Advanced Spaceborne InSAR for monitoring tectonic and anthropogenic ground deformation in the seismically sensitive Almaty region, Kazakhstan

This study investigates ground deformation in Almaty, Kazakhstan, and its surrounding mountainous areas between 2017 and 2023, with a focus on its spatial relationship to mapped faults and tectonic boundaries in this seismically sensitive region. Sentinel-1 imagery was processed using the Small Baseline Subset (SBAS) InSAR technique combined with three-dimensional decomposition to derive vertical and horizontal motion components. Vertical displacements ranged from –95 to +52 mm/year, with uplift concentrated in the southern sector and localized subsidence observed in the northern urban areas. Horizontal motions varied from –156 to +211 mm/year, revealing eastward movement in the south and westward shifts in the north, while north–south motions were more modest, ranging from –20 to +19 mm/year. The overall deformation pattern reflects a complex interaction of crustal shortening and lateral faulting. A sharp transition was identified along the central Almaty fault, where uplift and subsidence zones are clearly divided, indicating localized tectonic activity. In contrast, other mapped faults showed no consistent deformation signatures, suggesting limited activity or motions below the detection threshold. These findings highlight the importance of the central Almaty fault as a primary zone of tectonic strain accumulation and demonstrate the value of integrating InSAR and geospatial datasets for improving seismic hazard assessment, infrastructure monitoring, and urban risk planning in tectonically active urban regions.