How do scientists measure glacier movement and investigate ice hidden below the surface?

Scientists employ several methods to monitor glacier movement and investigate the ice hidden beneath the surface.

Measuring Glacier Movement

• Surface Surveys: A traditional and still-common technique involves surveying the position of stakes placed on the glacier surface to track flow velocities.1
• Borehole and Tunnel Deformation: Scientists measure the deformation of vertical boreholes drilled into the ice or lateral tunnels dug into the glacier to study internal movement.12
• Numerical Modeling: Researchers use mathematical models to analyze glacier flow, which is driven by the weight of the ice and its plastic deformation properties, often described by the Glen flow law.3

Investigating Subsurface Ice

• Radar Sounding: This is a primary method for examining the internal structure and thickness of glaciers and ice sheets. It is particularly effective in cold glaciers where the ice remains below its freezing point.124
• Deep Drilling: Scientists extract ice cores by drilling boreholes to bedrock, such as the projects conducted in Greenland and Antarctica, allowing for the analysis of ancient ice layers and oxygen isotope ratios.24
• Geophysical Surveys: Gravimetric and seismic surveys are used to determine the dimensions and base characteristics of large ice sheets.4