Large landslides are among the most effective agents of landscape change in the Andes, yet their role in the long-term evolution of this mountain system remains poorly integrated into Quaternary science. Steep relief, active tectonics, strong climatic contrasts from tropical to desert environments, and repeated glacial-interglacial cycles have created favorable conditions to slope failures. Along a latitudinal gradient spanning the hyperarid Central Andes, the semi-arid Dry Andes, and the humid, glaciated Patagonian ranges, such massive failures are widely documented. Geochronological studies indicate these failures cluster in time, with peaks coinciding with deglaciation and with wetter intervals of the Late Pleistocene and early Holocene. Although the relative importance of climatic, tectonic, and lithological controls remains uncertain, many of the largest landslides in Peru, Chile, and Argentina are linked to intense seismicity. Geotechnical analyses and back-modelling have identified the active faults associated with some earthquake-triggered events, providing evidence of regional palaeoseismicity.

Landslides are not isolated events but key components of sediment cascades. A single failure mobilizes large volumes of bedrock and regolith and abruptly shifts a catchment between sediment-production and sediment-storage regimes, converting valley floors into temporary sinks through damming and aggradation. Over longer timescales, the fate of this material, whether reworked by subsequent gravitational processes, stored in terraces, remobilized by dam breaching, or exported to foreland basins, governs lags between hillslope input and downstream sediment delivery. Landslides can therefore decouple erosion from sediment flux, buffer or amplify climate signals, and bias catchment-averaged denudation rates and interpretations of fluvial terraces.

These chain processes also underpin significant contemporary hazards. Valley blockage, landslide-dammed lakes, natural dam failures, outburst floods, and sediment-laden flows can propagate far downstream, affecting communities, infrastructure, and water resources. Climate warming, glacier retreat, permafrost degradation, and rapid urban expansion are altering susceptibility and exposure of Andean communities.