Illuminating the subglacial environment of Greenland’s fastest outlet glacier with passive seismic techniques
The current rapid mass loss of the Greenland Ice Sheet is caused by increasing surface melt intensity due to warmer air temperatures, and rapidly accelerated flow rates of outlet glaciers. Sermeq Kujalleq in Kangia (or Jakobshavn Isbræ), a major outlet glacier of the Greenland Ice Sheet, has a flow speed of 20-30 m/day. Sliding, sediment deformation and hydraulic processes at the base play a central role in ice flow dynamics, and understanding these is imperative for predicting the role of outlet glaciers in a changing climate. But the inaccessible nature of the ice-bed interface makes understanding rapid ice flow a challenge.
To better understand the process at the ice-bed interface, we will deploy seismic sensors at the surface of the fast-moving Sermeq Kujallek in Kangia. These seismic sensors will record vibrations throughout the ice mass. The measured vibrations will be used to determine basal icequakes, the response to calving events, and resonance frequencies over long periods of time. The time series of resonances will enable us to detect changes in elastic properties near the glacier bed, which in turn depend on pore pressures, stress, sediment dilatation and the wave field composition of the vibrations.
With the acquired data, we aim to monitor subglacial conditions and spatiotemporal variabilities. The results will provide a unique observational-based perspective on subglacial processes, which influence large-scale ice dynamics and eustatic sea level rise.
|Location||Sermeq Kujalleq in Kangia (also known as Jakobshavn Isbræ), Western Greenland|
|Funded amount||10,100 CHF|
|Project dates||1st July 2023 – 31st August 2023|
|Category||Polar Access Fund|