| 講演要旨(和文) | | 我々は，賦存量の推定に役立つ物理探査ツールを目標に，AUVや深海曳航体などに搭載可能な磁気探査装置の開発に取り組んでいる．2010年，ベヨネース海丘カルデラにおいて望星丸航海およびよこすか航海を実施し，それぞれ深海曳航体およびAUV「うらしま」を使った白嶺鉱床周辺の試験的な探査を行った．望星丸航海では，カルデラを東西と南東−北西に横切る測線上の海面下400〜570 mの深度において地磁気3成分データを取得した．よこすか航海では，高度60〜100 mで白嶺鉱床を中心としたカルデラ内および深度500 mでカルデラのほぼ東半分の範囲において地磁気3成分・全磁力データを取得した．現在，地磁気3成分データを用いて3次元の磁化構造解析を進めている．本講演では，ベヨネース海丘カルデラの地磁気測定と磁化構造解析について報告する． |
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| | 講演要旨(英文) | | We have been developing a magnetic exploration system by using AUV and deep-tow system. The purpose is to construct a magnetic exploration system that is useful to estimate accurate abundance of seabed resources like hydrothermal deposit. In 2010, that system was tested in the Bayonnaise Knoll caldera both using a titanium towing frame during the R/V Bosei-maru cruise and using AUV Urashima during the R/V Yokosuka cruise. A large hydrothermal deposit, Hakurei deposit, lies in the southeast part of the caldera. In the former, we observed vector magnetic anomalies at depths of 400-570 m along tracks across the caldera. In the latter, we observed vector and intensity magnetic anomalies at altitudes of 60-100 m around the Hakurei deposit and at depth of 500 m above the caldera. A 3D gridded data of the vector magnetic anomaly was made by solving the Laplace's equation in the areas where observation data were not available, which is the unique procedure for analysis of the vector anomalies. Several magnetization solutions have been so far obtained by successive approximation and inversion methods. We will here present the analysis of magnetization structure in the survey area. Note that this study has been supported by MEXT. |
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