UAV AND GROUND-BASED PHOTOGRAMMETRY APPLICATIONS FOR USE IN BOULDER MASS DISTRIBUTION FOLLOWING MORAINE-DAMMED LAKE FAILURES IN NORTHERN PATAGONIA

There is an increasing risk of glacial lake outburst flood (GLOF) hazards due to global environment change. As a result, new and efficient methods of studying GLOF mass distribution are becoming increasingly important to develop. This study investigated the use of unmanned aerial vehicles (UAV) and ground-based imagery to measure the mass of boulders deposited by a GLOF. The study was conducted in the upper Soler Valley, Northern Patagonia, Chile. The researchers used a DJI Mavic 2 Hasselblad UAV drone, Pix4DMapper, and Pix4DCatch software to construct 3D models of boulders. The 3D modeled boulders were used to determine factors of volume for boulder mass calculations. The mass of the boulders was calculated using volume estimates from Pix4DMapper. Results showed that the 3D models generated were accurate and detailed to a resolution of 2 in/pixel. The study showed that even with some likely inaccurate volume estimations, the boulders still showed the predicted decrease in mass with increased distance from the glacial lake. Overall, this study demonstrates the potential of UAV and ground-based imagery for measuring the mass of boulders following glacial lake outburst floods.