Measuring land deformation in a mega city Karachi-Pakistan with sentinel SAR interferometry

Abstract

This study incorporates European Space Agency (ESA) C-band Sentinel-1a data to evaluate and identify land deformation in natural and reclaimed land of coastal city Karachi, Pakistan on a multi-temporal scale (2014‒2018) using Differential Interferometric Synthetic Aperture Radar (DInSAR) analysis. Average displacement in LOS was between −78.81‒42.97 mm, whereas, the average vertical displacement was 179.74 to −85.05 mm. Few areas have shown an alarming annual subsidence of −21.26 mm/year. Korangi industrial area (−34.34 mm), Liaquatabad (−1.88 mm) and SITE (−2.93 mm) area has shown significant land subsidence that resulted in collapse of few buildings. Maximum subsidence was observed in industrial cum residential areas (−85.05 mm) compared to reclaimed areas (−33.69 mm). Major uplifting was observed along the Kirthar range due to various tectonic activities Rapid urbanization and excessive groundwater abstraction are identified as main reasons for land deformation leading which requires in-depth attention of policy makers to insure sustainable urban development.