| Co-Investigator(Kenkyū-buntansha) |
KUVSHINOV Alexey Inst.Geoelectromag.Rad., Russian Academy of Sciences, 主任研究員
PANKRATOV Oleg Inst.Geoelectromag.Rad., Russian Academy of Sciences, 主任研究員
ZHAO Guo-Zu Geological Inst., State Seismological Bureau, China, 教授
CHAVE Alan Woods Hole Oceanographic Institution, 主任研究員
KOGA Momoki Faculty of Science, Univ.Ryukyus, 理学部, 助教授 (50153515)
TANAKA Yoshikazu Fuculty of Science, Kyoto Univ., 理学部, 助教授 (00025420)
YUMOTO Kiyofumi Fuculty of Science, Kyushu Univ., 理学部, 教授 (20125686)
HAMANO Yozo Dept.Earth and Planet.Physics, Univ.Tokyo, 大学院・理学系研究科, 教授 (90011709)
SHIMIZU Hisayoshi Earthquake Research Institute, Univ.Tokyo, 地震研究所, COE非常勤研究員
UESHIMA Makoto Earthquake Research Institute, Univ.Tokyo, 地震研究所, 助手 (70242154)
SATO Toshinori Earthquake Research Institute, Univ.Tokyo, 地震研究所, 助手 (70222015)
KASAHARA Junzo Earthquake Research Institute, Univ.Tokyo, 地震研究所, 教授 (70012953)
GUOーZU Zhao 国家地震局地質研究所, 教授
ALEXEY Kuvsh ロシア科学アカデミー, 主任研究員
ALAN Chave Woods Hole海洋研究所, 主任研究員
OREG Pankrat ロシア科学アカデミー, 主任研究員
VANYAN Leon ロシア科学アカデミー, 教授
MEDZHITOV R ロシア科学アカデミー, 教授
木下 肇 海洋科学技術センター, 深海研究部, 研究員 (10110347)
行武 毅 九州大学, 理学部, 教授 (90012898)
VANYAN L. ロシア科学アカデミー, 教授
MEDZHITOV R. 太平洋海洋研究所, 教授
CHAVE A. WoodsHole海洋研究所, 主任研究員
LARSEN J. NOAA海洋環境研究所, 研究員
HELSLEY C. ハワイ大学, 教授
BUTLER R. IRISオーシャンケーブル, 所長
竹松 正樹 九州大学, 応用力学研究所, 教授 (50038535)
淡路 敏之 京都大学, 理学部, 助教授 (40159512)
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| Budget Amount *help |
¥14,900,000 (Direct Cost: ¥14,900,000)
Fiscal Year 1996: ¥4,600,000 (Direct Cost: ¥4,600,000)
Fiscal Year 1995: ¥5,200,000 (Direct Cost: ¥5,200,000)
Fiscal Year 1994: ¥5,100,000 (Direct Cost: ¥5,100,000)
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| Research Abstract |
This three-year project has been carried out for the purpose of constructing a submarine cable network to measure electrical potential variations in the Pacific. For the first and second years, recording systems were installed at the international cable landing stations at Guam, Ninomiya, Okinawa, and Nakhodka. Observations of geomagnetic field variations have been also made at Guam, Vladivostok, and Muntinlupa.
Using the data thus obtained, analyzes were carried out to study the electrical conductivity structure of the mantle in the western Pacific region. One-dimensional analysis indicated a presence of a highly conducting layr at about 150 km depth. A thin sheet modeling technique was applied to evaluate the effect of major surface heterogeneity such as ocean-continent distribution.
At period range longer than several hours, induction effects by water flow across the cable become dominant in the measured voltage. A study on the time variation in Kuroshio flux has been done by using the cable voltage data between Okinawa and Taiwan where Kuroshio flows into East China Sea through a narrow channel.
A simple theoretical work was done to calculate the induction effect on the electromagnetic variations originated from the Earth's core through the conducting mantle. This calculation showed that the electric field variations measured on the Earth's surface includes a component corresponding to the toroidal mode of the geomagnetic field variations which can never be observed by magnetic measurements. The calculation suggested that short term secular variations of a few decades' periods may be observed only by a cable voltage measurement. It also implied that a cable network may reveal not only the intensity but also information on the spatial distribution of the toroidal magnetic field near the core-mantle boundary.
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