Using the SBAS InSAR technique to monitor surface deformation in the Kuqa fold-thrust belt, Tarim Basin, NW China

Abstract

The Kuqa foreland fold-thrust belt is one of the key areas for gas exploration and a rare region with allochthonous salt outcrops well-preserved. In this study, twenty-eight Sentinel-1A Synthetic Aperture Radar (SAR) images acquired from 2015 to 2017 were utilized to detect and map the surface deformation in the western Kuqa fold-thrust belt (KFTB) based on the Small Baseline Subset (SBAS) Interferometric Synthetic Aperture Radar (InSAR) method. Spatial-temporal statistics analysis and comparison in different structural belts and geomorphology were made based on the inversion results. The results show that the spatial distribution characteristics of the surface deformation detected in subaerial salt structures are highly consistent with the previous studies, but the deformation rate in Daxiagu and Awate namakier increased to 25–35 mm/a. It indicates that the KFTB is still undergoing continuous north–south compression and shortening, which drives the underground salt to keep moving. Combined with the sufficient salt supply, increased activity of subaerial namakier and enhanced surface process in recent years, a variety of spatial–temporal surface deformation patterns are observed in the western KFTB. These varieties are attributed to the differences in structure and geomorphology in different belts, which can provide vital clues for exploring the roles of tectonics and surface processes in the spatial–temporal evolution of surface morphology in active tectonic regions.