Andean Rock Glaciers Under Surveillance : 24 Years of Satellite Imagery

Rock glaciers and other persistent mass-movement areas (PMAs) are key indicators of periglacial and gravitational processes. Monitoring them over large areas and across multiple decades remains challenging due to spatial variability and the lack of continuous data.



@pexels.com
Figure 3. Example of raw outputs from inversion time series, PMA detection and PMA validation using InSAR-wrapped interferograms. The upper-left map shows the locations of the small inner maps : (a) Tapado west, (b) Largo rock glacier, (c) Tapado complex and (d) Dos Lenguas. The image background corresponds to © Google Terrain. All inner maps show a cumulative surface displacement map (left) after time-series inversion (last date available), PMA detection after directional and magnitude filtering (middle), and 12 d ascending S1-wrapped interferograms (right). Red and green polygons represent raw “not confirmed” and “confirmed” PMAs, respectively.


To overcome these challenges, researchers have developed a method that combines image correlation, temporal inversion, and automatic detection of PMAs using 24 years of Landsat 7/8 imagery, validated by high-resolution imagery, Sentinel-1 radar interferometry, and GNSS measurements.

Using this approach, 382 confirmed PMAs were monitored, including 153 rock glaciers, 124 landslides, and 105 unclassified formations. The mean velocity over 24 years reaches 0.3 m/yr, with rock glaciers moving on average 23% faster than the other formations. Decadal-scale velocity variations were observed in 2% of the PMAs, notably in rock glaciers and rapidly moving landslides.

This study demonstrates the potential of medium-resolution optical imagery for mapping and analyzing periglacial dynamics, thereby contributing to a better understanding of the impact of permafrost warming on high-mountain landscapes.


The full study is published in The Cryosphere.

References :

Cusicanqui, D., Lacroix, P., Bodin, X., Robson, B. A., Kääb, A., & MacDonell, S. (2024).
Tracking Rock Glaciers in the Andes with 24 Years of Satellite Images
The Cryosphere, 19, 2559–2580.

Blöthe, J. H., Halla, C., Schwalbe, E., Bottegal, E., Trombotto Liaudat, D., & Schrott, L. (2021).
Surface velocity fields of active rock glaciers and ice-debris complexes in the Central Andes of Argentina
Earth Surf. Process. Landf., 46, 504–522.

Gruber, S. (2012).
Derivation and analysis of a high-resolution estimate of global permafrost zonation
The Cryosphere, 6, 221–233.

Obu, J. (2021).
Permafrost distribution modeling in mountain regions : Updated global Permafrost Favorability Index
The Cryosphere, 15, 123–140.

IANIGLA. (2018).
Inventario Nacional de Glaciares de Argentina – Resumen Ejecutivo
Ministerio de Ambiente y Desarrollo Sustentable, CONICET.

Scientific contacts :

  • Diego Cusicanqui – Chercheur, ISTerre – CNRS / CNES
  • Pascal Lacroix – Chercheur, ISTerre – IRD
  • Xavier Bodin – Chercheur, EDYTEM – CNRS
  • Benjamin Aubrey Robson – Chercheur, University of Bergen
  • Andreas Kääb – Chercheur, University of Oslo
  • Shelley MacDonell – Chercheuse, CEAZA


Funding and Support

  • Postdoctoral Program of the French National Centre for Space Studies (CNES)
  • French National Centre for Scientific Research (CNRS), through the Action Plan for the Prevention of Glacial and Periglacial Hazards (PAPROG)
  • Labex OSUG (Investissements d’avenir – ANR10 LABX56), PermANDES project
  • CEAZA, supported by ANID–Regional Centers (grant no. R20F0008)
  • European Space Agency (ESA), Permafrost_cci and EarthExplorer10 Harmony projects (grant nos. 4000123681/18/I-NB and 4000135083/21/NL/FF/ab)