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Accumulated absorbed dose rate - T=13.03.2011 - 25.07.2016(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 5280.48
Fukushima I MP8 570942.000 5280.48
Fukushima I MP6 240668.000 5280.48
Yamada Futaba Town 176983.000 4059.34 4837.25
Fukushima I MP2 140420.000 5280.48
Fukushima I MP5 111325.000 5280.48
Fukushima [32] (distance from Fukushima I: 30 km) 101500.000 3333.02 5351.62
Fukushima I MP3 93730.602 5280.48
Fukushima I MP4 86821.500 5280.48
Fukushima [33] (distance from Fukushima I: 30 km) 77197.703 3333.02 5351.62
Fukushima [79] (distance from Fukushima I: 40 km) 54008.602 3281.9 5269.54
Fukushima [31] (distance from Fukushima I: 30 km) 40677.398 3333.02 5351.62
Ono Okuma Town 38610.500 3748.15 4837.25
Shinzan Futaba Town 38332.801 3401.65 4837.25
Fukushima I MP1 31496.801 5280.48
Yonomori Tomioka Town 29815.900 3875.44 4837.25
Fukushima [46] (distance from Fukushima I: 20 km) 28842.500 3333.02 5351.62
Tomioka Tomioka Town 25324.500 4172.47 4837.25
Fukushima [62] (distance from Fukushima I: 40 km) 16464.100 3333.02 5351.62
Fukushima [61] (distance from Fukushima I: 40 km) 13102.800 3333.02 5351.62
Shimo-Kooriyama Tomioka Town 13057.000 4144.21 4837.25
Fukushima [21] (distance from Fukushima I: 30 km) 12103.800 3333.02 5351.62
Fukushima [3] (distance from Fukushima I: 45 km) 11985.000 3333.02 5351.62
Kami-kooriyama Tomioka Town 11803.900 3253.13 4837.25
Fukushima II MP3 11060.600 5280.48
Fukushima II MP1 10903.000 5280.48
Kooriyama Futaba Town 10352.900 3790.58 4837.25
Fukushima II MP4 9696.330 5280.48
Fukushima [34] (distance from Fukushima I: 30 km) 9540.450 3329.62 5346.14
Fukushima II MP5 9382.150 5280.48
Fukushima [2] (distance from Fukushima I: 55 km) 8841.760 3333.02 5351.62
Matsudate Naraha Town 8410.890 4427.06 4837.25
Shigeoka Naraha Town 8115.970 4893.81 4837.25
Fukushima II MP2 7875.320 5280.48
Namie Namie Town 7321.210 3571.37 4837.25
Radiation dose at Shirasawa branch office, Motomiya 7287.920 5296.9
Fukushima II MP6 7062.690 5280.48
Fukushima II MP7 6511.580 5277.74
Fukushima [1] (distance from Fukushima I: 60 km) 5615.310 3333.02 5351.62
Fukushima [11] (distance from Fukushima I: 40 km) 5491.310 3333.02 5351.62
Fukushima [63] (distance from Fukushima I: 45 km) 5448.820 3333.02 5351.62
Fukushima [45] (distance from Fukushima I: 20 km) 3981.200 3333.02 5351.62
Fukushima [42] (distance from Fukushima I: 30 km) 3850.600 3333.02 5351.62
Fukushima [10] (distance from Fukushima I: 40 km) 3734.160 3333.02 5351.62
Fukushima [78] (distance from Fukushima I: 45 km) 3716.820 3327.91 5343.41
Futatsunuma Hirono Town 3520.340 4243.2 4837.25
Fukushima [4] (distance from Fukushima I: 50 km) 3386.310 3333.02 5351.62
Fukushima [7] (distance from Fukushima I: 45 km) 3313.930 3333.02 5351.62
Radiation dose at Koriyama joint government building, Koriyama 3232.890 5294.16
Fukushima [15] (distance from Fukushima I: 35 km) 3178.670 3333.02 5351.62
Kiyohashi Namie Town 3162.000 3132.88 4837.25
Fukushima [71] (distance from Fukushima I: 25 km) 3161.650 3327.91 5343.41
Radiation dose at Agricultural center, Koriyama 3128.960 5294.16
Fukushima [41] (distance from Fukushima I: 20 km) 3111.490 3333.02 5351.62
Radiation dose at Koriyama city office, Koriyama 2803.520 5294.16
Fukushima [44] (distance from Fukushima I: 30 km) 2535.550 3333.02 5351.62
Fukushima [72] (distance from Fukushima I: 30 km) 2344.620 3327.91 5343.41
Fukushima [43] (distance from Fukushima I: 20 km) 2244.110 3333.02 5351.62
Yamadaoka Naraha Town 2205.340 3762.32 4837.25
Radiation dose at Iwane Fureai Plaza, Motomiya 2169.060 5296.9
Fukushima [22] (distance from Fukushima I: 35 km) 2020.650 3333.02 5351.62
Kuji Hitachi City 1990.890 8279.04 5362.56
Hitachinaka Hitachinaka City 1951.950 3635.89 5359.82
Fukushima [76] (distance from Fukushima I: 25 km) 1945.520 3327.91 5343.41
Fukushima [80] (distance from Fukushima I: 25 km) 1876.860 3327.91 5343.41
Momiyama Hokota City 1837.540 4147.38 5362.56
Fukushima [77] (distance from Fukushima I: 25 km) 1802.490 3327.91 5343.41
Horiguchi Hitachinaka City 1779.410 3623.93 5365.3
Onuma Hitachi City 1776.950 3087.4 5359.82
Fukushima [6] (distance from Fukushima I: 45 km) 1741.180 3333.02 5351.62
Tsukuriya Hokota City 1736.890 3488.82 5362.56
Radiation dose at Big palette Fukushima, Koriyama 1668.540 5294.16
Nemoto Hitachioomiya City 1633.190 3886.67 5359.82
Fukushima [13] (distance from Fukushima I: 40 km) 1624.150 3333.02 5351.62
Fukushima [23] (distance from Fukushima I: 35 km) 1551.750 3333.02 5351.62
Radiation dose at Tsukidatemachi kamitedo, Date 1545.300 5302.37
Fukushima [14] (distance from Fukushima I: 35 km) 1543.460 3333.02 5351.62
Radiation dose at JAEA Oarai (P12) 1512.140 5318.78
Radiation dose at Ose administration center, Koriyama 1494.270 5294.16
Araji Hokota City 1437.760 3496.62 5362.56
Ishigami Tokai Village 1431.690 3183.06 5362.56
Mawatari Hitachinaka City 1422.870 3676.98 5362.56
Radiation dose at JAEA Oarai (P11) 1399.370 5318.78
Onuki Oarai Town 1387.990 3818.1 5362.56
Sawa Hitachinaka City 1353.770 2883.63 5359.82
Toyooka Tokai Village 1321.760 3504.48 5362.56
Ajigaura Hitachinaka City 1313.890 3447.82 5359.82
Fukushima [5] (distance from Fukushima I: 45 km) 1282.090 3333.02 5351.62
Geiger Counter Feeds from Asao Kawasaki 1266.620 5272.27
Radiation dose at Tamokami elementary school, Koriyama 1256.140 5294.16
Isohama Oarai Town 1250.540 3328.58 5357.09
Ebisawa Ibaraki Town 1222.240 9036.48 5359.82
Muramatsu Tokai Village 1203.520 3535.86 5362.56
Kamitoda Hokota City 1184.740 2900.82 5362.56
Yanagisawa Hitachinaka City 1166.970 2954.16 5359.82
Tokushuku Hokota City 1159.730 2618.58 5362.56
Tasaki Hokota City 1153.300 3095.03 5332.46
Fukushima [20] (distance from Fukushima I: 45 km) 1145.390 3333.02 5351.62
Kadobe Naka City 1086.580 7036.74 5359.82
Radiation dose at Date city office, Date 1076.050 5296.9
Oshinobe Tokai Village 1041.340 3300.66 5362.56
Oba Mito City 1037.670 10842.7 5362.56
Godai Naka City 1031.270 2861.58 5362.56
Ishikawa Mito City 1030.810 3372.94 5365.3
Isobe Hitachiota City 1013.130 16275.8 5362.56
Yatabe Ibaraki Town 996.127 2830.26 5362.56
Radiation dose at Motomiya city office, Motomiya 992.703 5296.9
Fukushima [73] (distance from Fukushima I: 35 km) 981.984 3327.91 5343.41
Fukushima [75] (distance from Fukushima I: 45 km) 960.529 3327.91 5343.41
Yokobori Naka City 930.280 3316.32 5362.56
Sugaya Naka City 926.186 5067.24 5365.3
Kounosu Naka City 926.087 2587.2 5362.56
Funaishikawa Tokai Village 900.399 3433.92 5362.56
Nukada Naka City 899.900 3101.47 5357.09
Uridura Naka City 890.113 2960.5 5357.09
Shiraki Tsuruga City 881.330 6283.04 5365.3
Motokomezaki Naka City 880.851 2758.37 5329.73
Shiraki pass Tsuruga City 850.284 6581.1 5365.3
Radiation dose in Yamamoto 846.633 5318.78
Yoshizawa Mito City 837.646 2994.9 5362.56
Radiation dose at JAEA Oarai (P7) 831.135 5318.78
Mayumi Hitachiota City 828.119 2971.38 5362.56
Urasoko Tsuruga City 826.465 5216.24 5365.3
Nemoto Hitachioomiya City 825.588 3345.99 5359.82
Takenami Mihama Town 804.283 5475.1 5365.3
Radiation dose at JAEA Oarai (P15) 780.207 5318.78
Tateishi Tsuruga City 780.092 4337.75 5365.3
Radiation dose at JAEA Oarai (P14) 770.174 5318.78
Radiation dose at JAEA Oarai (P13) 769.612 5318.78
Ukishima Kawasaki Ward 735.475 10236.4 5365.3
Kume Hitachiota City 713.958 2908.62 5362.56
Radiation dose at JAEA Oarai (P2) 712.011 5318.78
Fukushima [74] (distance from Fukushima I: 35 km) 706.552 3327.91 5343.41
Nyuu Mihama Town 674.787 4988.78 5365.3
Fukushima [52] (distance from Fukushima I: 40 km) 672.743 3333.02 5351.62
Radiation dose in Iwanuma 670.242 5318.78
Fukushima [51] (distance from Fukushima I: 40 km) 665.376 3333.02 5351.62
Tsuruga Tsuruga City 655.360 4400.48 5365.3
Shiohama Kawasaki Ward 653.536 3514.13 5365.3
Radiation dose in Kakuda 649.863 5318.78
Sakajiri Mihama Town 649.252 5820.26 5365.3
North point of Kinki University Atomic Energy Research Instirute Station 639.566 3655.32 5365.3
Radiation dose in Onagawa (MP-2) 632.968 5316.05
Kumatori town Nishi primary school Station 631.491 4369.09 5365.3
Oshima Kawasaki Ward 630.402 3349.4 5365.3
Izumisano municipal Oike athletic field Station 629.920 4926.05 5365.3
Atom-kyoudou nursery school Station 625.566 4729.93 5365.3
South point of Kinki University Atomic Energy Research Instirute Station 625.202 4306.36 5365.3
Nakamachi Omaezaki City 623.494 5545.69 5365.3
Uraga Yokosuka City 622.492 2627.72 5365.3
Goritoge Shika Town 622.143 5890.86 5365.3
Kumatori town Minami primary school Station 606.134 5012.32 5365.3
Radiation dose at JAEA Oarai (P1) 603.643 5321.52
Yamanotedai-No.1 Park Station 599.140 4675.01 5365.3
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 595.502 5337.94
Noumi Shika Town 594.021 5828.08 5365.3
Radiation dose in Watari 591.851 5318.78
Hairando Yokosuka City 588.667 3294.48 5365.3
Fukushima [12] (distance from Fukushima I: 40 km) 588.291 3333.02 5351.62
Ningyotoge Kagamino Town 574.857 4675.01 5365.3
Ten-no Kagamino Town 569.960 5600.62 5365.3
Funagura Yokosuka City 563.909 3106.22 5365.3
Chidori Kawasaki Ward 560.211 3004.24 5365.3
Radiation dose at JAEA Oarai (P16) 556.365 5318.78
Shika Shika Town 551.376 5616.29 5365.3
Higashiosaka municipal Kamikosaka primary scool Station 550.277 3647.46 5365.3
Sahara Yokosuka City 547.404 2910.11 5365.3
Kazanashi Shika Town 545.377 5271.17 5365.3
Akasumi Shika Town 544.970 4824.06 5365.3
Kurahashi Maizuru City 540.820 4392.62 5365.3
Obama Obama City 540.809 3929.84 5365.3
Sakuragaike community hall Omaezaki City 540.772 5686.88 5365.3
Shirowa primary school Omaezaki City 535.692 5569.22 5365.3
Radiation dose at JAEA Oarai (P5) 529.759 5318.78
Uenohara Omaezaki City 529.333 5726.14 5365.3
Kumano Shika Town 529.019 5467.28 5365.3
Izumisano municipal Hineno filtration plant Station 527.471 4714.26 5365.3
Nishi-hamasada Matsue City 525.089 5215.96 5348.88
Kouno Minami-Echizen Town 525.028 3953.38 5365.3
Kurihama Yokosuka City 523.708 3145.43 5365.3
Osaka prefectural Kumatori off-site-center Station 522.808 4345.56 5365.3
Ogasa branch Kikugawa City 522.039 5789.74 5351.62
Izumisano municipal Hineno primary scool Station 518.181 3772.98 5365.3
Shirasuna Omaezaki City 499.479 5608.48 5365.3
Jitougata primary school Makinohara City 498.059 5380.97 5365.3
Kataku Matsue City 497.007 4180.84 5365.3
Nishihemi Yokosuka City 496.917 2510.06 5365.3
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 496.721 5337.94
Satsuma-sendai monitoring center Satsuma-sendai City 495.302 4118.1 5365.3
Otomi Takahama Town 494.821 4612.27 5365.3
Otsu Nanao City 493.895 4627.94 5365.3
The Observation point for comparison Tatsunokuchi 493.454 3812.18 5365.3
Hitsuhama Ohi Town 492.630 4290.68 5365.3
Kijiyama Misasa Town 489.284 4353.42 5365.3
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 487.055 5337.94
Hiraba Omaezaki City 485.878 5608.48 5365.3
Tayu Matsue City 484.956 4361.28 5365.3
Hamaokakita primary school Omaezaki City 484.537 5750.64 5351.62
Oitomi Ayabe City 474.670 5530.02 5365.3
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 472.017 5337.94
Kashiwazaki-shigai Kashiwazaki City 470.822 4400.48 5365.3
Mitsu Matsue City 466.897 4173.02 5365.3
Tonomachi Kawasaki Ward 463.967 5286.84 5365.3
Daitou branch Kakegawa City 463.829 5664.59 5351.62
Fukura Shika Town 462.493 5263.31 5365.3
Nagasawa Yokosuka City 462.365 3074.83 5365.3
The athletic field Station of Kinki University 461.661 3474.88 5365.3
Koura Matsue City 461.049 4980.92 5365.3
Sakurasan Ward Omaezaki City 459.434 5428.03 5365.3
Tsuchikawa Nanao City 458.915 5122.12 5365.3
Kumatori Town office Station 457.917 3584.72 5365.3
Shinkango Omaezaki City 449.013 6283.04 5365.3
Ogurui Takahama Town 448.279 4110.24 5365.3
Kusabue Omaezaki City 444.162 5922.2 5365.3
Omaezaki City monitoring center 443.946 5812.4 5365.3
Akawase Kagamino Town 442.246 3584.72 5365.3
Ibaraki 442.139 2631.55 5357.09
Hinode Town Yokosuka City 438.324 2070.82 5365.3
Nishiyama Kashiwazaki City 437.251 6228.12 5365.3
Kariwa Kariwa Village 436.307 4698.54 5365.3
Osaka prefectural Hineno high scool Station 435.745 4188.7 5365.3
Miyagawa Kashiwazaki City 435.245 4635.8 5365.3
Radiation dose in Natori 434.640 5318.78
Kami-koubu Matsue City 433.868 4557.35 5365.3
Shimo-Takamachi Kariwa Village 433.192 5114.3 5365.3
Osaka prefectural Sano supporting school Station 432.398 4565.21 5365.3
Arahama Kashiwazaki City 428.874 4777 5365.3
Doai Kashiwazaki City 425.681 4494.61 5365.3
Owashi Matsue City 424.452 4455.41 5365.3
Okayasu Maizuru City 422.568 5247.64 5365.3
Katsuyama Kariwa Village 421.280 4777 5365.3
Kita-koubu Matsue City 420.683 4886.8 5365.3
Kichisaka Maizuru City 413.065 6377.17 5365.3
Nagai Ohi Town 410.699 4636.56 5357.09
Shiokumi Maizuru City 407.938 7938.14 5365.3
Miyadome Ohi Town 407.831 3843.58 5365.3
Kariwa Kariwa Village 407.617 4949.58 5365.3
Ueno Satsuma-sendai City 394.248 3592.54 5365.3
Power Station-South 389.191 5231.96 5365.3
Radiation dose at JAEA Oarai (P6) 386.963 5318.78
Power Station- 385.546 5106.44 5365.3
Takae Satsuma-sendai City 379.551 3639.6 5365.3
Hokawaduura Genkai Town 378.015 5541.79 5365.3
Kou Itimatsu Suetsugu 377.929 4000.44 5365.3
Minato Satsuma-sendai City 377.656 3333.68 5365.3
Iwanai Iwanai Town 376.336 5433.12 5362.56
Hattari Kyowa Town 373.047 5284.14 5362.56
Chatsu Tomari Village 371.011 5048.94 5362.56
Oyama Maizuru City 358.223 4596.6 5365.3
Kodaira Satsuma-sendai City 355.545 3372.94 5365.3
Kayanuma Tomari Village 354.809 4492.32 5362.56
Anojiri Obama City 353.215 3765.12 5365.3
Kushi Genkai Town 349.738 7647.9 5365.3
Yamaguchi 348.715 6014.98 5357.09
Sadahongou Matsue City 348.228 4682.87 5365.3
Sakibe Karatsu City 347.801 7247.86 5365.3
Hirao Genkai Town 343.814 7640.04 5365.3
The Meteorological Obsevatory of kyowa Town 343.275 5009.76 5362.56
Minami-Horoni Kyowa Town 335.180 4696.14 5362.56
Kounoura Takahama Town 330.353 3969.05 5365.3
Kyoudomarisaki Karatsu City 328.622 7765.56 5365.3
Horikappu Jinja Tomari Village 328.230 4860.78 5362.56
Hukada-kita Matsue City 327.031 3851.39 5365.3
Radiation dose in KEK, Tsukuba 326.240 5337.94
Herokaruusu Tomari Village 324.242 5041.14 5362.56
Yorita Satsuma-sendai City 323.218 3945.52 5365.3
Kamoenai Kamoenai Village 322.032 4257.12 5362.56
Radiation dose in Onagawa (MP-6) 316.267 5316.05
Imamura Genkai Town 314.749 65811 5365.3
Yamanaka Takahama Town 314.185 5122.12 5365.3
Sendai (Miyagi) 312.585 2410.69 5357.09
Radiation dose in Onagawa (MP-1) 300.147 5316.05
Gumisaki Satsuma-sendai City 295.693 3184.68 5365.3
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 286.142 5337.94
Aomori Aomori City 285.372 3237.9 5362.56
Misawa City hall Misawa City 283.728 6279.84 5362.56
Kashu Ikata Town 277.173 3286.62 5365.3
Noheji Town Office Noheji Town 272.004 2775.36 5362.56
Takasimamati 271.103 3498.41 5365.3
Radiation dose in Onagawa (MP-3) 270.563 5316.05
Kucho Ikata Town 269.545 2902.3 5365.3
Radiation dose in Marumori 269.436 5318.78
Kawanagata Ikata Town 266.821 2831.7 5365.3
Tochigi 260.733 3148.46 5357.09
Chikagawa Mutu City 256.719 3614.22 5362.56
Yokohama Town Office Yokohama Town 254.846 4429.62 5362.56
Tokyo 251.877 3712.37 5357.09
Hiranuma Rokkasho Village 251.186 2908.62 5362.56
Taisei Ikata Town 246.293 2125.74 5365.3
Chitose-daira Rokkasho Village 245.868 3136.02 5362.56
Gifu 243.951 5169.12 5357.09
Fukkoshi Yokohama Town 243.102 3041.94 5362.56
Shimane 240.651 5169.12 5357.09
Sunagomata Higashidoori Village 238.012 4398.24 5362.56
Obuchi Rokkasho Village 237.506 3496.62 5362.56
Tomari Rokkasho Village 230.636 4892.16 5362.56
kanagawa 226.339 3242.45 5357.09
Saitama 219.770 2819.52 5357.09
Ikatagoshi Ikata Town 217.515 2674.79 5365.3
Touhoku Branch office Touhoku Town 215.416 2532.3 5362.56
Radiation dose at Tohoku University 214.824 5318.78
Odanosawa Higashidoori Village 210.287 3504.48 5362.56
Kagawa 205.829 3618.38 5357.09
Oippe Higashidoori Village 205.182 3018.42 5362.56
Oita 200.921 3994.32 5357.09
Touhoku Town office Touhoku Town 200.811 11713 5362.56
Kuchogoshi Ikata Town 198.646 2714.04 5365.3
Minatoura Ikata Town 186.776 2439.47 5365.3
Radiation dose in Koyadori, Ojika 184.905 5313.31
Toyama 184.580 6907.82 5357.09
Fukushima [9] (distance from Fukushima I: 45 km) 184.232 3333.02 5351.62
Radiation dose in Tukahama, Ojika 183.417 5313.31
Chiba 182.407 2067.65 5357.09
Nara 182.387 3759.36 5357.09
Okayama 181.976 4887.17 5357.09
Yamagata 181.598 3853.34 5357.09
Ehime 180.745 3477.41 5357.09
Ishikawa 180.445 5991.48 5357.09
Niigata 177.483 7189.78 5357.09
Hiroshima 176.816 3242.45 5357.09
Mie 174.867 3707.67 5357.09
Fukui 170.045 4558.22 5357.09
Radiation dose in Terama, Ojika 168.036 5313.31
Yamanashi 164.561 3007.49 5357.09
Nagano 162.242 4577.02 5357.09
Saga 161.421 4041.31 5357.09
Tottori 161.392 3712.37 5357.09
Radiation dose in Enoshima, Ojika 160.091 5313.31
Osaka 159.103 2866.51 5357.09
Ibaraki-city Environment 157.249 5272.27
Aichi 149.345 3477.41 5357.09
Toyonoura Ikata Town 149.214 2800.31 5365.3
Shizuoka 148.639 3594.89 5357.09
Kyoto 144.522 4088.3 5357.09
Kagoshima 144.449 4431.35 5357.09
Tokushima 143.627 3148.46 5357.09
Gunma 143.572 2114.64 5357.09
Hyogo 139.710 3571.39 5357.09
Fukuoka 136.511 3712.37 5357.09
Wakayama 133.857 2631.55 5357.09
Radiation at Tamaki-cho Mie Japan 133.138 5272.27
Akita 132.832 4041.31 5357.09
Shiga 124.919 2866.51 5357.09
Nagasaki 109.459 3242.45 5357.09
Hokkaido 109.189 4934.16 5357.09
Kumamoto 103.568 3148.46 5357.09
Aomori 101.819 4793.18 5357.09
Miyazaki 100.354 3120.27 5357.09
Kochi 95.931 3571.39 5357.09
Fukushima [35] (distance from Fukushima I: 35 km) 91.917 3324.5 5337.94
Iwate 90.324 3947.33 5357.09
Environment Feeds from Ohta 83.623 5272.27
Okinawa 82.305 2702.04 5357.09
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