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Accumulated absorbed dose rate - T=13.03.2011 - 24.01.2018(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 6779.81
Fukushima I MP8 570942.000 6779.81
Fukushima I MP6 240668.000 6779.81
Yamada Futaba Town 176983.000 5317.55 6336.58
Fukushima I MP2 140420.000 6779.81
Fukushima I MP5 111325.000 6779.81
Fukushima [32] (distance from Fukushima I: 30 km) 101500.000 4266.82 6850.94
Fukushima I MP3 93730.602 6779.81
Fukushima I MP4 86821.500 6779.81
Fukushima [33] (distance from Fukushima I: 30 km) 77197.703 4266.82 6850.94
Fukushima [79] (distance from Fukushima I: 40 km) 54008.602 4215.7 6768.86
Fukushima [31] (distance from Fukushima I: 30 km) 40677.398 4266.82 6850.94
Ono Okuma Town 38610.500 4909.9 6336.58
Shinzan Futaba Town 38332.801 4456 6336.58
Fukushima I MP1 31496.801 6779.81
Yonomori Tomioka Town 29815.900 5076.65 6336.58
Fukushima [46] (distance from Fukushima I: 20 km) 28842.500 4266.82 6850.94
Tomioka Tomioka Town 25324.500 5465.74 6336.58
Fukushima [62] (distance from Fukushima I: 40 km) 16464.100 4266.82 6850.94
Fukushima [61] (distance from Fukushima I: 40 km) 13102.800 4266.82 6850.94
Shimo-Kooriyama Tomioka Town 13057.000 5428.72 6336.58
Fukushima [21] (distance from Fukushima I: 30 km) 12103.800 4266.82 6850.94
Fukushima [3] (distance from Fukushima I: 45 km) 11985.000 4266.82 6850.94
Kami-kooriyama Tomioka Town 11803.900 4261.46 6336.58
Fukushima II MP3 11060.600 6779.81
Fukushima II MP1 10903.000 6779.81
Kooriyama Futaba Town 10352.900 4965.49 6336.58
Fukushima II MP4 9696.330 6779.81
Fukushima [34] (distance from Fukushima I: 30 km) 9540.450 4263.41 6845.47
Fukushima II MP5 9382.150 6779.81
Fukushima [2] (distance from Fukushima I: 55 km) 8841.760 4266.82 6850.94
Matsudate Naraha Town 8410.890 5799.25 6336.58
Shigeoka Naraha Town 8115.970 6410.67 6336.58
Fukushima II MP2 7875.320 6779.81
Namie Namie Town 7321.210 4678.34 6336.58
Radiation dose at Shirasawa branch office, Motomiya 7287.920 6796.22
Fukushima II MP6 7062.690 6779.81
Fukushima II MP7 6511.580 6777.07
Fukushima [1] (distance from Fukushima I: 60 km) 5615.310 4266.82 6850.94
Fukushima [11] (distance from Fukushima I: 40 km) 5491.310 4266.82 6850.94
Fukushima [63] (distance from Fukushima I: 45 km) 5448.820 4266.82 6850.94
Fukushima [45] (distance from Fukushima I: 20 km) 3981.200 4266.82 6850.94
Fukushima [42] (distance from Fukushima I: 30 km) 3850.600 4266.82 6850.94
Fukushima [10] (distance from Fukushima I: 40 km) 3734.160 4266.82 6850.94
Fukushima [78] (distance from Fukushima I: 45 km) 3716.820 4261.7 6842.74
Futatsunuma Hirono Town 3520.340 5558.4 6336.58
Fukushima [4] (distance from Fukushima I: 50 km) 3386.310 4266.82 6850.94
Fukushima [7] (distance from Fukushima I: 45 km) 3313.930 4266.82 6850.94
Radiation dose at Koriyama joint government building, Koriyama 3232.890 6793.49
Fukushima [15] (distance from Fukushima I: 35 km) 3178.670 4266.82 6850.94
Kiyohashi Namie Town 3162.000 4103.93 6336.58
Fukushima [71] (distance from Fukushima I: 25 km) 3161.650 4261.7 6842.74
Radiation dose at Agricultural center, Koriyama 3128.960 6793.49
Fukushima [41] (distance from Fukushima I: 20 km) 3111.490 4266.82 6850.94
Radiation dose at Koriyama city office, Koriyama 2803.520 6793.49
Fukushima [44] (distance from Fukushima I: 30 km) 2535.550 4266.82 6850.94
Fukushima [72] (distance from Fukushima I: 30 km) 2344.620 4261.7 6842.74
Fukushima [43] (distance from Fukushima I: 20 km) 2244.110 4266.82 6850.94
Yamadaoka Naraha Town 2205.340 4928.47 6336.58
Radiation dose at Iwane Fureai Plaza, Motomiya 2169.060 6796.22
Fukushima [22] (distance from Fukushima I: 35 km) 2020.650 4266.82 6850.94
Kuji Hitachi City 1990.890 10593.8 6861.89
Hitachinaka Hitachinaka City 1951.950 4652.97 6859.15
Fukushima [76] (distance from Fukushima I: 25 km) 1945.520 4261.7 6842.74
Fukushima [80] (distance from Fukushima I: 25 km) 1876.860 4261.7 6842.74
Momiyama Hokota City 1837.540 5306.95 6861.89
Fukushima [77] (distance from Fukushima I: 25 km) 1802.490 4261.7 6842.74
Horiguchi Hitachinaka City 1779.410 4636.63 6864.62
Onuma Hitachi City 1776.950 3951.05 6859.15
Fukushima [6] (distance from Fukushima I: 45 km) 1741.180 4266.82 6850.94
Tsukuriya Hokota City 1736.890 4464.26 6861.89
Radiation dose at Big palette Fukushima, Koriyama 1668.540 6793.49
Nemoto Hitachioomiya City 1633.190 4973.91 6859.15
Fukushima [13] (distance from Fukushima I: 40 km) 1624.150 4266.82 6850.94
Fukushima [23] (distance from Fukushima I: 35 km) 1551.750 4266.82 6850.94
Radiation dose at Tsukidatemachi kamitedo, Date 1545.300 6801.7
Fukushima [14] (distance from Fukushima I: 35 km) 1543.460 4266.82 6850.94
Radiation dose at JAEA Oarai (P12) 1512.140 6818.11
Radiation dose at Ose administration center, Koriyama 1494.270 6793.49
Araji Hokota City 1437.760 4474.25 6861.89
Ishigami Tokai Village 1431.690 4073.01 6861.89
Mawatari Hitachinaka City 1422.870 4705.03 6861.89
Radiation dose at JAEA Oarai (P11) 1399.370 6818.11
Onuki Oarai Town 1387.990 4885.6 6861.89
Sawa Hitachinaka City 1353.770 3690.28 6859.15
Toyooka Tokai Village 1321.760 4484.3 6861.89
Ajigaura Hitachinaka City 1313.890 4412.3 6859.15
Fukushima [5] (distance from Fukushima I: 45 km) 1282.090 4266.82 6850.94
Geiger Counter Feeds from Asao Kawasaki 1266.620 6771.6
Radiation dose at Tamokami elementary school, Koriyama 1256.140 6793.49
Isohama Oarai Town 1250.540 4260.18 6856.42
Ebisawa Ibaraki Town 1222.240 11564.3 6859.15
Muramatsu Tokai Village 1203.520 4524.45 6861.89
Kamitoda Hokota City 1184.740 3711.86 6861.89
Yanagisawa Hitachinaka City 1166.970 3780.54 6859.15
Tokushuku Hokota City 1159.730 3350.71 6861.89
Tasaki Hokota City 1153.300 3965.26 6831.79
Fukushima [20] (distance from Fukushima I: 45 km) 1145.390 4266.82 6850.94
Kadobe Naka City 1086.580 9005.16 6859.15
Radiation dose at Date city office, Date 1076.050 6796.22
Oshinobe Tokai Village 1041.340 4223.49 6861.89
Oba Mito City 1037.670 13874.3 6861.89
Godai Naka City 1031.270 3661.66 6861.89
Ishikawa Mito City 1030.810 4315.5 6864.62
Isobe Hitachiota City 1013.130 20826.4 6861.89
Yatabe Ibaraki Town 996.127 3621.57 6861.89
Radiation dose at Motomiya city office, Motomiya 992.703 6796.22
Fukushima [73] (distance from Fukushima I: 35 km) 981.984 4261.7 6842.74
Fukushima [75] (distance from Fukushima I: 45 km) 960.529 4261.7 6842.74
Yokobori Naka City 930.280 4243.54 6861.89
Sugaya Naka City 926.186 6483.28 6864.62
Kounosu Naka City 926.087 3310.56 6861.89
Funaishikawa Tokai Village 900.399 4394.02 6861.89
Nukada Naka City 899.900 3969.5 6856.42
Uridura Naka City 890.113 3789.07 6856.42
Shiraki Tsuruga City 881.330 8038.84 6864.62
Motokomezaki Naka City 880.851 3534.34 6829.06
Shiraki pass Tsuruga City 850.284 8420.18 6864.62
Radiation dose in Yamamoto 846.633 6818.11
Yoshizawa Mito City 837.646 3832.24 6861.89
Radiation dose at JAEA Oarai (P7) 831.135 6818.11
Mayumi Hitachiota City 828.119 3802.15 6861.89
Urasoko Tsuruga City 826.465 6673.92 6864.62
Nemoto Hitachioomiya City 825.588 4281.98 6859.15
Takenami Mihama Town 804.283 7005.11 6864.62
Radiation dose at JAEA Oarai (P15) 780.207 6818.11
Tateishi Tsuruga City 780.092 5549.93 6864.62
Radiation dose at JAEA Oarai (P14) 770.174 6818.11
Radiation dose at JAEA Oarai (P13) 769.612 6818.11
Ukishima Kawasaki Ward 735.475 13097 6864.62
Kume Hitachiota City 713.958 3721.85 6861.89
Radiation dose at JAEA Oarai (P2) 712.011 6818.11
Fukushima [74] (distance from Fukushima I: 35 km) 706.552 4261.7 6842.74
Nyuu Mihama Town 674.787 6382.9 6864.62
Fukushima [52] (distance from Fukushima I: 40 km) 672.743 4266.82 6850.94
Radiation dose in Iwanuma 670.242 6818.11
Fukushima [51] (distance from Fukushima I: 40 km) 665.376 4266.82 6850.94
Tsuruga Tsuruga City 655.360 5630.2 6864.62
Shiohama Kawasaki Ward 653.536 4496.15 6864.62
Radiation dose in Kakuda 649.863 6818.11
Sakajiri Mihama Town 649.252 7446.73 6864.62
North point of Kinki University Atomic Energy Research Instirute Station 639.566 4676.8 6864.62
Radiation dose in Onagawa (MP-2) 632.968 6815.38
Kumatori town Nishi primary school Station 631.491 5590.03 6864.62
Oshima Kawasaki Ward 630.402 4285.39 6864.62
Izumisano municipal Oike athletic field Station 629.920 6302.63 6864.62
Atom-kyoudou nursery school Station 625.566 6051.71 6864.62
South point of Kinki University Atomic Energy Research Instirute Station 625.202 5509.76 6864.62
Nakamachi Omaezaki City 623.494 7095.43 6864.62
Uraga Yokosuka City 622.492 3362.04 6864.62
Goritoge Shika Town 622.143 7537.06 6864.62
Kumatori town Minami primary school Station 606.134 6413 6864.62
Radiation dose at JAEA Oarai (P1) 603.643 6820.85
Yamanotedai-No.1 Park Station 599.140 5981.44 6864.62
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 595.502 6837.26
Noumi Shika Town 594.021 7456.73 6864.62
Radiation dose in Watari 591.851 6818.11
Hairando Yokosuka City 588.667 4215.12 6864.62
Fukushima [12] (distance from Fukushima I: 40 km) 588.291 4266.82 6850.94
Ningyotoge Kagamino Town 574.857 5981.44 6864.62
Ten-no Kagamino Town 569.960 7165.7 6864.62
Funagura Yokosuka City 563.909 3974.26 6864.62
Chidori Kawasaki Ward 560.211 3843.77 6864.62
Radiation dose at JAEA Oarai (P16) 556.365 6818.11
Shika Shika Town 551.376 7185.76 6864.62
Higashiosaka municipal Kamikosaka primary scool Station 550.277 4666.74 6864.62
Sahara Yokosuka City 547.404 3723.34 6864.62
Kazanashi Shika Town 545.377 6744.19 6864.62
Akasumi Shika Town 544.970 6172.14 6864.62
Kurahashi Maizuru City 540.820 5620.14 6864.62
Obama Obama City 540.809 5028.04 6864.62
Sakuragaike community hall Omaezaki City 540.772 7276.08 6864.62
Shirowa primary school Omaezaki City 535.692 7125.54 6864.62
Radiation dose at JAEA Oarai (P5) 529.759 6818.11
Uenohara Omaezaki City 529.333 7326.3 6864.62
Kumano Shika Town 529.019 6995.11 6864.62
Izumisano municipal Hineno filtration plant Station 527.471 6031.66 6864.62
Nishi-hamasada Matsue City 525.089 6678.02 6848.21
Kouno Minami-Echizen Town 525.028 5058.14 6864.62
Kurihama Yokosuka City 523.708 4024.42 6864.62
Osaka prefectural Kumatori off-site-center Station 522.808 5559.92 6864.62
Ogasa branch Kikugawa City 522.039 7411.82 6850.94
Izumisano municipal Hineno primary scool Station 518.181 4827.34 6864.62
Shirasuna Omaezaki City 499.479 7175.76 6864.62
Jitougata primary school Makinohara City 498.059 6884.68 6864.62
Kataku Matsue City 497.007 5349.17 6864.62
Nishihemi Yokosuka City 496.917 3211.5 6864.62
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 496.721 6837.26
Satsuma-sendai monitoring center Satsuma-sendai City 495.302 5268.9 6864.62
Otomi Takahama Town 494.821 5901.17 6864.62
Otsu Nanao City 493.895 5921.22 6864.62
The Observation point for comparison Tatsunokuchi 493.454 4877.5 6864.62
Hitsuhama Ohi Town 492.630 5489.71 6864.62
Kijiyama Misasa Town 489.284 5569.98 6864.62
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 487.055 6837.26
Hiraba Omaezaki City 485.878 7175.76 6864.62
Tayu Matsue City 484.956 5580.04 6864.62
Hamaokakita primary school Omaezaki City 484.537 7361.76 6850.94
Oitomi Ayabe City 474.670 7075.38 6864.62
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 472.017 6837.26
Kashiwazaki-shigai Kashiwazaki City 470.822 5630.2 6864.62
Mitsu Matsue City 466.897 5339.17 6864.62
Tonomachi Kawasaki Ward 463.967 6764.24 6864.62
Daitou branch Kakegawa City 463.829 7251.6 6850.94
Fukura Shika Town 462.493 6734.14 6864.62
Nagasawa Yokosuka City 462.365 3934.09 6864.62
The athletic field Station of Kinki University 461.661 4445.93 6864.62
Koura Matsue City 461.049 6372.84 6864.62
Sakurasan Ward Omaezaki City 459.434 6944.89 6864.62
Tsuchikawa Nanao City 458.915 6553.49 6864.62
Kumatori Town office Station 457.917 4586.47 6864.62
Shinkango Omaezaki City 449.013 8038.84 6864.62
Ogurui Takahama Town 448.279 5258.84 6864.62
Kusabue Omaezaki City 444.162 7577.16 6864.62
Omaezaki City monitoring center 443.946 7436.68 6864.62
Akawase Kagamino Town 442.246 4586.47 6864.62
Ibaraki 442.139 3368.06 6856.42
Hinode Town Yokosuka City 438.324 2649.5 6864.62
Nishiyama Kashiwazaki City 437.251 7968.56 6864.62
Kariwa Kariwa Village 436.307 6011.54 6864.62
Osaka prefectural Hineno high scool Station 435.745 5359.22 6864.62
Miyagawa Kashiwazaki City 435.245 5931.28 6864.62
Radiation dose in Natori 434.640 6818.11
Kami-koubu Matsue City 433.868 5830.9 6864.62
Shimo-Takamachi Kariwa Village 433.192 6543.49 6864.62
Osaka prefectural Sano supporting school Station 432.398 5840.95 6864.62
Arahama Kashiwazaki City 428.874 6111.92 6864.62
Doai Kashiwazaki City 425.681 5750.63 6864.62
Owashi Matsue City 424.452 5700.47 6864.62
Okayasu Maizuru City 422.568 6714.08 6864.62
Katsuyama Kariwa Village 421.280 6111.92 6864.62
Kita-koubu Matsue City 420.683 6252.41 6864.62
Kichisaka Maizuru City 413.065 8159.27 6864.62
Nagai Ohi Town 410.699 5934.23 6856.42
Shiokumi Maizuru City 407.938 10156.5 6864.62
Miyadome Ohi Town 407.831 4917.66 6864.62
Kariwa Kariwa Village 407.617 6332.74 6864.62
Ueno Satsuma-sendai City 394.248 4596.47 6864.62
Power Station-South 389.191 6694.03 6864.62
Radiation dose at JAEA Oarai (P6) 386.963 6818.11
Power Station- 385.546 6533.44 6864.62
Takae Satsuma-sendai City 379.551 4656.68 6864.62
Hokawaduura Genkai Town 378.015 7090.43 6864.62
Kou Itimatsu Suetsugu 377.929 5118.36 6864.62
Minato Satsuma-sendai City 377.656 4265.28 6864.62
Iwanai Iwanai Town 376.336 6952.18 6861.89
Hattari Kyowa Town 373.047 6761.55 6861.89
Chatsu Tomari Village 371.011 6460.59 6861.89
Oyama Maizuru City 358.223 5881.12 6864.62
Kodaira Satsuma-sendai City 355.545 4315.5 6864.62
Kayanuma Tomari Village 354.809 5748.34 6861.89
Anojiri Obama City 353.215 4817.28 6864.62
Kushi Genkai Town 349.738 9785.1 6864.62
Yamaguchi 348.715 7698.43 6856.42
Sadahongou Matsue City 348.228 5991.49 6864.62
Sakibe Karatsu City 347.801 9273.26 6864.62
Hirao Genkai Town 343.814 9775.04 6864.62
The Meteorological Obsevatory of kyowa Town 343.275 6410.45 6861.89
Minami-Horoni Kyowa Town 335.180 6009.15 6861.89
Kounoura Takahama Town 330.353 5078.2 6864.62
Kyoudomarisaki Karatsu City 328.622 9935.64 6864.62
Horikappu Jinja Tomari Village 328.230 6219.82 6861.89
Hukada-kita Matsue City 327.031 4927.66 6864.62
Radiation dose in KEK, Tsukuba 326.240 6837.26
Herokaruusu Tomari Village 324.242 6450.6 6861.89
Yorita Satsuma-sendai City 323.218 5048.09 6864.62
Kamoenai Kamoenai Village 322.032 5447.38 6861.89
Radiation dose in Onagawa (MP-6) 316.267 6815.38
Imamura Genkai Town 314.749 84201.8 6864.62
Yamanaka Takahama Town 314.185 6553.49 6864.62
Sendai (Miyagi) 312.585 3085.39 6856.42
Radiation dose in Onagawa (MP-1) 300.147 6815.38
Gumisaki Satsuma-sendai City 295.693 4074.64 6864.62
Radiation via www.houshasen-pref-ibaraki.jp (unofficial information) 286.142 6837.26
Aomori Aomori City 285.372 4143.2 6861.89
Misawa City hall Misawa City 283.728 8035.63 6861.89
Kashu Ikata Town 277.173 4205.06 6864.62
Noheji Town Office Noheji Town 272.004 3551.33 6861.89
Takasimamati 271.103 4476.04 6864.62
Radiation dose in Onagawa (MP-3) 270.563 6815.38
Kucho Ikata Town 269.545 3713.34 6864.62
Radiation dose in Marumori 269.436 6818.11
Kawanagata Ikata Town 266.821 3623.02 6864.62
Tochigi 260.733 4029.65 6856.42
Chikagawa Mutu City 256.719 4624.73 6861.89
Yokohama Town Office Yokohama Town 254.846 5668.1 6861.89
Tokyo 251.877 4751.38 6856.42
Hiranuma Rokkasho Village 251.186 3721.85 6861.89
Taisei Ikata Town 246.293 2719.78 6864.62
Chitose-daira Rokkasho Village 245.868 4012.82 6861.89
Gifu 243.951 6615.84 6856.42
Fukkoshi Yokohama Town 243.102 3892.44 6861.89
Shimane 240.651 6615.84 6856.42
Sunagomata Higashidoori Village 238.012 5627.95 6861.89
Obuchi Rokkasho Village 237.506 4474.25 6861.89
Tomari Rokkasho Village 230.636 6259.97 6861.89
kanagawa 226.339 4149.94 6856.42
Saitama 219.770 3608.64 6856.42
Ikatagoshi Ikata Town 217.515 3422.26 6864.62
Touhoku Branch office Touhoku Town 215.416 3240.32 6861.89
Radiation dose at Tohoku University 214.824 6818.11
Odanosawa Higashidoori Village 210.287 4484.3 6861.89
Kagawa 205.829 4631.09 6856.42
Oippe Higashidoori Village 205.182 3862.34 6861.89
Oita 200.921 5112.24 6856.42
Touhoku Town office Touhoku Town 200.811 14987.8 6861.89
Kuchogoshi Ikata Town 198.646 3472.48 6864.62
Minatoura Ikata Town 186.776 3121.18 6864.62
Radiation dose in Koyadori, Ojika 184.905 6812.64
Toyama 184.580 8841.17 6856.42
Fukushima [9] (distance from Fukushima I: 45 km) 184.232 4266.82 6850.94
Radiation dose in Tukahama, Ojika 183.417 6812.64
Chiba 182.407 2646.34 6856.42
Nara 182.387 4811.52 6856.42
Okayama 181.976 6254.98 6856.42
Yamagata 181.598 4931.81 6856.42
Ehime 180.745 4450.66 6856.42
Ishikawa 180.445 7668.36 6856.42
Niigata 177.483 9202.03 6856.42
Hiroshima 176.816 4149.94 6856.42
Mie 174.867 4745.36 6856.42
Fukui 170.045 5833.97 6856.42
Radiation dose in Terama, Ojika 168.036 6812.64
Yamanashi 164.561 3849.22 6856.42
Nagano 162.242 5858.03 6856.42
Saga 161.421 5172.38 6856.42
Tottori 161.392 4751.38 6856.42
Radiation dose in Enoshima, Ojika 160.091 6812.64
Osaka 159.103 3668.78 6856.42
Ibaraki-city Environment 157.249 6771.6
Aichi 149.345 4450.66 6856.42
Toyonoura Ikata Town 149.214 3582.85 6864.62
Shizuoka 148.639 4601.02 6856.42
Kyoto 144.522 5232.53 6856.42
Kagoshima 144.449 5671.58 6856.42
Tokushima 143.627 4029.65 6856.42
Gunma 143.572 2706.48 6856.42
Hyogo 139.710 4570.94 6856.42
Fukuoka 136.511 4751.38 6856.42
Wakayama 133.857 3368.06 6856.42
Radiation at Tamaki-cho Mie Japan 133.138 6771.6
Akita 132.832 5172.38 6856.42
Shiga 124.919 3668.78 6856.42
Nagasaki 109.459 4149.94 6856.42
Hokkaido 109.189 6315.12 6856.42
Kumamoto 103.568 4029.65 6856.42
Aomori 101.819 6134.69 6856.42
Miyazaki 100.354 3993.56 6856.42
Kochi 95.931 4570.94 6856.42
Fukushima [35] (distance from Fukushima I: 35 km) 91.917 4258.3 6837.26
Iwate 90.324 5052.1 6856.42
Environment Feeds from Ohta 83.623 6771.6
Okinawa 82.305 3458.28 6856.42
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