| 講演要旨(和文) | | 阿寒湖温泉は北海道東部にある阿寒カルデラの南縁に広がっている．本研究では，MT探査により得られる比抵抗構造を基に，地化学データやこれまでのボーリングデータも含めてこの地域の地熱系について議論した．MT探査は，温泉地を横切る湖岸測線上で5点と南側の山中をほぼ東西に横切る山側測線上で9点実施した．得られた比抵抗構造には，深部に延びるダイク状の顕著な低比抵抗構造が両方の測線の西側に見られた．それらを結ぶとこの構造はほぼ南北方向に延びており，この構造に沿って自然溶出の温泉が並ぶことから，断裂帯に伴う熱水上昇帯であると考えられる．また，この構造の浅部から東に延びて湖岸温泉の地下に広がる厚さ200-800m位の層状の低比抵抗構造も見られ、この層は温泉貯留層に対応している．これらの構造を基に西側から熱水が上昇し温泉貯留層の中を天水と混合しながら東へ流れる地熱系モデルを提案した． |
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| | 講演要旨(英文) | | A MT survey was conducted in the Akanko hot springs to clarify a geothermal structure. MT measurements were carried out at 14 survey sites on two lines installed at the lake side and mountain side. 2D resistivity structure revealed conductive dike-like structures at the west site in both lines. A NS direction lineament detected by connecting two sites in each line and many geothermal manifestations are seen along the lineament. This suggests that the conductive structure is interpreted as a fracture zone channeling up flow of geothermal water. Low resistivity layers, 200 to 800m thick, spread over beneath the hot spring area and is interpreted as the reservoir of hot spring. These resistivity structures imply that geothermal water is supplied from the fracture zone in the west area and it flows to the east in the reservoir that formed by mixing it with the meteoric water. The new geothermal model was proposed based on this survey data. |
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