通过InSAR与GPS数据融合获取汶川地震同震三维形变场

COSEISMIC 3D DEFORMATION FIELD ACQUISITION OF THE WENCHUAN EARTHQUAKE BASED ON INSAR AND GPS DATA

针对In SAR与GPS两类独立的观测数据,利用广义测量平差理论中方差分量估计法,合理分配权重,有效地融合了这两类观测数据,从而估算出了地表在三维方向上的形变场。以四川汶川地震为例,利用In SAR干涉测量结果和一定数量的GPS观测值,通过该方法获取了地震断层两侧高相干区域上三维形变场,清晰地显示了汶川地震的逆冲和右旋走滑分量的位置分布整体特征。结果表明,在EW、SN和UD方向上地表形变量与GPS结果能够很好地吻合,融合结果在三维方向上的均方根误差均不超过5cm,证明了该方法能够得到精度较高的地震同震三维形变场,也揭示了利用方差分量估计法对相互独立数据之间有效融合的可行性。

The variance component estimation method（ VCEM） in generalized surveying adjustment theory,which realizes optimal weights allocation for different data sources,is applied to jointly invert two independent datasets,In SAR and GPS,for 3-D deformation field acquisition in this paper. Illustrated by the case of the Wenchuan earthquake,3-D deformation field in high coherent area near the fault is achieved by using this method,which shows clearly a whole picture for the locations of right-lateral and thrust components movements generated by the earthquake. The 3-D deformation results are quantitatively consistent with GPS observations with RMS errors less than 5cm in 3-D directions,which demonstrates the feasibility to acquire precise 3-D deformation field by employing VCEM to fuse independent deformation datasets.