An assessment of the most suitable DEM for tectonogeomorphic analysis in tectonic basins

Digital Elevation Models (DEMs) are a fundamental data source for the calculation of tectonogeomorphic indices in areas with active tectonic deformation. There are, however, hardly any studies available that compared the strength and weaknesses of the various, freely available medium-resolution DEMs for these kinds of applications. As such, it is difficult for researchers to make a well-informed choice regarding the most suitable DEM for their specific study. We have therefore carried out an exhaustive analysis of the five, most commonly used medium-resolution DEMs. These are the 30-m SRTM v.3.0, AW3D30, ASTER GDEM3, Copernicus and the 12-m TanDEM-X. We have analysed the performance of these DEMs by calculating the most commonly used tectonogeomorphic indices for 22 river basins in two geographically contrasting tectonic basins in the Peruvian Andes. Calculated metrics included drainage basin areas, fluvial network length and position, longitudinal profile and knickpoint representation, concavity indices θ and m/n, the normalised steepness index ksn and the Hypsometric integral. We also performed a mapping exercise of fluvio-tectonic landforms such as fluvial terraces, folds and fault traces. Statistical analysis were carried out to highlight similarities and differences in performance between the five DEMs. Copernicus and TanDEM-X were the best performing DEMs across the whole range of analysed metrics, closely followed by AW3D30. SRTM3 v. 3.0 and ASTER GDEM3 performed well in some of the tests, but lacked in other areas and are therefore not recommended.