Mapping Three-Dimensional Co-Seismic Deformations Fields by Combining Multiple-Aperture Interferometry and Differential Interferometric Synthetic Aperture Radar Techniques

DInSAR technique based displacement measurement is sensitive to only radar line-of-sight, which renders it hard to determine 3D co-seismic deformations. To infer these deformations, a method based on the robust least squares method by combining the multiple-aperture interferometry (MAI) and DInSAR is applied to one ascending and one descending interferometric pair for the 2003 Bam, Iran, earthquake. The results reveal that co-seismic deformations not has the level strike-slip in north-south direction, but also has a large vertical component and a horizontal component in east-west direction. In areas with high interferometry coherence (>0.6), the standard deviation of MAI results is less than 0.075 m, and the 3D deformations are consistent with results of combining DInSAR and Offset Tracking technology in up-down and east-west directions with the maximum difference of 0.031 m. But the differences in south-north direction are relatively large on decimeter level. Therefore, the proposed method can be used to model reliable and accurate 3D surface displacement fields and benefit for analyzing the causes and effects of the earthquake.