| Summary: | Debris-covered glaciers and rock glaciers have been increasingly studied in recent years because of the role they play within local watersheds, glacial ablation models due to climate change, and as analogs for buried ice features on planetary bodies such as Mars. Characterizing the supraglacial debris layer is a large part of these efforts. Geophysical exploration of debris- covered glaciers has mostly excluded active seismic methods, with the exception of refraction studies, due to the attenuating properties of the debris cover and field survey efficiency. We evaluate the accuracy, field efficiency, and effectiveness of seismic refraction, reflection, and surface-wave surveys for determining the elastic properties of the debris layer and any underlying layers on debris-covered glaciers using sites from Sourdough Rock Glacier and in the Malaspina Glacier forelands in Southcentral Alaska. We compare our seismic results with our results from ground-penetrating radar. Our results indicate that the interface between the debris layer and the ice can be imaged using seismic reflection methods, and that multi-channel analysis of surface waves (MASW) can provide insight to the variability of the shear-wave structure within the debris layer. We image an ultra-shallow seismic reflection from the bottom of the loose debris layer using ultra-dense receiver arrays. This study also presents results using multi-channel analysis of surface waves (MASW) on a debris-covered glacier, which we find could be a valuable addition to the toolbox of future geophysical investigations on these landforms.
|
|---|