不同地球模型的位错理论在地壳形变研究中的影响
发布时间：2019-02-21 08:11
【摘要】：断层面上质点的运动与地表观测到的地面变形的关系可以通过位错理论来描述,断层面上质点的平移与地面形变场、应变场和应变梯度间存在数学对应关系,借助于位错理论模型,利用地震破裂模型可以对地震进行数学模拟,正演计算地震在地表产生的位移、应变等物理量;同时,也可以通过大地测量观测资料(GPS、InSAR等)对地震破裂面上的滑动分布进行反演计算,进而了解和认识地球内部断层活动的动力学过程,为地震、海啸等自然灾害的预测研究提供必要的理论基础。自从位错理论被引入到地震学之后,有关的位错理论研究迅速发展起来,很多学者基于不同地球模型的位错理论研究了同震形变问题。Okada(1985)总结并整理了前人的工作,给出了一套完整简洁的半无限空间均匀介质地球模型的同震变形计算公式,但由于这种模型过于简单,半无限空间地球模型给出的结果往往存在较大误差。在Okada(1985)研究结果基础上,Wang et al.(2003)给出了基于水平层状地球模型的位移格林函数表达式。随后考虑地球的曲率和层状构造,Sun(1992)、Sun和Okubo(1993)基于层状球对称模型发展了新的层状球体位错理论。相对于其他几种模型,层状球形地球模型是较接近真实地球模型的位错理论模型,由于其同时考虑了地球的曲率和径向的层状构造,使得计算结果的精度得到了提高,为更准确地解析大地形变观测数据提供理论支持。为了较全面的研究现有的四种不同的位错理论模型之间的差异,本论文中分别从正演和反演两方面进行分析研究。论文的主要研究工作包括以下几个部分:1.以现有的位错理论模型(均匀半无限、水平层状、均质球形及层状球形地球模型)为基础,计算不同情况(深度、震级、断层类型等)的点震源产生的同震形变,定量分析地球曲率以及地球层状构造对同震形变产生的影响;然后,利用已有的地震破裂模型(2013 Mw 6.6芦山地震),计算该地震在这几种不同的地球模型下在地表产生的同震形变场,讨论不同的地震位错理论在正演计算中的差异及适用性。2.地震形变分布特征主要取决于地震断层破裂模型,不同震级的地震引起形变响应特征(区域范围和大小)存在差异,地震形变分布、形变量和震级之间是非线性相关的。本文也基于球体位错理论,定量分析了不同类型不同震级的地震的形变响应特性,研究地震在垂直断层走向方向上的形变响应范围和震级之间的关系。3.通过模拟反演计算,分析在不同观测数据密度的情况下,地球的层状构造对走滑断层和逆冲断层反演结果的影响;然后,以2001年Ms 8.1昆仑山地震为例,利用GPS观测资料,分别基于均匀半无限模型和水平层状模型位错理论下,对本次地震断层面上的滑动分布进行反演计算,分析地球的层状构造在实际走滑地震破裂模型反演计算中的差异及适用性。
[Abstract]:The relationship between the motion of particles on fault plane and the ground deformation observed on the surface can be described by dislocation theory. There is a mathematical correspondence between the translation of particle on fault plane and ground deformation field, strain field and strain gradient. With the aid of the dislocation theory model, the earthquake can be simulated by using the earthquake rupture model, and the displacement, strain and other physical quantities generated by the earthquake on the ground can be calculated forward. At the same time, through geodetic observation data (GPS,InSAR et al.), the slip distribution on the rupture surface of earthquake can be inversely calculated, and the dynamic process of fault activity in the earth can be understood and understood. The prediction of natural disasters such as tsunamis provides the necessary theoretical basis. Since the introduction of dislocation theory into seismology, the research on dislocation theory has developed rapidly. Many scholars have summarized and sorted out the previous work based on the dislocation theory of different Earth models and the coseismic deformation problem (. Okada (1985). In this paper, a set of formulas for calculating coseismic deformation of a complete and concise homogeneous medium earth model in semi-infinite space are given. However, due to the simplicity of the model, there are often large errors in the results given by the semi-infinite space earth model. Based on the results of Okada (1985), Wang et al. (2003 gives the expression of displacement Green's function based on horizontal layered Earth model. Then, considering the curvature of the earth and the layered structure, Sun (1992), Sun and Okubo (1993) developed a new theory of stratiform spherical dislocation based on the layered spherical symmetry model. Compared with other models, the layered spherical Earth model is a dislocation theoretical model which is closer to the real earth model. The accuracy of the calculation results is improved because the curvature of the earth and the radial stratified structure are taken into account simultaneously. It provides theoretical support for more accurate analysis of geodetic deformation observation data. In order to study the differences between four different dislocation theory models, this paper analyzes and studies them from forward and inverse aspects respectively. The main research work includes the following parts: 1. Based on the existing theoretical models of dislocation (homogeneous semi-infinite, horizontal layered, homogeneous spherical and stratified spherical earth models), the co-seismic deformation caused by different conditions (depth, magnitude, fault type, etc.) is calculated. The influence of earth curvature and stratified structure on coseismic deformation is quantitatively analyzed. Then, using the existing earthquake rupture model (2013 Mw 6.6 Lushan earthquake), the coseismic deformation field produced by the earthquake on the surface under these different Earth models is calculated. The difference and applicability of different seismic dislocation theories in forward modeling are discussed. The characteristics of seismic deformation distribution mainly depend on the rupture model of earthquake faults. The characteristics of deformation response (regional range and magnitude) caused by different magnitude earthquakes are different. The distribution of earthquake deformation, shape variables and magnitude are nonlinear correlation. Based on the theory of spherical dislocation, the deformation response characteristics of earthquakes with different types and different magnitudes are quantitatively analyzed, and the relationship between the range of deformation response and magnitude of earthquakes in the direction of vertical fault strike is studied. The influence of the stratified structure of the earth on the inversion results of strike-slip fault and thrust fault is analyzed by simulated inversion calculation under the condition of different observed data density. Then, taking the Ms 8.1 Kunlun Mountain earthquake in 2001 as an example, based on the dislocation theory of homogeneous semi-infinite model and horizontal layered model, the slip distribution on fault plane of this earthquake is inversely calculated using GPS observation data, respectively. This paper analyzes the difference and applicability of the layered structure of the earth in the inversion calculation of the actual strike-slip seismic rupture model.
【学位授予单位】：中国地震局地震预测研究所
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P315.725
本文编号：2427371
[Abstract]:The relationship between the motion of particles on fault plane and the ground deformation observed on the surface can be described by dislocation theory. There is a mathematical correspondence between the translation of particle on fault plane and ground deformation field, strain field and strain gradient. With the aid of the dislocation theory model, the earthquake can be simulated by using the earthquake rupture model, and the displacement, strain and other physical quantities generated by the earthquake on the ground can be calculated forward. At the same time, through geodetic observation data (GPS,InSAR et al.), the slip distribution on the rupture surface of earthquake can be inversely calculated, and the dynamic process of fault activity in the earth can be understood and understood. The prediction of natural disasters such as tsunamis provides the necessary theoretical basis. Since the introduction of dislocation theory into seismology, the research on dislocation theory has developed rapidly. Many scholars have summarized and sorted out the previous work based on the dislocation theory of different Earth models and the coseismic deformation problem (. Okada (1985). In this paper, a set of formulas for calculating coseismic deformation of a complete and concise homogeneous medium earth model in semi-infinite space are given. However, due to the simplicity of the model, there are often large errors in the results given by the semi-infinite space earth model. Based on the results of Okada (1985), Wang et al. (2003 gives the expression of displacement Green's function based on horizontal layered Earth model. Then, considering the curvature of the earth and the layered structure, Sun (1992), Sun and Okubo (1993) developed a new theory of stratiform spherical dislocation based on the layered spherical symmetry model. Compared with other models, the layered spherical Earth model is a dislocation theoretical model which is closer to the real earth model. The accuracy of the calculation results is improved because the curvature of the earth and the radial stratified structure are taken into account simultaneously. It provides theoretical support for more accurate analysis of geodetic deformation observation data. In order to study the differences between four different dislocation theory models, this paper analyzes and studies them from forward and inverse aspects respectively. The main research work includes the following parts: 1. Based on the existing theoretical models of dislocation (homogeneous semi-infinite, horizontal layered, homogeneous spherical and stratified spherical earth models), the co-seismic deformation caused by different conditions (depth, magnitude, fault type, etc.) is calculated. The influence of earth curvature and stratified structure on coseismic deformation is quantitatively analyzed. Then, using the existing earthquake rupture model (2013 Mw 6.6 Lushan earthquake), the coseismic deformation field produced by the earthquake on the surface under these different Earth models is calculated. The difference and applicability of different seismic dislocation theories in forward modeling are discussed. The characteristics of seismic deformation distribution mainly depend on the rupture model of earthquake faults. The characteristics of deformation response (regional range and magnitude) caused by different magnitude earthquakes are different. The distribution of earthquake deformation, shape variables and magnitude are nonlinear correlation. Based on the theory of spherical dislocation, the deformation response characteristics of earthquakes with different types and different magnitudes are quantitatively analyzed, and the relationship between the range of deformation response and magnitude of earthquakes in the direction of vertical fault strike is studied. The influence of the stratified structure of the earth on the inversion results of strike-slip fault and thrust fault is analyzed by simulated inversion calculation under the condition of different observed data density. Then, taking the Ms 8.1 Kunlun Mountain earthquake in 2001 as an example, based on the dislocation theory of homogeneous semi-infinite model and horizontal layered model, the slip distribution on fault plane of this earthquake is inversely calculated using GPS observation data, respectively. This paper analyzes the difference and applicability of the layered structure of the earth in the inversion calculation of the actual strike-slip seismic rupture model.
【学位授予单位】：中国地震局地震预测研究所
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P315.725
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