasan Ward Omaezaki City 459.434 6106.19 6035.62
Tsuchikawa Nanao City 458.915 5762.05 6035.62
Kumatori Town office Station 457.917 4032.59 6035.62
Shinkango Omaezaki City 449.013 7068.02 6035.62
Ogurui Takahama Town 448.279 4623.76 6035.62
Kusabue Omaezaki City 444.162 6662.1 6035.62
Omaezaki City monitoring center 443.946 6538.58 6035.62
Akawase Kagamino Town 442.246 4032.59 6035.62
Ibaraki 442.139 2960.83 6027.41
Hinode Town Yokosuka City 438.324 2329.54 6035.62
Nishiyama Kashiwazaki City 437.251 7006.24 6035.62
Kariwa Kariwa Village 436.307 5285.56 6035.62
Osaka prefectural Hineno high scool Station 435.745 4712.02 6035.62
Miyagawa Kashiwazaki City 435.245 5214.98 6035.62
Radiation dose in Natori 434.640 5989.1
Kami-koubu Matsue City 433.868 5126.73 6035.62
Shimo-Takamachi Kariwa Village 433.192 5753.27 6035.62
Osaka prefectural Sano supporting school Station 432.398 5135.57 6035.62
Arahama Kashiwazaki City 428.874 5373.82 6035.62
Doai Kashiwazaki City 425.681 5056.15 6035.62
Owashi Matsue City 424.452 5012.05 6035.62
Okayasu Maizuru City 422.568 5903.26 6035.62
Katsuyama Kariwa Village 421.280 5373.82 6035.62
Kita-koubu Matsue City 420.683 5497.33 6035.62
Kichisaka Maizuru City 413.065 7173.91 6035.62
Nagai Ohi Town 410.699 5216.72 6027.41
Shiokumi Maizuru City 407.938 8929.91 6035.62
Miyadome Ohi Town 407.831 4323.78 6035.62
Kariwa Kariwa Village 407.617 5567.96 6035.62
Ueno Satsuma-sendai City 394.248 4041.37 6035.62
Power Station-South 389.191 5885.63 6035.62
Radiation dose at JAEA Oarai (P6) 386.963 5989.1
Power Station- 385.546 5744.42 6035.62
Takae Satsuma-sendai City 379.551 4094.32 6035.62
Hokawaduura Genkai Town 378.015 6234.16 6035.62
Kou Itimatsu Suetsugu 377.929 4500.24 6035.62
Minato Satsuma-sendai City 377.656 3750.18 6035.62
Iwanai Iwanai Town 376.336 6112.26 6032.88
Hattari Kyowa Town 373.047 5944.66 6032.88
Chatsu Tomari Village 371.011 5680.06 6032.88
Oyama Maizuru City 358.223 5170.88 6035.62
Kodaira Satsuma-sendai City 355.545 3794.34 6035.62
Kayanuma Tomari Village 354.809 5053.86 6032.88
Anojiri Obama City 353.215 4235.52 6035.62
Kushi Genkai Town 349.738 8603.4 6035.62
Yamaguchi 348.715 6767.62 6027.41
Sadahongou Matsue City 348.228 5267.93 6035.62
Sakibe Karatsu City 347.801 8153.38 6035.62
Hirao Genkai Town 343.814 8594.56 6035.62
The Meteorological Obsevatory of kyowa Town 343.275 5635.98 6032.88
Minami-Horoni Kyowa Town 335.180 5283.16 6032.88
Kounoura Takahama Town 330.353 4464.93 6035.62
Kyoudomarisaki Karatsu City 328.622 8735.76 6035.62
Horikappu Jinja Tomari Village 328.230 5468.38 6032.88
Hukada-kita Matsue City 327.031 4332.57 6035.62
Radiation dose in KEK, Tsukuba 326.240 6008.26
Herokaruusu Tomari Village 324.242 5671.28 6032.88
Yorita Satsuma-sendai City 323.218 4438.45 6035.62
Kamoenai Kamoenai Village 322.032 4789.26 6032.88
Radiation dose in Onagawa (MP-6) 316.267 5986.37
Imamura Genkai Town 314.749 74033.2 6035.62
Yamanaka Takahama Town 314.185 5762.05 6035.62
Sendai (Miyagi) 312.585 2712.33 6027.41
Radiation dose in Onagawa (MP-1) 300.147 5986.37
Gumisaki Satsuma-sendai City 295.693 3582.56 6035.62
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 286.142 6008.26
Aomori Aomori City 285.372 3642.64 6032.88
Misawa City hall Misawa City 283.728 7064.82 6032.88
Kashu Ikata Town 277.173 3697.24 6035.62
Noheji Town Office Noheji Town 272.004 3122.28 6032.88
Takasimamati 271.103 3935.49 6035.62
Radiation dose in Onagawa (MP-3) 270.563 5986.37
Kucho Ikata Town 269.545 3264.9 6035.62
Radiation dose in Marumori 269.436 5989.1
Kawanagata Ikata Town 266.821 3185.48 6035.62
Tochigi 260.733 3542.42 6027.41
Chikagawa Mutu City 256.719 4066 6032.88
Yokohama Town Office Yokohama Town 254.846 4983.32 6032.88
Tokyo 251.877 4176.89 6027.41
Hiranuma Rokkasho Village 251.186 3272.2 6032.88
Taisei Ikata Town 246.293 2391.32 6035.62
Chitose-daira Rokkasho Village 245.868 3528.02 6032.88
Gifu 243.951 5815.92 6027.41
Fukkoshi Yokohama Town 243.102 3422.18 6032.88
Shimane 240.651 5815.92 6027.41
Sunagomata Higashidoori Village 238.012 4948.02 6032.88
Obuchi Rokkasho Village 237.506 3933.7 6032.88
Tomari Rokkasho Village 230.636 5503.68 6032.88
kanagawa 226.339 3648.17 6027.41
Saitama 219.770 3172.32 6027.41
Ikatagoshi Ikata Town 217.515 3008.97 6035.62
Touhoku Branch office Touhoku Town 215.416 2848.84 6032.88
Radiation dose at Tohoku University 214.824 5989.1
Odanosawa Higashidoori Village 210.287 3942.54 6032.88
Kagawa 205.829 4071.14 6027.41
Oippe Higashidoori Village 205.182 3395.72 6032.88
Oita 200.921 4494.12 6027.41
Touhoku Town office Touhoku Town 200.811 13177.1 6032.88
Kuchogoshi Ikata Town 198.646 3053.12 6035.62
Minatoura Ikata Town 186.776 2744.25 6035.62
Radiation dose in Koyadori, Ojika 184.905 5983.63
Toyama 184.580 7772.18 6027.41
Fukushima [9] (distance from Fukushima I: 45 km) 184.232 3750.5 6021.94
Radiation dose in Tukahama, Ojika 183.417 5983.63
Chiba 182.407 2326.37 6027.41
Nara 182.387 4229.76 6027.41
Okayama 181.976 5498.69 6027.41
Yamagata 181.598 4335.5 6027.41
Ehime 180.745 3912.53 6027.41
Ishikawa 180.445 6741.18 6027.41
Niigata 177.483 8089.42 6027.41
Hiroshima 176.816 3648.17 6027.41
Mie 174.867 4171.6 6027.41
Fukui 170.045 5128.58 6027.41
Radiation dose in Terama, Ojika 168.036 5983.63
Yamanashi 164.561 3383.81 6027.41
Nagano 162.242 5149.73 6027.41
Saga 161.421 4546.99 6027.41
Tottori 161.392 4176.89 6027.41
Radiation dose in Enoshima, Ojika 160.091 5983.63
Osaka 159.103 3225.19 6027.41
Ibaraki-city Environment 157.249 5942.59
Aichi 149.345 3912.53 6027.41
Toyonoura Ikata Town 149.214 3150.17 6035.62
Shizuoka 148.639 4044.71 6027.41
Kyoto 144.522 4599.86 6027.41
Kagoshima 144.449 4985.83 6027.41
Tokushima 143.627 3542.42 6027.41
Gunma 143.572 2379.24 6027.41
Hyogo 139.710 4018.27 6027.41
Fukuoka 136.511 4176.89 6027.41
Wakayama 133.857 2960.83 6027.41
Radiation at Tamaki-cho Mie Japan 133.138 5942.59
Akita 132.832 4546.99 6027.41
Shiga 124.919 3225.19 6027.41
Nagasaki 109.459 3648.17 6027.41
Hokkaido 109.189 5551.56 6027.41
Kumamoto 103.568 3542.42 6027.41
Aomori 101.819 5392.94 6027.41
Miyazaki 100.354 3510.7 6027.41
Kochi 95.931 4018.27 6027.41
Fukushima [35] (distance from Fukushima I: 35 km) 91.917 3741.98 6008.26
Iwate 90.324 4441.25 6027.41
Environment Feeds from Ohta 83.623 5942.59
Okinawa 82.305 3040.14 6027.41
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