masterThesis
Zonificación de amenazas por avenidas torrenciales a partir del análisis geomorfológico de los depósitos asociados y su datación. Caso de estudio : cuencas de la vertiente oriental de la Cordillera Occidental Colombiana, Andes del Norte
Autor
Pérez Hincapié, Ana María
Institución
Resumen
Understanding of debris flows and related hazards constitutes an essential ingredient in the planning and management of mountainous territories. In this work, we analyzed geomorphological, stratigraphic and hydraulic data from five watersheds located in the central zone of the Cordillera Occidental of Colombia in the Northern Andes, by estimating the flow with a return period of 100 years, increased by 40% in order to take into account the contribution of sediment and debris in the flow. Observations from the Tapartó and Farallones rivers, and La Arboleda, La Linda and Los Monos stream allowed the characterization of debris flow deposits under conditions of high slope, heavy rainfall, and an important development of soil profile. Geomorphological and stratigraphic analyses were complemented with 10Be ages Holocene ages between 6.22 ka and 8 ka (Unpublished) and 100 ± 30 and 2790 ± 30 14C yr BP . Our observations support the existence of three morphodynamic stages related to debris flow dynamics: (1) “old” stage with deposits older than 2000 14C yr BP; (2) “sub-recent” stage represented by deposits of age between 1200 and 2000 14C yr BP; and (3) “recent” stage, with lowly incised deposits and ages that do not exceed 1200 14C yr BP. Although basins studied have evidenced debris flow events of relatively high magnitude, our analyses suggest a decrease in magnitude during the last 1000 years.