核幔边界反射震相ScS对远震体波反演震源参数精度影响

发布时间：2018-03-31 16:26

本文选题：远震体波　切入点：震源深度　出处：《地球物理学报》2016年06期

【摘要】：研究表明,远震直达体波波形(P波、SH波)是有效反演中强地震(M5.5~7)震源参数的重要资料.但是当震中距较大时,核幔边界全反射波ScS会进入SH波反演窗口,其未被传统的基于体波震源参数反演算法所考虑,从而导致反演结果偏差.本文通过TEL3与fk方法合成理论地震图,使用Jackknifing统计方法定量测试了不同情况下ScS震相对远震体波反演的影响.结果表明,当反演数据震中距位于70°~90°时,ScS震相会造成震源质心深度1km左右、机制解最大8°的系统偏差;使用震中距40°~90°的SH波进行抽样反演,机制解最大系统偏差可达5°;SH波与P波联合反演可减少ScS震相引起的震源参数结果系统偏差.因此,ScS震相对基于射线理论的远震体波震源机制解反演所造成的误差是需要给予考虑的.
[Abstract]:The results show that the direct body wave waveform of distant earthquakes / P wave / SH wave) is an important data for effective inversion of the focal parameters of moderate and strong earthquakes (M 5.55). However, when the epicentral distance is large, the total reflection wave ScS of the core and mantle boundary will enter the SH wave inversion window. It is not considered by the traditional inversion algorithm based on volume wave focal parameters, which leads to the deviation of inversion results. In this paper, the theoretical seismograms are synthesized by TEL3 and fk methods. The effect of ScS earthquake on remote body wave inversion under different conditions is quantitatively measured by using Jackknifing statistical method. The results show that when the inversion data epicentral distance is at 70 掳~ 90 掳, the SSS phase will cause the focal mass center depth (1km) to be about, and the mechanism solution will be the maximum systematic deviation of 8 掳. Using SH waves with a distance of 40 掳to 90 掳from the epicentre to carry out the sampling inversion, The maximum systematic deviation of the mechanism solution can be up to 5 掳SH-wave and P-wave inversion, which can reduce the systematic deviation of the focal parameter result caused by the ScS phase. Therefore, the error caused by the inversion of the focal mechanism solution of the SCS earthquake relative to the source solution of the distant body wave based on the ray theory can be reduced. It needs to be considered.
【作者单位】：中国科学技术大学地球和空间科学学院;中国科学院测量与地球物理研究所大地测量与地球动力学国家重点实验室;
【基金】：国家重点基础研究发展计划项目(2014CB845901) 国家自然科学基金(41274069)资助
【分类号】：P315.33

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