一种定量地消除波速横向变化影响的三叉震相一维波速结构反演计算方案  

A Computational Scheme for Quantitatively Removing the Effects of Lateral Velocity Variation on 1-D Triplicated Wave Velocity Inversion

作　　者：李嘉琪[1] 王曙光[2] 蔡晨 宁杰远[1] 

机构地区：[1]北京大学地球与空间科学学院,北京100871 [2]中国地震局地震预测研究所,北京100036 [3]Department of Earth and Planetary Sciences,Washington University,Saint Louis,MO 63130-4899

出　　处：《北京大学学报（自然科学版）》2016年第3期420-426,共7页Acta Scientiarum Naturalium Universitatis Pekinensis

基　　金：中国地震局地震预测研究所基本科研业务专项(02092438);国家自然科学基金(41130316)资助

摘　　要：通过数值模拟分析,定量讨论震源区附近高速异常、接收区附近低速异常以及目标区浅部局地波速异常对三叉震相反演一维波速结构的影响,结果说明波速横向变化在传统的一维波速结构反演中会产生与异常体相同量级的波速异常假象。提出一种借助区域或全球层析成像结果定量地消除波速横向变化对利用三叉震相走时进行一维波速结构反演影响的解决方案。利用射线追踪法进行的测试计算表明,提出的计算方法能有效地消除波速横向变化对计算结果的影响,使得反演结果更接近于真实结构。Theoretical analysis quantitatively shows that high velocity anomaly near source, low velocity anomaly near receiver and the lateral velocity variation above the target inversion area have the influence of the same dimension of anomaly on the traditional inversion of 1-D wave velocity by triplicated wave arrival times. A quantitative computation scheme is proposed to remove the smearing effects with the help of regional or global tomograpby results when using 1-D inversion by triplicated wave arrival times. Tests imply that the velocity smearing could be eliminated to great extent and the real 1-D structure might be recovered.

关 键 词：地震反演 地球内部结构 地幔转换带 三叉震相 波速污染 

分 类 号：P315[天文地球—地震学]