Formation mechanisms of the ancient giant basalt landslide in Yanyuan County, China

This study examined the Boli ancient landslide to improve the general understanding of the formation of ancient basalt landslides in the Emeishan large igneous province, China. The morphological, geomechanical, and structural features of the landslide were studied to reconstruct its characteristics. Field investigations, interpretations of remote sensing imagery, and topographical analyses were conducted to assess its formation mechanisms and to clarify the structural, geological, and geomorphological contexts in which the landslide developed. Inherited brittle tectonic features such as fault and joint sets determined the location, geometry, and development of rock slope failures. The Maijiaping thrust fault that cuts through the landslide area was found to be the major controlling factor in its evolution. The ductile tectonic features and sedimentary rock intercalations in the study area created the basal sliding surface for the landslide as it has weak mechanical properties and is hydrophilic unlike the surrounding basalt rock masses, resulting in a landslide-prone structure in the basalt slope.