地球信息科学学报 ›› 2011, Vol. 13 ›› Issue (3): 418-423.doi: 10.3724/SP.J.1047.2011.00418

• 遥感技术与地图应用 • 上一篇    下一篇

青海玉树地震的InSAR数据同震形变场模拟与参数反演分析

周慧芳1,2, 张景发2, 胡乐银3, 罗毅2   

  1. 1. 中国地震局地壳应力研究所,北京 100085;
    2. 山东科技大学地质学院,青岛 266510;
    3. 北京市地震局,北京 100080
  • 收稿日期:2010-10-10 修回日期:2011-03-30 出版日期:2011-06-25 发布日期:2011-06-15
  • 通讯作者: 张景发(1962-),男,江苏扬中人,博士,研究员,研究方向为遥感及干涉雷达技术应用。 E-mail:zhangjingfa@hotmaili.com E-mail:zhangjingfa@hotmaili.com
  • 作者简介:周慧芳(1986-),女,山东滕州人,硕士生,研究方向为应用地球物理。E-mail:zhou-huifang@live.cn
  • 基金资助:

    国家科技支撑项目"基于空间对地观测的地震监测技术、预测方法与应用示范-专题InSAR误差分析与校正方法研究"(2008BAC35B04-1);国家自然科学基金项目"永久散射干涉雷达测量当雄断裂活动性的关键技术研究"(40774023)。

Co-seismic Deformation Field and Parameters Inversion of the Yushu Earthquake from InSAR

ZHOU Huifang1,2, ZHANG Jingfa2, HU Leyin3, LUO Yi2   

  1. 1. Institute of Crustal and Dynamics, China Earthquake Administration, Beijing 100085, China;
    2. Shandong University of Science and Technology, Qingdao 266510, China;
    3. Earthquake Administration of Beijing Municipality, Beijing 100080, China
  • Received:2010-10-10 Revised:2011-03-30 Online:2011-06-25 Published:2011-06-15

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。

关键词: 玉树地震, 同震形变, 合成孔径雷达差分干涉测量, 断层参数

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 Mw=6.9 earthquake.

Key words: Yushu Earthquake, co-seismic deformation, D-InSAR, fault parameters