7. Tectonic compression

Because of specific formulas for density and constant thermal properties of ice used in the study, the modules with rheology and material properties need to be modified in addition to the parameter file.

Compression of Europa’s ice shell following the setup by Kihoulou et al. (2025) .

Download

Here you can download the bash scriptthe parameter file, and the matplotlib script. Detailed explanation is given below.

Note

Copy the bash script, parameter file, and plotting script from /demos/demo7/ into the main directory.

Parameter file modification

In case of compression, most parameters will be the same as in the previous example. However, we will modify the boundary conditions for the Stokes problem.

Stokes problem settings

We prescribe the pressure boundary condition at the bottom boundary to allow ice-water interface evolution and switch the sign of lateral velocities from divergent to convergent.

BC_Stokes_problem = [["free_surface"],                # top boundary       (1)
                ["pressure"],    # bottom boundary    (2)
                ["velocity_x", +10e3/Myr],       # left boundary      (3)
                ["velocity_x", -10e3/Myr]]       # right boundary     (4)

At the same time, we will take into account the phase transition with a rather strong DAL effect, which will tend to keep the interface flat

# --- Phase transition at the bottom boundary ----
phase_transition = True

# --- Strength of the phase transition at the ice-water boundary ---
DAL_factor = 1e-2 # W/m3

Finally, we turn on the adaptive smoothing of the top surface, which prevents buckling of the mesh during compression.

# --- Adaptive topography diffusion and topography diffusion factor ---
adaptive_smoothing = True
topo_diff = 1e-8