A SATELLITE VIEW OF ANDEAN ROCK GLACIERS: INTERFEROMETRIC SYNTHETIC APERTURE RADAR (INSAR) ANALYSIS OF ROCK GLACIER FLOW KINEMATICS

Rock glaciers are ubiquitous landforms in alpine periglacial landscapes frequently suggested to represent a geomorphic process of significance for sediment transport and alpine landscape evolution; however, questions remain regarding details of the kinematics of rock glacier flow and their implications for the geomorphic evolution of alpine periglacial landscapes. Investigations in these themes are typically site-specific and of limited duration, and the results are often contradictory. In order to address these questions from a generalist perspective, an investigation of rock glacier flow at a regional scale is essential. Satellite-based Synthetic Aperture Radar Interferometry (InSAR) provides a potential means of quantitatively and remotely investigating rock glacier flow over large regions, at multi-decadal scales, and with sub-centimeter accuracy. Preliminary analysis of two active rock glaciers in the Cordillera Principal of western San Juan Province, Argentina, indicates that InSAR can be an effective tool to measure rock glacier velocities of the magnitude observed in this region (i.e., 20 – 170 mm/yr), despite the significant obstacles created by the rugged and steep terrain, intense seasonal variation, and the small footprint of these rock glaciers. When InSAR analysis is successful, comparison of InSAR-derived rock glacier velocities to three-year GPS survey results show broadly consistent rock glacier flow magnitudes and directions. Expansion of this technique to a large sample of the over 400 rock glaciers throughout the region will provide insights into rock glacier kinematics that will help to explain rock glacier variability, environmental controls, and geomorphic significance.