7 April 2022
The long term history of fatal landslides in Colombia
Colombia is one of the most landslide-prone countries in the world. In the last few days heavy rainfall has triggered flooding and landslides, including at least one death in Marulanda Municipality in Caldas. Understanding the patterns of landslides in time and space is an important element of managing the risk in such countries.
In a paper just published in the journal Landslides (Garcia-Delgado, Petley et al. 2022), an international team has constructed a long term dataset of fatal landslides in Colombia, extending right back into historical times. This comprises 2.351 individual fatal landslides causing 37,959 fatalities. The earliest event was in October 1743, but the vast majority have been recorded since 1912, when the data becomes more robust.
The temporal pattern of the landslides in time is really interesting – this is illustrated in the graph below:-
This is an incredibly rich and interesting figure. Note the huge jump in the cumulative fatalities associated with the lahars caused by the Armero–Chinchiná lahars, which killed over 23,000 people). Also notable is the increase in fatalities through the period from 1912 to the 1970s. Since then the number of fatal landslides has remained high but the strong positive growth has slowed. The two decades with the highest numbers of fatalities were 2001-2010 and 2011-2020. The inset graph normalises fatalities with the population (which has grown over the study period), suggesting that the per capita rate of loss has remained about the same.
The paper looks at this data in a great deal more detail, including the role of mining and road construction in landslide trends, and also the impact of the El Nino / La Nina cycle. I will return to these themes in subsequent posts. Putting together a dataset like this is an epic job – Helbert Garcia-Delgado of the Department of Earth and Environmental Sciences at Syracuse University Servicio Geológico Colombiano, who led the research, has been brilliant.
Garcia-Delgado, Petley, D.N., Bermúdez, M.A. and Sepúlveda, S. 2022. Fatal landslides in Colombia (from historical times to 2020) and their socio-economic impacts. Doi: https://doi.org/10.1007/s10346-022-01870-2.