Continuous river incisions, heavy precipitation events, reservoir water-level fluctuations, and changes in groundwater flow are the main driving factors of extensive landslide activities in the Three Gorges area of the Yangtze River in China. Although the triggers for these major landslide events can be technically detected, predicting and mitigating them remains challenging. This is especially the case where ancient, deep-seated, multi-stage landslides have created complex geological structures that make it difficult to uncover their evolutionary processes and to determine slip surfaces. This study, based on elaborate investigation of the Outang landslide in the Three Gorges Reservoir area, proposes a general framework for analyzing the spatial and temporal evolution of a multi-stage riverbank landslide. The framework applies three-dimensional geological modeling to integrate large amounts of data from earth surface investigations, subsurface explorations, in-situ monitoring and geological dating. The results indicate that the Outang landslide has a total volume of 8.3 × 10⁷ m³ and a maximum thickness of 114 m. It consists of four individual sliding bodies that have been formed consecutively since 130 ka BP. Furthermore, the original slip surfaces of the sliding bodies are found to be interconnected, forming one large active landslide continually creeping towards the Yangtze River. While the entire landslide is in motion, the western, eastern and up-slope portions of the sliding mass are moving at a faster velocity of up to 12.6 cm per year. Our analysis of the Outang landslide reveals that its evolution can be subdivided into three sliding modes. These modes could serve as a reference for analyzing the spatial and temporal evolution of similar multi-stage landslides along riverbanks.

河流连续下切、强降水事件、水库水位波动和地下水流量变化是我国长江三峡地区广泛滑坡活动的主要驱动因素。尽管可以从技术上检测到这些重大滑坡事件的触发因素，但预测和减轻它们仍然具有挑战性。尤其是在古老的、深部的、多级滑坡造成复杂地质结构的情况下，很难揭示其演化过程并确定滑动面。本研究基于对三峡水库区欧塘滑坡的详细调查，提出了分析多级河岸滑坡时空演化的总体框架。该框架应用三维地质建模，整合来自地表调查、地下勘探、原位监测和地质年代测定的大量数据。结果表明，Outang滑坡总体积为8.3×10⁷  m ³和最大厚度 114 m。它由自 130 ka BP 以来连续形成的四个独立的滑动体组成。此外，发现滑动体的原始滑动面相互连接，形成了一个大型活动滑坡，不断向长江蠕动。虽然整个滑坡都在运动，但滑坡的西部、东部和上坡部分正在以每年高达 12.6 厘米的更快速度移动。我们对 Outang 滑坡的分析表明其演化可细分为三种滑动模式。这些模式可为分析类似的多级滑坡沿河岸的时空演化提供参考。