Deformation monitoring of Pidie Jaya earthquake using pairwise logic of multitemporal Sentinel-1 SAR data

Interferometric synthetic aperture radar (InSAR) based on radar satellite data has emerged as a powerful technology for observing the Earth’s surface, especially for monitoring the Earth’s topography and deformations. However, it is well known that the InSAR measurements are often significantly affected by the atmosphere. This paper applies the pairwise logic (PWL) and the Differential Interferometric Synthetic Aperture Radar (D-InSAR) technique using multitemporal SAR image from Sentinel-1A (S1A). The objective of this study was to investigate the possibility of using PWL in reducing atmospheric delay and improve the results in capturing the deformation signal from the artifact. We stacked twelve pairs of S1A data before and after the December 6, 2016, M_w 6.5 Pidie Jaya earthquake in Aceh, Indonesia. Multitemporal interferograms of S1A in ascending and descending orbits were used to obtain Line of Sight (LOS) motion maps. To generate the differential interferogram of the PWL, then the first and the second interferogram were computed by summation process. Next, the second interferogram was added with the third, until the last interferogram of D-InSAR data pairs. The final data pair summation produced six pairwise interferogram. The results indicated that the summation of interferogram can increase the deformation twice in the line of sight of the satellite which represents movement toward or away from the satellite (e.g. uplift or subsidence), and also eliminated positive and negative signals in the line of sight velocities, which represent the atmospheric phase delay. The PWL simplified the complexity of atmospheric correction in the D-InSAR processing by reducing atmospheric artifact and increasing the deformation signal.