Landslide deformation in the loess area of northwest China based on SBAS-InSAR technique: spatial distribution, factors and risk assessment

Abstract

Landslides are prevalent in the ecologically fragile loess plateau of central China. However, research on the monitoring and assessment of large-scale landslides is scarce. This study collected 31 ascending and descending Sentinel-1A images from January 4, 2020, to August 9, 2022. The Small Baseline Subset Synthetic Aperture Radar Interferometry (SBAS-InSAR) technique was utilized to quantify subsidence, indirectly reflecting the deformation rate of landslides in the Loess Plateau. The research findings reveal that during the study period, the average line-of-sight (LOS) surface displacement rate in the region reached 118 mm/yr, with a maximum offset distance of 298 mm. The results showed, 491 active, hazardous landslides clustered within the region, with 14 landslides posing extreme risks to the Yellow River, highways and over 10,000 residents. We discovered an uneven distribution of landslides within the study area, likely attributed to complex geological backgrounds and environmental conditions. Continuous tension crack formation was observed as landslide fronts slid rapidly, which could be easily detected on satellite maps. The formation of landslides was influenced by various factors, and this study statistically investigated factors such as DEM, Aspect, Slope, and NDVI. landslides were mainly distributed within a slope range of 20–40°. Additionally, a comprehensive analysis was conducted on the geomorphological features, displacement magnitudes, and potential hazards and risk levels to the surrounding environment for 14 representative landslides. we observed a high correlation between landslide displacement and monthly precipitation. The research findings are of significant importance in understanding landslide activity, deformation processes, and conducting risk assessments for landslides.