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:198 2年以来 ,中国科学院海洋研究所在东海海域进行了二十多个站位的遥测浮标折射地震测量 ,1991年又在东海陆架区进行了OBS测量 .本文在我国东海海域选择了横穿东海陆架、冲绳海槽、琉球岛弧、琉球海沟和菲律宾海盆的一条剖面 ,利用上述折射地震资料及其它该剖面附近的折射地震资料 ,对该剖面的地壳速度结构进行了研究 ,并进行了速度年代对比 .研究表明 :剖面的速度结构在纵向上和横向上都表现出明显的差异 ,横向上可分为三隆三盆 ,纵向上大致可划分为1.8～ 2 .2km/s、2 .4～ 2 .8km/s、3.0～ 3.6km/s、4 .2～ 5.1km/s和 5.75～ 6.0km/s的速度层 .从地壳的速度结构推测本海区至少有如下的沉积旋回 :除冲绳海槽的中轴外 ,上新世至第四纪本海区沉积环境稳定 ,而冲绳海槽中轴可能一直处于构造活跃的状态 ;始新世为本区沉积的全盛期 ;渐新世该区域处于抬升的时期 ,钓鱼岛隆起区、琉球岛弧隆起区在此时期的沉积被剥蚀殆尽 ,东海陆架和冲绳海槽此时期的沉积也受到相当程度的剥蚀 .东海陆架盆地和冲绳海槽盆地的出现可能在 5.75～ 6.0km/s的速度层沉积之后 .菲律宾海盆为典型的大洋地壳结构 .
: 198 Two years ago, the Institute of Oceanology, Chinese Academy of Sciences conducted telemetry buoy refraction seismic surveys of more than 20 stations in the East China Sea, and conducted OBS surveys in the East China Sea shelf area in 1991. In this paper, The East China Sea shelf, the Okinawa Trough, the Ryukyu Island arc, the Ryukyu Trench and the Philippine Basin, a section of the use of the above refraction seismic data and other refraction seismic data near the section of the crustal velocity structure of the section studied and carried out the speed The results show that the velocity structure of the section shows obvious differences in vertical and horizontal directions, which can be divided into three longan and three basins in the horizontal direction and can be divided into 1.8-2.2km / s, 2.8km / s, 3.0 ~ 3.6km / s, 4.2 ~ 5.1km / s and 5.75 ~ 6.0km / s respectively.According to the velocity structure of the crust, it is estimated that there are at least the following sedimentary cycles in this area: Outside the central axis of the trough, the depositional environment was stable from Pliocene to Quaternary, but the central axis of the Okinawa Trough may have been in an active tectonic setting. Eocene was the heyday of sedimentation in this area. Oligocene The area was uplifted When During this period, sediments of the Ryukyu Island arc uplifted area were eroded away and the sediments of the East China Sea shelf and the Okinawa Trough during this period were also considerably eroded. The occurrence of the East China Sea Shelf Basin and the Okinawa Trough Basin may occur at After the velocity of 5.75 ~ 6.0km / s is deposited, the Philippine basin is a typical oceanic crust.