Resumo

ARISTIZABAL, Edier; RIANO, Felipe  e  JIMENEZ-ORTIZ, Julián. Rainfall thresholds as triggering factor in the Central cordillera of the Colombian Andes. Bol. geol. [online]. 2022, vol.44, n.2, pp.183-197.  Epub 18-Jul-2022. ISSN 0120-0283.  https://doi.org/10.18273/revbol.v44n2-2022009.

The Colombian Andes are characterized by its tropical climate and mountainous topography, where short duration and high intensity rainfall events are common. Rainfall often triggers hydrometeorological hazards caused by diverse concatenated processes. The analysis of historical rainfall records plays a key role for understanding landslide occurrence and its relationship with antecedent precipitation as triggering factor. This analysis was realized with satellite rainfall data with daily temporal resolution and 25 km2 as spatial resolution, with the purpose to find a rainfall pattern of the antecedent cumulative rainfall for 90 days using 100 landslides registered in the database of SIMMA and DesInventar. The results indicate that the role of rainfall as the main triggering factor in the foothills of the Llanos is controlled by the soil permeability. In fine soils, antecedent rainfall is fundamental, while for sandy soils it plays a secondary role. This relationship makes it possible to propose an Early Warning System (SAT) based on triggering rainfall and historical antecedent rain conditions.

Palavras-chave : Landslides; Rainfall; Hazard; Early warning system.

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