Increasing landslide deformation and activity in a changing local environment: a case study of Zhouqu County in the Bailong River Basin

Climate change and frequent earthquakes influence the surface deformation of landslides and further lead to catastrophic event. However, due to the deficiency effective long-term monitoring data for landslides, it is difficult to quantitatively analyze the actual impact of the changing local environment on landslide deformation. In this study, we quantitatively analyzed the effects of rainfall and earthquakes on landslides deformation in Zhouqu County, China, using Multi-Temporal Interferometric Synthetic Aperture Radar (MT-InSAR) technique. The results showed that in recent years, the unstable areas and the fastest deformation velocity of the five occurred landslides (Suoertou, Daxiaowan, Xieliupo, Zhongpai and Qinyu landslides) studied have significantly increased. Meanwhile, the time series displacement data of five landslides showed that the deformation trend changed from a steady state to an accelerated state. Furthermore, our findings revealed that an augmentation in precipitation not only exacerbated the incidence of rainstorms, thereby facilitating the occurrence frequency of devastating landslides, but also demonstrated a correlation between annual precipitation and variations in the deformation trend of landslides. Smaller values of the magnitude (reciprocal), depth, and epicentral distance resulted in greater surface displacement of the landslide; conversely, larger values resulted in smaller surface displacement. These quantitative correlations suggest that, due to the perpetual alterations in the environment, landslides are progressively transitioning from a state of relative stability to one of heightened activity.