The Landslide Blog is written by Dave Petley, who is widely recognized as a world leader in the study and management of landslides.
As landslides in Ecuador are currently in the news, it is interesting to reflect on perhaps the largest failure there in recent years. On 12 February 2021, the massive Chunchi landslide occurred in the La Armenia sector of the Andean region of Ecuador. I wrote about this at the time (on the AGU Blogosphere site, which is still online), but an open access paper (Macías et al. 2025) has just been published in the journal Natural Hazards that provides a proper analysis.
This landslide was captured in action in a remarkable set of videos (please accept my apologies for the very irritating music!):-
The centre of the landslide is at [-2.2900, -78.9353] – this is a Google Earth image of the site from July 2024:-
This is a very large failure – Macías et al. (2025) estimate that the volume was 30 million m3, with a runout distance of about 1.8 km. The source area failure was a rotational landslide, but this transitioned into a mobile flow, as shown in the videos. No-one was killed, but 30 houses were destroyed and a further 38 were damaged, and two people were injured.
Whilst this area is seismically active, analysis by Macías et al. (2025) indicates that there was no earthquake trigger. However, January and February 2021 saw record high precipitation for the time of year, suggesting that high pore water pressures were the likely cause. There has also been considerable land use change in this area, moving from natural woodland and shrubs to farmland, with the use of irrigation. THis may also have played a role.
The Chunchi landslide was a remarkable event, causing substantial hard to the local population. This would be a good target for retrospective InSAR analysis to determine whether the failure could have been anticipated.
Reference
Macías, L., Bonifaz, H., Toulkeridis, T. et al. 2025. Geotechnical and geophysical evaluation of the remarkable Chunchi landslide of 2021 in the Andean Ecuador. Natural Hazards. https://doi.org/10.1007/s11069-025-07219-x