Analysis of kinematic characteristics of geohazards along the Karakoram Highway using multi-track time series InSAR observations

Abstract

The Karakoram Highway traverses geologically complex terrain that extends acrossthe Himalayas, the northern Pamir Plateau, and the Kunlun Mountains, regions characterized by active tectonics, frequent seismicity activity, and intense rainfall events. These factors collectively drive recurrent geological hazards, including landslides, glacial debris flows, and glacial lake outburst floods along the corridor. This study employed Sentinel-1 SAR imagery from ascending and descending tracks (June 2018–November 2024) to document surface deformation across the Karakoram region through multi-temporal interferometric synthetic aperture radar (MT-InSAR) analysis. Multi-track SAR integration effectively expanded the observable coverage area by mitigating geometric shadows and layover effects inherent to side-looking radar imaging, which enabled comprehensive identification of multiple geohazards along the Karakoram Highway corridor. To better characterize kinematics of diverse geohazards, this study proposes an interval estimation-based deformation projection method that converts line-of-sight deformation rates into slope-parallel displacement components. Integrated analysis of MT-InSAR deformation measurements and local hydrometeorological data reveals deformation characteristics of diverse geohazards in the Karakoram region, including ablation-driven glacial debris flows, frontal debris accumulation at glacier termini, deformation patterns of slow-moving landslides, periglacial deformation around glacial lakes, and other phenomena. This synthesis underscores the significant influence of seasonal temperature fluctuations and concentrated rainfall on the deformation signatures of these geohazards, which may induce potential threats to road infrastructure integrity.