Abstract

ARISTIZABAL, Edier et al. Concatenated Natural Hazards: Modeling of the November 13, 2020 Debris Flow in the Municipality of Dabeiba (Antioquia). Bol. geol. [online]. 2025, vol.47, n.2, pp.107-123.  Epub Sep 16, 2025. ISSN 0120-0283.  https://doi.org/10.18273/revbol.v47n2-2025005.

On the night of November 13, 2020, an intense storm in the basins of the El Mohán and El Botón streams (Dabeiba, Colombia) triggered numerous landslides, which generated high-velocity debris flows with significant destructive power. This article presents a comprehensive description and analysis of the landslides and the concatenated debris flow event. The study was conducted in four stages. First, the morphometry of the basins was characterized to obtain information on the geomorphological features influencing hydrological responses. Then, the dynamics of the hydrometeorological event were reconstructed using satellite data and meteorological records. The third stage involved fieldwork to identify physical evidence and characterize the sequence of landslides and debris flows. Finally, sediment generation was modeled using TRIGRS to assess landslide susceptibility and RUSLE to estimate erosion. Additionally, the r.ava.flow model was used to simulate flow hydrodynamics and delineate flood-prone areas.The results include a cartographic representation of the extent of torrential floods, flow paths, and deposition zones, as well as the identification of 175 landslides that affected 75.4 hectares. Precipitation reached maximum intensities of 74 mm/h in the El Mohán basin and 52 mm/h in the El Botón basin, causing widespread slope instability. As a result, debris flows reached peak discharge rates of 146 m3/s in El Mohán and 73 m3/s in El Botón, underscoring their significant hydrological and geomorphological impact.

Keywords : Landslides; Rainfall; Debris flow; Concatenated hazards.

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