| 講演要旨(和文) | | 放射性廃棄物の地層処分事業において,沿岸域は処分場の建設候補地として十分考えられる地域である.筆者らは,北海道幌延町の沿岸域において,地下深部の地質環境を調査する物理探査技術として,沿岸陸域から海域に至る連続した場所で電磁法探査を実施した.電磁法探査と並行して,沿岸陸域でボーリング孔を掘削し,地質構造や地下水性状を調査した結果,陸域から海域にわたる褶曲構造やそれに伴う断層構造が推定された.また,比抵抗分布と地下水性状の対比結果から,高比抵抗部分は天水起源の地下水が分布することが推定できた.海岸線を挟んだ沿岸域に於いて技術的課題に答える電磁法探査の実証を示すことができた. |
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| | 講演要旨(英文) | | Considering geological disposal, there are still several research tasks existing in geological environment understanding in coastal region including land and offshore in which the geographical features influences less investigation cases as compared to inland. It is also necessary to consider seawater influence and distribution of seawater/fresh water boundaries for the underground characterization. In order to solve the issues, we have performed application test of electromagnetic technique which is developed in the national RTD project, focusing faults and groundwater boundaries at Horonobe coastal area, in Hokkaido. The survey result by seamless analysis from land through offshore indicates that the resistivity distribution suggests large scale fold accompanying faults under seafloor, and spatially distributed different salinity concentration groundwater under inland as well. It is confirmed to be able to apply the electromagnetic technique to the geological structure in the coastal region and the investigation of groundwater properties. |
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