| 講演要旨(和文) | | 地下水流動の把握手法の開発を目的とし,シラス台地における地下水涵養試験の比抵抗法2次元電気探査結果について,3次元の差トモグラフィー解析を行い,地下水涵養試験の地下水流動把握を試みた.地下水涵養試験開始後の比抵抗変化は体積含水率の変化と調和的であり,地下水涵養による不飽和帯の飽和度変化によるものと推定された.2次元解析結果との比較では,3次元解析結果の方が比抵抗変化の範囲が狭く,体積含水率の変化に近い結果が得られた.また,比抵抗変化が等値である面で囲まれた領域は測線間での連続的な不均一な分布を示し、不均一な涵養状況を反映した結果を示した.これらより3次元解析による地下水流動のより詳細な把握の可能性が示された. |
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| | 講演要旨(英文) | | Resistivity monitoring of a groundwater recharge test in a pyroclastic flow plateau was conducted to examine a method for understanding groundwater flow. The three-dimensional (3-D) distributions of resistivity change ratio were obtained from 3-D constrained non-linear differential tomography of apparent resistivity data. Electrical resistivity was largely controlled by variations in water saturation in a vadose zone. Resistivity change ratios of 3-D analyses gave more accurate estimation in volume change of water content than the 2-D analyses. The volume of low-resistivity zone well agreed with the total amount of recharged water and reflected the recharge test of not uniform. These results indicated the possibility of understanding more detailed ground water flow by 3-D analyses. |
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