基于差分干涉雷达的汶川地震同震形变特点

CO-SEISMIC DEFORMATION OF "5.12" WENCHUAN EARTHQUAKE BASED ON D-INSAR

地震同震形变场是认识震源机制、确定发震断裂、分析发震断裂活动方式、评估震害损失及揭示未来发震趋势的重要依据。但在龙门山地区复杂的自然环境中,现有的地震同震形变场获取方法(GPS测量、构造形迹分析、震源机制解结合数值模拟计算)难以快速、全面的捕捉到这种信息,这突显出差分干涉雷达技术(D-InSAR,Differential Interferometry SAR)在同震形变场研究中的优势。本文介绍了其观测原理,在地震同震形变监测中的研究现状,并重点分析了已获取的D-InSAR汶川地震同震形变场的观测结果。基于差分干涉雷达观测及相关资料,对龙门山断裂在本次地震中活动性进行了初步分析,结果表明干涉雷达形变图像与地表破裂范围、逆冲角度的变化、上下盘升降关系及大型余震的展布存在很强的相关性。

Co-seismic deformation is important original information to determine seismogenic faults, to understand mechanism of earthquake, to analyze fault movement, to evaluate the earthquake property losses as well as to discover the trend of future earthquakes. However, ways to survey co-seismic deformation are unable to quickly and comprehensively capture this kind of information. Therefore, a new spatial surveying method, D-InSAR （i. e. Differential Interferometry SAR）, is highlighted. This paper presents D-InSAR principle and reviews progress of D-InSAR applied to co-seismic deformation observation, then qualitatively analyzes characteristics of D-InSAR image about ＂5.12＂ Wenchuan earthquake. Results show that many geological phenomena, surface ruptures, change of fault dip angle, vertical displacement of two plates alone fault and distribution of huge geo-hazards, are highly related with D-InSAR image.