Evaluación del índice SL para la identificación de movimientos de ladera que afectan a la red de drenaje

Abstract

Many quantitative geomorphic parameters, like the Stream Length-Gradient (SL) index, have been demonstrated to be suitable for detecting anomalies on stream-profiles. These knickpoints are generally related to active tectonics, lithological changes and large landslides. This study aims to detect drainage areas affected by landslides using SL index in La Vall d’Àssua, Romadriu y La Vall de Tor basins (Catalan Axial Pyrenees). The methodology used consists of computing the SL index using Chi-Map script and then, applying a couple of ArcGIS Toolboxes to provide a better localisation of knickpoints. SL anomalies have been compared with the landslide inventory of La Vall d’Àssua basin, indicating a well-correlation between SL anomalies and landslides. Additionally, this geomorphic index provided the identification of 13 new mass movements which had not been described before. To conclude, this geomorphic parameter is a useful tool for the identification of drainage network areas affected by landslides, which allow focusing geomorphological studies on these areas for a better characterization of the landslides and the associated hazard and risk.