Research for the correlation between relief amplitude and landslides:a case study of Lishui City

Lishui City is located in the southwest mountainous area of Zhejiang Province. With complex topography and large variation of terrain, landslides frequently happen in local. Based on the data obtained from DEM with 5 m resolution, spatial neighborhood analysis was carried out with grids in 49 different sizes (from 2×2, 3×3,4×4, …, 50×50). It was found that there is a significant positive correlation between the average relief amplitude and the analysis grid sizes. Then, mean change-point analysis was adopted to select the best statistical unit (the grid size) and a grade diagram of relief amplitude can be completed in the study area with mesh area of 8 100 m²(the grid of 18×18). This paper divides the relief amplitude into nine levels at equal intervals, and then analyzes the correlation between landslides and relief amplitude by information acquisition analysis and certainty factor analysis.The results reveal a close relation between relief amplitude and landslides occurred in Lishui area, where the small relief amplitude is more conducive to the development of landslides. The relief amplitude ranging from 15~60 m is the landslide-prone region, among which 15~30 m is the most prone extent.