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.水库滑坡是全球水电开发进程中一类重要的地质灾害，尤以多滑动面滑坡（multi-slip surface landslides, MSSLs）最为突出。然而，学界对多滑动面滑坡的区域分布规律及其控制因素仍知之甚少，这给灾害预测与防治工作带来了极大挑战。本研究基于过去二十年在三峡库区开展的地质调查工作，构建了一套完整的多滑动面滑坡编目数据库，并系统评估了地貌与地质条件对多滑动面滑坡分布及演化机制的控制作用。研究结果显示，多滑动面滑坡呈非均匀聚集特征，主要分布于长江干流岸坡及褶皱核部附近；在地形与岩性条件各异的三个次级区域内，这类滑坡表现出显著迥异的类型与发育特征。多滑动面滑坡的发育主要受河流侵蚀、地质构造及含软弱层基岩的共同作用影响，而地形条件与距断裂带的距离对其发育的影响可忽略不计。这类滑坡显著偏好特定地层（T2b与J2s）及坡度区间（15°-25°），在上述范围内，多滑动面滑坡占比约为所有滑坡总数的两倍。此类滑坡多为复合堆积体，是中更新世以来河谷地貌演化过程中，受间歇性构造抬升、河流下切与古气候变化共同驱动的多期次块体运动的产物。本研究提出了多滑动面滑坡多期演化的概念模型，强调岩性与坡体结构对滑坡启动及演化机制的控制作用，并进一步阐释了多滑动面滑坡分布格局的空间异质性。本研究成果可为多滑动面滑坡活跃区域的早期识别、灾害防控工作提供重要支撑。