Helicopter, Unmanned Aerial Vehicle (UAV) and Ground Based Photogrammetric Monitoring of Mass Movements in Deglaciating Landscapes

Abstract:

When valley glaciers retreat and/or thin, they expose stores of sediment prone to failure and rapid reworking through a range of mass movement processes. The newly exposed bedrock slopes are also thought to undergo a period of more intense, or more frequent, failure before returning to the background norm. However, the magnitude-frequency of failures above and in front of ice is poorly constrained, as are their spatial relationship to previous ice extents. Here we show the results from a combination of repeat helicopter, UAV and ground based photogrammetry that has been processed using Structure from Motion (SfM) techniques to produce high-resolution elevation and change models. These data require few ground control and so lend themselves to deployment in remote, or difficult to access high-mountain regions where our understanding of failure patterns has been limited by a lack of high-quality monitoring data. Our initial data cover the valley walls of Glacier d’Argentiere, Mer De Glace, Glacier des Bossons and the Bionnassay Glacier on the French side of the Mt Blanc massif at the start and end of the summer 2014 season. These glaciers have a rich documented history of ice retreat, thinning, and permafrost locations to link to the spatial patterns of failure.