Fast-flowing Antarctic glaciers primarily transport ice through sliding over the subglacial substrate, or bed. This sliding can occur through stable sliding, where ice flow is relatively steady, or through stick-slip motion, where rapid accelerations and decelerations are separated by periods of little slip. Stick-slip motion generates seismic waves, which can be recorded at the glacier surface using seismometers.

 

Across two field campaigns, we deployed a dense regional array of seismometers on Thwaites Glacier, close to a subglacial ridge that acts as an obstacle to flow. The array recorded over a million icequakes caused by stick-slip motion at the ice-bed interface, representing some of the highest rates of basal seismicity ever observed. By analyzing the frictional processes driving this stick-slip behavior, we can use these observations to better understand the magnitude and spatial variability of basal friction resisting the flow of Thwaites Glacier.