小江断裂带北段上地壳P波速度各向异性分析
发布时间：2018-10-19 18:35
【摘要】：通过宽泛的文献阅读,学习和认识了地震各向异性研究现状及其研究方法,并重点调研了我国大陆、尤其是小江断裂带周边的地震各向异性研究主要进展。在学习和调研的基础上,根据小江断裂带北段地震观测的特殊性,本文初步尝试了一种新的比较简单的地震波速各向异性分析技术-剩余慢度矢量技术,并将这种技术用于小江断裂带北段上地壳P波速度各向异性分析。应用的结果表明，剩余慢度矢量技术是分析地震波速各向异性的有用工具,小江断裂带北段地壳浅层的P波速度各向异性与当地长期的应力状态有关。具体而言,以二维情形下观测速度场为各向同性场和各向异性场的叠加为前提,阐释了利用走时残差估计地震波速各向异性的原理并提出具体计算流程,最后利用小江断裂带北段的巧家流动地震台阵的24个台站记录的6746次地震事件的P波走时残差,计算了各观测站点周围的剩余慢度矢量,由此得到P波的快波方向或慢波方向。计算结果表明,大部分观测点周围的P波快波方向保持一致性,快波方向指向南东东,而慢波方向指向北北东。非常有趣的是,快波的方向与当地应力场P轴的方向比较一致,而慢波的方向与T轴的方向比较一致,这意味着当地应力的长期作用是P波速度各向异性的重要因素。
[Abstract]:Through extensive literature reading, the present situation and research methods of seismic anisotropy are studied and recognized, and the main research progress of seismic anisotropy in mainland of China, especially around the Xiaojiang fault zone, is emphatically investigated. On the basis of study and investigation, according to the particularity of seismic observation in the north section of Xiaojiang fault zone, a new and simple seismic wave velocity anisotropy analysis technique, called residual slowness vector technique, is preliminarily tried in this paper. This technique is applied to the analysis of P wave velocity anisotropy in the upper crust of the northern part of the Xiaojiang fault zone. The application results show that the residual slowness vector technique is a useful tool for analyzing seismic wave velocity anisotropy. The P-wave velocity anisotropy in the shallow crust of the northern section of the Xiaojiang fault zone is related to the local long-term stress state. Specifically, on the premise that the observed velocity field is isotropic and anisotropic in two-dimensional case, the principle of estimating seismic velocity anisotropy by using travel time residuals is explained and the detailed calculation flow is proposed. Finally, the P-wave travel time residuals of 6746 seismic events recorded by 24 stations of Qiaojia mobile seismic array in the northern section of the Xiaojiang fault zone are used to calculate the residual slowness vectors around the observation stations, and the direction of fast wave or slow wave of P-wave is obtained. The results show that the direction of P wave around most observation points is consistent, the direction of fast wave is pointing to east, south and east, while the direction of slow wave is pointing to north and east. It is very interesting that the direction of the fast wave is consistent with the direction of the P-axis of the in-situ stress field, while the direction of the slow wave is more consistent with the direction of the T-axis, which means that the long-term action of the in-situ stress is an important factor for the velocity anisotropy of the P-wave.
【学位授予单位】：中国地震局地球物理研究所
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P315.2
[Abstract]:Through extensive literature reading, the present situation and research methods of seismic anisotropy are studied and recognized, and the main research progress of seismic anisotropy in mainland of China, especially around the Xiaojiang fault zone, is emphatically investigated. On the basis of study and investigation, according to the particularity of seismic observation in the north section of Xiaojiang fault zone, a new and simple seismic wave velocity anisotropy analysis technique, called residual slowness vector technique, is preliminarily tried in this paper. This technique is applied to the analysis of P wave velocity anisotropy in the upper crust of the northern part of the Xiaojiang fault zone. The application results show that the residual slowness vector technique is a useful tool for analyzing seismic wave velocity anisotropy. The P-wave velocity anisotropy in the shallow crust of the northern section of the Xiaojiang fault zone is related to the local long-term stress state. Specifically, on the premise that the observed velocity field is isotropic and anisotropic in two-dimensional case, the principle of estimating seismic velocity anisotropy by using travel time residuals is explained and the detailed calculation flow is proposed. Finally, the P-wave travel time residuals of 6746 seismic events recorded by 24 stations of Qiaojia mobile seismic array in the northern section of the Xiaojiang fault zone are used to calculate the residual slowness vectors around the observation stations, and the direction of fast wave or slow wave of P-wave is obtained. The results show that the direction of P wave around most observation points is consistent, the direction of fast wave is pointing to east, south and east, while the direction of slow wave is pointing to north and east. It is very interesting that the direction of the fast wave is consistent with the direction of the P-axis of the in-situ stress field, while the direction of the slow wave is more consistent with the direction of the T-axis, which means that the long-term action of the in-situ stress is an important factor for the velocity anisotropy of the P-wave.
【学位授予单位】：中国地震局地球物理研究所
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P315.2
【参考文献】
中国期刊全文数据库 前10条
1 张中杰;地震各向异性研究进展[J];地球物理学进展;2002年02期
2 高原,滕吉文;中国大陆地壳与上地幔地震各向异性研究[J];地球物理学进展;2005年01期
3 乔学军 ,王琪 ,杜瑞林;川滇地区活动地块现今地壳形变特征[J];地球物理学报;2004年05期
4 徐震;徐鸣洁;王良书;刘建华;钟锴;童蔚蔚;;用接收函数Ps转换波研究地壳各向异性——以哀牢山—红河断裂带为例[J];地球物理学报;2006年02期
5 崔仲雄;裴顺平;;青藏高原东构造结及周边地区上地幔顶部Pn速度结构和各向异性研究[J];地球物理学报;2009年09期
6 程佳;徐锡伟;甘卫军;马文涛;陈为涛;张勇;;青藏高原东南缘地震活动与地壳运动所反映的块体特征及其动力来源[J];地球物理学报;2012年04期
7 杨晓松,马瑾;大陆岩石圈解耦及块体运动讨论——以青藏高原—川滇地区为例[J];地学前缘;2003年S1期
8 陈睿,李s，
本文编号：2282006
本文链接：https://www.wllwen.com/kejilunwen/diqiudizhi/2282006.html
