| 講演要旨(和文) | | 相模湾北部沿岸域（小田原市沖から三浦市沖）で浅部地下構造を広域的に把握するため海底重力調査を実施した．既存の陸上および船上重力データと新規取得データを編集し，海陸を接続したブーゲー異常図を作成した．この結果，既往の重力データ空白域の詳細な重力異常分布が明らかとなった．三浦半島北部ではWNW−ESE方向の南北2列の高重力異常帯からなる高重力異常域が分布し，北側および南側の高重力異常帯は，各々葉山隆起帯北列と南列とに対応する．また，三浦半島断層群の衣笠断層は，北側の高重力異常帯の南端に対応する．葉山隆起帯北列に対応する北側の高重力異常帯は葉山付近から海域に延長し江の島を経て相模川河口付近まで至ることから，葉山隆起帯および衣笠断層の西方海域への延長が推定される． |
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| | 講演要旨(英文) | | To better understand the shallow underground structure of the northern coastal zone of Sagami Bay, ocean bottom gravity surveys were conducted in Novembers of 2014 and 2015. 142 measurement points were arranged offshore between Odawara and Miura, Kanagawa Pref., at an interval of 0.5 ~ 2 km. These newly measured ocean bottom gravity data were compiled with the existing onshore and offshore gravity data and a Bouguer anomaly map with an assumed density of 2.3 g/cm3 was created. In the Miura Peninsula, an ESE-WNW trending gravity high belt extends from Hayama to close to the mouth of the Sagami River by way of Enoshima Island. This suggests a western continuation of the northern Hayama Unit, one of the Cenozoic accretionary complexes and the Kinugasa Fault which was traced as the southern boundary of the gravity high belt. |
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