8 November 2021
Mallama: a deadly landslide in Colombia on 2 November
Posted by Dave Petley
Mallama: a deadly landslide in Colombia on 2 November
On 2 November 2021 heavy rainfall triggered a deadly landslide in the village of Mallama in Nariño Province of Colombia, killing 17 people and injuring a further nine.
The best image that I can find that provides a good view of this failure is on the Nariño Government website:-
The 2 November 2021 landslide at Mallama in Colombia, which killed 17 people. Image via the Gobernacion de Nariño.
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Based on this image this is a failure in deeply weathered regolith on a very steep slope. It appears to have demolished a number of houses. This is probably best characterised as a debris avalanche, although with a comparatively moderate runout distance.
RCN Radio has this very dramatic image of the aftermath of the landslide from a different perspective:-
The aftermath of the 2 November 2021 landslide at Mallama in Colombia. Image by JHR Ingeniería via RCN Radio.
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According to news reports, the site had not previously been identified as being at risk of landslides, and the reason for the failure at this time is not clear. There is however a risk of further failures that will necessitate the relocation of people whose houses are as yet undamaged.
Dave Petley is the Vice-Chancellor of the University of Hull in the United Kingdom. His blog provides commentary and analysis of landslide events occurring worldwide, including the landslides themselves, latest research, and conferences and meetings.
Was that valley-spur with remaining buildings formed by the run-out of an older slide ??
What degree of excavation was done at the base of this slide escarpment? It appears there are water filled tire tracks on the near side of the second image below the slide. Were there slides before the main slide, that were being dealt with prior to the main slide? Sorry for those affected. I hope they can keep track of land motions, new fractures and/or somehow ensure the remaining houses will not also be impacted.