【摘要】 2010年4月我国青海省玉树藏族自治州的玉树县发生了Ms7.1级地震,这次地震(震中33.2°N 96.6°E,Ms=7.1)是由甘孜-玉树断层的强烈活动引起。甘孜-玉树断裂带大部分分布于青海-西藏高原,北西走向。该断裂带和鲜水河断裂带共同组成了巴颜喀拉地块的南边界,二者在甘孜附近成左阶错列分布。在区域构造背景分析和卫星图像、航片解译的基础上,本文给出了玉树地震地表破裂带的空间展布特征。利用D-InSAR(合成孔径雷达差分干涉测量)技术获得了玉树地震的同震形变场,继而得到了地震引起的LOS向的地表位移和发震断层的大致位置。通过对玉树地震同震形变场的分析得到本次地震的动力学特征为明显的左旋走滑。另以同震形变场和发震断层的初始模型,模拟了本次地震的同震形变场,同时通过边界元反演方法得到了断层的特征参数。反演得出的结论和野外调查的结果基本一致。更多还原

【Abstract】 An earthquake(33.2°N,96.6°E,Ms=7.1) struck Yushu Zang Autonomous Prefecture,Qinghai Province of China on 14 April 2010,which was triggered by the strong activity of Ganzi-Yushu Fault.And the Ganzi-Yushu Fault which distributes mostly in Qinghai-Tibet Plateau orientates NW direction.Also it is the south boundary of Bayanhar Belt together with Xianshuihe Fault,and they are left step nearby Ganzi area.From regional geological results and aero-photos in combination with detailed field study,the ground ruptures show a series of compressional bumps and tension fissures,therefore we can draw a conclusion that all these characteristics reflect the kinematics properties of left-lateral and strike-slip fault.Then D-InSAR(Differential Synthetic Aperture Radar Interferometry) technique is used to acquire the co-seismic deformation field,it gives the spatial distribution of the ground rupture zone of the earthquake in the one hand,and in the other hand the surface displacement in LOS direction was derived and the location of the source fault was determined.According to the analysis of the co-seismic deformation field,it also shows typical characteristics of left-lateral and strike-slip fault.Geodetic inversions are a useful tool for estimating source parameters of earthquakes.Thereby based on the dislocation of co-seismic and the fault plane model,we got the simulation co-seismic deformation field,and simultaneously the fault’s attitude is obtained by the boundary element inversion method.There is evident surface rupture along the main shock’s causative in the interferogram,and the co-seismic deformation field is about 75km in length and 55km in width.The seismogenic fault of the main shock strikes about N61°W,dips NE,and inverted fault dipping direction and dip-slip are consistent with field investigation.During the process of simulation,we adopted the different fault models respectively.Through the comparison and analysis of different simulation results,we prefer the segmentation fault model.The maximum dislocation in LOS of the earth surface is 0.57m,the seismic moment is about 2.86×1019Nm,which equals to a M_w=6.9 earthquake.更多还原