基于GIS的InSAR结果分析方法及在汶川Mw7.9级地震同震解释中的应用

利用GIS对InSAR结果进行分析可以更全面地解释地表形变机制。介绍了利用GIS对SAR影像进行裁剪、切割和拼接处理、剖面和等值分析的方法。在此基础上,以汶川Mw7.9级地震为例介绍了基于GIS的InSAR结果分析方法在地震形变机制解释方面的应用:①根据InSAR距离向偏移量和同震形变场,利用GIS技术提取了汶川Mw7.9级地震发震断层的地表迹线;②将基于位错模型正演得到的视线向形变场与InSAR同震形变场进行比较,得到了汶川地区InSAR同震形变场的上盘和整体改正数,进一步借助GIS进行修正得到了更为真实的InSAR同震形变场;③利用2D/3DInSAR同震形变场、干涉纹图和剖面分析结果对汶川Mw7.9级地震同震形变特征进行了具体分析和解释。

Analyzing InSAR Results Using GIS and Its Application on the Coseismic Interpretation of Mw7.9 Wenchuan Earthquake

InSAR results’ analysis assisted with GIS can give more comprehensive interpretation on surface deformation mechanism.In this paper,we present the methods to clip,split and merge SAR images with the help of GIS.Besides,the profile and contour analysis to SAR images are illustrated.In order to demonstrate the effectiveness on interpreting earthquake deformation mechanism using the InSAR results assisted with GIS,we analyze the Mw7.9 Wenchuan earthquake as follows.First,the seismic fault surface trace is extracted according to the InSAR range offset and coseismic deformation field.Second,through the comparison between the LOS deformation field obtained by geophysical forward using dislocation model and the InSAR coseismic deformation field,the whole and hanging wall corrections of InSAR deformation field are obtained,with which the more actual coseismic deformation are got by correction using GIS.Finally,more comprehensive analysis and interpretation on the characteristics of coseismic deformation are presented by using the 2D/3D coseismic deformation field,interferograms and profile analysis.