Ground Deformation and Its Causes in Abbottabad City, Pakistan from Sentinel-1A Data and MT-InSAR

Abstract

Land subsidence, as one of the engineering geological problems in the world, is generally caused by compression of unconsolidated strata due to natural or anthropogenic activities. We employed interferometric point target analysis (IPTA) as a multi-temporal interferometric synthetic aperture radar (MT-InSAR) technique on ascending and descending Sentinel-1A the terrain observation with progressive scans SAR (TOPSAR) images acquired between January 2015 and December 2018 to analyze the spatio-temporal distribution and cause of subsidence in Abbottabad City of Pakistan. The line of sight (LOS) average deformation velocities along ascending and descending orbits were decomposed into vertical velocity fields and compared with geological data, ground water pumping schemes, and precipitation data. The decomposed and averaged vertical velocity results showed significant subsidence in most of the urban areas in the city. The most severe subsidence was observed close to old Karakorum highway, where the subsidence rate varied up to −6.5 cm/year. The subsidence bowl profiles along W–E and S–N transects showed a relationship with the locations of some water pumping stations. The monitored LOS time series histories along an ascending orbit showed a close correlation with the rainfall during the investigation period. Comparative analysis of this uneven prominent subsidence with geological and precipitation data reflected that the subsidence in the Abbottabad city was mainly related to anthropogenic activities, overexploitation of water, and consolidation of soil layer. The study represents the first ever evidence of land subsidence and its causes in the region that will support the local government as well as decision and policy makers for better planning to overcome problems of overflowing drains, sewage system, littered roads/streets, and sinking land in the city.

Monitoring Subsidence in Urban Area by PSInSAR: A Case Study of Abbottabad City, Northern Pakistan

“…These uncontrolled and unplanned growths in a region are affecting the natural resources. The demand for daily water exploitation is increasing and, as a result, excessive extraction of groundwater is causing ground subsidence [2,[7][8][9].…”

“…Ground subsidence is a serious issue in many cities of Pakistan, especially Abbottabad City [8], which has a population of around two million and hosts many educational institutions, including medical, engineering, and military institutes. To facilitate urban growth, various water supply projects have been launched by the local government in coordination with the Japanese government [31].…”

“…To facilitate urban growth, various water supply projects have been launched by the local government in coordination with the Japanese government [31]. Deep bore-wells for water supply have disturbed subsurface water levels [8]. Furthermore, the main drainage for water flow has been blocked by unplanned construction, which leads to contamination and blockage of water outflows [8].…”

“…Deep bore-wells for water supply have disturbed subsurface water levels [8]. Furthermore, the main drainage for water flow has been blocked by unplanned construction, which leads to contamination and blockage of water outflows [8]. In order to avoid serious disasters caused by ground subsidence in the future.…”

SBAS-InSAR-Based Analysis of Surface Deformation in the Eastern Tianshan Mountains, China

“…Moreover, it costs less time and money than manual measurements with comparable precision. Differential interferometric synthetic aperture radar (D-InSAR) (Massonnet and Feigl, 1998;Hanssen, 2001;Simons and Rosen, 2007;Lu and Dzurisin, 2014) has been developed based on InSAR technology, and multi-temporal InSAR (MT-InSAR) (Pepe and Calò, 2017;Zhu et al, 2019;Gatsios et al, 2020;Shahzad et al, 2020) including persistent scatterer InSAR (PS-InSAR) (Ferretti et al, 2001;Colesanti et al, 2003;Zhang et al, 2013;Li et al, 2020;Ge et al, 2021), small baseline subset InSAR (SBAS-InSAR) (Ferretti et al, 2001;Mora et al, 2002;Colesanti et al, 2003;Hu et al, 2021a;Du et al, 2021b), and distributed scatterer InSAR (DS-InSAR) ( Zhu et al, 2018;He and Zhao, 2020;Du et al, 2021d;Hu et al, 2021a) have been developed based on D-InSAR. Their practical scope varies, and each has its own advantages and disadvantages.…”