Abstract

SURFACE DEFORMATION MONITORING OF THE QUILLCAY GLACIER SUB-BASIN USING DIFFERENTIAL INTERFEROMETRY.

Climate change effects are causing atypical changes in the tropical glacier basin's dynamics as the Cordillera Blanca in Peru, where the total glacier area (800–850 km2) in 1930 decreased to 600 km2 at the end of the 20th century. Ice reserve has been reduced by more than 20% (11 303 million m3). The continuous glacial tongues retreat left the formation of lakes dammed by moraine fronts and formations with debris deposits along the glacial basins from the flow stagnation. The debris deposit areas above the Quillcay basin are particularly vulnerable to the impacts of climate change as flood and GLOF hazards. The rapid snow melting and glacier initially increase runoff and erosion. In addition, slopes of 25° could lead to slippage in areas covered by warm glaciers. Glacial masses in higher regions with slopes >49° and till deposits between 7° to 14° on steep slopes are dissected by runoff from glacial melting. Due to ice adhesion, the underlying bedrock is highly airborne temperature-dependent. Quillcay basin dynamics as cover processes, moraine or rock dikes, and erosion might be monitored using interferometric differentiation. The 3d-geometric composition of the displacement was made using the "multi-geometry data fusion of LOS" technique. The products were periodic images from January 08, 2021, to May 22, 2022. The results show that the maximum rainfall in September (12.5 mm) was correlated with an anomalous basin displacement (11.7 cm). In addition, the highest displacement values (1.5 - 2.4 m) were observed around the Llaca, Palcacocha, Cuchillacocha, and Shallap lakes glaciers. However, the most significant mass gain recorded was around the Cuchillacocha and Shallap lakes glaciers (21-51cm). Finally, a mass loss (30-60 cm) was recorded over the lower to the middle basin, while gains were recorded in the basin headwater regions.