Characterization of subglacial marginal channels using 3-D analysis of high-density ground-penetrating radar data

Abstract Studying subglacial drainage networks is important for understanding the potential relationship between channel dynamics and rapid glacier recession as well role of channels in sediment evacuation. In order to delineate planform geometry snout marginal channels, densely spaced ground-penetrating radar (GPR) measurements at a frequency ~70 MHz were carried out over zones two temperate glaciers southwestern Swiss Alps, Haut Glacier d'Arolla d'Otemma. Three-dimensional (3-D) data processing amplitude analysis GPR reflection along bed was used map channels. At d'Arolla, relatively straight several meters width identified. The positions these correspond with locations outlets terminus, fractures appearing on surface one month after acquisition. latter are believed represent beginning ice collapse above d'Otemma, major conduit detected similar dimensions those identified but greater sinuosity. position this confirmed by drone-based imagery acquired margin collapse. Our results confirm that high-density 3-D surveys can be near alpine margins.