南海中部海域地震速度分析

从南海中部海域多次地球物理调查获得的速度资料中,挑选3 000多个速度谱点,经过解释直接或间接地获得该区200多条剖面上各点的叠加速度、均方根速度、层速度等多种速度资料,并计算出该区的时深转换和砂岩百分含量。综合各剖面上的速度变化和Ps值(砂岩百分含量)特征,编制了晚始新世以来地层速度和Ps值平面图,分析各时代层速度和Ps值的纵向和横向变化规律。得出南海中部海域物源早期来自西北方向,中期西南方向,最后远离物源的变化过程,海水进侵方向为东南方向。进而说明该区经历了初期冲积平原、中期滨海—浅海和晚期浅海—半深海的充填演化过程。为研究该区的地层沉积特征和沉积模式提供依据。

Analysis of Seismic Velocity in the Middle of the South China Sea

Stacking velocity,rms velocity and interval velocity in 200 seismic profiles were calculated with more than 3 000 velocity spectrums in the middle of the South China Sea,and Ps value in each sedimentary layer from Paleocene was analyzed later.The result shows that material resource to the middle of the South China Sea is first from the northwest,then from the southwest and last from the material resource,which has revealed the transformation of the sedimentary environment of the area from alluvial plain to shallow sea and to semi-deep sea.