Spatial and temporal analysis of debris flow occurrence in three adjacent basins of the western margin of Grande River: Quebrada de Humahuaca, Jujuy, Argentina

Abstract

Numerous slides, rock falls and flows occur in the arid mountainous areas of northwestern Argentina. On 10 January 2017, torrential rain caused the acceleration of large-scale and slow-moving landslides mainly in the Los Filtros basin and it produces important damage in the Volcán village causing fatalities, dozens of evacuees and great economic losses, with the total destruction of buildings, services and infrastructure. However, in the two adjacent creek basins, the Coiruro basin to the north and Del Medio basin to the south, the effects were smaller. A morphometric analysis of these three adjacent basins was carried out in order to understand this catastrophic event and to explore its causes. The geological characteristics of the study basins are very favourable conditioning factors in landslide generation. Precambrian-age low grade metaclastics shatter in the frost climate of the higher mountains and poorly consolidated Quaternary deposits along the sides of the gully erode readily and become source material for landslides. Also, the area, shape, relief and slope of the basins would have been other key factors in the debris/mud flow generation in the Los Filtros creek basin. The Melton ratio number has been a key morphometric index to discriminate river basins susceptible to different types of flows. Finally, this study aims to increase knowledge of all the above mentioned events in order to provide several methods of analysis for landslide prevention and control in adjacent basins whit different dynamics in the Central Andes.