Analysis on non-tectonic origin of linear scarps in alluvial-proluvial fan of the west bank of Xidong in Hexi Corridor

The formation and discovery of linear scarps in alluvial-proluvial fan are affected by many factors, such as structure, erosion and human activities. In this paper, combined with the UAV high resolution remote sensing image interpretation, the topographic and the geomorphological profile analysis, the trench excavation, the engineering geological profile analysis and the audio magnetotelluric detection etc., we analyzed comprehensively the landform of the linear scarp developed in the alluvial-proluvial fan of the west bank of Xidong in Hexi Corridor from the shallow layer to the deep layer. The conclusions are as follows: the topographic and geomorphological profile indicates that the terrain elevation on both sides of the linear scarp is turning gradually flat without deformation; The trench reveals that the underlying strata on both sides of the linear scarp are continuous, and the bottom strata are nearly horizontal with the occurrence being significantly less than the top strata and there is no stratigraphic fault; The engineering geological section shows that the top surface of Q₃ alluvial-proluvial sandy gravel layer on both sides of the linear scarp is continuous, and there is no formation dislocation; The audio magnetotelluric detection results show that the underlying bedrock interface on both sides of the linear scarp is continuous and complete, with no sign of fault passing. Therefore, it is concluded that the linear scarp landform developed in the alluvial-proluvial fan of the west bank of Xidong in Hexi Corridor is formed by not the tectonic effect rather than the lateral erosion of the Daciyao river.