Unraveling the controls of unstable slopes in mining-affected coalfields through InSAR observations and multivariate modeling

Unstable slopes are highly susceptible to external triggers, representing a critical challenge for disaster risk management. However, few studies have systematically developed approaches for their regional-scale identification, and even fewer have explored their controlling factors in mining-affected regions with strong anthropogenic disturbances. To address this gap, this study investigates the composite factors influencing unstable slopes in the Datong Coalfield, China. Specifically, we used the Small Baseline Subset (SBAS) interferometric synthetic aperture radar (InSAR) technique to measure line-of-sight (LOS) surface deformation and subsequently identified unstable slopes as those with significant deformation velocities within a slope-unit framework. To examine the spatiotemporal effects of factors influencing slope instability, we conducted multivariate modeling at both long- and short-term scales. The results reveal that long-term modeling captures broadly consistent contributions of these factors across different periods, whereas short-term modeling highlights distinct seasonal associations with slope instability. Furthermore, cross-wavelet coherence analysis revealed that intermittently unstable slopes exhibit periodic lagged responses to dynamic environmental forcing, underscoring the significant role of environmental forcing in driving deformation of intermittently unstable slopes. Overall, this work provides new insights into the mechanisms of slope instability in mining-affected coalfields and proposes a transferable framework for regional-scale slope monitoring and risk management.