| 講演要旨(和文) | | 断層構造抽出の検討に資するため，海域から陸域にわたるシームレスな地震波速度構造を描き出すことを目的として，青森県下北半島を東西に横断する測線上において反射法及び屈折法地震探査を実施した．得られた地震波速度構造の主な特徴は以下の通りである．（１）深度2500mまでの浅層部に関しては，東通沖大陸棚部直下では，小規模の堆積盆が存在し，その西側の陸域区間には短波長の速度不均質領域が卓越する．（２）下北半島中軸部から陸奥湾にかけては，緩やかな西傾斜の反射波列が明瞭であり，陸奥湾側の堆積盆形状が把握できる．陸奥湾側の海陸接合点から西側の陸奥湾沿岸海域では，顕著な褶曲構造が確認でき，反射パターンと屈折法解析による速度構造は調和的である． |
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| | 講演要旨(英文) | | A joint analysis of the data obtained by seismic reflection and refraction survey, with special reference to the existence of faults and folds structure assumed to extend thorough land from sea revealed detailed seismic velocity structure from the shallow to the deeper part of the Shimokita Peninsula, Northeast Japan. The main characteristics of the seismic velocity structure were summarized as follows: (1) A low velocity layer, having a small-scale basin structure, is clearly distributed to a maximum depth of about 2,500m extends from the eastern part of the land region toward the offshore of the Pacific Ocean. (2) A few strong seismic reflectors, with dipping to the westward, are situated in the western part of the land region extending toward the offshore of the Mustu Bay. In this survey, we succeeded to illustrate the detailed seismic velocity structure and find the basin and the folds structure beneath the Shimokita Peninsula. |
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