Tectonic fracturing and clay enrichment in basalt slip zones: A key factor of 2019 Shuicheng landslide in southwest China
Citation
He, X., Xu, C., Aretusini, S., Feng, W., Wang, H., Li, H., Di Toro, G. (2025). Tectonic fracturing and clay enrichment in basalt slip zones: A key factor of 2019 Shuicheng landslide in southwest China. Engineering Geology, 108463. Link to paper
Abstract
Landslides are common geological phenomena influenced by multiple factors and pose serious threats to human settlements, infrastructure, and the environment. Numerous large-scale landslides occurred in the Emeishan basalt area of the southwestern China. Previous studies have primarily focused on the movement characteristics, development patterns, and numerical simulations of such landslides. This study innovatively integrates paleo-landslide statistical methods with typical landslide case studies, with a primary focus on the key controlling role of regional geological factors such as tectonics and lithology in the instability of such landslides. Taking the Shuicheng landslide as a case study, this research systematically combines, for the first time, the multi-scale geological characteristics of the macroscopic structure, microscopic structure, and rock mineral composition of the sliding surface basalt, to provide an in-depth explanation of the internal mechanisms of landslide instability. The results show that the basalt is cut by multiple groups of structural surfaces, one of which is similar to the sliding surface, and the rock is fragmented and severely weathered. The clay minerals of the rock are as high as nearly 50 % with developed interlayer pores. Combined with the research and discussion of similar landslides in the region, we suggest that the regional tectonic movement not only provides structural surfaces for the landslide, but also causes rock fractures, rapid weathering, and increased clay minerals content. These factors weaken the slope, making it susceptible to deformation and eventually failure (landslide) due to rainfall infiltration.