Application of radar and seismic methods for the investigation of temperate glaciers

Abstract

The capabilities of seismic and radar methods for the study of ice sheets have been analysed by other authors in the past. The joint use of both techniques has allowed the comparison of information, such as ice thickness, retrieved from both sources. Though these methods, specially the radar sounding, have also been widely used for the study of polythermal and temperate glaciers, the literature lacks joint analysis of their use for the study of temperate glaciers, where physical processes absent in the cold ice masses come into play. We have used seismic and radar methods collected at Johnsons Glacier, a temperate ice mass located in Livingston Island (Antarctica), to show the glaciological information that can be retrieved from such data. The aspects considered include the determination of ice thickness, the retrieval of information concerning the internal structure of the glacier (distinction between accumulation and ablation zones, determination of the depth of the firn–ice transition, detection of buried crevasses), the estimation of physical parameters such as seismic and radio wave velocities, water content in temperate ice and firn density, and the use of radar and seismic data to infer the presence of water channels at the ice–bed interface and to determine the nature of subglacial sediments.