A case study on causation of the landslide on 26 October 2016 in the northern Colombian Andes

Abstract

This paper presents the results of a technical investigation on the causation of the landslide that occurred in Las Nieves quarry on October 26, 2016 in the municipality of Copacabana, located in the northern part of the Colombian Andes. This landslide caused the highest number of fatalities in Colombia in 2016, totalling 16 deaths. The study included field visits, soil sampling, study of the geology and geomorphology, as well as analysis of rainfall and groundwater flows presented in the area. The information collected in this study is consistent with the hypothesis that the regional groundwater flow which comes from recharge zones, generated an increase in water levels in the landslide zone thus triggering the landslide. Finally, a stability analysis (statistical analysis and sensitivity analysis) was performed using the limit equilibrium method, where the effect of the rise in the ground water table was modelled as the trigger. The results of the stability analysis showed a low safety factor for the slope, even when low water levels were considered.

Keywords

• Landslide Susceptibility
• Failure Mechanism
• Ground Water Table