Quantitative deformation analysis of landslides based on multi-period DEM data

Quantitative deformation analysis of the landslide is a difficult problem in landslide study. To reveal the deformation and evolution process of landslides in Heifangtai, the authors established the quantitative deformation analysis model of landslide based on multi-period DEM data by ArcGIS using four periods of topographic maps obtained respectively in 1977, 1997, 2001, and 2010. The deformation degree and rate of 32 landslides were calculated in stages at Heifangtai terrace in Yongjing, Gansu Province. Between 1977 and 1997, the average retrograde eroding velocity of landslide scarp was 4.47m/a. Between 1997 and 2001, the average retrograde eroding velocity of landslide scarp was 3.46m/a. Between 2001 to 2010, the average retrograde eroding velocity of landslide scarp was 1.10m/a. At the same time, the related formula for irrigation amount and landslide deformation degree was established, and the prediction of the development tendency of landslides was carried out. The calculation results show that the average retrograde distance of the landslide scarps will be 0.79m by 2015, and the retrograde distance will be reduced to 0.20m by 2020.