东海陆架盆地南部区域地震速度分析

ANALYSIS OF VELOCITY DATA FROM THE SOUTH OF EAST CHINA SEA SHELF BASIN

在利用速度谱资料进行速度研究的可行性基础上,使用多种方法对速度谱资料进行甄别、筛选,对有效的速度谱资料进行统计、分析,计算出瓯江、闽江、基隆、晋江4个区域及全区的平均速度趋势,阐明了制作各反射层位平均速度分布图的方法,为本区时深转换提供基础资料。同时,分析了地震地质构造与速度趋势的相关性和一致性,对盆地内构造活动不强的区域等速度线与地层分布趋势及密度的关系进行了探讨,指出其对研究重力资料有一定的指导作用。

Based on the feasibility of using speed spectrum data for velocity study, a variety of methods are used in this paper to identify and filter the velocity spectrum data. Statistics and analysis are per- formed by using effective velocity spectrum data to calculate the velocity distribution in the Oujiang, Minjiang, Keelung, and Jinjiang regions and the average speed trend of the whole region has been worked out. The methodology for mapping average velocity of each reflection layer is discussed so as to provide data for basic time-depth conversion. In this paper, we also analyzed the consistency be- tween the seismological and geological structures and their velocity trend, discussed the regional isovelocity pattern and stratigraphic distribution trend as well as density distribution in a structurally inactive basin as such. The results are helpful for study of gravity data.