Slide-controlling modes and classification system of the mélange high slopes: insight into a disaster-causing mechanism of the Jinsha River mélange belt in the eastern Tibetan Plateau

Tectonic mélanges have diverse origins, variable lithologies, complex structures, and significant differences in engineering characteristics; they are the fundamental source of crucial geological safety risks and cause large-scale geohazards. Based on an analysis of the basic characteristics of 7 tectonic mélange belts in the eastern Tibetan Plateau, this article focuses on the Jinsha River tectonic mélange belt. This study employed remote sensing image interpretation and geological surveys, and the basic characteristics of 87 landslides with volumes greater than 1 × 10⁶ m³ that are distributed in the mélange belt along the upstream Jinsha River were identified. According to an engineering geological theory analysis and typical cases investigation, a comprehensive classification method was established for the slide-controlling modes of mélange high slopes, including 3 categories and 7 subcategories, revealing the main controlling factors and structural features for deformation and failure. In this study, the distribution of high-susceptibility zones and high-risk zones for large-scale landslides along the Sichuan‒Tibet section upstream of the Jinsha River was delineated. The results provide a basic theory and insights into the early identification and risk prevention of potential large-scale landslides and disaster prevention and mitigation of major engineering projects in the alpine gorge area of tectonic mélange belts.