| 講演要旨(和文) | | 産総研の研究テーマ「関東平野の地震動特性と広域地下水流動系の解明に関する地質学的総合研究」の一環として,平野中央部において地下構造調査を実施してきた.主な調査対象は深度数10mから500m程度の中層地層である.本テーマの地下構造調査では,ボーリング地点近傍を通る調査測線の反射断面を作成し,個々の反射面と地層を詳細に対比し平野中央部の広域的な地層変形を明らかにするとともに,地下水の水質異常と地下構造との関係解明の基礎データを提供する.加須低地において綾瀬川断層と並行する方向で新規に実施した北西-南東方向の反射断面では,おおむね水平かわずかに南東に傾斜する成層構造が捉えられ,顕著な構造変化は無さそうである. |
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| | 講演要旨(英文) | | A chloride concentration and characteristic isotopic distribution occur in the center of the Kanto plain. The area almost corresponds to the Motoarakawa tectonic zone delineated by the Ayasegawa fault and Kuki fault. We had conducted seismic surveys crossing the Motoarakawa tectonic zone from northeast to southwest. The Ayasegawa fault is perceived on the seismic section and probably acts as a southwest barrier of groundwater system, but the Kuki fault is not recognized in the seismic section and the northeast boundary of the system may not be a structural one but a change of facies and so on. As a additional survey, we carried out a new seismic survey parallel to the Ayasegawa fault in the Motoarakawa tectonic zone. There seem no distinctive geologic structures which acts as a barrier around the northwest boundary of the system. |
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