Effect of transient deformation in southeast Greenland

Recent studies have shown that in the area of the Kangerlussuaq glacier, a large GPS velocities residual after removing predicted purely elastic deformations caused by present-day ice loss suggests the possibility of a fast rebound to little ice age (LIA) deglaciation. We previously investigated this area with a Maxwell viscoelastic rheology Earth model and compared the model predictions with GPS residual. We found a match for a rather thick lithospheric thickness and a rather low mantle viscosity structure beneath SE-Greenland. In this study we are going to examine the effect of a Burger model: 1) we compare the results with those from the Maxwell model and 2) we estimate if and where the differences can be discriminated with observational data.
Maxwell models describe a steady state mantle deformation and they are the most commonly model used in post glacial rebound problems. Burgers models, instead, describe a time-varying mantle deformation, which include an initial fast transient components followed by a steady-state phase of mantle deformation. This kind of transient deformation would allow to reconcile the Earth rebound caused by the Pleistocene deglaciation and the faster rebound caused by the recent LIA deglaciation.
We then analyze several scenarios of ice retreat in the last 2000 years in the fiord in front of Kangerlussuaq glacier, in view of the difference between the two rheologies.