Decadal high-resolution mapping of land subsidence driven by severe groundwater overdraft in Balochistan, Pakistan

Groundwater overdraft in arid and semi-arid regions poses a significant threat to sustainable water resources. In Balochistan, Pakistan, a region with limited precipitation (<400 mm/yr) but high reliance on groundwater for agriculture and urban supply, excessive water extraction has led to dramatic land subsidence in the inhabited valleys. These deformations, have been documented since the 1990s. Using two-dimensional Interferometric Synthetic Aperture Radar (InSAR) analysis, we generated high-resolution surface deformation maps to characterize subsidence and its evolution over the Kharan drainage system between 2014 and 2024. Subsidence rates exceed 15 cm/year in urban centers like Quetta, while surrounding agricultural valleys show variable deformation patterns, including seasonal motion of about 2 cm. To identify dominant deformation modes, we applied independent component analysis (ICA) to decompose temporal signals, linking them to precipitation variability, groundwater level changes, and land use dynamics. Our results also highlight the potential role of faults in modulating aquifer connectivity and deformation patterns. By combining spatio-temporal deformation analyses with meteorological and geographic data, we provide insights into groundwater recharge, aquifer behavior, and the sustainability of water resources in the face of ongoing population growth and climate change.