Datasets for: Landslides with multi-slip surfaces in reservoir areas: occurrence, geomorphic and geologic controls

Reservoir landslides constitute a significant geohazard amidst global hydropower expansion, particularly those with multiple slip surfaces. However, the regional occurrence and controlling factors of multi-slip surface landslides (MSSLs) remain poorly understood, posing challenges for hazard prediction and mitigation. Here, we established a comprehensive inventory of MSSLs based on geological investigations in the Three Gorges Reservoir Area over the past two decades and evaluated the geomorphic and geologic controls on MSSL distribution and process mechanisms. Results indicated that MSSLs are unevenly clustered along the bank slopes of the Yangtze River mainstream and near fold cores, displaying distinct types and developmental characteristics across three subregions of different topography and lithology settings. Their occurrence is largely determined by the combined effects of river erosion, geological structures and bedrock with weak layers, while the effects of topography and distances to faults are negligible. MSSLs showed a distinct preference for specific strata (T2b and J2s) and slope intervals (15°-25°), where their proportion was roughly twice that of all landslides in the same range. These landslides are commonly composite deposits formed through multistage mass movements during the valley geomorphic process, driven by the interplay of episodic tectonic uplift, river incision, and palaeoclimatic changes since the Middle Pleistocene. We proposed conceptual models for their multistage evolution, emphasizing the significance of lithology and slope structure in governing MSSL initiation and process mechanisms, and further explaining the spatial variability in MSSL distribution patterns. These findings contribute significantly to the early identification, hazard prevention, and mitigation in MSSL-active areas.