NHESSD Natural Hazards and Earth System Sciences Discussions NHESSD Nat. Hazards Earth Syst. Sci. Discuss. 2195-9269 Göttingen, Germany 10.5194/nhess-2021-32 GNSS and RPAS integration techniques for studying landslide dynamics: Application to the areas of Victoria and Colinas Lojanas, (Loja, Ecuador) Zárate Torres Belizario A. 1 El Hamdouni Rachid https://orcid.org/0000-0002-1271-3839 2 Fernández del Castillo Tomas https://orcid.org/0000-0002-6822-775X 3 Departament of Geology, Mines and Civil Engineer, Private Technical University of Loja, Loja, AP. 1101608, Ecuador Department of Civil Engineering, ETSICCP, University of Granada, Spain, Campus Fuentenueva s/n, Granada 18071, Spain Department of Geology, University of Jaén, Campus de las Lagunillas s/n, 23071 Jaén, 23071, Spain 08 02 2021 2021 1 36 Copyright: © 2021 Belizario A. Zárate Torres et al. 2021 This work is licensed under the Creative Commons Attribution 4.0 International License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/4.0/ This article is available from https://nhess.copernicus.org/preprints/nhess-2021-32/ The full text article is available as a PDF file from https://nhess.copernicus.org/preprints/nhess-2021-32/nhess-2021-32.pdf

<p>This research tests the application of GNSS and RPAS techniques to the spatiotemporal analysis of landslide dynamics. Our method began by establishing non-permanent GNSS networks on the slope surfaces to perform periodic measurements by differential GNSS. Similarly, RPAS flights were made to acquire high-resolution images, which were oriented and georeferenced using ground control points and structure-from-motion algorithms to obtain digital surface models and orthophotos ultimately. Based on GNSS measurements, the direction and velocity of displacements were accurately calculated, and orthophotos and DSMs were used to calculate horizontal and vertical displacements in a set of significant points throughout the study area, reaching accuracies higher than 0.035&thinsp;m in the GNSS data and 0.10&thinsp;m in the RPAS data. These values were within the accuracy required for such studies. Based on the field observations and the results from the photogrammetric studies, the two studied landslides were classified as very slow flows.</p>