subsection Material model
  # Parameters controlling the rheology.
  subsection Steinberger model
    set Lateral viscosity file name                   = temp-viscosity-prefactor.txt
    set Radial viscosity file name                    = radial-visc-simple.txt
    set Use lateral average temperature for viscosity = false
    set Maximum lateral viscosity variation           = 1e3
    set Maximum viscosity                             = 5e23
    set Minimum viscosity                             = 1e20
  end
end
