Abstract
Objectives: The eastern of the Tibetan Plateau, characterized by the alpine canyons of the Jinsha River, exhibits extensive development of large deep-seated landslides. The complex terrain, geological environment, and intense tectonic activity have resulted in the formation and evolution of landslides through multiple stages, types, and overlapping processes. Analyzing the spatial structural characteristics of these large deep-seated landslides characterized by the alpine canyons remain a key challenge in geological hazard research, disaster prevention and mitigation. In the Diwu section of Batang County along the Jinsha River, a series of large deep-seated landslides have developed, among which the Diwuxiang landslide exhibits intense deformation, necessitating the relocation of the village. However, the deep structural characteristics of this landslide remain unclear. Methods: To further investigate the spatial structural characteristics of large deep-seated landslides in this region, a variety of techniques including field surveys, remote sensing interpretation, LiDAR (Light Detection and Ranging) aerial surveys, high-density electrical resistivity tomography, and Microtremor Survey Method (MSM). These methods reveal the spatial development characteristics of the Diwuxiang landslide were employed. Results: The study finds that the surface deformation of the Diwuxiang landslide is intense, characterized by tensile cracks, retaining wall fissures and steep scraps, with 152 secondary landslides identified within the landslide zone. High-density electrical resistivity tomography reveals that the Diwuxiang landslide generally exhibits low resistivity, with some localized areas displaying high resistivity. The MSM indicate that the stratigraphy of the landslide can be divided into a shallow cover layer (150-550 m/s), a medium-strongly weathered bedrock layer (430-840 m/s), and a weakly to unweathered bedrock layer (630- 930 m/s). Combining the results from the two geophysical methods, it is concluded that the Diwuxiang landslide develops 2- 3 sliding zones, with significant variability in resistivity at these locations, generally displaying low resistivity values of 100- 150 Ω·m. The maximum depth of the sliding zones can reach up to 70 meters. The results from the two geophysical methods are in good agreement, with the relative error in the revealed thickness of the sliding body being within 10%. Conclusions: Based on the established geophysical response technology process for detecting the spatial structure of large deep-seated landslides in alpine canyon areas, can effectively guide the spatial structural detection of large deep-seated landslides in alpine canyon areas.
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