| 講演要旨(和文) | | 地下の比抵抗分布を求める電気探査は多くの分野に用いられている.その理由の一つは,岩石や土壌の比抵抗が幅広い範囲の値を示すので,地層の識別に役に立つからである.しかし,極端に比抵抗の高い場所や低い場所を対象とするときは,電気探査装置の選択が非常に重要となる.比抵抗が高い地域では出力電圧の高い装置が必要であり,低い地域では大電流を流す装置が必要である.つまり,電気探査を効果的に行うためには,フィールドに適した装置を使用することが望ましい.そこで発表者は必要に応じて,フィールドの特徴に合わせた新たな電気探査装置の設計・開発を行ってきた.個々のフィールドごとに適した方法で電気探査を行うことを「カスタムメイド電気探査」と呼び,本報告では極端に比抵抗の高い場所や低い場所で実施した「カスタムメイド電気探査」の事例を紹介する. |
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| | 講演要旨(英文) | | The electrical prospecting which investigates a subsurface resistivity distribution is used for many fields. When the resistivity of the subjects of investigation is high like hard rocks or dry sands, it is required to use electrical survey equipment with high voltage since contact resistance is generally high. On the other hand, using the equipment which can send large electric current is required for a low resistivity area like a clay deposit or an alteration zone, since the measured electric potential is low. Thus, equipment suitable for the survey area is required in order to perform electrical prospecting effectively. Selection of electrode arrays is also important since exploration depth and resolution change with the purposes of investigation. However, restrictions of the survey area or the limitation of the capacity of electrical survey equipment may make use of some arrays difficult. I have developed some electrical survey systems suitable for the characteristic of each survey area if needed. I have also chosen the investigating method which suits the survey purpose as much as possible. I call it custom-made electrical prospecting to perform electrical prospecting suitable for the field. This paper reports some of those case studies. |
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