Performance evaluation and sensitivity analysis of ASTER and SRTM (30m) DEM derived terrain variables in landslide susceptibility assessment: a case from the Western Ghats
Performance and sensitivity of freely available equal resolution space borne digital elevation model derivatives in landslide susceptibility analysis were carried out in a selected part of the Western Ghats, India. ASTER and SRTM digital elevation models having 30m resolution were used to derive the terrain variables such as slope, aspect, relative relief, slope length and steepness, curvature, landform and stream networks. Most of the variables shown spatial variability in distribution pattern, which affects the results of geo-environmental processes analyzed. Sensitivity and performance of each variable derived from the digital elevation models were assessed by preparing a landslide susceptibility index (LSI) maps using the Information Value (InfoVal) technique and was validated through receiver operator characteristics (ROC) curve analysis. LSI maps generated point towards the capability of the SRTM digital elevation model, to correctly generate the terrain variables than the ASTER elevation surface, by giving the accuracy of LSI maps greater than those produced using the ASTER derived parameters (0.77 and 0.72 for SRTM; 0.67 and 0.65 for ASTER). The results of the present study suggest, the SRTM digital elevation data is more sensitive and suitable for terrain analysis and earth surface process modelling than the ASTER elevation data sets, though both possess equal resolutions .