Received: 23 Dec 2018 – Discussion started: 11 Jan 2019
Abstract. The fluctuation of water levels and seasonal rainfall in a reservoir may induce various types of slope movements. Some of these movements are new, whereas others are old but reactivated. The primary aim of this study is to investigate the formation mechanism and process, deposit characteristics, and identification signs of a giant multi-translational reactivated ancient landslide in the Three Gorges Reservoir region based on field observations, on-site surveys, and Electron Spin Resonance experiments. The Outang landslide, located at the south bank of the Yangtze River, has a total volume of approximately 90 million m3 and can been divided into three independent subzones with an apparent age of 120–130 ka (ka represents a thousand years) for subzone O1, 65–68 ka for subzone O2, and 47–49 ka for subzone O3. The features of mobilized material structure and slip surface morphology in each subzone are similar and are in the form of a spoon. A conceptual model, including sliding, bending, suspending, and accumulating, is deduced to explain the formation mechanism and evolutionary process of this instability. Three types of evidences are proposed to recognize the ancient landslide. Currently, landslide stability is obscure based on the significant landslide movement and reactivated features; more attention and long-term monitoring is necessary in the future.
This preprint has been withdrawn.
How to cite. Luo, S., Jin, X., Huang, D., and Zhu, T.: Formation of a multi-translational reactivated ancient landslide in the Three Gorges Reservoir, China, Nat. Hazards Earth Syst. Sci. Discuss. [preprint], https://doi.org/10.5194/nhess-2018-399, 2019.
The field survey and laboratory tests were conducted and analyzed in detail. A conceptual model was proposed to elaborate the formation process and mechanism of this instability. The structural characteristic of mobilized material, rupture surface, topography saltation, and seasonal variation of groundwater exposure could be regarded as valid proofs in identifying ancient landslides. Long-term monitoring and emergency civil protection actions are necessary.
The field survey and laboratory tests were conducted and analyzed in detail. A conceptual model...