title: Terrestrial gamma radiation dose rate in Ryukyu Islands, subtropical region of Japan.
abstract: In order to explain the distribution of natural radiation level in the Asia, in situ measurements of dose rate in air due to terrestrial gamma radiation have been conducted in a total of 21 islands that belong to Ryukyu Islands (Ryukyu Archipelago), subtropical rejoin of southwest Japan. Car-borne surveys have also been carried out in Okinawa-jima, the biggest island of the archipelago. Based on the results for these measurements, arithmetic mean, the maximum and the minimum of the dose rates at 1 m in height from the unpaved soil ground in the archipelago were estimated to be 47, 165 and 8 nGy h(-1), respectively. A comparative study of car-borne data obtained prior to and subsequent to the 2011 Fukushima nuclear accident, as for Okinawa-jima, indicated that the nuclear accident has no impact on the environmental radiation at the present time.
authors.affiliation: Faculty of Science, University of the Ryukyus, 1 Senbaru, Nishihara-cho, Okinawa 903-0213, Japan m_furu@sci.u-ryukyu.ac.jp.
authors.forename: M
authors.initials: M
authors.lastname: Furukawa
authors.affiliation: Graduate School of Engineering and Sciences, University of the Ryukyus, 1 Senbaru, Nishihara-cho, Okinawa 903-0213, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Kina
authors.affiliation: Faculty of Science, University of the Ryukyus, 1 Senbaru, Nishihara-cho, Okinawa 903-0213, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Shiroma
authors.affiliation: Graduate School of Engineering and Sciences, University of the Ryukyus, 1 Senbaru, Nishihara-cho, Okinawa 903-0213, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Shiroma
authors.affiliation: Graduate School of Engineering and Sciences, University of the Ryukyus, 1 Senbaru, Nishihara-cho, Okinawa 903-0213, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Masuda
authors.affiliation: Faculty of Science, University of the Ryukyus, 1 Senbaru, Nishihara-cho, Okinawa 903-0213, Japan.
authors.forename: D
authors.initials: D
authors.lastname: Motomura
authors.affiliation: Graduate School of Engineering and Sciences, University of the Ryukyus, 1 Senbaru, Nishihara-cho, Okinawa 903-0213, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Hiraoka
authors.affiliation: Faculty of Science, University of the Ryukyus, 1 Senbaru, Nishihara-cho, Okinawa 903-0213, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Fujioka
authors.affiliation: Faculty of Science, University of the Ryukyus, 1 Senbaru, Nishihara-cho, Okinawa 903-0213, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Kawakami
authors.affiliation: Faculty of Science, University of the Ryukyus, 1 Senbaru, Nishihara-cho, Okinawa 903-0213, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Yasuda
authors.affiliation: Faculty of Science, University of the Ryukyus, 1 Senbaru, Nishihara-cho, Okinawa 903-0213, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Arakawa
authors.affiliation: Faculty of Science, University of the Ryukyus, 1 Senbaru, Nishihara-cho, Okinawa 903-0213, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Fukahori
authors.affiliation: Faculty of Science, University of the Ryukyus, 1 Senbaru, Nishihara-cho, Okinawa 903-0213, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Jyunicho
authors.affiliation: Faculty of Science, University of the Ryukyus, 1 Senbaru, Nishihara-cho, Okinawa 903-0213, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Ishikawa
authors.affiliation: Faculty of Science, University of the Ryukyus, 1 Senbaru, Nishihara-cho, Okinawa 903-0213, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Ohomoto
authors.affiliation: Graduate School of Engineering and Sciences, University of the Ryukyus, 1 Senbaru, Nishihara-cho, Okinawa 903-0213, Japan.
authors.forename: R
authors.initials: R
authors.lastname: Shingaki
authors.affiliation: National Institute for Fusion Science, 322-6 Oroshi-cho, Toki-shi, Gifu 509-5292, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Akata
authors.affiliation: Institute of Radiation Medicine, Fudan University, No. 2094, Xietu Road, Shanghai 200032, China.
authors.forename: W
authors.initials: W
authors.lastname: Zhuo
authors.affiliation: Institute of Radiation Emergency Medicine, Hirosaki University, 66-1 Hon-cho, Hirosaki-shi, Aomori 036-8564, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Tokonami
mesh_terms: D001417:Background Radiation; D062406:Fukushima Nuclear Accident; D005720:Gamma Rays; D062312:Islands; D007564:Japan; D011829:Radiation Dosage; D011834:Radiation Monitoring / Q000295:instrumentation / Q000379:methods*; D011847:Radioactive Fallout / Q000032:analysis*; D012588:Scintillation Counting; D012990:Soil Pollutants, Radioactive / Q000008:administration & dosage*; D014329:Tropical Climate
chemical_list: D011847:Radioactive Fallout; D012990:Soil Pollutants, Radioactive