Formation and evolution of a successive landslide dam by the erosion of river: a case study of the Gendakan landslide dam on the Lancang River, China

• DOI: 10.1007/s10064-020-01743-9
• Publication Date: 2020-02-18T06:03:06Z
• Authors: Guoxiang Tu; Hui Deng
• Keywords: Mass movement; Elevation (ballistics)

A landslide dam located on the Lancang River in Southwest China was used as a case to study the landslide formation and evolution process induced by river erosion. The Lancang River has been blocked at least twice by landslides at the same location and formed a landslide dam with a length of over 162 m, a height of over 96.8 m, and a volume of over 2.7 × 106 m3. The rapid and continuous downcutting of the Lancang River induced the steeply dipping layered rock mass to intensively topple, and multiple toppling fracture zones formed in the rock mass. The Gendakan landslide was formed at the base of a deep-seated toppling failure of the rock mass. The Yagong intensively toppled rock mass, which is located 800 m upstream of the Gendakan landslide, has topographical, geological, and stratigraphic conditions similar to those of the studied landslide. The Yagong rock mass has a probability of evolving into a large landslide and blocking the Lancang River during further river erosion. In addition, the residual deposits of the Gendakan landslide, which has a volume of 4.7 × 107 m3 and is distributed at a relatively high elevation on the right bank of the Lancang River, have a probability of reactivating and blocking the river again due to further river erosion and rainstorms.