Surface deformation analysis due to the Poso earthquake on May 29, 2017 using the DInSAR method

Abstract

Abstract Deformation can be a significant parameter in determining the presence and impact of an earthquake. The amount of deformation can be obtained from SAR image data using the InSAR and DinSAR methods. The DinSAR (Differential Interferometric Synthetic Aperture Radar) method is a well-developed method for observing subsidence and uplift with high accuracy in centimeters (cm). In this study, SAR imagery is used to detect surface deformation caused by the earthquake was happened on May 29, 2017, at 21:35:23 WIB in the Poso Regency, Central Sulawesi. The data used is Sentinel-1 satellite imagery data in single-look complex (SLC) format consisting of Master image recorded on May 19, 2017 (10 days before the main earthquake occurred) and Slave image recorded on May 31, 2017 (2 days after the main earthquake occurred). The interferogram formed during the Poso earthquake is around the main earthquake directions from the Southwest, South, to the Southeast. The amount of deformation generated in the deformation phase (wrapped phase) is in the form of negative and positive phase values. Negative phase values indicate areas experiencing deformation in the form of subsidence. The positive phase values indicate areas experiencing uplift. The results of unwrapping the SAR imagery obtained a maximum uplift deformation value of 0.0663 meters, spread over the areas of North Pesisir Poso District, Lore Peore District, Central Lore District, South Coastal Poso District, and East Lore District. The maximum subsidence deformation values (0.076 meters) that are quite large are spread in the North Coastal Poso District, Poso Coastal District, Lage District, and Lore Tengah District.