Using the Elsasser model for postseismic deformation, and assuming an elastic layer of thickness 15 km, an asthenospheric channel of 15 km, a shear modulus of 3 × 1010 Pa, and a viscosity of 1018 Pa-s, what is the predicted displacement at 15 km from the fault after 1 year? At 30 km from the fault after 4 years? Why does the displacement behave in this way?