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方颖  江在森  顾国华 《大地测量与地球动力学》2008,28(4):25-30

????GPS?????????????????????????????????????????????????????????????????GPS????????????????????Χ????λ??????к??????????????????????????????????????????????????????????????ε?????????????ó????3???????????????????????????η?Χ????????????????λ???仯???????????????????Χ????????????????飬???????????????????С???????????λ????е??????????????????????????ο????????????????????????????????????????ο??嶫????γ????????η?????????????硪??????????????γ????????????????????????ο???????????ο??嶫????????????????й????????????  相似文献   

Types of focal mechanism solutions and parameter consistency of the sub-blocks in Sichuan and Yunnan Provinces   总被引：1，自引：0，他引：1  

程万正阮祥  张永久 《地震学报(英文版)》2006,19(6):605-619

Based on P- and S-wave amplitudes and some clear initial P-wave motion data, we calculated focal mechanism solutions of 928 M≥2.5 earthquakes （1994-2005） in four sub-blocks of Sichuan and Yunnan Provinces, namely Sichuan-Qinghai, Yajiang, Central Sichuan and Central Yunnan blocks. Combining these calculation results with those of the focal mechanism solutions of moderately strong earthquakes, we analyzed the stress field characteristics and dislocation types of seismogenic faults that are distributed in the four sub-blocks. The orientation of principal compressive stress for each block is： EW in Sichuan-Qinghai, ESE or SE in Yajiang, Central Sichuan and Central Yunnan blocks. Based on a great deal of focal mechanism data, we designed a program and calculated the directions of the principal stress tensors, σ1, σ2 and σ3, for the four blocks. Meanwhile, we estimated the difference （also referred to as consistency parameter θ^- ） between the force axis direction of focal mechanism solution and the direction of the mean stress tensor of each block. Then we further analyzed the variation of θ^- versus time and the dislocation types of seismogenic faults. Through determination of focal mechanism solutions for each block, we present information on the variation in θ^- value and dislocation types of seismogenic faults.  相似文献   

利用GPS数据研究川滇块体东边界主要断裂带运动特性   总被引：1，自引：0，他引：1  

魏文薪  江在森  武艳强  赵静 《武汉大学学报(信息科学版)》2012,37(9):1041-1044,1063,1006

利用1999～2007时段的GPS速度场,对块体刚体旋转模型、块体整体旋转与均匀应变模型及块体整体旋转与线性应变模型的速度残差及无偏性进行估计;针对川滇块体东边界主要断裂带变形的复杂性,结合3种块体变形模型,求得各断裂带的平均滑动速率,并给出了该研究区域断裂带的近场滑动速率。在确定各断裂带可能变形宽度的基础上,利用断裂带构造变形定量分析方法确定了鲜水河-安宁河-则木河-小江断裂带的相对闭锁且剪切应变积累速度较高的异常区域为安宁河断裂带。  相似文献   

Determinations of directions of the mean stress field in Sichuan-Yunnan region from a number of focal mechanism solutions     

钟继茂  程万正 《地震学报(英文版)》2006,19(4):359-369

Introduction With the model of double couple point source, both orientations of the T, B, and P axes of a single focal mechanism solution and parameters of the two nodal planes may be determined. The focal mechanism solution under ″the model of the best double couple″ can also be given by seis- mic moment tensor, such as those provided by Harvard CMT solutions. The orientations of the T, B, and P axes from one earthquake are associated with the released stress, but they cannot be re- gar…  相似文献   

Numerical simulation of the influence of lower-crustal flow on the deformation of the Sichuan-Yunnan Region     

王辉曹建玲  张怀张国民  石耀霖申旭辉 《地震学报(英文版)》2007,20(6):617-627

On the basis of distribution of active fault and regional rheological structure, a three-dimensional finite element model of Sichuan-Yunnan region, China, is constructed to simulate contemporary crustal motion and stress distri- bution and discuss the dynamic mechanism of crustal motion and deformation in the Sichuan-Yunnan region. Lin- ear Maxwell visco-elastic model is applied, which includes the active fault zones, the elastic upper crust and vis- cous lower crust and upper mantle. Four different models with different boundary conditions and deep structure are calculated. Some conclusions are drawn through comparison. Firstly, the crustal rotation about the eastern syntaxis of the Himalaya in the Sicuan-Yunnan region may be controlled by the special dynamic boundary condition. The drag force of the lower-crust on the upper crust is not negligible. At the same time, the main active fault zones play an important role in the contemporary crustal motion and deformation in Sichuan-Yunnan region.  相似文献   

Fault plane solutions in Sichuan-Yunnan rhombic block and their dynamic implications   总被引：1，自引：1，他引：1  

刘平江刁桂苓  宁杰远 《地震学报(英文版)》2007,20(5):479-488

Harvard Centroid Moment Tensor (CMT) solutions for earthquakes from 1977 to 2004 showed that the stress fields are obviously different in northwestern Sichuan sub-block (NWSSB), western parts of Central Yunnan sub-block (CYSB) and eastern part of CYSB. The characteristics of the mean stress fields in these three regions are obtained by fitting to CMT solutions. The stress state in NWSSB is characterized by its sub-horizontal tensile principal axis of stress (T axis) in roughly N-S direction and west dipping compressive principal axis of stress (P axis); the one in western part of CYSB is characterized by its ENE dipping T axis and sub-horizontal medium prin-cipal axis of stress (B axis) in roughly N-S direction; the one in eastern part of CYSB is characterized by its sub-horizontal P axis in roughly NNW-SSE direction and sub-horizontal T axis in roughly WSW-ENE direction. Finite element method simulation clearly shows that the Indian Plate imposes great extrusion on Sichuan-Yunnan rhombic block (SYRB) near Assam massif. The value of the simulated compressive principal stress decreases with the distance from Assam massif. The simulated directions of the T axes in SYRB form annular distribution encir-cling Assam. For a homogeneous elastic medium with free boundary conditions on the top and bottom surfaces as well as the displacement boundary conditions derived from the GPS observations on the lateral boundaries, the computation results are consistent with the Harvard CMT solutions in NWSSB and western part of CYSB, while inconsistent with the Harvard CMT solutions in eastern part of CYSB. The inconsistency in eastern part of CYSB can be reduced when it includes inhomogeneous elastic media. The stress states in NWSSB and western part of CYSB revealed by the Harvard CMT solutions are not local, which are mainly controlled by the boundary force on the whole region. On the other hand, the stress state in eastern part of CYSB given by the Harvard CMT solutions is local, which may be affected by local topography, material inhomogeneity, and the drag force underneath.  相似文献   

四川强地震活动的可公度性初探     

徐水森 《四川地震》2007,(2):8-10

强地震活动表现为周期性或准周期性,在地震预测实践中用地震活动的分期、分幕来区分,也可用数学上的可公度性来研究强地震三要素之一的时间要素。  相似文献   

震源分布和强度指标控制因素的模型研究-红河断裂地震环境因素的实例分析ca   总被引：1，自引：0，他引：1       下载免费PDF全文

张超  谢富仁  张世民 《地震学报》2001,23(2):125-135

参照并综合应用国内外相关资料、实验和研究成果，建立了一种涉及多种环境因素的模型，分析了不同因素对构造运动能量指标的影响．其中包括地壳纵向结构、断层产状、岩性条件、地壳应力状态、孔隙压力和地温条件等．模型计算结果表明，断裂的剪切破裂能随深度增加通常呈现先上升，在某一深度上达到峰值后逐渐衰减的形态．在诸多因素中，孔隙压力和地温条件对能量指标的影响相对显著．高孔隙压力和地温环境可导致剪切破裂能曲线的峰值降低、峰值和铃腰值所在的深度下移．这种效应限制了强震事件，而适于中小地震活动或低能量释放的断层活动，其震源深度分布的下限较低．反之，低孔隙压力和低地温环境使剪切破裂能曲线的峰值加大、形态变陡，其结果利于高强度、高能量积累的闭锁段的形成．如果这两种段落在断裂带上相邻，则可能促进断裂带不同段落之间的能量转换，从而形成能量积累程度高而邻区锁定强度低的孕震环境．红河断裂北西段温泉密度和热储温度分布与该地区的地震频度、强度和震源深度分布之间的关系与模型结果基本相符，从而为模型的主要推论提供了佐证．   相似文献   

川滇地区地震活动演化特征分析   总被引：3，自引：0，他引：3  

兰从欣  郭大庆  郭心 《中国地震》2001,17(4):378-385

结合川滇菱形块体的活动特征，应用图型动力学的损伤演化诱致突变分析方法，研究了川滇地区两条地震带中强地震的损伤演化过程，并给出各地震带演化到破坏态的所有可能的各单元初始状态的组合形式图。研究结果对指导该区地震预测实践有一定的积极作用。  相似文献   

The Volutionary Characteristics of Seismic Activity in the SichuanYunnan Region,China     

Lan Congxin  Guo Xin  Zhang Yafang 《中国地震研究》2002,16(2):138-146

Based on the earthquake activity characteristics of the diamond block in the Sichuan-Yunnan region and by using the method of the meso-scope damage dynamics and damage evolution,we studied the damage evolution process for moderately strong earthquakes along two seismicbelts.The original combination patterns of all the units which illuminate the changes from stable state to destroyed state are given.All these patterns can direct the earthquake prediction practice in this region  相似文献