Evolution of Oceanic Crust of the Marginal Seas in the South China Sea

南海边缘海洋壳演化

• 批准号: 04044043
• 负责人: KINOSHITA Hajimu
• 金额: $ 10.05万
• 依托单位: University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for international Scientific Research
• 财政年份: 1992
• 资助国家: 日本
• 起止时间: 1992 至 1993
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-04044043/
• 关键词: Marginal basin; Seafloor spreading; Fluxgate magnetometer; Seismic reflection; Oceanic crust; Continental crust; 人工地震; 海底地殻熱流量; 南シナ海域; 地殻構造; 海洋性地殻; 受動的縁辺; 大陸地殻; 地震波速度構造探査; 地磁気探査; 重力探査

There are number of marginal basins in the Northwestern Pacific region of which the Japan and South Chine Seas are studied far better than other marginal basins of the region. It is frequently referred that Japan Sea and South China Sea have good similarities from the viewpoint of not only general topographic shape but also seismic and magnetic data. Both marginal basins have oceanic and continental crust with some clearly definable magnetic lineations. The similar characteristics of the erratic change in the trend of the magnetic trend in both seas infers number of faults hidden under the thick sediment cover hardly noticeable only by bathymetric observations. These marginal seas are thought to be in the tension-induced rifting stage along the boundary between oceanic and continental plates.A series of marine geophysical observations by the R/V Shi Yan II in the northern margin of the South China Sea were carried out in early summer of 1993. The objective of this scientific cruise is … More to collect data to study comparative geosciences on the marginal seas, i.e., Japan and South China Seas, in terms of the transition in the seismic structure and magnetic characteristics in the transient boundary between continental and abyssal basin. The data include single channel seismic reflection, airgun - OBS refraction profiles, total and three component magnetic data, and gravity data.The proton, precession and fluxgate magnetometer data, tilt of the measuring devices by use of horizontal and vertical gyroscope are collected by a microcomputer and recorded on a MO disk every two seconds along 400 km-long track lines. Number of complete circular turns of the vessels heading were run during the cruise in order to eliminate the effect of the ship's magnetization from the field data. The three component anomalies can then be calculated by referring to the IGRF90.The set of new three vector geomagnetic anomalies obtained by this study, and the total magnetic profiles compiled so far show that asymmetric and discontinuous seafloor geography and roughness of the acoustic basement reflect the variability of the spatial and temporary spreading rate and direction. Less

西北太平洋地区有许多边缘盆地，其中日本海和中国南海的研究远比该地区的其他边缘盆地要好。日本海与南海不仅在总体地形上有很好的相似性，而且在地震和磁测资料上也有相似性。两个边缘盆地都有洋壳和陆壳，并有一些明确的磁线理。这两个海洋的磁趋势的不规则变化具有相似的特点，这意味着在厚厚的沉积物覆盖层下隐藏着许多断层，只有通过测深观测才很难发现。1993年初夏，“石岩二号”考察船在南海北方边缘进行了一系列海洋地球物理观测。这次科学考察的目的是 ...更多信息 收集数据，研究边缘海的比较地球科学，即，日本海和中国南海，在大陆和深海盆地之间的过渡边界的地震结构和磁性特征的过渡。资料包括单道地震反射、气枪- OBS折射剖面、全磁、三分量磁、重力资料，质子、旋进、磁通门磁力仪资料，水平和垂直陀螺仪倾斜，沿沿着400公里长的轨道线，每隔2秒由微机采集并记录在磁光盘上。在巡航期间，对船舶航向进行了多次完整的圆周旋转，以消除磁场数据中船舶磁化的影响。通过本研究获得的一组新的三矢量地磁异常和迄今为止编制的总磁剖面表明，不对称和不连续的海底地形和声学基底的粗糙度反映了空间和暂时扩展速率和方向的变化。少

项目成果

T.Ouchi: "Population dynamics of earthquakes and mathematical modeling" Pure and Applied Geophys.140. 15-28 (1993)

T.Ouchi：“地震的人口动态和数学建模”纯粹与应用地球物理学.140。

Y.Nakasa: "Japan-China Joint Geophysical Survey in the nothern part of the South China Sea:Total and three components magnetic anomalies" JUly 1994,Western Pacific Geophysical Meeting. (印刷中). (1994)

Y. Nakasa：“南海北部的日中联合地球物理调查：总磁异常和三分量磁异常”，1994 年 7 月，西太平洋地球物理会议（1994 年出版）。

M.Sekine: "Seismic Crustal Structure of the Northern South China Sea by the Japan-China Joint Study" 1994, Western Pacific Geophysical Meeting. (in press). (1994)

M.Sekine：“日中联合研究南海北部地震地壳结构”，1994年，西太平洋地球物理会议。

M.Sekine: "Seismic Crustal Structure of the Northern South China Sea by the Japan-China Joint Study" 1994,Western Pacific Geophysical Meeting. (印刷中). (1994)

M.Sekine：“日中联合研究的南海北部地震地壳结构”，1994 年，西太平洋地球物理会议（1994 年）。

T.Ouchi: "Wide regional activation of seismic activities revealed by the OBS observation" Proceeding of International Symposium on “Continental Earthquakes"Beijing,China. 334-342 (1993)

T.Ouchi：“OBS观测揭示的地震活动的广泛区域”“大陆地震”国际研讨会论文集，中国北京334-342（1993）。