中文摘要：

2006年秋,国家海洋局第二海洋研究所在东沙隆起和潮汕（潮南）坳陷完成了OBS2006-3剖面。在整条剖面速度模型的基础上,采用2D层析成像方法,对潮汕（潮南）坳陷区7个站位的中生界折射震相进行了精细的反演成像。结果表明,坳陷内可分3个沉积层,前两层是新生代沉积,速度分别为2.2km/s和3.6km/s,厚度较小,不超过2km。中生代沉积地层的速度从顶部的4.4km/s向下逐渐增加到底部的5.4km/s,厚度较大,最厚处为8km左右。坳陷内速度是比较均匀地随深度增加的,成水平层状分布。重力反演表明,潮汕坳陷中生代沉积的平均密度为2.45g/cm^3,地壳密度为2.86g/cm^3,下地壳高速层密度为3.05g/cm^3,莫霍面下面的上地幔密度为3.32g/cm^3。

英文摘要：

The wide angle seismic profile OBS2006-3 crossing the Dongsha Rise and the Chaoshan and Chaonan Depressions of South China Sea was completed by the Second Institute of Oceanography, SOA in the autumn of 2006. Based on the inversed velocity model of the whole profile, a more accurate 2D tomography imaging was carried out in this paper for a smaller model and only refracted waves recorded by seven OBS stations in the Chaoshan and Chaonan Depressions were used. The imaging results show that there are three sediment layers in/he depression area. The thicknesses of the first two layers of/he Cenozoic sediments are very thin, less than 2 km with velocities of 2.2 km/s and 3.6 km/s, respectively. In the Mesozoic sediment layer the velocity increases gradually from 4.4 km/s at the top to 5.4 km/s at the bottom with a maximum thickness of 8 km and can be considered as a horizontal sub-layer. Based on the gravity simulation of OBS2006-3, the average density of the Mesozoic layer in the Chaoshan and Chaonan Depressions is 2.45 g/cm^3. The average densities of the profile OBS2006-3 in the crust, the high velocity layer and the upper mantle beneath Moho are 2.86 g/cm^3, 3.05 g/cm^3 and 3.32 g/cm^3, respectively.