Probing sub-ice sediments using geophysical surveys and geomechanical modeling to understand the response of Alaska and Greenland glaciers to climate change

Juneau Icefield Research Program.

Photo credit: Seth Campbell, Juneau Icefield Research Program

Bracing for future sea-level rise requires detailed planning by local and global communities.  We therefore need forecasts of the future flow of key glaciers into the ocean.  

This project targets one Greenland glacier that has the potential to raise global sea level by >1 meter, but whose flow over a strange mix of hard rock and soft sediments is not well understood.  We will develop tools to measure the mechanical and chemical character of these inaccessible glacial sediments, which will improve our ability to forecast glacier flow and sea-level rise.

This innovative project applies a novel geophysical technique, the seismoelectric method, toward understanding the sediment layer under glaciers. The scales involved are difficult: we must look through 2000 meters of solid ice and detect sediments that may be only 1-2 meters thick.  This is like the Princess and the Pea being able to sense a pea hidden underneath a stack of ten fluffy, thick, pillow-top mattresses.

Before attempting to deploy new technology in faraway Greenland, we will visit the Juneau Icefield, Alaska.  There, we will test the suitability of the seismoelectric method, alongside other known geophysical technologies, on three different glaciers.  We will use our data to determine the strength, wetness, and chemical and mechanical properties of the sediments under these Alaskan glaciers.  Sediments on earth have a wide range of mineralogies, yet those of rocks under glaciers have been nearly impossible to measure.  Therefore, we will test whether the seismoelectric method can constrain the mineral composition of the sediments under the glaciers.  Finally, we will apply a state-of-the-art geomechanical model to understand how fast or slow the ice flows over these sediments.

The project’s principal investigator is Kristin Poinar, PhD, assistant professor in the Department of Geology.  Co-investigators are Kamelia Atefi Monfared, PhD, assistant professor in the Department of Civil, Structural and Environmental Engineering; Erasmus Oware, PhD, assistant professor in the Department of Geology; and Beáta Csathó, PhD, professor in the Department of Geology.