青藏块体东北缘及其周围地区现今时空运动变形特征

依据非连续变形分析(DDA)方法，考虑特定块体边界不同程度的适度侵入，利用3期GPS观测资料(1991、1999、2001年)，建立了青藏块体东北缘及其周围地区的一级块体运动模型和划分较细的、反映较小区域运动变形的较理想块体运动模型。模拟得到了研究区内北西西向大断裂间一级块体的运动变化特征、研究区主应变率场的分布特征及青藏块体北边界断裂的分段非均匀时空运动特征。     

中国大陆活动地块变形与地震活动的关系

本文在中国大陆及邻区活动地块研究的基础上，利用球面上的非连续变形分析方法(DDA)和近10年来的GPS测量结果，对整个中国大陆及其周边地区各活动地块的运动和变形状况进行了初步研究。研究结果表明，虽然中国大陆东西部各活动地块的运动速率和应变率相差较大，但位于同一个地块区的各个活动地块之间的运动和变形具有一定的协调性。文中还计算了活动地块边界带之间的相对运动，讨论了现今地壳运动和强震活动的关系。发现1988年以来，中国陆区的7级以上地震都发生在GPS测量所给出最大剪切应变率差异大的活动地块的边界带和现今滑动速率大的活动地块的边界断裂上。     

青藏块体东北缘及其周围地区现今时空运动变形科特征

依据非连续变形分析(DDA)方法,考虑特定块体边界不同程度的适度侵入,利用3期GPS观测资料(1991、1999、2001年),建立了青藏块体东北缘及其周围地区的一级块体运动模型和划分较细的、反映较小区域运动变形的较理想块体运动模型.模拟得到了研究区内北西西向大断裂间一级块体的运动变化特征、研究区主应变率场的分布特征及青藏块体北边界断裂的分段非均匀时空运动特征.     

应用非连续性模型模拟断层活动对青藏高原应力应变场的影响

在青藏高原的运动变形过程中，断层活动起着至关重要的作用.本文利用有限元数值模拟的方法，分别计算了在GPS做边界约束下青藏高原及周边区域的连续体模型和含断层的不连续体模型的运动状态和应力场分布.从连续性模型和非连续体模型的差异发现，断层存在与否很大程度上影响了青藏高原现代运动场的分布.主要体现在，断层的滑移运动（1）增加了青藏高原东西两侧的拉张趋势；（2）加大了青藏高原物质东移的速度；（3）改变了塔里木和柴达木盆地的运动状态.模拟结果显示，非连续模型的运动场分布与GPS观测结果吻合程度大大高于连续体模型结果，表明断层活动在青藏高原的运动学和动力学过程中起着重要的作用，在研究青藏高原的动力学机制中，必须考虑断层作用的影响.     

2001年8.1级昆仑山大震破裂过程及对2008年汶川8.0级大震孕育发生影响的研究

本文用三维流变非连续变形(块体边界)与有限元(块体内)相结合(DDA+FEM)的方法,在青藏高原及其东侧四川盆地,鄂尔多斯块体地区三维构造块体相互制约的大环境中,考虑了龙门山断裂带东西两侧地势、地壳厚度和分层的明显变化,及断裂带东侧四川盆地及鄂尔多斯块体坚硬地壳阻挡的影响,通过用GPS资料做位移速率边界约束和震源机制约...     

断层带及周围块体系统的非连续运动变形模拟

从工程块体系统非连续变形分析的基本理论出发，在严谨的运动学、力学基础上，给出了利用大地测量数据（包括空间大地测量，跨断层测量，形变测量等）分析断层带及其周围块体系统非连续运动变形的基本方程和方法。此方法除具有有限单元法的优点外，还能根据具体情况采用各种形状的弹性块体划分，对不同的断层和块体间的接触、滑动、张开选取不同物理参数，并把系统的大位移和大变形视为小位移和小变形的迭加。文中给出了计算公式和正反分析算例。     

1997年玛尼地震对青藏川滇地区构造块体系统稳定性影响的三维DDA+FEM方法数值模拟

本文用三维非连续变形与有限元相结合（DDA+FEM）的方法,在青藏川滇地区三维构造块体相互制约的大背景中,通过用GPS资料做位移速率边界约束和震源机制约束,计算得到研究区的初始位移场和应力场与该地区GPS测量结果和震源机制分布结果基本一致.在此基础上进一步数值模拟1997年玛尼7.9级大震的发生过程,研究大震引起研究区各块体边界断层应力状态变化的特征.（1）发震断层两侧发生左旋走滑错动,最大水平位错大约7 m;（2）深部位错面上位错分布与用地震波资料震源反演的结果类似;（3）最大差应力变化等值线图与由星载D\|INSAR技术获取的地表形变场图像相似;（4）地表垂直位移表明地震断层面略向北逆冲.计算模拟得到了玛尼地震发生引起青藏川滇地区构造块体系统各边界断层上库仑破裂应力变化的分布,表明玛尼大震的发生除了使其发震断层的两端库仑破裂应力增大,应力进一步集中外,位于上地壳层上东昆仑断裂中段的2001年昆仑山8.1大震（H=11 km）发震断层段的库仑破裂应力增加约2 MPa,位于中地壳层上喀拉昆仑断裂带中的2008年改则6.9级地震（H=30 km）发震断层段的库仑破裂应力也增加约0.7 MPa,可见这两个已接近破裂强度地段的失稳对发生大震起了一定促进作用.研究结果也表明：作者发展的三维DDA+FEM方法能有效地用于大震活动与各构造块体相互作用关系的研究.     

玛尼昆仑山大震对青藏川滇块体系统稳定性影响数值模拟

用三维流变非连续变形与有限元相结合(DDA+FEM)的方法,在青藏川滇地区三维构造块体相互制约的大背景中,通过用GPS资料做位移速率边界约束和震源机制分布约束,计算得到研究区的初始位移场和应力场与该地区GPS测量结果和震源机制分布结果基本一致.表明青藏及其邻近地区由于受印度板块俯冲的强烈挤压及其内部物质东流的影响,现今位移速率场、构造应力场相当复杂.位移场从南边拉萨块体的北北东方向到其北面的羌塘、昆仑、柴达木块体的东部逐渐转为向东方向.     

2008年5月12日汶川8.0级地震孕震机理研究

本文用三维流变非连续变形与有限元相结合(DDA+FEM)的方法,在青藏高原及邻近地区三维构造块体相互制约的大背景中,考虑了龙门山断裂带东西两侧地势、地壳厚度和分层的明显变化,及断裂带东侧四川盆地及鄂尔多斯块体坚硬地壳阻挡的影响,通过用GPS资料做位移速率边界约束和震源机制约束,计算得到研究区的速度场和应力场与该地区GPS测量结果和震源机制分布结果基本一致.     

1966年以来华北地区一系列七级大震破裂过程的数值模拟

用非连续变形分析方法(DDA+FEM)数值模拟，在华北地区各地块相互制约的块体系统环境中，地块边界断层上发生1966年邢台地震、 1969年渤海地震、 1975年海城地震、 1976年唐山地震等不同类型破裂模式大震的破裂过程. 数值模拟结果给出每个大震释放的主应力场，最大剪应力变化等值线图，地震前后位移变化矢量图，发震断层滑移随时间变化以及走滑错距和应力降等震源参数. 这些结果与地震的震源机制，用地震波资料研究得到的震源参数,宏观等震线,地表观测的水平位移矢量图基本一致. 其中1969年渤海地震正交破裂模式的结果与宏观等震线及小震分布图像更接近. 1976年唐山地震复杂震源模式与该震早期余震分布图像更相符. 表明用DDA+FEM方法进行数值模拟研究，能较好地模拟地震破裂过程.     

块体系统非连续变形数值方法──DDA及其在地壳应力分析中的应用

介绍了块体系统非连续变形分析数值方法的基本理论及特点,讨论了DDA解算大地测量资料应解决的问题根据地质构造背景建立大华北块体网络系统,利用华北GPS网3期观测资料进行地壳应力场反演,结果与原地应力测量资料和传统网平差最小二乘配置法吻合,表明DDA具备实际应用前景。最后对研究方向做了探讨。     

用（DDA+FEM）方法数值模拟1975年海城、1999年岫岩地震发生的过程l

用非连续变形分析方法（DDA+FEM）， 数值模拟了华北地区各地块相互制约构造环境中发生的1975年海城地震及1999年岫岩地震的过程. 通过对岫岩前震及近期余震分布图象的研究， 以及前人对海城地震的研究， 提出了海城、 岫岩地震发震构造块体模型. 数值模拟结果给出了两次地震释放的主应力变化、 最大剪应力变化等值线图， 地震前后位移变化矢量图， 及发震断层滑移随时间的变化， 分别与相应地震的震源机制、 宏观等震线、 发震断层的走滑性质等的结果基本一致.      

Numerical simulation for 1975 Haicheng and 1999 Xiuyan earthquake processes by DDA+FEM

Introduction The Xiuyan earthquake(MS=5.4)on Nov.29,1999,occurred between Hushan town and Pi-anling town at the southeast end of the aftershocks of Haicheng earthquake(MS=7.3).These two earthquakes′sequences are highly similar in the way that the foreshocks are very frequent,focal mechanisms of the main shocks are about the same and fault strikes are approximately in the same direction.It is important to study these earthquakes for further research on seismogenesis to fore-cast earthquake…     

基于速度-状态摩擦本构定律的三维DDA方法

原有三维非连续变形分析(DDA)方法采用常摩擦系数的Mohr-Coulomb定律作为切向破坏准则,然而当描述更大尺度构造块体的运动与变形时,常摩擦系数不再适用.速度-状态摩擦本构定律能够定量描述地震周期各阶段断层面剪应力变化,解释发震断层行为.本文将速度-状态摩擦定律与三维DDA方法相结合,首先推导了计算摩擦系数的实用公式,随后通过滑动-保持-滑动实验与速度步进实验算例对改进的三维DDA方法进行了验证.结果表明,应用速度-状态摩擦本构定律的三维DDA方法能够比较准确地模拟静摩擦的时间依赖性与动摩擦的速度依赖性,解决了将三维DDA方法在地学中应用的基本问题.     

Dynamic failure numeric simulations of model concrete-faced rock-fill dam

Conventional numeric simulations of rock-fill dams are generally performed finite element method (FEM), in which the rock-fill body is treated as continuum material. But the rock-fill body possesses strong discontinuity and FEM based on continuum idealization cannot simulate its failure process. The discontinuous deformation analysis (DDA) method is just the right tool of solving this problem satisfactorily. In this paper, two kinds of model dams, i.e. homogeneous rock-fill dam and concrete-faced rock-fill dam, are simulated using DDA method, their characteristics of response and failure process are presented. The results from numerical simulations are consistent with those from the author's previous dynamic experiments.     

Site response analysis with two‐dimensional numerical discontinuous deformation analysis method

The capability of the numerical discontinuous deformation analysis (DDA) method to perform site response analysis is tested. We begin with modeling one‐dimensional shear wave propagation through a stack of horizontal layers and compare the obtained resonance frequency and amplification with results obtained with SHAKE. We use the algorithmic damping in DDA to condition the damping ratio in DDA by changing the time step size and use the same damping ratio in SHAKE to enable meaningful comparisons. We obtain a good agreement between DDA and SHAKE, even though DDA is used with first order approximation and with simply deformable blocks, proving that the original DDA formulation is suitable for modeling one‐dimensional wave propagation problems. The ability of DDA to simulate wave propagation through structures is tested by comparing the resonance frequency obtained for a multidrum column when modeling it with DDA and testing it in the field using geophysical site response survey. When the numerical control parameters are properly selected, we obtain a reasonable agreement between DDA and the site response experiment in the field. We find that the choice of the contact spring stiffness, or the numerical penalty parameter, is directly related to the obtained resonance frequency in DDA. The best agreement with the field experiment is obtained with a relatively soft contact spring stiffness of k = (1/25)(E × L) where E and L are the Young's modulus and mean diameter of the drums in the tested column. Copyright © 2013 John Wiley & Sons, Ltd.     

Aseismio fault slip and block deformation in North China

In North China, the tectonic fault-block system enables us to use the Discontinuous Deformation Analysis (DDA) method to simulate the long-term cross-fault survey and other geodetic data related to aseismic tectonic deformation. By the simulation we have found that: (1) Slips on faults with different orientation are generally in agreement with the ENE-WSW tectonic stress field, but the slip pattern of faulting can vary from nearly orthogonal, to pure shear along the strike of the faults, this pattern cannot be explained by simple geometric relation between the strike of the fault and the direction of the tectonic shortening. This phenomenon has been observed at many sites of cross-fault geodetic surveys, and might be caused by the interactions between different blocks and faults. (2) According to the DDA model, if the average aseismic slip rate along major active faults is at the order of several tenths of millimeter per year as observed by the cross-fault geodetic surveys, the typical strain rate inside a block is at the order of 10^–8 year^–1 or less, so that the rate of 10^–6 year^–1, as reported by observations in smaller areas, cannot be the representative deformation rate in this region. (3) Between the slips caused by regional compression and block rotation, there is a possibility that the sense of slip caused by rigid body rotation in two adjacent blocks is opposite to the slip caused by the tectonic compression. But the magnitude of slip resulting from the tectonic compression is much larger than that due to the block rotation. Thus, in general, the slip pattern on faults as a whole agrees with the sense of tectonic compression in this region. That is to say, the slip caused by regional compression dominates the entire slip budget. (4) Based on (3), some observed slips in contradiction to ENE tectonic stress field may be caused by more localized sources, and have no tectonic significance.     

Study of the Difference between Seismogenic Deformation and Deformation by Permanent Tectonic Movement

Ground deformation may be caused by crustal movement and non-crustal movement.The non-crustal movements include those caused by temperature,rainfall,ground water,etc.Deformation caused by crustal movement includes seismogenic deformation(that appearing in the process of earthquake preparation and that directly caused by the earthquake)and general tectonic activities.The key point in the study of the relationship between ground deformation and earthquakes is how to eliminate information of deformation caused by non-crustal movement and permanent(or slow)tectonic deformation in observed data.In this paper an analysis is made on the short leveling data recorded at Dahuichang Deformation-Observing Station,Beijing,for 22 years(1970-1991)by using the LMS algorithm method after lateral adaptive filtering of the modern digital signal processing technique.Eliminating the approximate annual variation in deformation caused by non-crustal movement such as temperature,rainfall,ground water,etc.,a unified standard is