Cartografía de fenómenos de remoción en masa del valle de la Armenia, provincia del Chimborazo.

Abstract

Mass removal phenomena or mass movements are recurring and destructive threats that, over time, have caused various disasters, affecting the population with damage to infrastructure and human losses. This research is carried out in the Valle de La Armenia sector, which is located in the Chunchi canton to the south of the Province of Chimborazo, an area that presents a morphology of high reliefs that are mostly medium to very high slopes (16.7 ° to 71.63 °), composed of light/dark fine tuffs and Quaternary deposits such as colluvial deposits, mostly quite weathered that are giving rise to the formation of clay, causing the study area to be an unstable area and prone to mass movements. With the help of IGM photogeology and aerial photographs, 1989 and Google Earth Pro software for the year 2022, 13 ancient landslides and 24 current landslides were identified, including landslides, creeps, and water erosion features such as gullies. With the comparison of the cartographic maps of 1989 and 2022, it was observed that the old landslides maintain their features up to the present, while the current movements are distributed mainly towards the edges of the Picay River, developing on the Cisarán formation and colluvial deposits. The La Armenia landslide is the most relevant morphological change due to its extension. The triggering factor for mass movements is rain because the study area has significant rainfall throughout the year according to SNGRE, 2021; increasing the infiltration of water into the soil and the acceleration of weathering of the material which decreases the resistance of the medium, destabilizing the topography. The preliminary susceptibility analysis with the Brabb method in which the cartography of mass movements, the slope map and the lithology map were used; identified that the old landslide zones present medium susceptibility while the current landslide zones present high and very high susceptibility.