Earth Planets Space, Vol. 63 (No. 8), pp. e9-e12, 2011
Hisatoshi Ito1, Toru Mogi2, Akira Jomori3, Youichi Yuuki4, Kenzo Kiho1, Hideshi Kaieda1, Koichi Suzuki1, Kazuhiro Tsukuda1, and Sabry Abd Allah2
1Civil Engineering Research Laboratory, Central Research Institute of Electrical Power Industry, 1646 Abiko, Abiko City, Chiba Prefecture 270-1194, Japan
2Institute of Seismology and Volcanology, Hokkaido University, N10W8, Kita-ku, Sapporo 060-0810, Japan
3NeoScience Co., 5-11-22, Onosato, Sennan, Osaka 590-0526, Japan
4Geotechnical Center, Oyo Co., 2-61-5 Toro, Saitama 331-8688, Japan
(Received May 23, 2011; Revised August 2, 2011; Accepted August 4, 2011; Online published October 6, 2011)
Understanding geological and hydrogeological characteristics in coastal areas is an issue of paramount importance considering its socio-economic relevance, whereas, to date, limited information has been acquired due to the lack of suitable survey methods. We have conducted an airborne electromagnetic survey in an alluvial coastal plain, Kujukuri, in southeast Japan, to examine the effectiveness of elucidating the subsurface electric-resistivity structure both on land and offshore. Our approach was to use a grounded electrical dipole source and a helicopter-towed magnetic field receiver. Repeated surveys both at high and low tides revealed that a reliable resistivity structure is available to a depth of 300-350 m in coastal areas where shallow (∼5 m deep) water prevails.
Key words: Airborne electromagnetics, resistivity, coastal area, Kujukuri.