| 講演要旨(和文) | | 磁気探査で目的の地下構造を探る場合，しばしば金属製の廃棄物やガードレール，鉄骨の入った側溝，崩落防止の金属網などの影響を受ける場合がある。これら金属製の人工物は，磁気探査でターゲットとする磁化構造よりも強力な磁化も持つことが多く，測定場所のすぐ近くに存在することも多い。これらの人工物による，磁気探査にとってはいわばノイズになる磁場の除去は厄介である。そのような人工物による磁場は，正と負の磁気異常がセットになって現れることが多いことに着目し，部分的に最適な磁気双極子をあてはめて除去する方法を試みた。秋田県仙北市にある白岩瀬戸山の登り窯跡の磁気探査に，この人工物による磁場ノイズ除去法を適用した例を示す。ここでの磁気探査の最終的な目的は，熱残留磁化による磁気異常を検出することにより，窯跡を特定することである。 |
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| | 講演要旨(英文) | | In the magnetic exploration field, we are sometimes suffered from the intense magnetic field due to artificial obstacles such as guard rails along the road, ditches made by iron and concrete, metal nets or wires to prevent collapsing the rock wall, and so on. A method of removal of such artificial noises is introduced here. The method of reduction is fitting the noise data into theoretical magnetic field producing by magnetic dipoles using a kind of inversion by the Marquardt method. These reductions of magnetic noises are applied to practical data at a field of a pottery site where the magnetic anomalies due to thermal remanent magnetization are expected. The selected site is the Shiraiwa pottery vestige in Senboku city, Akita prefecture. The production of potteries, however, had ceased more than one hundred years ago. In the vicinity of the pottery vestige, now a ditch made by concrete and iron is there for use of supplying the water for agriculture. Due to irons included by the ditch, intense magnetic field are produced and it becomes sometimes noise for positioning the old kilns by magnetic exploration. |
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