Distribution of supraglacial landslides in the Southern Andes

Supraglacial landslides constitute an important component of glacier–landscape interactions, with the potential to influence glacier dynamics, mass balance, surface evolution, and sediment transport. From a geomorphological perspective, they contribute to the formation of large, anomalously positioned moraines and may, in some cases, facilitate the transition from glacier ice to rock glaciers. However, the glaciological and geomorphological significance of supraglacial landslides is highly variable and depends on landslide geometry, position relative to glacier accumulation and ablation zones, event timing, and the potential for long-term preservation of deposits.

This study investigates the spatial distribution and timing of large supraglacial landslides (>0.2 km² of deposits) across the Southern Andes. Landslide mapping was conducted using a multi-stage remote-sensing approach. First, potential supraglacial landslide locations were identified using high-resolution satellite imagery. Second, time series of medium-resolution satellite data (Landsat, ASTER, and Sentinel) were analysed to constrain the timing of individual events by estimating the occurrence window length (OWL), defined as the interval between the most recent image without a visible landslide and the oldest image in which the landslide deposit is observed. Third, morphometric characteristics were derived, and landslide locations were analysed in relation to glacier zones.

A total of 334 potential supraglacial landslides were identified, of which 198 deposits larger than 0.2 km² were detected on more than one satellite image between 1984 and 2025. For 59 of these landslides, sufficient time-series satellite imagery was available to constrain the OWL and thus approximate event timing. The results indicate that supraglacial landslides in the Southern Andes are substantially more frequent than previously recognised. The mapped inventory and timing constraints provide a basis for future analyses assessing the impact of individual landslides on glacier dynamics and their broader geomorphological significance.

This research was funded by the National Science Centre, Poland, project number 2021/42/E/ST10/00186